What is the main function of lecithin in chocolate?
It acts as an emulsifier to reduce viscosity and improve texture.
What are flavonoid phytochemical compounds that appear predominantly in green tea,that are also found in black tea, grapes, wine, and chocolate in small amounts?
Catechins
Duplicates of naturally occurring aromatic compounds that are synthesized and added to foods are called:
Nature-identical flavors
Name five polar amino acids.
Serine, threonine, cysteine, tyrosine, asparagine and glutamine.
What compound in black pepper stimulates a heat sensation?
Piperine
In what two ways can a xanthan gum stabilize an emulsion?
Reduce surface activity, increase viscosity
Bitter compounds in coffee after roasting?
Chlorogenic acid, phenyl indane
What is the most water-soluble amino acid at room temp?
Proline
What does TBHQ stand for and what is its function in food?
Tertiary butylhydroquinone, it is used as an antioxidant in fats and oils
In kJ per mol, what is the bond dissociation energy of the O-H bond in a water molecule?
460
The chlorophyll reaction in food processing whereby the magnesium is lost by replacement with hydrogen results in the formation of what pigment and what is the color?
Pheophytin – dull olive – brown
What are surfactants?
Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants.
What is the main protein fraction in wheat gluten responsible for dough elasticity?
Glutenin.
What are the stabilization factors for colloidal suspension?
Give the Henderson Hasselbach equation and define each term.
The Henderson-Hasselbalch equation is used to calculate the pH of a buffer solution, or to relate the pH of a solution to the concentrations of a weak acid and its conjugate base.
ph=pKa + log[A-/HA]
Where:
- pH: The hydrogen ion concentration, which indicates the acidity or alkalinity of the solution.
- pKâ‚: The negative logarithm of the acid dissociation constant (Kâ‚) of the weak acid. It represents the pH at which half of the acid is dissociated into its conjugate base and hydrogen ions.
- (A-): The concentration of the conjugate base (the ion formed when the acid loses a proton).
- (HA): The concentration of the weak acid (the undissociated form of the acid).
When starch granules are heated for an extended period of time at a high temperature, the product will become thin, the physical change that takes place is called:
Implosion
Phospholipases react with what?
Phospholipids
What class of chemical compounds are responsible for the brilliant red color in paprika?
Carotenoids
Why do carrots not lose their orange color during cooking?
Carotenoids are heat stable and fat soluble
What is the bitter compound found in the skin of oranges?
Naringin
What happens to lipids in deep frying?
Hydrolytic oxidation and color change
Thermal treatment of Ginger will give?
Shogaol and gingerone
What is the pH range of the indicator, phenolphthalein?
8-9.6
What is the structural difference between chlorophyll and pheophytin?
Pheophytin does not have magnesium in porphyrin ring.
What is the major antioxidant in rosemary extract?
Diterpenes - carnosic acid
This spice consists of the stigmas of a crocus native to the eastern Mediterranean
Saffron
What does DHA stand for?
Docosahexaenoic Acid
What structural property gives emulsifiers their emulsification ability?
Hydrophilic (polar) head and a hydrophobic (hydrocarbon) tail
What is the isoelectric point of casein?
Around pH 4.6
A naturally occurring emulsifying agent in a common food is:
Lecithin in egg yolk
When whipping egg whites, what chemical compound is often added to stabilize the foam by denaturing proteins and lowering the pH?
Cream of Tartar (or Tartaric Acid)
What is the full name of EGCG?
Epigallocatechin gallate.
Which 2 enzymes are required for the determination of the degree of gelatinization?
Pullulanase and Beta-amylase
Why should you store olive oil in a dark environment?
Light oxidation
What are catechins?
Flavonoid phytochemical compounds that appear predominantly in green tea. Smaller amounts of catechins are also found in black tea, grapes, wine, and chocolate.
In relation to colloid theory, give the full form of the acronym DVLO.
Derjaguin, Verway, Landau, and Overbeek
What is the compound that occurs naturally in dairy products and wine? It is responsible for strong buttery flavor.
Diacetyl
Does volume increase or decrease when a liquid becomes a gas?
Increases
Define water activity (aâ‚“) and explain its role in food stability.
Water activity measures the free water available for microbial growth and chemical reactions; lower aâ‚“ improves shelf stability.
C18:3n3 represents which fatty acid?
(Unsaturated FA that has 18C, 3 double bonds and is an omega 3) a-Linolenic Acid
What are the described flavors of the following compounds: Diacetyl, acetic acid, acetaldehyde, ethyl hexanoate, propionic acid, 1-octen-3-ol?
What plant lipid is normally a solid at room temperature?
Cocoa butter
What compound is formed when glycerol is heated?
Acrolein
Enzyme pills available over the counter can be added to milk to predigest lactose to glucose and galactose. The name of the enzyme is ....
The enzyme is called lactase (β-galactosidase).
Is freezing endothermic or exothermic?
Freezing is exothermic
Is evaporation endothermic or exothermic?
Evaporation is endothermic
Give an example of a food oil which contains as its principal fatty acid each of the following: Lauric Acid, Oleic Acid, Linoleic Acid, Linolenic Acid, Erucic Acid
What is the main intramolecular force responsible for the formation of secondary structure of proteins: A.disulfide bonding, B.Electrostatic interactions, C.Hydrogen bonding, or D.Van der Waal's interactions?
C. Hydrogen bonding
What is the term for a material that naturally absorbs water?
Hygroscopic
What is the name for the phenomenon that draws water into food materials?
Capillary action (surface tension).
What two factors determine the melting range of a lipid?
Unsaturation and carbon chain length
Name four compounds that may be used as humectants.
Glycerol, sorbitol, propylene glycol, honey, xylitol, or polyols
Name the 3 positively charged amino acids.
Lysine, arginine, and histidine
Milk micelles contain protein and 6 – 8% of this salt.
Calcium phosphate
Butyric acid is typically found in which food?
Milk
What is the temperature scale that follows Fahrenheit, but gives you absolute temperature?
Rankine
Name 5 common chemical food additives for food preservation.
BHA, BHT, TBHQ (antioxidants), benzoates and calcium propionate (antimicrobials), sodium nitrite (curing agent with antimicrobial properties)
How many PKa(s) does ascorbic acid have?
2: one at 4.10 and another at 11.79
What is the term for the process where starch granules swell and lose their crystalline structure when heated in the presence of water?
Gelatinization
What is the eutectic point?
The lowest point on the freezing point depression curve/ The eutectic point is the lowest temperature at which a mixture of substances will remain liquid before solidifying simultaneously.
Explain the chemical mechanism of lipid hydrogenation, and state its primary effect on the physical properties of a fat.
Hydrogenation is the process of chemically adding hydrogen atoms to the double bonds (C=C) of unsaturated fatty acids, converting them into single bonds (C-C). The primary effect is to increase the melting point and solid fat content of the fat, making a liquid oil more solid at room temperature and increasing stability.
What do we call the prolamines in corn?
Zein
Anthocyanins are pigments responsible for what colors, and in what type of foods?
Red, blue, and purple colors of some flowers, fruits, vegetables, juices, wines, etc.
Which of the following statements about water is not correct:
A. Water is an important nutrient for human body
B. Water is used as a quality indicator for jams and jellies
C. Water activity indicates the amount of bound water in a food system
D. There is no D.
C
Name 3 components that effect water activity in a food product.
Solute concentration, moisture concentration, temperature
The preserving activity of vinegar has been known from ancient time. The active component is
Acetic Acid
What is Oswald Ripening?
Ostwald Ripening is a process in which larger particles or droplets in a solution grow at the expense of smaller ones due to differences in solubility. Smaller particles dissolve more easily and then redeposit onto larger particles, leading to a gradual increase in particle size over time.
What is the common name of methoxybenzene?
Anisole
What color are anthocyanins at Basic and Acidic pH?
Basic=Blue; Acidic=red
What are two common reducing agents that break disulfide bonds in proteins?
2-mercaptoethanol (2-ME), dithiothreitol (DTT)
Which amino acid is most susceptible to oxidative degradation in proteins?
Methionine.
What is BHT and what is it used for?
Butylated hydroxytoluene; phenolic antioxidant used to preserve fats and oils
What amino acids comprise aspartame?
Phenyl alanine and aspartic acid.
Which non-covalent interaction is primarily responsible for protein tertiary structure stability in aqueous food systems?
Hydrophobic interactions.
Which enzymes are responsible for breakage of proteins, particularly peptide bonds?
Proteases
What is the compound in red food coloring that is extracted from insects?
Carmine
Smoke point comparisons of oils: canola, grapeseed, sunflower, safflower, olive
Do enzymes become a part of the final product of enzymatic reactions?
No
What are five functions of surfactants in foods?
Emulsification, aeration and foam stabilization, prevention of starch complexing, protein interaction, fat crystal modification, wetting agents, dispersion of flavors or colors
BHA and BHT are used for what purpose?
To control fat autoxidation.
what stands for negative log of molar concentration of free hydrogen ions in solution?
pH
Someone has suggested that you use sucrose in your confectionary product where Maillard browning is desireable, will this cause a problem?
Yes, because sucrose is a non-reducing sugar
Differentiate between Maillard browning and caramelization.
Maillard browning involves a reaction between reducing sugars and amino acids/proteins (occurs at lower temps, gives savory notes); caramelization involves sugar degradation without amino acids (higher temps, sweeter notes).
Name two components of the SNF portion of milk
Lactose, casein, and whey
What does the % overrun measure in whipping cream and ice cream?
The amount of incorporated air into the product.
If 2 M NaOH solution contains 80 g of NaOH, how much NaOH does a 1 M solution contain?
40 g
What is "unsaponifiable matter"?
Fat soluble matter remaining after saponification
What is a substance that has a high affinity for water?
Humectant (hygroscopic also acceptable)
What is the enzyme that softens tomatoes?
Pectin Esterase
The two chemical components of a triacylglycerol are what?
Glycerol and fatty acids
What substance is formed when collagen is heated in the presence in water?
Gelatin
What chemical compound is determined as an indicator of maillard browning?
Hydroxymethylfurfural
Michaelis-Menten equation?
Relates the velocity of a reaction to the concentration of substrate; used for enzyme kinetics.
What is the geometric configuration of double bonds in most natural fatty acids?
Cis
What two amino acids are found in B-turns?
Glycine, proline
What compound is responsible for the distinct odor present in goat's milk cheese?
Capric acid
What proteolytic enzymes are located in lysosomes?
Cathepsins
What is the difference between a foam and an aerosol dispersion system?
Foam – inner phase is gaseous, outer phase is liquid
Aerosol – inner phase is liquid or solid, outer phase is gaseous.
TWEEN belongs to which group of food additives?
Emulsifiers
What is the flavor/antimicrobial compound associated with Vanilla Beans?
Vanilla Beans= Vanillin
The internal pressure in plant cells is ___.
Turgor pressure
What is the first law of thermodynamics?
The total energy of a system and its surroundings must remain constant, although it may be changed from one form to another.
In a protein, what do the terms N-terminal and C-terminal refer to?
N-terminal is the end of the peptide chain w/an un-bonded amino group, C-terminal is the end w/and un-bonded carboxyl group
Which tree nut has the lowest lipid content: pecans, chestnuts, or walnuts?
Chestnuts (2-5%)
What are the minimum reactant requirements for Maillard browning?
Amino-bearing compound (usually a protein) and a reducing sugar
What is the name of the reaction between sugars and amines that causes changes in color of some food products during heat treatment?
Maillard Reaction
What is the major whey protein in milk?
Beta lactoglobulin (about 65%)
Combustion of 10 g of food in a bomb calorimeter increases the temperature of 1 kg of water by 5°C. How many calories are present in 100 g of this food?
50 (kcal)
Name three ways one could reduce the occurrence of Maillard browning.
Increasing moisture levels to very high, lowering pH or temperature, removing one of the substances (usually sugar).
Withering, rolling, fermenting and firing are all processes associated with the production of which beverage?
Tea
S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds in what foodstuff?
Onions (or leeks)
How can bloom be delayed in chocolate?
Proper solidification and tempering processes create stable crystals, preventing bloom.
Why does water have a high dielectric constant?
Because water molecules form extensive hydrogen-bonding networks that enable strong dipole interactions and proton transport.
When nonfat dry milk solids are stored for a long time, the browning and off-flavor are a result of:
Maillard reaction
During freezing what are the two stages in the crystallization process?
Nucleation (or crystal formation) and crystal growth.
Name 5 proteins with good foaming properties.
Egg white proteins, whey proteins, gelatin, soy proteins, bovine serum albumin
What is the isoelectric point of casein?
4.6
Which of the following foods contain the highest content of water: A.fresh carrots, B.fresh tomatoes, C.whole milk, or D.fresh celery?
D. fresh celery (contains 94.1% water).whole milk contains 87.2% water, Carrots contain 88.2% water, and fresh tomatoes contain 93.5% water
Food that absorbs water, resulting in increased % moisture without an increase in water activity are called_______.
Hygroscopic
Name the principal organic acid in apples.
Malic acid
Which tannins can tan? hydrolysable, condensed tannins, phyto, non-condensed
Condensed tannins
What is a substance not naturally part of a food but deliberately added to fulfill some specific purpose?
Food additive
Which of the following has the largest diffusion coefficient in water at 20 degrees C: A.ammonia, B.Hydrogen, C.Oxygen, or D.Chlorine?
B. Hydrogen
This recently approved (1996) non-caloric fat substitute is a mixture of hexa, hepta, and octa esters formed from the reaction of sucrose with long chain fatty acids.
Olestra
Retrogradation of pudding is caused by which structural change in starch?
Change of amylose order during storage
What is the basic chemical subunit of carotenoids?
Isoprene units (joined head to tail in a system of conjugated double bonds).
When the coordination number decreases during the transition from water to ice, what happens to the density?
Density decreases
According to the Arrhenius equation, what happens to the rate of a reaction if the temperature increases?
Increases.
For the D configuration of sugars, the reference hydroxyl group is on the _________ side in fischer projection formulas.
Right
What is BHA's full name and purpose?
Butylated hydroxyanisole; used as an antioxidant to prevent rancidity in fats and oils
Stability of eggs not dependent on: Protein conc, pH, H2O addition, presence of sugar
H2O addition
Which law explains vapor pressure lowering in solutions?
Raoult’s law.
Thiobarbituric acid number or value indicates what?
Lipid oxidation; measures malondialdehyde
In directed interesterification, higher melting and least soluble TG molecules in the mixture crystallize. This is achieved by _________________.
Lowering the reaction temperature
Which of the following pH values in a food would yield the highest rate of non-enzymatic browning: A.5.5, B.8.5, C.9.5, or D.3.5
B. 8.5
What are the x and y axes in isotherm water activity chart?
X: Aw, Y: moisture.
What is the main water soluble component of coffee?
Caffeine
What is the effect of pH and temperature on the Maillard reaction?
High temperature and high pH increase the reaction rate.
EDTA and citric acid are examples of what group of additives used in foods?
Metal chelators - prevent oxidation
Flavonoids include what two color groups?
Anthoxanthin and Anthocyanin
How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
What happens to French fries that are made from potatoes stored in the refrigerator?
They will brown unevenly due to sugar content. Cold storage increases reducing sugars (glucose, fructose), leading to excessive Maillard browning and acrylamide formation.
Which one of a saturated or unsaturated fatty acid from animal fats with the same number of carbons have a higher melting point?
Saturated fat
With regard to protein gelation, define thermally irreversible gel and thermally reversible gel. Give the predominant type of inter protein bonding and an example of food gels in each classification
A thermally reversible gel forms upon cooling after heating; hydrogen bonding is primary; gelatin is an example. A thermally irreversible gel forms during heating; covalent (disulfides) is primary bonding; examples include egg white, whey protein, soy protein, etc.
What are 3 mesomorphic structures associated with lipids in the liquid state?
Lamellar, Hexagonal I and II, Cubic
What happens to both the coordination number and distance between nearest neighbor molecules during the transtion from ice to water?
Both increase
Which chemical class is catechin in?
Flavan-3-ol
What is the principle flavor compound in hazelnuts?
Filbertone
20 grams of amylose is added to 80 grams of water in a beaker; the boiling point is measured with an ordinary mercury-in-glass thermometer. What is the observed boiling point of the material in the beaker?
100 Degrees Celsius (it is not a true solution - there is no boiling point of elevation)
How many carbon atoms are there in the fatty acid myristic acid?
14
What is the major nutraceutical compound found in red wine and grape skins?
Resveratrol
What is the act of debasing food using food additives?
Adulteration
Which will be coldest at its freezing point: 1M dispersion of amylose, 1M solution of NaCl, distilled water, or 1M solution of sucrose?
NaCl (it dissociated to a 2M solution)
Name a food that has an alkaline pH.
Egg whites, pretzels, hominy, olives, shrimp.
Why do O-H covalent bonds have partial ionic character?
Because the oxygen molecule is highly electronegative
What is the movement of molecules through a semi-permeable membrane from a region of high to low solute concentration called?
Osmosis
What are the three main classes of carrageenan?
Iota, Kappa, Lambda
What class of compounds is responsible for the pungency of mustard and wasabi?
Isothiocyanates
What are the 6 syrup behaviors of a sugar syrup in the Cold-Water test?
Thread, Soft Ball, Firm Ball, Hard Ball, Soft Crack, and Hard Crack
What is the function of EDTA in foods?
Chelating agent
What compound is the major cause of red grapefruit's red flesh?
Lycopene
What are the dispersed and continuous phases of each of the following: Foam, aerosol, emulsion?
Foam: gas in liquid/solid
aerosol: liquid/solid in gas
emulsion: liquid in liquid
What is an emulsion?
A system containing 2 immiscible liquids
A good emulsifier for an oil in water emulsion will have what HLB value (High or Low)?
High value (8 to 16)
Goat stench or goaty flavor is due to which fatty acids (give name and number of carbons)?
Theobromine and caffeine are in what chemical class?
Methylxanthine
What is the name of the reaction when an acid and base react to give water?
Neutralization
What water activity value is where monolayer moisture value is present?
0.25
Which starch fraction retrogrades faster and is primarily responsible for short-term bread staling?
Amylose.
What are the various complex proteins produced by living cells that act independently of these cells. They are capable of producing certain chemical changes in other substances w/o themselves being changed in the process?
Enzymes
Common names of following fatty acids: C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, C20:0
What type of chemical reaction occurs when fats become rancid due to oxygen exposure?
Lipid oxidation.
The rate of gelatinization is increased or decreased in the presence of added sucrose?
Decreased; sucrose competes for water and reduces peak viscosity and gel strength.
In the SI system what are the units that are applied to the following five dimensions or measurements; length, mass, time, electric current, thermodyanamic temperature?
Length = meter
Mass = kilogram
Time = second
Electric current = Ampere
Thermodynamic temp = Kelvin
What is another name for phosphatidylcholine?
Lecithin
Explain the difference between enzymatic and non-enzymatic browning reactions, and give one example of each.
Enzymatic browning: Caused by polyphenol oxidase catalyzing oxidation of phenolic compounds (e.g., browning of cut apples).
Non-enzymatic browning: Includes Maillard reaction (reducing sugars + amino acids) or caramelization (sugar heating).
Describe the flow direction of water across a cell membrane in an isotonic, hypotonic, and hypertonic solution.
Isotonic: no net flow (equilibrium); Hypotonic: water flows into the cell; Hypertonic: water flows out of the cell
Which reaction is responsible for flavor deterioration in stored fats and oils?
Lipid oxidation.
What is the difference between zero order reaction and 1st order reaction?
In zero order reaction, rate is independent of the concentration of reactant(s). 1st order reaction has a rate proportional to the concentration of one of the reactant(s).
What are the origins of charges in colloids?
Ionization (from colloids themselves) and counterions (derived from solvent).
Name the sulfur containing essential amino acids.
Methionine
Peptide bond formation results in the formation of what secondary compound?
Water
Does the volume increase or decrease when a solid becomes a liquid?
Increases
How many C (carbons) are in capric acid?
10
What are covalent chemical bonds linking two consecutive amino acid monomers along a protein chain called?
Peptide bonds
Name the compound responsible for pungency in mustard, horse radish, wasabi, radish.
Allyl isothiocyanate (breakdown product of singirin)
What's the meaning of salting in and salting out?
Salting out decreases solubility (precipitating proteins), salting in increases solubility.
Why is baking soda used in making pretzels?
Raises the pH, hence allows browning to occur more readily
Name 2 reasons why pectin is used in the processing of fruit juice.
To increase clarity and yield
What is the flour to liquid ratio in a popover batter?
12/31/1899 1:01:00 AM
Which lipid oxidation product is most commonly used as a marker for early-stage oxidation in polyunsaturated fats?
Hydroperoxides.
What reaction leads to the browning of cut apples?
Enzymatic oxidation by polyphenol oxidase
In food irradiation, what does URP stand for?
Unique Radiolytic products
What are the uncontrolled fat crystallizations which give chocolate an impaired texture and a grey surface called?
Fat bloom
The Maillard reaction, responsible for the browning and flavor of many cooked foods, requires a reducing sugar and what type of compound?
Amino acid (or Protein)
Classify the following baking powders as fast or slow acting: Tartrates, Na Al phosphate, Na acid pyrophosphate
Tartrates: F; Na Al Phosphate: S; Na acid pyrophosphate: S;
What pigment is formed when chlorophyll loses its magnesium, phytol group, or both?
a. Pheophytin (loss of magnesium) b. Chlorophyllide (loss of phytol) c. Pheophorbide (loss of both magnesium and phytol).
What is Graham's Law of Diffusion?
Graham’s Law states the rate of diffusion is inversely proportional to the square root of the molar mass.
Which of the following acids is NOT an organic acid: A.phosphoric acid, B.citric acid, C.nitric acid, or D.benzoic acid?
C. nitric acid
What is the food dye carmine made from?
Insects
What water activity value is where max rate of quality loss occur?
0.8
What is the common name of the n-acetylmuramidase enzyme found in egg whites that hydrolyzes the cell walls of Gram-positive bacteria?
Lysozyme
At what temperature is all detectable water frozen?
-72F, -60C
High density polyethylene is made up of carbon chains that are highly branched.
False
What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure, but yield identical liquid phases upon melting.
Name 4 classes of phenolic compounds in tea.
Catechins, Flavonoids, Theaflavins, Tannins
What is the name when its negative 273 degrees C?
Absolute zero
What may occur in vegetable oil if trace heavy metals leach into the product from processing equipment?
Lipid oxidation may accelerate
What is the driving force of osmosis?
Chemical potential
As temperature increases, what happens to the density of a solution?
Decrease
A high molecular weight polyester deposited in the waxy cuticle of some plant epidermal cells is called what?
Cutin
What pigment is responsible for the red color in tomatoes and watermelons?
Lycopene
What does IMF stand for and what is the range of water activity?
Intermediate moisture foods, 0.6-0.9 water activity
A schiff base structure is formed between what two functional groups?
Carbonyl and amine
What is struvite?
Struvite is magnesium ammonium phosphate crystals that resemble glass and are sometimes found in canned tuna.
Name the four classes of proteolytic enzymes based on active site.
Serine, metallo, aspartyl, cysteine
Name the Maillard reaction product responsible for the brown color in baked goods.
Melanoidins.
Name the polyol that is found in triglycerides.
Glycerol
An enzyme the removes methanol from pectin is called what?
Pectin methylesterase
Which of the following fats has the highest percent of mono unsaturated fat: Lard, canola oil, or olive oil?
Olive oil
What are the acids used to determine titratable acidity in the following foods: Orange Juice, Apple Juice, Yogurt, Grape Juice, Vinegar, Coca-cola, Peach Juice, Sprite, Grapefruit?
A substance that reduces molecular damage due to Oxygen, such as free radical damage to cellular tissue is called what?
Antioxidant
What kinds of food emulsions are? (1) Butter (2) Mayonnaise (3) Milk
Butter = water in oil, Mayonnaise = oil in water, Milk = oil in water
Why are caseinates good functional ingredients in a number of processed food products that have both water and fat?
Caseinates have amphiphilic structure; this means that these protein derivatives both have regions that are hydrophobic and hydrophilic
Carotenoids are formed from multiple units of what five carbon compound?
Isoprene
Explain the mechanism of lipid oxidation and name two common antioxidants used to prevent it.
Lipid oxidation proceeds via initiation (radical formation), propagation (radical chain reactions forming peroxides), and termination (formation of stable products). Antioxidants such as BHA, BHT, or tocopherols donate hydrogen atoms to quench free radicals.
What is 1 UNIT in determining enzyme activity?
Micromoles/minute
What happens to a catalyst in a chemical reaction?
A catalyst can increase the rate of a reaction but the catalyst itself remains unchanged
What is the chemical name for the traditional term "muriatic acid"?
Hydrochloric acid
What are the 3 forms of water in food and what is the difference between them?
Free water, adsorbed water, and water of hydration. Free water retains its physical properties and is available for reaction. Adsorbed water is held tightly to proteins. Water of hydration is the chemically bound water.
Name 6 major pigment groups found in food sources.
What is a monosaccharide. A) polyalcohol b) poly acid c) polyether d) all of the above
A
What type of bond stabilizes the α-helix structure in proteins?
Hydrogen bonds.
Describe the mechanism by which CaCl2 firms plant tissues.
Divalent Ca++ binds the carboxyl groups of adjacent pectin polymers forming bridges and tightening the structure
What is the name for the Maillard reaction intermediate containing an C=N bond between a sugar and an amine?
Schiff Base or glycosylamine
Name the theory that originally explained the phenomenon of protein gelation.
Ferry's Mechanism, 1948
What chemical compound is responsible for the fishy smell?
Trimethylamine
What food ingredient can be used as thickeners, stabilizers, and emulsifiers?
Gums/ hydrocolloids
What two common compounds are used together as an antioxidative system in food?
Ascorbic Acid and Citric Acid
What is gingerol and where is it found?
Characteristic ginger flavor from the ginger root
Name the fatty acid commonly associated with butter?
Butyric acid
True or False: Yeast contains glutamic acid.
True, 8-10% of whole yeast
What is the main pigment responsible for the red and purplish-blue colors in berries, red cabbage, and wine?
Anthocyanins
What is the maximum pH at which sorbic acid is effective as a preservative in foods:A.3.5, B.4.5, C.5.5, or D.6.5?
D.6.5
What compound class is responsible for the characteristic flavor of cabbages?
Glucosinolates and their breakdown products (e.g., isothiocyanates, such as allyl isothiocyanate)
What is TBHQ?
Antioxidant, tert-butylhydroquinone.
Emulsifying proteins are called what because of their ability to harden during the cooking cycle?
Heat-coagulable proteins
At what temperature does water have its maximum density?
3.92 or 4°C
What are the two types of bloom in chocolate?
Sugar bloom and fat bloom
The gradual browning of a loaf of bread during baking is due to:
Maillard reaction
An element found in proteins but not in carbohydrates is what?
Nitrogen
Which step in the Maillard reaction involves a reaction between a dicarbonyl and amino acid?
Strecker Degradation
What is the difference between single and double acting baking powder?
Single has 1 acid whereas double has 2 acids; single acting reacts once it is exposed to moisture, double acting reacts when it is exposed to moisture and reacts again when it is exposed to heat
Part of a browning reaction, where an amino acid and a dicarbonyl produce CO2 and characteristic flavor aldehydes
What color are anthocyanins at acidic pH and basic pH?
Acidic=red, basic=blue or yellow
An enzyme that catalyzes formation of hydroperoxide from fatty acids is what?
Lipoxygenase
Name 4 polyunsaturated fatty acids in foods and give the number of double bonds in each.
Linoleic (2), linolenic (3), arachidonic (4), EPA (5), DHA (6).
A sugar solution is holding more solute than usually soluble at a particular temperature is known as a ______ solution.
1. saturated
2. supersaturated
3. unsaturated
4. none of the above
b. Supersaturated
Trans fatty acids occur naturally in what type of animal?
Ruminant animals
What is the term for the temperature at which an amorphous polymer (like hard candy or starch) transitions from a hard, brittle state to a rubbery, viscous state?
Glass Transition Temperature (Tg)
What is the scale to measure percent sugar?
Brix
What are the class of food pigments which have similar structure and properties to anthocyanins, but are yellow in color called?
Flavonoids (from the Latin word flavus meaning yellow)
What functional group is characteristic of reducing sugars?
Free aldehyde or ketone group
Name two main gluten proteins.
Gliadins and Glutenins
What are 2 disadvantages of using rosemary as an antioxidant compared to synthetic antioxidants?
Higher cost, larger amount (higher level) needed to be effective
What are the toxic glycosides present in lima beans and cassava?
Cyanogenic glycosides
What type of emulsion is foam?
A gas-in-liquid emulsion or air-in-water emulsion
What is the non-amino part of a conjugated protein called?
Prosthetic group
A liquid dispersed in a solid is an example of:
Gel
Describe three roles of lipids in food.
They carry flavor, fat-soluble vitamins, and help with heat transfer.
Categorize the following pigments in water or fat soluble and plant or animal source based: Carotenoid, myoglobin, anthocyanin, chlorophyll, melanin
Mixture of a weak acid and its conjugate base (or salt), or a weak base and its conjugate acid.
Name three water-soluble antioxidants.
Vitamin C (Ascorbic Acid), Glutathione, Polyphenols, Beta-glucans, Vitamin B2 (Riboflavin), Uric Acid, Selenium (in selenoproteins), Taurine, L-carnitine
C20:5n3 represents which fatty acid?
(Unsaturated fatty acid) EPA or Eicosapentaenoic Acid (from elongating a-linolenic)
What colors are anthocyanins at the following pH's? <3.5, 3.5-4.5, >4.5
<3.5 red; 3.5 - 4.5 purple; >4.5 blue
Name the strongest biochemical bond and the weakest biochemical bond.
Covalent (strongest) and Hydrophobic (Weakest)
What protein structure refers to the spatial arrangement obtained when a linear protein chain with a secondary structure folds further into a compact three dimensional form?
Tertiary structure
Is condensation endothermic or exothermic?
Exothermic
Inulin is a polysaccharide found in some plants. What is the monosaccharide that makes up this polymer?
Fructose
Cleavage of K-casein gives:
Para kappa casein, glycomacropeptide
Rank in increasing water activity: Honey, bread, condensed milk, peanut butter
Peanut butter, honey, condensed milk, bread
Name 2 straight chain polyhydric alcohols used as food additives.
Sorbitol - modifying agent, humectant, flavor, and crystal modifier;
Mannitol - flavor modifier, inert base
What are the three main steps in the autooxidation of lipids?
Initiation, Propagation, Termination
What are the components of total acidity?
Volatile acidity and fixed acidity
At what pH is Iodophor effective?
pH 4-5
What compund in chocolate stimulates the central nervous system and also makes dogs sick?
Theobromine
What is the pH of a 0.1 N HCl solution?
pH = 1
Give the four main classifications of proteins and the solvents with which they can be extracted.
Albumins (water and dilute saline), Globulins (dilute saline), Prolamines (70% ethanol), Glutelins (dilute acid or alkali)
Define apparent acidity.
Apparent acidity is the measure of the total acid content (free and bound acids) in a food, often determined by titration, reflecting the overall acidic character rather than just free hydrogen ions.
What is the heat requirement to raise 1 gram of water by 1 degree C?
One calorie
If a protein is present in a solution at a pH greater than its isoelectric point, what charge would it be carrying?
Negative Charge
What is the most abundant protein in the egg white?
Ovalbumin
Which vitamins can also be used as antioxidants?
Vitamins C and E
Name three factors useful in controlling enzyme activity.
Temperature, Water Content and Activity, Extremes of pH, Chemicals, Alterations of Substrates, Alterations of Products, Preprocessing Controls
Name three of the four cinnamic acid derivatives that are widely distributed in plants.
p-coumaric, caffeic, ferulic, and sinapic
What is the flavor/antimicrobial compound associated with Oregano?
Carvacrol
C18:2n6 represents which fatty acid?
(Unsaturated FA that has 18C, 2 double bonds, and omega 6) Linoleic Acid
How is the boiling point of water affected by boiling on the moon, adding gelatin, boiling on Mount Everest, and adding table sugar?
Decrease, no effect, decrease, increase.
What does EDTA stand for?
Ethylenediamine Tetraacetic Acid
Which of the following statement(s) is/are true regarding Food/organic acids: A.they are weak acids, B.they have good buffering capacity, C.can buffer at multiple pHs, or D.All of the above?
D. All of the Above
Describe the initiation, propagation, and termination steps of lipid autoxidation and explain how metal chelators inhibit the reaction.
Initiation forms lipid radicals, propagation generates peroxyl radicals and hydroperoxides, termination forms stable non-radical products. Chelators bind pro-oxidant metals (Fe²âº, Cu²âº), preventing radical initiation via Fenton reactions.
Lecithins are structurally like fats but contain what?
Phosphoric acid
What term describes the difference between the absorption and desorption isotherms?
Hysteresis
What water activity value is where there is a loss of crispness and onset of caking occurs?
0.4
Give 5 initiators of lipid oxidation.
Metal ions, UV light, temp., oxygen, presence of conjugated double bonds, and free radicals
What is the lachrymatory factor in onions?
Propanethial S-oxide
When heated, ammonium bicarbonate decomposes to form what end products?
Ammonia, Water, Carbon Dioxide
What is the equation for ideal gas law?
pV = nRT
What is the main polysaccharide found in plant cell walls?
Cellulose.
The dispersion of one liquid in another immiscible liquid is called what?
Emulsion
What is a peptide bond?
Covalent bond between 2 amino acid molecules.
What term refers to water-insoluble pigments that color by dispersion throughout a food material?
FD&C lakes
What are the main classes of flavonoids?
Neoflavonoids, isoflavonoids, bioflavonoids (the general class that includes flavonols, flavones, flavanones)
What are colligative properties?
Physical properties of a solution that depend entirely on the number of solute molecules present in a solution and not upon the chemical nature of the solute ie vapor pressure, osmotic pressure, boiling point
What are the two phases in a colloidal dispersion?
Continuous phase (dispersion medium) and dispersed phase (internal).
Which component in wheat is responsible for viscoelastic properties of dough?
Gluten (gliadin and glutenin)
Name 3 ways to slow or prevent lipid oxidation in a food.
Exclude oxygen (packaging), lower temp, protect from light, formulate w/antioxidants, inactivate lipoxygenase, or chelate metal catalysts
What common enzyme can be used to modify lipids from their original triacylglycerol form?
Lipase
The combination of wintergreen, vanilla, and cassis (cinnamon) make up this commonly recognized flavor
Bubblegum
At room temperature, which phase are oils generally in?
Liquid
What is the artificial color number of Sunset Yellow?
Yellow No. 6
What is responsible for warmed-over flavor?
Fat oxidation
What is the normality of a 1 M solution of citric acid?
3 N.
Pigments that are manufactured by precipitating a dye with a metallic salt are called what?
Lakes
What is the main acid in lemon juice?
Citric acid
Put these nuts in order from least fat content to greatest based on a 1 ounce serving. Pine nuts, cashews, macadamia, chestnuts, almonds
Chestnuts, cashews, almonds, pine nuts, macadamia
What does CLA stand for in fats?
Conjugated Linoleic Acid
What water activity value is where mold growth can occur?
0.6
An emulsified with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Oil in water
What class of pigments has 2 cyclic aromatic rings, one with oxygen included?
Flavonoids
What is the function of benzoate in food?
Benzoate acts as a preservative by inhibiting the growth of mold, yeast, and some bacteria.
What are 5 characteristics for selecting lipid antioxidants?
1. Non-toxic 2. No flavor or odor 3. Fat soluble 4. Anti-oxidant activity 5. Economic
What is the general mechanism of enzyme action?
Decrease of activation energy of transition state
For what purpose are mono and di-glycerides used in food production?
Emulsifiers
What reaction between reducing sugars and amino acids produces browning and flavor during heating?
Maillard reaction
What salt causes coagulation in tofu?
Ca sulphate or MgCl2
What is measured on the basis of the dipole moment of a single molecule?
Dielectric constant
How many carbon atoms are in one molecule of beta-carotene?
40 (most carotenoids are made up of 8 isoprene units)
Is boiling endothermic or exothermic?
Boiling is endothermic
What is elaidic acid?
Trans-9-octadecenoic acid
What does it mean when pectin is classified as 150-grade?
The pectin will gel 150lbs of sugar with 1lb of pectin
What is the name of a 18 carbon unsaturated fatty acid with the double bond at the 12-13 position?
Oleic acid
What is another name for yellow #5?
Tartrazine
What does EPA (fatty acid) stand for?
Eicosapentaenoic Acid
Higher alcohols esterified with fatty acids are called?
Waxes
What is the difference between a nanoparticle and a colloid?
Size, nano particles are smaller than colloids. Nanoparticles are 1-100nm, colloids range from a nanometer to micrometers.
What is the SI unit of force per area?
Pascal
Name the only amino acid containing an indole group.
Tryptophan
If oxygen attacks an unsaturated fatty acid at the double bond what is the resultant product?
The primary reaction forms a hydroperoxide (lipid peroxide) at the double bond. Secondary breakdown products of hydroperoxides include aldehydes, ketones, and alcohols.
Proteins which are soluble in 50-80% ethanol are known as _________
Prolamines
Gelato’s texture is due to its density as it is denser than ice cream. How much of gelato is air (%)?
30%, ice cream is 50%
What are the six colors of teas?
White, Green, Yellow, Oolong (blue-green), Black, and Dark (Pu-erh)
The molecular structure that makes emulsifying agents effective is _____?
Lipophilic (hydrophobic) part and hydrophilic part
Name three nonpolar, polar, and charged amino acids.
What is the name of the temperature at which dissolved fats are no longer completely soluble, precipitating out as a second phase?
Cloud point
Define water activity.
Aw= vapro pressure of solution/ vapor pressure of pure H2O at same temp
What is the isoelectric point of casein approximately?
pH 4.6.
What color of anthocyanin pigment predominates at an acidic pH?
Red (it is purple-blue at alkaline pH)
Name three effects of protein denaturation.
Decreased solubility, altered water-binding capacity, loss of biological activity, increased susceptibility to attack by proteases, increased intrinsic viscosity, inability to crystallize.
What is the least stable form of a lipid crystal?
Alpha
What is the definition of a saturated fatty acid?
A fatty acid with no double bonds on the alkyl chain.
What is the main emulsifier in egg yolk?
Lecithin.
When the double bonds of carotenoids change from trans to cis forms, what happens to the carotenoid color?
Cis is lighter/yellowish; trans is deeper red-orange.
At what pH is benzoic acid most effective?
pH 4.5-5
Saccharin is: A.a methyl ester of phenylalanine and aspartic acid, B.200X sweeter than sucrose, C.is metabolized (yielding 4kcal/g), or D.is temp sensitive?
B.200X sweeter than sucrose
What is an enantiomer?
Two stereoisomers that are non-superimposable mirror images (stereoisomers are compounds w/the same molecular formula but different arrangement)
Which compounds found in grapefruit act to inhibit Cytochrome P450 Enzyme and cause potentially dangerous drug interactions?
Furanocoumarins interfere with blood settings so they can be dangerous.
The Aw of a food stands for what, and what does it measure?
Water Activity; it measures the amount of unbound or free water available for chemical reactions and microbial growth.
Give 3 factors that determine the stability of emulsions.
Particle size, pH of phases, type of emulsifier, size of globules, viscosity, interfacial tension, temperature
What is the name of the main carotenoid pigment responsible for the color of annatto?
Bixin
What has more saturated fat: lard, coconut oil or corn oil?
Coconut oil then lard then corn oil (when compared to the same weight (not by serving size)
What three amino acids correspond to I, F, T?
Isoleucine, phenylalanine, threonine
The HLB value is a number from 1 to 18 used to describe the solubility of effectiveness of what?
An emulsifying agent
Give two examples of xanthophyll pigments and natural products in which they may be found.
Lutein: Spinach, kale, broccoli, corn, egg yolks.
Zeaxanthin: Corn, peppers, spinach, kale, oranges.
Violaxanthin: Spinach, kale, and other green leafy vegetables.
Neoxanthin: Spinach, lettuce, and other green leafy vegetables.
The reaction of secondary amine with nitrous acid results in the formation of powerful carcinogens called
Nitrosamines
Almost all flavor compounds that have a branched chain structure are derived from what group of precursors?
Amino acids
If the temperature of a solution is -40 F, what will it temperature be in degrees Celsius?
-40 deg C (-40 is the equivalence point for the 2 temp scales)
What is "double acting" baking powder?
The first acid reacts by creating gases when mixed with the liquid in the recipe. The second type reacts by creating gases when the batter is exposed to oven heat.
What is the major acid found in vinegar?
Acetic acid.
What purpose Na pyrophosphate serve in foods?
Leavening agent, chelating and buffering agent, moisture retention and texture improvement, emulsifier, anti-browning agent, crystal inhibitor
What is the difference between rennet and rennin?
Rennet - the commercial extract from cleaned, frozen, and dried 4th stomach of calves, kids, or lamb. Rennin - the actual enzyme (known as chymosin)
The occurence of which amino acid along a peptide chain is primarily responsible for a disruption of secondary structure of proteins?
Proline
Name the two types of water crystal nucleation and name the type that occurs in food systems.
1) Homogeneous and heterogeneous 2) Heterogeneous occurs in foods
What are the biological catalysts that promote a wide variety of biochemical reactions?
Enzymes
Why do the crystals in lard readily transform to the coarse beta form?
The homogeneity of the crystals causes them to associate in large crystals and transform
What is petroleum ether?
Mixture of low molecular weight hydrocarbons
What is the class of compounds of low molecular weight that yield two or more amino acids on hydrolysis?
Peptide
What are three forms of water in foods?
Free Water, Adsorbed Water (loosely bound), and water of hydration (tightly bound)
In chemistry, what is a mixture of of two liquids with the same constant boiling point and composition throughout distillation called?
Azeotrope
In a water molecule, what are the H-bond acceptor sites?
Unshared oxygen electrons
What happens to the melting point of a lipid/oil when its overall level of saturation is increased?
Melting point increases
What is an antioxidant?
Substance used to retard rancidity of food due to exposure to oxygen.
What off-flavor compound is associated w/ascorbic acid browning?
Furfural
What is the alkaloid in irish potatoes?
Solanine
What are the two primary fatty acids in palm oil?
Oleic and palmitic
What is the active ingredient in sichuan pepper that induces a tingling sensation?
Hydroxyl-alpha-sanshool
Which general class of tannins contain catechin or epicatechin as its monomeric units? hydrolyzable tannins, condensed tannins, Non condensed tannins, phytotannins
Condensed tannins
Why do chelating agents increase the efficiency of antioxidants?
They bind trace minerals that catalyze fat oxidation
What is the 1st chemical preservative approved for use by the US food and drug administration?
Sodium benzoate
Which fatty acid would be expected to have the highest iodine value - linoleic, oleic, or ricinoleic acid?
Linoleic acid
What is the primary flavor compound of clove?
Eugenol
How does high moisture content of foods affect browning?
High moisture content causes browning to happen more slowly
What is the sweetest occurring substance known to man?
Guanidine (discovered in 2016) however thaumatin is also acceptable as this is what is in the Guinness book of world records.
What main compound is responsible for the smell of lavender?
Linalool or linalyl acetate
What chemical compound is responsible for the "hot" principle of jalapeño peppers?
Capsaicin
What is the name of the alternate liquid crystalline forms of the same fat?
Mesomorphs
What is the difference between a "dextrin" and a "dextran"?
Both are intermediate length carbohydrate chains composed of glucose units. Dextrins are formed by acid or enzymatic hydrolysis of starch; dextrans are synthesized by microorganisms
What is the most important factor affecting stability and color of anthocyanins during processing and storage?
pH (stable under acidic conditions)
example: pelargonidin in strawberries -- pH 1-3: stable deep red (cation)
7: colorless (uncharged)
>7: purple (anhydro base)
>>7: mauve to blue (anion)
Name 5 primary functions of food thickeners.
Thickening, emulsion stabilization, suspending, gelation, crystallization, water binding, mouth feel, foam stabilization, flavor fixation, film formation
Categorize each product as suspensions, foam, or an emulsion; cream, fondant, beer, Italian dressing, crab bisque, milk
What lipid oxidation mechanism involves free radical chain reactions?
Autoxidation
What enzyme is most responsible for browning bananas?
Polyphenol Oxidase
Name the microbial gum used in salad dressings.
Xanthan gum
What is the name of the law that states if two systems are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other?
Zeroth law of thermodynamics
What are the five types of bonds found in proteins?
True/False: Chlorophylls which are responsible for the green color of plants are permitted as food colors in the US.
False. Chlorophyllins (modified chlorophyll) are permitted, but native chlorophyll is generally not.
What are the precursors of apocarotenoids?
Carotenoids
Which of the following examples of browning is enzymatic in nature? 1. Browning of sugars as a result of heating 2. Browning of freshly cut surfaces of fruits and vegetables 3. Browning of bread during toasting 4. Browning of potato chips
Browning of freshly cut surfaces of fruits and vegetables.
Rank cheeses from highest to lowest protein content. Cheddar, swiss, cottage, feta.
Swiss>Cheddar>Feta>Cottage
What are the main volatile compounds in turmeric responsible for the flavor and
color of turmeric?
Alpha-turmerone and beta-turmerone (flavor); Curcumin (color)
What is a racemic mixture?
50:50 mixture of two enantiomers (mirror-image isomers) of a chiral molecule, resulting in an optically inactive compound because the enantiomers' effects on polarized light cancel each other out.
What is the approximate number of flavorists in the world?
500
What is the difference between a high-methoxyl pectin and low methoxyl pectin?
High-methoxyl pectin requires a significant amount of sugar to gel properly, but low-methoxyl pectin requires less.
EPA and DHA number of unsaturation and carbon number and name.
Realignment (crystallization) of the amylose and amylopectin to form crystalline regions, leading to firmness or staling
With regard to chemical structure, what do seed gums (locust bean, guar, arabic, mesquite) all have in common?
They are galactomannans
Fat crystals are held together by what forces?
Van der Waals
Why is "Japanese" or "short grain" rice more sticky than "indian" or "long grain" rice after cooking?
Waxy variety (high amylopectin). Long grain rice has more amylose, and gives off less starch than short grain, high amylopectin rice.
Name two diamines responsible for the odor in meats (spoiled)?
Cadaverine, putrescine
What is the desired crystallization type for tempering chocolate?
Type 5
Name 3 factors that influence the rate of lipid oxidation in foods.
Fatty acid composition, free fatty acid content versus the corresponding glycerols, oxygen concentration, temperature, surface area, moisture, pro-oxidants, antioxidants
What is Maillard reaction?
Reaction that occurs between reducing sugars and free amino acids, results in brown, flavorful compounds
Which fruit can be added without destroying the gel: pineapple, papaya, kiwi, strawberry, fig
Strawberry (no proteolytic enzyme)
What does IU stand for?
International Units
Potassium sorbate is primarily used as a food preservative. Why is it used more than its acid form, sorbic acid?
Because the salt is more soluble in foods than the acid.
Which chemical bond has functional groups on opposite sides of the chain?
Trans-bond
What is the process of converting unsaturated fatty acids to saturated fatty acids?
Hydrogenation
Which of the following gels can be set chemically: A. Agar, B. Low-methoxy pectin, or C. Locus bean gum?
B. Low-methoxy pectin
What is the bitter component of grapefruit called?
Naringin
In which year did belgian chemist ernest solvay patented his method for the industrial production of sodium carbonate?
1882
Bromate is added to flour for what purpose?
Oxidizing agent
What is the common name for n-hexadecanoic acid?
Palmitic acid
What is the irreversible first product produced during Maillard Browning?
Amadori rearrangement product (involves the isomerization of N-substituted glycosamines)
Give the 3 main polymorphic forms of crystalline fat and their general characteristics.
Alpha (α) – lowest melting point, least stable, least dense, forms quickly, used in foams
Beta-prime (β′) – intermediate melting point and stability, desirable for smooth texture and creaming properties (e.g., margarine, shortening)
Beta (β) – highest melting point, most stable, highest density, coarse crystals
What does the BET equation relate to for foods?
Aw of monolayer of water
Which lipoprotein transports triglycerides from the liver to adipose tissue?
VLDL
What pigment was first designated as anthocyanins?
Blue pigment in flowers
What 2 divalent cations are important promoters of gel formation in foods?
Calcium and Magnesium
In cooking, what is the function of arrowroot powder?
It is a thickening agent
How is cocoa butter different from other types of fats?
It is more resistant to rancidity and has a long shelf life due to its stable triglyceride composition.
What color is phenolphthalein under acidic conditions?
Colorless
The principle lipid component in milk is the class called which of the following: A) steroids B) phospholipids C) triacylglycerides
C) triacylglycerides
Which of the following food fats contain the highest proportion of saturated fatty acids: A.lard, B.beef tallow, C.butter fat, or D.coconut oil?
D. coconut oil
Name 3 practiced chemical modifications of maize starch in the US.
What percent of the O-H bond in a water molecule is ionic character?
0.4
What are proteolytic enzymes?
Proteolytic enzymes hydrolyze proteins into peptides or amino acids
What is the fundamental force driving electrophoresis?
The driving force is the electric field (voltage gradient) acting on charged molecules, and their speed depends on charge, size, and the medium’s resistance.
Which pigment gives green vegetables their color?
Chlorophyll.
Does kosmotropic ion discourage water structure?
No. Kosmotropes encourage water structure (they stabilize the hydrogen bond network).
What are dyes and lakes?
Food colors. A dye is water soluble (it dissolves). A lake or pigment is a solid (on a carrier of Al or Ca salt) which disperses.
What are emulsifiers?
Polar chemicals that help bind two unmixable liquids together.
What part of the banana is used to make banana oil?
No part - Banana oil is a synthetic compound made with amyl alcohol
95% alcohol has a lower boiling point than 100% alcohol (True/False)
True
List 3 in vitro assays for determing alternative oxidase(AOX) activity.
What chemical structure is common to all phenolic compounds?
Aromatic ring w/a hydroxyl group
What is the primary function of the additive sodium silicoaluminate in salt?
To prevent caking and maintain free-flowing properties.
List 3 reasons for controlling Maillard browning in foods.
1. Undesirable browning in foods causing strong colors and odors; 2. Prevent anti-nutritional effects; 3. Some products of the Maillard reaction are mutagenic 4. Undesirable flavor; 5. Nonuniform color consistency
What is the primary use of sodium hypochlorite in the food industry?
Sanitizer
What is the common name for sodium bicarbonate?
Baking soda
What is the chemical nature of oleuropein?
Phenolic glycoside
Name 3 factors influencing the consistency of commercial fats.
Proportion of solids in the fat, number, size, and kinds of crystals, viscosity of the liquid, temperature treatment, and mechanical working.
In the purification of cottonseed oil, what is the name of the toxin removed?
Gossypol
What is the main components causing browning in bananas?
Enzyme (PPO) and phenols
What are natural casings made of?
Sheep intestine.
What is the predominant character compound in banana oil?
Isoamyl acetate
What is penaltemate carbon?
The penultimate carbon is the second-to-last carbon in the chain, counting from the end opposite the functional group (important in sugar stereochemistry).
Casein coagulates at pH 4.6; what is this point called?
Isoelectric point
Difference between gelato and ice cream.
Gelato is the Italian word for ice cream. It starts out with a similar custard base as ice cream, but has a higher proportion of milk and a lower proportion of cream and eggs (or no eggs at all). It is churned at a much slower rate, incorporating less air and leaving the gelato denser than ice cream.
What does Reichert-Meissert Number measure?
The Reichert-Meissl (RM) Number (or Reichert-Meissl Value) measures the amount of water-soluble, volatile fatty acids (mainly short-chain fatty acids like butyric acid and caproic acid) present in fats and oils.
What are the two equations for water activity?
P/Po ( partial vapor pressure of food moisture at T divided by saturation vapor pressure of water at T) and ERH/100 (equilibrium relative humidity at T divided by 100)
An oil in water emulsion is best achieved with an emulsifier having a low HLB value.
False
What is the name of compounds that can act as either an acid or a base?
Amphoteric
Carotenoid color is destroyed during processing and storage by what two molecular changes?
Oxidation and isomerization of the double bonds
Rate the following materials from lowest to highest thermal conductivity: Water, Aluminum, Stainless Steel, Glass, Air, Copper
Air < Water < Glass < Stainless Steel < Aluminum < Copper
For water, the effect of increasing coordination number is most noticeable at what temperature range?
0-4 degrees celsius
What ingredient makes tonic water fluoresce?
Quinine
What is activation energy?
Energy required to start a chemical/enzymatic reaction
What is the term that describes polymeric crosslinking that entraps the solvents between junction zones?
Gelation
Anthocyanins belong to what general class of chemical compounds (or structures)?
Flavonoids
What is responsible for the bitterness in plants?
Alkaloids, tannins, glycosides, or other phenolic compounds
What non-enzymatic browning reaction involves amino groups reacting with reducing sugars?
Maillard reaction
At what temperature is sugar syrup considered to be in a soft, cracked stage?
270-290°F
Natural connection (covalent bond) between food proteins?
Disulfide bonds.
What is the main function of food additives know as emulsifiers?
To stabilize water-in-oil or oil-in-water systems
What pigment gives the orange color to carrots and corn?
Carotene
What does the process of blanching do?
Used to inactivate enzymes and set color
Under what conditions is the formation of lysinoalanine favored in foods?
Alkaline treatment of proteins
Name two reasons why fats are hydrogenated.
It allows the conversion of liquid oils into semisolid or plastic fats; it improves the oxidative stability of the fat; Improves texture/mouthfeel; Used in shortening and margarine production
The elastic characteristic of the gluten is mostly attributed to which protein compound?
Glutenin
What is pyrolysis?
Thermal decomposition of organic material at high temperatures in the absence of oxygen. Ex. Caramelization
The color change from green to red/yellow in ripening fruit is due to the breakdown of chlorophyll and the synthesis of which class of pigments?
Carotenoids
In order for a liquid to foam it must have:
A low surface tension
The Fehlings test uses CuO, which reacts with aldehydes. In glucose presence, what is the color of the precipitate formed?
Red
Name the properties and applications of three types of Carrageenan.
Kappa Carrageenan: Forms gels with potassium ions, known for their strong, brittle nature. It's widely used in dairy products like puddings and milkshakes, and in meat products as a water binder.
Iota Carrageenan: Creates elastic gels that are thixotropic (break down with agitation and reform when at rest). This makes it suitable for applications like cold-filled dairy desserts and pet food gravy.
Lambda Carrageenan: Primarily acts as a thickening agent, as it doesn't form a gel network. It's cold water soluble and used in applications like thickening solutions in personal care products.
What field of science investigates the physical nature of chemical compounds by applying the methods and theories of physics to chemical phenomena?
Physical chemistry
Which edible oil can be used as a lubricant?
Rapeseed oil
What are the major pigments in yellow peppers?
Carotenoids
What are the dominant organic acids present in grapes, spinach, and blackberries?
Tartaric, oxalic, and isocitric acid
What is piperine and where is it found?
An alkaloid that is responsible for the strong peppery kick in black and white pepper
At what pH does phenolphthalein change color?
pH 8.5
Shortening is defined as any ______ used in baked products.
Fat or oil
What is the pungent compound in mustard seed, cabbage and horseradish?
Sinigrin
How many water molcules can one water molecule bind to?
4
What colorant is added to make foods white?
Titanium dioxide.
How many valence electrons does oxygen have, and what orbitals are they hybridized to?
6, 4 sp3 orbitals
In milk, what does lactose react with to cause maillard browning?
Lactose reacts with the free amino acid side chain of milk protein (Mainly e-amino group of lysine residue)
The carboxy end of the fatty acid is called the _____ position.
Alpha
What is the name of a typical plant sterol (phytosterols)?
Sitosterol or stigmasterol
When does the maximum buffering capacity occur in a food product?
At the pKa, the point where equal amounts of the undissociated acid and weak base (salt) exist in the food matrix
What British dessert shares name with atomic model?
Plum pudding
What is the isoelectric point?
The pH where the sum of the charges (+ and -) is equal to zero for an amino acid/protein
What is a conjugated protein?
A protein with chemical components, in addition to amino acids (examples: lipoproteins and metalloproteins)
Which fatty acid would be expected to have the highest iodine value: linoleic, oleic, or linolenic?
Linolenic (18:3) more unsaturation
Which kind of Carageenan is associated with the formation of a thixotropic gel?
Iota carrageenan
Polygalacturonase catalyzes what reaction?
Hydrolysis of alpha-1,4 bonds of pectin.
Which is the Sweetner developed by Cargill?
Eversweet
Intermediate moisture foods chiefly rely on WHAT food ingredients for the desired texture and lowering of water activity?
Sugar, other humectants like glycerol, sorbitol
What enzyme causes hydrolytic rancidity in milk?
Lipase
The wavelength of which color in the visible spectrum is closest to the x-rays?
Violet (Purple not acceptable)
If a reaction has "zero-order" kinetics, upon what does the reaction rate depend?
It is independent of reactant concentrations and remains constant under fixed conditions.
Name three functions of Vitamin C.
Eessential nutrient, antioxidant, color stabilizer.
Another name for triacylglycerol is?
Triglycerides
What is a chemical leavening system, and what are the two essential components of a chemical leavening system?
A Chemical leavening system is a system of controlled carbon dioxide release to give rise to baked products, the two components are a leavening agent. sodium bicarbonate) and acidic agent
Which of the following elements is found in a molecule of the pigment xanthophyll but not in a molecule of betacarotene: nitrogen, oxygen, hydrogen, carbon
Oxygen (this is the difference between betacarotene and retinol/al)
What is the most effective synthetic antioxidant in edible oils?
TBHQ (Tertiary-Butylhydroquinone)
Name four molecular characteristics of proteins desirable for film and foam formation.
Soluble; large; amphipathic; flexible domains; interactive regions; disposition of charged groups; retention of structure; and polar residues
If you have a method that you want to use to measure % fat in a product and it is not AOAC approved, how would you determine if it is accurate?
Take known fat percentages and run them with the method to perform a standard curve so that you can determine the linear range of your method and assure its accuracy
What are enantiomers?
Compounds that have the same molecular formula but different structures. They are mirror images of each other and refract light differently
What are the major antioxidants found in Rosemary extract?
Rosmarinic acid, carnosol and carnosic acid
Differentiate between a gas and a vapor at room temp.
A vapor is the gaseous state of a substance which is normally liquid at room temp. A gas is a substance with a boiling point below room temp
Gluten is a very unusual protein, partly because over 50% of the protein is composed of just 3 amino acid residues; name 2 of these 3 amino acids.
Glutamate, glutamine, proline
What are the chemical classes in the carotenoid compounds?
Xanthophylls (which contain oxygen) and carotenes (which are purely hydrocarbons and contain no oxygen)
What are the two main types of rancidity in fats and oils?
Hydrolytic and oxidative rancidity
What type of structure is whipped cream?
Foam
Flour bleaching targets what type of food pigment?
Carotenoids
Does enzymatic browning involve carbohydrates?
No, it is oxygen plus a phenolic substrate. Catalyzed by polyphenol oxidase.
What are two examples of natural antioxidants?
Vitamin C, vitamin E, beta carotene
This is the term for temperature at which oil loses clarity under refrigerated conditions.
Cloud point
In brightly colored carotenoid pigments, is the configuration of the double bonds in the isoprenoid chain cis or trans?
Trans
Name the four types of chemical bonding that occur during bread dough mixing and kneading.
Disulfide interchange, hydrogen bonding, hydrophobic interactions, and ionic interactions
Name the type of rancidity, which occurs by the hydrolysis of an ester bond and produces free fatty acids.
Hydrolytic rancidity
What is the enzyme that reacts with phospholipids?
Polyphenols tend to interact with proteins, caffeine, and metal cations to form colloidal suspensions of haze and ‘tea cream’, which are detrimental to product appearance and taste.4 While haze formation can affect color and impair aesthetic appeal, it can also diminish both the shelf-life and the health-promoting properties of the tea.
Chlorophyll is easily destroyed by which physical agent?
Heat
The color pigment that produces white color in vegetables is:
Anthoxanthin
What is the term associated with the oxidation of unsaturated oils?
Rancidity
In an emulsion, which law gives a qualitative indication of the physical factors that influence the stability of an emulsion?
Stoke's Law
In a solution with a pH of 5, what is the charge of chitosan?
Positive (pKa at 6.5)
A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Mg is more effective than Li in causing the salting out phenomenon in hydrocolloids.
TRUE.
Enzymatic browning requires which agents?
Polyphenols, polyphenoloxidase, and oxygen
The products of superoxide ion O2-dismutation are ___________
O2 and H2O2
With regard to pectins, what is HMP and LMP?
HMP = high methoxy pectin; LMP = low methoxy pectin
Hydrolysis of RNA with 5-phosphodiesterase yields 5-nucleotides that are used in the food industry as ______________________.
Flavor enhancers, GMP, IMP
Glucuronic acid is an example of: fructose metabolite, sugar acid, sugar alcohol, glucose metabolite
Sugar acid
How many molecules are in a mole?
6.022 x 10^23
Name two compounds that result in mushroom aroma.
2-octanol, 1-octan-3-one
What are the two products formed when a triglyceride is completely hydrolyzed?
Glycerol and three fatty acids
Define absolute zero and provide the kelvin, Celsius, and Fahrenheit temperatures for this point.
temperature at which particle motion stops (is minimal), 0 kelvin, -273.15 Celsius, -459.67 Fahrenheit.
What kind of emulsion system is butter?
W/O
What is glucono delta lactone?
GdL (glucono-delta-lactone) is a widely used acidulant in meat products, especially for dry cured sausages. It is used when a slow release of acid is required. In the presence of water it reverts to gluconic acid. The lowering of the pH inhibits growth of bacteria and accelerates the drying
They are compounds used to enhance the rising of dough in the manufacture of bakery
What graphs the relationship betwee water content and water activity?
Moisture sorption isotherm
Water has high specific heat due to what?
H bonding
When used as an oxygen scavenger in a redox reaction, ascorbic acid serves as a ________.
Reducing agent
What is syneresis?
The extraction or expulsion of a liquid from a gel.
In whipped cream, the foam stiffens; what stabilizes it?
Clumping of fat globules on the surface of the gas bubbles
What is the cheapest thickener in the U.S. and what is the most expensive?
Cheapest - unmodified corn starch ($0.18/gk) expensive - agar ($26-31/kg)
Depot fats and related animal fats are characterized by their high content of which fatty acids?
Primarily C16 – C18 saturated, and C18:1 and C18:2
What plant pigment is the precursor of Vitamin A?
β-carotene
What compound forms when lipids undergo oxidation producing rancid flavors?
Aldehydes (e.g., hexanal).
What milk protein is a cofactor for the synthesis of lactose?
Alpha lactalbumin
Which two physical phenomena play a role in colloidal stability?
Van der Waals attractive forces and electrostatic repulsion due to charge.
Regular orange extract contains 250 flavor compounds. How many are found in artificial orange?
6
The structure of the enzyme polyphenol oxidase (PPO) contains which metal?
Copper
What is the name for the compound that has a cyclic structure of glucose units?
Cyclodextrin
Which of the following is NOT a globular protein: A.myoglobin, B.collagen, C.amylase, or D.pepsin?
B. Collagen
Which of the following is not a major mineral? Ca, Fe, K, S, Na
Fe
Name 2 natural surfactants.
Lecithin, whey protein
What are the end products of hydrolysis of phosphotidyl acid?
Glycerol, phosphoric acid, fatty acid
T/F Chocolate prevents dental caries.
True
What are the types of intermolecular forces that can be formed in colloids?
Van der Waals forces; Electrostatic (ion-ion) interactions; Hydrogen bonding; Hydrophobic interactions; Steric hindrance (if polymers involved); Ion-dipole or dipole-dipole interactions
What is latent heat of fusion?
The latent heat of fusion is the amount of heat energy required to change a substance from a solid to a liquid at its melting point, without changing its temperature. This energy is used to break the intermolecular bonds holding the solid together.
What are four ways to inhibit enzymatic browning?
Decrease pH, HPP, addition of sulfites, addition of antioxidants, chelation of minerals, prevent exposure to oxygen, MAP, freezing, dehydration
If you wanted to keep bread from staling, which would be the best storage temperature? A. 5â°C B. 15â°C C. 25â°C D. 35â°C
B. 15â°C
What is the strongest biochemical bond?
Covalent
How many times more acidic is something with a pH of 2 than a substance with a pH of 5?
1000x more
Caffeine belongs to what class of compounds?
Methylxanthine
Give an example of fats/oils classed as Oleic-Linoleic Acid fats.
Name the enzyme found in onions responsible for irritating the eyes once an onion is
cut; also, name the compound formed by this enzyme and describe the mechanism in the eye this
compound stimulates.
Chrymatory-factor synthase. Chrymatory-factor synthase forms sulfenic acid which
rearranges into syn-propanethial-S-oxide. This stimulates the lachrymal glands within the eyes
which causes the irritation.
Why do bubbles form in boiling but not during evaporation?
In evaporation bubbles do not form because the vapor pressure is less than the atmospheric pressure. Bubbles form in boiling because the vapor pressure overcomes atmospheric pressure
Which non-enzymatic browning reaction involves the interaction between a reducing sugar and a free amino group, typically from a protein?
Maillard reaction
What is the color pigment in turmeric?
Brilliant yellow
C22:6n3 represents which fatty acid?
(Unsaturated fatty acid) DHA or Docosahexaenoic Acid (from elongating a-linolenic)
Which of the following foods contain the lowest content of water? A) Fresh Carrots B) Fresh Tomatoes C) Whole Milk D) Fresh Celery
C) Whole Milk
"SAP" is used as a buffer, leavening agent, and emulsifier, among others. What is "SAP"?
Sodium acid pyrophosphate
What compounds oxidize to form brown color in fruits and vegetables?
Polyphenols
Name the simplest amino acid.
Glycine
What enzyme is responsible for the development of garlic aroma upon cutting or cellular damage?
Allinase
What term describes the ability of fat to exist in different crystalline forms?
Polymorphism
What is the acid in onions that results in tears when the onion is cut?
There are two kinds of food colorants, what are they?
1. Certified, synthetic, derived from petroleum-based sources and undergo batch testing; 2. Exempt from certification, do not undergo batch testing, derived from plants.
Name the most common functional property of phospholipids in food systems.
Emulsification
If the pressure on a fixed volume of an ideal gas is increased, what will happen to the temperature?
It must increase (PV = nRT).
What is the most commonly used proteolytic enzyme, an extract from the papaya plant?
Papain
Why should olive oil be stored in a dark environment?
Prevent photooxidation of PUFAs
What happens to the melting point of a vegetable oil when it is hydrogenated?
Increases the melting point
If you take 20 mL of a 0.1M NaOH salutation to titrate 40 mL of an HCL solution to the phenolphthalein end point. What is the molarity of the HCL solution?
0.05M HCL
What is the effect of pH on benzoate mechanisms and effectiveness as a food additive?
Benzoate is most effective at a pH below 4.5, where it exists in its undissociated form.
What is the formula weight of sodium chloride within 1/2 a gram?
58.5g
Caramelization is an example of nonenzymatic browning.
True
Name 4 colligative properties of water.
Freezing point, boiling point, vapor pressure, osmotic pressure; properties that depend on the number of solute molecules in water.
The process by which a chemical compound is split into other simpler compounds by the elements of water, as in manufacture of infant formulas, to produce easier-to-digest derivatives of the main protein (casein) on the cow's milk base?
The first digit of an enzyme's EC number assigned by the international union of biochemistry identifies ________________.
General reaction type that they catalyze.
What is the definition of a gel?
A liquid dispersed in a solid.
What is FAD?
Flavin adenine dinucleotide
What is the scientific name for vitamin E?
Alpha-Tocopherol
The saturated 12 carbon fatty acid is commonly known as what?
Lauric Acid
List three phytonutrients present in raisins that are associated with its health benefits.
Phenolic acids: caftaric and coutaric, flavonols: quercetin and kaemferol
What enzyme is responsible for bleaching and production of hay-like off flavors in frozen beans?
Lipoxygenase.
What is the hydrogen ion concentration of a solution with a pH of 4.0?
10â»â´ M.
What is the chemical name of enzyme lactase?
Beta-D-galactosidase
What is the structural difference between carotene and xanthophyll?
Xanthophyll contains oxygen
What common food additive is used as a sequestrant, binding metal ions to prevent oxidation and rancidity in various food systems?
EDTA (Ethylenediaminetetraacetic acid)
Name the two primary fatty acids within coffee beans.
Linoleic and palmitic acid
What mineral is best known as an antioxidant?
Selenium
What 2 antibiotics are legal food additives?
Nisin & natamycin
Give two examples of carotene pigments and natural products in which they may be found.
α and β carotene (carrots)
lycopene (tomatoes)
What is the difference between an aldose and ketose?
Aldose has a carbonyl group at the end of the atom, while the carbonyl group is at any other position in a ketose
The HLB value is a number from 1 to 18 used to describe effectiveness of what?
Emulsifying agents
What are the primary, secondary, tertiary, and quaternary structures?
Primary - amino acid sequence. Secondary - alpha-helix, beta sheet. Tertiary - one complete protein chain with cross bonds linking it together. Quaternary - four separate protein chains assembled as one.
Which monosaccharide is the sweetest?
Fructose
What does HLB stand for and what does a high and low HLB value indicate?
HLB (hydrophilic-lipophilic balance); a low value (3-6) promotes water in oil emulsions and a high value (8-18) promotes oil in water emulsions.
Rank the following fatty acids from lowest to highest melting point: oleic, elaidic, lauric, linolenic.
Linolenic, oleic, elaidic, lauric
Lactose is composed of which two monosaccharides?
Glucose and galactose
Tonka beans have a high concentration of which dangerous compound?
Coumarin
C18:0 saturated fatty acid is commonly known as?
Stearic acid
What are the Positive/Acidic Amino acids?
Aspartic acid and glutamic acid
Describe the chemical basis of the Maillard reaction and name the initial reactants involved.
A reducing sugar reacts with a free amino group (amino acid or protein), forming a Schiff base and Amadori compounds, leading to flavor and color development.
List 5 types of bonds that important for the structure of proteins.
Covalent, hydrogen, van der waals, disulfide, electrostatic
What is caramelization?
Reaction to the removal of water from the sugar molecules by heat. This changes the structure and results in darkening, occurs quicker in foods with lower moisture content
What is the molar concentration of disassociated H+ in pure water at 25°C?
1 x 10^-7 M
Compared to unsaturated fats, saturated fats contain more?
Hydrogen
Which reaction is responsible for non-enzymatic lipid polymerization during frying?
Thermal oxidation.
What is the name that is associated with the 1889 discovery of the temperature dependence of reaction rates?
Arrhenius
Rank the relative sweetness of the following polyhydric alcohols: sorbitol, glycerol, xylitol, mannitol
Most to least: xylitol, sorbitol, mannitol, glycerol
What does p mean in pH?
#NAME?
Which of the following is used for coloring foods such as fish, butter, rice and cheese: a) Annatto b) Yellow #5 c) Saffron
a) Annatto
The acetic acid in vinegar is derived from the bacteria oxidation of what substance?
Ethanol
What is oleostearin?
The solid portion of beef fat after removal of oleo oil
What is the major protein in milk?
Casein
How many amino acids are found in one turn of an alpha helix in DNA?
3.6
Give two amino acids which contain two ammonium and related groups.
Arginine, lysine
Name the 2 main types of secondary structures of proteins.
Alpha-helix and beta-sheet
What is the reaction to make triglycerides?
Fatty acid reacting with a glycerol with the release of water
Furfural mercaptan is a volatile largely found in what food?
Fresh roasted coffee
What structural feature of carotenoids is responsible for the color of these plant pigments?
Alternating double bonds in alkyl chain between the rings.
The bitter glucoside in olives is called ______________
Oleuropein
What does DPA stand for in food chemistry?
Dipicolinic Acid
Name four bonds involved in tertiary structure of protein.
Hydrophobic, ionic, hydrogen, disulfide
What is the phenomenon when two particles merge and don't retain their properties?
Coalescence
What common food additive is used as a sequestrant, binding metal ions to prevent oxidation and rancidity?
The temperature at which water boils_______ as elevation increases?
Decreases
Name 3 chemical properties of food phosphates that governs their usefulness as food additives.
Buffering Capacity, Water Retention, Chelation of Metal Ions, Emulsifying Properties, Phosphorylation and Gelation, Saltiness Control, Antimicrobial Activity, Stabilizing Proteins
How does ERH relate to water activity?
ERH=100 x Aw
What is phenolphthalein use for?
pH indicator, acid=colorless, base=red violet
What are sequestrants?
Sequestrants are metal chelators that bind metal ions to prevent oxidation and degradation.
Name two standard amino acids containing sulfur.
Methionine, cysteine (non-standard: homocysteine and taurine)
Will lipid oxidation be higher at a water activity of 0.05 or 0.5?
0.05
The smoke point temperature for fats is:
~250-520°F
What base is used in the saponification process?
Potassium Hydroxide or Sodium Hydroxide
Rank the following foods by their corresponding water activities from highest to lowest: syrups, jams, potato chips, and bread
Falling number measures the activity of which enzyme in cereals?
Amylase. The falling number test does not directly measure amylase enzyme activity, but measures changes in the physical properties of the starch portion of the wheat kernel caused by these enzymes during the test.
What is the isoelectric point of casein?
Around pH 4.6
What causes the yellow – green pigment of skim milk and whey?
Riboflavin (vitamin B2)
The acidulant responsible for the "flat" sourness in cola drinks is what?
Phosphoric acid
For the following saturated fatty acids, give the systematic name or molecular formula: Palmitic acid, Stearic acid and acetic acid
The two polysaccharides that comprise starch are _________ and _______________
Amylose and amylopectin
The structure of a lipoprotein allows it to do what?
Form a fluid membrane structure
What does SASP stand for?
Small Acid Soluble Protein
What does the iodine value tell you about fat and what physical state is most likely for a lipid with a high iodine number at room temperature?
Iodine value refers to the degree of unsaturated fatty acids in a lipid or the number of grams of iodine absorbed by 100g of fat. A high iodine value is associated with an unsaturated fat, which is typically liquid at room temp.
Name 3 charged amino acids.
Arginine, lysine, aspartic acid, glutamic acid
Define inter-esterification
The shuffling of fatty acid within or between triglycerides to render them better shortenings. The fat crystals are less dense and the product has improved texture
Explain the mechanism of lipid oxidation, including initiation, propagation, and termination steps.
Initiation involves the formation of lipid free radicals, often due to heat, light, or metal catalysts. Propagation occurs when lipid radicals react with oxygen to form peroxyl radicals, which then attack other lipids to form hydroperoxides. Termination happens when radicals combine to form non-radical, stable products.
What is the scale for water activity?
0 – 1.0
What year was the Maillard reaction discovered?
1912
What are the 2 classes of food colorants?
Certified and noncertified
What is the initiation step in crystal formation?
Nucleation
What are the main forces stabilizing the gluten structure of dough systems?
Hydrogen bonding and disulfide linkages
Which fatty acid has the longest hydrocarbon chain? Hexadecanoic acid, tetracosinoic acid, octadecanoic acid, Triacontanoic acid
Triacontanoic acid (30C)
What is pheophytin?
The olive green pigment found in broccoli that has been either overcooked or cooked in acid
What is Allose?
D-Allose is a rare monosaccharide, which rarely appears in the natural environment. D-Allose has an 80% sweetness relative to table sugar but is ultra-low calorie and non-toxic and is thus an ideal candidate to take the place of table sugar in food products.
What is the major fatty acid in soybeans?
Linoleic acid
What is the predominant fatty acid found in olive oil, characterized by having one double bond at the omega-9 position?
Oleic acid
What is the approximate energy content of 1 gram of fat?
9 kcal.
When you open a bottle of carbonated beverage and listen to the hiss of escaping carbon dioxide, you are observing the consequence of what physical law?
Henry's law
What is a brine of salt, water, and sugar cure?
Sweet pickle
Define and differentiate between the terms “thermoset†and “thermoplastic†with regard to protein gel formation and give an example of each.
Thermoset gels form irreversible cross-links and cannot revert back to initial state like muscle proteins (myosin), egg white proteins (ovalbumin).
Thermoplastic gels form gels on cooling after heating, and can revert fully or partially back to solution upon reheating like collagen (gelatin).
What is the chemical nomenclature for caffeine?
1,3,7-trimethylxanthine
What can chelating agents be used for in foods?
Antioxidants
Describe the Maillard reaction and name two key factors that influence it.
A non-enzymatic browning reaction between reducing sugars and amino acids during heating. Key factors: temperature, pH, water activity, and sugar/amino acid type.
What is acid proteolysis?
Breakdown of proteins by proteolytic enzymes under acidic conditions, such as pepsin in the stomach
What is the name given to a mixture of equal parts of Darel Isomers?
Racemic Mixture
Name and describe the four structures of protein.
Primary (amino acid sequence), secondary (local folding patterns like alpha-helices and beta-sheets), tertiary (overall 3D shape of a single polypeptide chain), and quaternary (arrangement of multiple polypeptide chains in a protein)
A saturated fat has how many double bonds?
None
How many percentage of sugar is in semi-bitter chocolate? a. 15%, b. 30%, c. 45%, d. 70%
b. 30%
What does HLB stand for?
Hydrophilic lipophilic balance
Why store olive oil in dark?
To prevent photooxidation
What is the molarity of pure HCL in a pH 7 solution?
10-7 molar
What are the only phenols approved for use in the microbiological preservation of foods?
Parabens
Name two betalains and describe their colors.
Betacyanins (reddish to violet) and betaxanthin (yellowish to orange)
At which pH does the indicator phenolphthalein turn from colorless to red?
8.2-8.3
What are FD&C lakes?
Aluminum salts of the FD&C dyes chemically-bound on an alumina hydrate substratum
List four main functional properties of egg protein.
Solubility, emulsification, foaming, gelling
What is case hardening?
A condition in drying where outer cells collapse to form a water-impenetrable layer, making rehydration difficult.
How does sugar affects starch gelatinization temperature in water?
Sugar lowers the starch gelatinization temperature in water.
What amino acid in fried potatoes leads to the formation of acrylamide?
Asparagine
The ester of which 2 compounds compose chlorogenic acid?
Quinic acid and caffeic acid
The step in which fatty acids of higher melting point are separated by cooling during edible oil manufacturer is called?
Winterization
What are the additive primaries?
Red, green, and blue light
What pigments cause yellow, red, and green colors in plants and vegetables?
Yellow is due to carotene, green is from chlorophyll, and red is due to lycopene
What is Raoult’s law?
The partial vapor pressure of each component in a solution equals the vapor pressure of the pure component multiplied by its mole fraction in the solution.
Colloids that are stabilized by a layer of solvation are called ____________
Emulsoids
How many carbons are in lactose?
12
1-aminocyclopropane-1-carboxylic acid is the precursor of what plant hormone?
Ethylene
Which enzyme is used as indicator in blanching?
Peroxidase
Which of the following solutions would have the lowest freezing point: A.1L of water w/1 mole of sucrose, B.1L of water w/1mole of amylase, C.1L of water w/1mole of NaCl, or D.1L of water w/1 mole of glucose
C. 1L of water w/1 mole of NaCl
Describe the chemical that causes burning eyes when chopping onions.
Propanethial S-oxide
What are the main chemical browning reactions in cake?
Maillard, caramelization
The safety of seafood is influenced by the presence of the biologically active amine, histamine. How is it formed?
It is formed in spoiling fish by decarboxylation of the amino acid histidine
Three main polymorphic forms of fats.
Alpha, beta prime, beta
What type of bond links amino acids together in proteins?
Peptide bond.
Anions form hydration shells in water by what type of interaction?
Ion-dipole
In sucralose, some hydroxyl groups are replaced with which element?
Chlorine
Antioxidants are almost always what class of chemical compounds?
Phenols
The molecular structure which makes emulsifying agents effective is _____
Contain both a lipophilic part and a hydrophilic part
How does rennin act to destabilize the casein micelle?
It divides k-casein into para-k-casein and glycomacropeptide
Give an example of a component of unsaponifiable matter.
Sterols, cholesterol
The basic chemical structure of flavonoids has how many rings?
Three
What is Capsaicin and where is it found?
Pungent heat of chilli peppers
When hydrated, a linear polymer has higher viscosity than a branched polymer (linear polymer and branched polymer have the same MW).
TRUE.
What amino acids, with an aromatic side chain, have hydrophilic properties?
Tyrosine
What is the predominant organic acid found in grapes?
Tartaric acid
What is the coordination number of stable ice-I?
4
Name the two principal methods of describing the dependence of the reaction rate constant, k, on temperature.
1) The Arrhenius equation 2) Thermal death time curves
What is the primary alkaloid found in cocoa and chocolate?
Theobromine
What is the name for dehydration and fragmentation of sugar molecule?
Caramelization
What are the most commonly used surfactants in the food industry?
Monoglycerides and Diglycerides
Solanine found in bittersweet nightshade is a toxin belonging to what chemical compound family?
Glycoalkaloids
Please define water activity.
The ratio between the vapor pressure of the food itself and the vapor pressure of distilled water under identical conditions. It indicates the availability of water for microbial growth and chemical reactions.
Name a commonly available food source of the isoflavones genistein and daidzein.
Soybeans
What is the common name for a 10 carbon saturated fatty acid?
Capric
What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
What carotenoid when bound to specific protein is responsible for lobster's distinct pink orange color after cooking?
Astaxanthin
Is crystallization endothermic or exothermic?
Crystallization is exothermic
What is the full form of ERH?
Equilibrium Relative Humidity
Water A) Is the major component of most foods. B) Controls shelf-life or storage capability C) Regulates chemical and microbiological reactions D) All of the above
D) All of the Above
What are exopeptidases and endopeptidases?
Exopeptidases are enzymes that cleave amino acids or dipeptides in a stepwise manner from terminal end of protein. Endopeptidases are proteinases that hydrolyze linkages within the peptide chain, and don't touch the terminal peptide bonds.
What index is used to specify directions and planes that are determined by three integers (h,k and L) in lattices and crystals?
Miller Index
What does fresh lime juice do to protein solubility?
Fresh lime juice lowers the pH, which typically decreases protein solubility by causing proteins to approach their isoelectric point and precipitate.
Discuss starch gelatinization, including temperature range, molecular changes, and functional consequences.
Gelatinization occurs when starch granules absorb water and swell upon heating, disrupting hydrogen bonds and crystalline regions. Amylose leaches out, viscosity increases, and pastes or gels form, affecting texture and stability.
The Maillard reaction is responsible for the browning and flavor of baked goods. Name one other common browning reaction in foods.
Caramelization (or Enzymatic browning)
Used for clarification in beers, what does PVPP stand for?
Polyvinylpolypyrrolidone
What is the spontaneous loss of fluid from a food gel is called?
Syneresis
What is the primary pigment responsible for the red color of tomatoes?
Lycopene
What does the Peroxide Value indicate?
Amount of autoxidation in fats
In Maillard browning, reducing sugar reacts with which amino acid and destroys its nutritional value?
Lysine
Which of the following is a non-reducing sugar? A. Lactose, B. glucose, C. sucrose, D. maltose
C. sucrose
What are three applications of lactase?
Hydrolyzes lactose to glucose and galactose, prevent sandiness in ice cream, lactose intolerance.
In a water molcule, what are the H-bond acceptor sites?
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