Food Chemistry

Name 3 components that effect water activity in a food product.

Solute concentration, moisture concentration, temperature

Name three functions of enzymes used as food additives.

Speed up reaction; lower viscosity; improve extractions; enhance separations; improve their flavor, texture, digestibility, and nutritional value, enhancing product yield, improve preservation

What are 5 fatty acids found in vegetable oil?

Stearic, linoleic, oleic, palmitic, and alpha-linolenic

Categorize each product as suspensions, foam, or an emulsion; cream, fondant, beer, Italian dressing, crab bisque, milk

Suspension – bisque, fondant Foam – beer, bread Emulsion – Italian dressing, milk

Rank cheeses from highest to lowest protein content. Cheddar, swiss, cottage, feta.

Swiss>Cheddar>Feta>Cottage

Name the two synthetic antioxidants and two natural antioxidants.

Synthetic: BHA, BHT, PG, TBHQ; Natural: alpha-tocopherol, ascorbic acid, ferulic acid, sesamol

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;

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.

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

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. - pKₐ: The negative logarithm of the acid dissociation constant (Kₐ) 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).

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).

Describe three roles of lipids in food.

They carry flavor, fat-soluble vitamins, and help with heat transfer.

Name 5 primary functions of food thickeners.

Thickening, emulsion stabilization, suspending, gelation, crystallization, water binding, mouth feel, foam stabilization, flavor fixation, film formation

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 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

Name three water-soluble antioxidants.

Vitamin C (Ascorbic Acid), Glutathione, Polyphenols, Beta-glucans, Vitamin B2 (Riboflavin), Uric Acid, Selenium (in selenoproteins), Taurine, L-carnitine

Define water activity (aₓ) and explain its role in food stability.

Water activity measures the free water available for microbial growth and chemical reactions; lower aₓ improves shelf stability.

What are the six colors of teas?

White, Green, Yellow, Oolong (blue-green), Black, and Dark (Pu-erh)

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

Give two examples of carotene pigments and natural products in which they may be found.

α and β carotene (carrots) lycopene (tomatoes)