Food analysis

Give the temperature of liquid nitrogen in celcius, farenheit, kelvin, and rankin units.

–196 °C; –320.8 °F; 77 K; 138.6 °R

What food components are measured by the following. 1. Karl Fischer Titration, 2. Nessler’s reagent, 3. Anthrone method

1. Water, 2. Protein, 3. Carbohydrate

Based on the National institute of alcohol abuse and alcoholism, what is the volume in fluid ounces of a standard drink for the following, beer (5%), malt liquor, wine and distilled spirit?

12 fl oz of beer, 8-9 fl oz of malt liquor, 5 fl oz of wine, 1.5 fl oz of distilled spirits

You have a solution with a concentration of 2 mg/L. Please convert this concentration to ug/L, ng/mL, and ug/g

2000 ug/L, 2000 ng/mL and 2 ug/g

How many grams of pure HCl are needed in 1 liter of distilled, deionized water to produce 1 molar HCl?

36.45 grams

How much volume of 37% HCl (the commercial product) is required to make a litre of 1 M HCl with DI water?

82 ml (80-85 ml acceptable)

Describe the Soxhlet extraction method used for fat analysis.

A weighed sample is placed in a thimble. Solvent (e.g., petroleum ether) repeatedly washes through the sample by reflux. Fat dissolves and accumulates in a flask. Solvent is evaporated; fat residue is weighed for percent fat.

If you have 2 different foods, food A w/pH=4 and food B w/pH=6. Which one is more acidic and by how many times?

A, 100 times more acidic than B

Name the five different modes of chromatography.

Adsorption; Partition; Size exclusion/gel permeation/gel filtration/molecular sieve; Ion exchange; Affinity. PAISA.

Name the 1st 5 letters of the Greek alphabet.

Alpha, beta, gamma, delta, epsilon

Explain what beer's law equation is used for, state the equation, and explain what each variable is.

Beer's law is used in calculations dealing with spectrophotmetric analyses. Absorbance = elc. E is the molar absorbtivity constant, L is the length of the cell holder/cuvette and c is the concentration of the solution

Name 3 methods to determine water activity.

Bithermal equilibration, Vapor pressure manometer, Hair hygrometer, Isopeistic hygrometry, Psychrometry, Dew point, Freezing-point depression

Identify the terms BOD, COD, SS, and FOG wrt water quality analysis and their units of measurement.

BOD - biological (or biochemical) oxygen demand; COD - chemical oxygen demand; SS - suspended solids; FOG - fats, oils, and grease. Units for all is mg/L or ppm.

Name the 4 layers in a sandwich ELISA.

capture antibody, sample, enzyme-labeled antibody, enzyme substrate

Various microscopic techniques are used to evaluate the microstructure of foods and food products. What do the following microscopic techniques stand for: CLSM, SEM, and TEM

CLSM= Confocal Laser Scanning Microscopy; SEM= Scanning Electron Microscopy; TEM=Transmission Electron Microscopy

Name four statistical tools often used for solving food quality problems.

Control charts; Scatter diagrams; Stem-and-leaf plots; Cause-and-effect (fishbone) diagrams; Histograms; Flow Charts; Pareto diagrams; Brainstorming; Check Sheets; Stratification

Name 3 major functions of sulfuric acid in the Babcock test?

Digest and dissolve proteins; dissolve fat globule membranes; produce heat to liquefy fat; provide differences in specific gravity for easier separation of liquid fat

List and briefly describe three types of sensory panels.

Discrimination panel – detects differences between products. Descriptive panel – quantifies specific sensory attributes. Affective panel – measures consumer preference or acceptance.

Name three types of GC detectors using their full name.

FID (Flame Ionization Detector); NPD (Nitrogen phosphorus detector); FPD (Flame Photometric detector); ECD (electron capture detector); MS (Mass Spectrometer); AED (atomic Emission Detector); PID (Photoionization detector); TCD (Thermal Conductivity Detector); ELCD (electrolytic conductivity detector)

Give 3 alternate names of size exclusion chromatography.

Gel filtration chromatography, gel permeation chromatography, and molecular sieve chromatography