# Food Analysis Flashcards

Which type of HPLC analysis involves the use of a polar stationary phase and a non-polar mobile phase?

Normal phase HPLC

What types of carrier gases are used to carry samples in a gas chromatograph?

Helium and Nitrogen

What test is used to detect adulteration of milk with water?

Freezing point analysis

What symbol is used to express the O/R potential of a system?

The symbol Eh

What statistic is equal to the square root of the sample variance?

Standard deviation

What property is the Westphal balance used to measure?

Specific gravity

What property does a piezometer measure?

Pressure

What phenomenon occurs when a compound absorbs light and then immediately re-emits energy as light of a longer wavelength?

Fluourescence

What law describes the relationship between absorbance and concentration?

Beer’s law

What is the unit of expression of transmittance in spectrophotometry?

%T

What is the standard method for determining total nitrogen in food?

Kjeldahl Nitrogen Determination

What is the specific gravity of sulfuric acid used in the Babcock Test for milk?

1.82-1.83

What is the scale to measure percent sugar?

Brix

What is the principle of Atomic Absorption Spectroscopy?

Determination of elements based on absorption of radiation by the free atoms

What is the official method for determining sulfites in foods?

Modified Monier-Williams Procedure

What is the most commonly used test for the detection of improperly pasteurized milk?

Alkaline Phosphatase test

What is the most accurate and sensitive method for quantitative determination of metals and metalloids?

Atomic Absorption Spectroscopy

What is the Michaelis Menten equation?

Vo = Vmax[S] / Km + [S]

What is the Henderson Hasselbach equation?

pH=pKa + log [base]/[acid]

What is the denominator of a t-test?

Standard error of the mean

What is the common term used to describe -log(H+)?

pH

What is provitamin A?

β-carotene

What is an Operating Characteristic or OC curve?

A plot of the probability of acceptance of a lot of material at various levels of defects in the lot at a given AQL (acceptable quality level).

What is a type II error?

Falsely accepting a null hypotheses

What is a Mojonnier test used for?

Percentage milk fat

What instrument is used to determine Brix?

Hydrometer or refractometer

What instrument is used for measuring optical activity of compounds?

Polarimeter - Dextrorotatory (+), Levorotatory (-)

What does the Schaal Oven test measure?

Susceptibility of fat to undergo lipid oxidation

What does the phenol sulfuric acid assay measure?

Reducing sugars

What does the ninhydrin assay measure?

primary amines; amino acids

What does the Karl Fisher test measure?

Water concentration