Food Analysis

Question 1

Define Beer’s law.

Answer 1

Concentration and absorbance are proportional in spectroscopy

Question 2

What is ELISA used for?

Answer 2

Detection of aflatoxin-to detect and quantify

Question 3

What is the iodine value?

Answer 3

Number of centigrams of iodine absorbed by 1 gram of fat

Question 4

What does p mean in pH?

Answer 4

-log

Question 5

What is the gel most common used for protein analysis?

Answer 5

PAGE-polyacrylamide gel electrphoresis

Question 6

What is the amount of energy to raise the temperature of 1 gram of water from 14.5 C to 15.5 C?

Answer 6

1 Calorie

Question 7

What is phenolphthalein use for?

Answer 7

pH indicator, acid=colorless, base=red violet

Question 8

What is Ohm’s Law and what is Power Equation?

Answer 8

V=IR and P=VI or I x I x R

Question 9

What does Reichert-Meissert Number measure?

Answer 9

Primary butyric acid also caproic acid.

Question 10

Name the most common functional property of phospholipids in food systems.

Answer 10

Emulsification

Question 11

What are the two underlying principals of the Babcock test?

Answer 11

To dissolve fat from solids-non fat (SNF). To separate fat from SNF by centrifugal force.

Question 12

The Delvo test is a commonly used rapid method for detection of antibiotic residue in milk. What organism is used in this test?

Answer 12

Bacillus Stearothermophilus

Question 13

What are the Delvo and Charm tests used for?

Answer 13

Testing for the presence of antibiotics in milk.

Question 14

Full name of WVTR?

Answer 14

Water vapor transmission rate

Question 15

Isotherm water activity chart, x and y axis?

Answer 15

X: Aw, y: moisture.

Question 16

Phases of colloidal dispersion?

Answer 16

Continuos phase or dispersion medium and dispersed phase or internal

Question 17

Colligative properties of water?

Answer 17

Freezing point, boiling point, vapor pressure, osmotic pressure. Properties that depend on the number of solute molecules in water.

Question 18

Define triple point?

Answer 18

Pressure-Tº at which substance is at solid, liquid and vapour phase at same time. For water is 611.73 Pa and 273.16 K.

Question 19

What does Kjeldahl and how does it quantify proteins?

Answer 19

Measures nitrogen content

Question 20

Michaelis menten equation?

Answer 20

Used for many enzyme kinetic, relates the velocity of a reaction with the concentration of substrate.

Question 21

Henderson- Hasselbach equation?

Answer 21

pH = pKa + log[dissasociated salt]/log[associated salt]

Question 22

What is pH?

Answer 22

The negative log of the concentration of hydrogen ion in solution.

Question 23

Two isotopes used for food irradiation?

Answer 23

Co60 and Cs137

Question 24

Test to detect carcinogenic antigen?

Answer 24

AMES test

Question 25

NMR is often used as the technique to characterize the linkage types.

Answer 25

False, should be methylation analysis