Week9C1 : Nutrients

Question 1

Vitamin C is very easily oxidized but is only active in its ____ form: accordingly, its exposure to air hence must be minimized.

Answer 1

reduced

Question 2

_-isoascorbic acid is cheaper but has 20× less vitamin activity

Answer 2

D-isoascorbic acid

Question 3

What is the other name of D-isoascorbic acid

Answer 3

erythorbic acid

Question 4

Why sulfite is not permitted as a food additive for meat?

Answer 4

because meat is a good source of thiamin and sulfite destroys thiamin

Question 5

What is the vitamin responsible for the yellow/green color to whey?

Answer 5

Riboflavin (B2)

Question 6

Why is milk packaged in light blocking cartons

Answer 6

because riboflavin is light sensitive

Question 7

T or F : milk is considered a good source of B2 but cheese is not

Answer 7

true

Question 8

What is the antinutritional factor that ca n be found in cereals and legumes

Answer 8

phytates (inositol hexaphosphate)

Question 9

What does phytate binds?

Answer 9

cations (calcium, iron, phosphorus)

Question 10

What is the antinutritional factor found in soy?

Answer 10

trypsin inhibitor

Question 11

Why is the kjeldahl method not always accurate?

Answer 11

because it assumes that all the nitrogen in food is from the protein content

Question 12

What is the conversion factor for the kjeldahl method

Answer 12

6,25

Question 13

How is the moisture content of a food calculated?

Answer 13

with a vaccuum oven (weight difference before and after drying

Question 14

What is the method to measure the fat content of a food?

Answer 14

soxhlet (ether extraction)

Question 15

How is measured the inorganic method of a food

Answer 15

with ashing (combustion)

Question 16

How is measured the cho content of a food?

Answer 16

by difference with other content (100-(protein+moisture+fat+ash)

Question 17

T or F : in the proximate analysis, the CHO calculated will include the fiber content

Answer 17

T

Question 18

T or F : water soluble vitamins are less stables than fat-soluble vitamin and more easily lost during blanching

Answer 18

t

Question 19

What form of vitamin C is used as anti-oxidant?

Answer 19

both, the D-isoascorbic acid and the L-ascorbic acid.

Question 20

Name de sources of vitamin B1

Answer 20

animal products and grain based products

Question 21

Name de good sources of vitamin B2

Answer 21

dairy poducts, meat, liver, leafy veg, yeast

Question 22

T or F : B2 is heat resistant

Answer 22

t

Question 23

What is the percentage of iron present in food that is absorbed

Answer 23

1-10%

Question 24

T or F : processing can help enhance the bioavailability by enabling the antinutritional factors

Answer 24

True

Question 25

What food constituent does inositol hexaphosphate bind? How?

Answer 25

it binds calcium, iron, phosphorus and other cations with its 6 phosphate groups

Question 26

How does the phytate got reduced in corn?

Answer 26

by genetic modif.

Question 27

T or F : GMO can make food more nutritious

Answer 27

true

Question 28

How can you enable trypsin inhibitor?

Answer 28

by cooking.

Question 29

T or F : all food processing can enhance the bioavailability

Answer 29

false, some processing reduce the bioavailability