Week9C1 : Nutrients Flashcards
Vitamin C is very easily oxidized but is only active in its ____ form: accordingly, its exposure to air hence must be minimized.
reduced
_-isoascorbic acid is cheaper but has 20× less vitamin activity
D-isoascorbic acid
What is the other name of D-isoascorbic acid
erythorbic acid
Why sulfite is not permitted as a food additive for meat?
because meat is a good source of thiamin and sulfite destroys thiamin
What is the vitamin responsible for the yellow/green color to whey?
Riboflavin (B2)
Why is milk packaged in light blocking cartons
because riboflavin is light sensitive
T or F : milk is considered a good source of B2 but cheese is not
true
What is the antinutritional factor that ca n be found in cereals and legumes
phytates (inositol hexaphosphate)
What does phytate binds?
cations (calcium, iron, phosphorus)
What is the antinutritional factor found in soy?
trypsin inhibitor
Why is the kjeldahl method not always accurate?
because it assumes that all the nitrogen in food is from the protein content
What is the conversion factor for the kjeldahl method
6,25
How is the moisture content of a food calculated?
with a vaccuum oven (weight difference before and after drying
What is the method to measure the fat content of a food?
soxhlet (ether extraction)
How is measured the inorganic method of a food
with ashing (combustion)
How is measured the cho content of a food?
by difference with other content (100-(protein+moisture+fat+ash)
T or F : in the proximate analysis, the CHO calculated will include the fiber content
T
T or F : water soluble vitamins are less stables than fat-soluble vitamin and more easily lost during blanching
t
What form of vitamin C is used as anti-oxidant?
both, the D-isoascorbic acid and the L-ascorbic acid.
Name de sources of vitamin B1
animal products and grain based products
Name de good sources of vitamin B2
dairy poducts, meat, liver, leafy veg, yeast
T or F : B2 is heat resistant
t
What is the percentage of iron present in food that is absorbed
1-10%
T or F : processing can help enhance the bioavailability by enabling the antinutritional factors
True
What food constituent does inositol hexaphosphate bind? How?
it binds calcium, iron, phosphorus and other cations with its 6 phosphate groups
How does the phytate got reduced in corn?
by genetic modif.
T or F : GMO can make food more nutritious
true
How can you enable trypsin inhibitor?
by cooking.
T or F : all food processing can enhance the bioavailability
false, some processing reduce the bioavailability
