Vitamins Flashcards
The vitamin portion of the coenzyme does what
Responsible for attachment of the attachment of enzyme to substrate
In the absence of the vitamin no reaction takes place and substrate accumulates in the tissue
How many vitamins recognized
13
Deficiency caused by
Inadequate ingestion, poor absorption, inadequate utilization, increased requirement poor digestion , increased excretion or catabolism
Function of Ascorbic acid
Active reducing agent, along with carotene , enables iron absorption keeping it in + form , metabolism of folic acid, , tyrosine, non inflam steroids , wound healing
Vit c properties chem
Reducing agent, acid , readily oxidized by sodium nitrite , prevents formation of nitrosamines,
Vit c stability
Leeches into cooking water, oxidases, non enzymatic browning to furfural , anaerobic , light in the presence of riboflavin , sulphites protect vit c destroy b1 heat light oxy, metL, ph salt sugar , time
B1 deficiency
Beriberi , muscle weakness, nerve destruction, caused by only eating white rice , chronic alcoholism. Cardiac problems
Mild is like chronic fatigue syndrome
Thiamin properties
Energy releasing co factor , make RNA DNA , power protein synthesis , neurotransmitter a
Different forms of B1
Free thiamin, phosphoric ester ( pyramiding and thiazole linked by a methylene group)
Thiamin di phosphate
Pyro phosphate coenzyme in carb metabolism
Bound to enzyme
Thiamin destruction
Alkaline and heat , co2 released
Thiamin distribution
High in the germ , milling removes most of the nutrient
Thiamin stability
Ph above 8 destroyed, neutral unstable , baking or roosting produces losses smells like meat , more stable in food matrix , freezing doesn’t dAmage , sulphites break the methylne bridge , nitrites too . 2nd least stable of the vitamins. Less damage when proteins are in the food , extensive leeching
What is thiamin stable too
Stable to light and acid , protected by proteins and animo acids and starch
Naturally occurring thiamin destruction
Thiaminases in seafood , polyphenols
Riboflavin in cell and properties in body
Oxide reduction , Ribitil deficiencies in developing world for skin and vision , fatty acids broken down , energy yielding
Stability of riboflavin
Alkali, heAt and light.
Lumiflavin
When ribitol is split off , stronger oxidizing agent , destroys other vitamins upon exposure to light loss or high ph of vitamin activity
Lumichrome
When exposed to acid , blue fluorescence
Riboflavin deficiency
Glossit’s, cataracts swollen red lips
Niacin
Pellagra preventing factor , nicotine acid , NRg metabolism
Forms of niacin
Free form of niacin in carcass.
Stability of niacin
Niacin is stable too heat light air acid alkali
Niacin deficiency
Four ds , niacin bound to protein niacytin must be released by acid, corn eaters disease pellagra rough skin
Losses of niacin
During milling , biochem reactions in carcass, drippings of roast meat