VITAMINS IN MILK AND DAIRY PRODUCTS^2750aadults aged 25 years and over are 80 and 65 pgday-’. The Department of
Health (1991) suggested that a vitamin K intake of 1 pg per kg body weight
per day is safe and adequate. The principal food sources of vitamin K are
liver, green leafy vegetables and milk.
Whole cows’ milk contains 0.4-1.8pg vitamin K per 1OOg while human
milk contains about 0.2pg per 1OOg. Human colostrum contains higher
concentrations of vitamin K, which are necessary since bacteria capable of
synthesizing vitamin K take time to become established in the intestine of
the neonate. Irradiation under anerobic and apolar conditions can result in
cis-trans isomerization, resulting in loss of activity since only the trans
isomer has vitamin K activity. However, unit operations in dairy processing
are unlikely to have an effect on the stability of this nutrient.6.3 B-group vitaminsThe B-group is a heterogeneous collection of water-soluble vitamins, most
of which function as co-enzymes or are precursors of co-enzymes. The
B-group vitamins are thiamin, riboflavin, niacin, biotin, pantothenic acid,
pyridoxine (and related substances, vitamin B6), folate and cobalamin (and
its derivatives, vitamin B,J.
6.3. I Thiamin (vitamin B,)
Thiamin (vitamin B,; 6.16) consists of two heterocyclic rings (substitued
pyrimidine and substituted thiazole), linked by a methylene bridge. Thiamin
acts as a co-enzyme in the form of thiamin pyrophosphate (TPP; 6.17)