Milk loses much of its nutritional value when heated intermittently. Dilution of milk with water and removal of fat layer robs it of vitamins important for the healthy growth of individuals

By Syed Akbar
Hyderabad:  Milk loses much of its nutritional value when
heated intermittently. Dilution of milk with water and removal of fat
layer robs it of vitamins important for the healthy growth of
individuals.

A team of researchers has found that boiling milk brings down the
content of vitamins to a significant extent. Each step adopted during
household practices plays a significant role in varying the
concentration of nutritional components, which affect the quality of
milk.

Though boiling of pasteurized milk is not advisable from nutritional
point of view, the team from Punjab suggested boiling of milk once as
prevention of food-borne diseases remains a priority in the Indian
context.

“Dilution of milk significantly affects the nutritional profile which
might lead toinsufficient nutrient deliveries especially in infants and young
children. Milk should not be diluted before consumption and the
practice of storage and intermittent heating of milk should be avoided
to prevent the vitamin loss,” reveals the research study by senior
scientists S Bahman, N Yadav, A Kumar, S Ganguly, V Garg and SS Marwaha.

Boiling of milk increases the concentration of most of the components and
minerals but reduces the level of vitamins A (by 21 per cent), B3 (13
per cent), B5 (three per cent) and B12 (21 per cent). Addition of
water also decreases the concentration of minerals and vitamins.
Storage of milk leads to a decrease in total solids by 19 per cent and
vitamins A, B3, B5, and B12 by 26 per cent, 17-19 per cent, 23 per
cent, and 18-26 per cent respectively.

“Milk contains over a hundred biochemical compounds of which the majority has
substantial nutritional values. When boiled milk is stored at
different conditions (room temperature and refrigeration), and unboiled milk under
refrigerated conditions, the level of total solids decreased up to 19
per cent. After storage for 24 hours, when the deposited the fat layer
at the top was removed, 71-76 per cent loss of fat was
observed,” the researchers said.

Storage of milk at low temperature results in the deposition of the
fat layer on the wall of the storage utensil/pouch carrying away fat-soluble vitamins
resulting in their substantial quantitative loss. Also, exposure to light during storage has a
deleterious effect on water-soluble vitamins. An appreciable loss in
their contents during storage at lower temperature has been reported.

Adding sugar to milk leads to reduction in the concentration of
calcium and magnesium.

However, an appreciable increase in total solids, SNF (solids not fat)
and carbohydrate contents was found.