Page 285 - Natural Antioxidants, Applications in Foods of Animal Origin

264 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir (Ip et al., 1999; Pariza et al., 1999; Truitt et al., 1999; Benjamin & Spener,

2009). Phytanic acid, a branched chain fatty acid presents in milk fat, has
been shown to increase insulin-independent glucose uptake by cells and to
decrease liver triglyceride accumulation in some mouse models (Hein et al.,
2002; Hellgren, 2010; Palmquist, 2010). Besides fat and protein, milk is
naturally a good source of lactose and contains ~5% w/w. Lactose, present
as true solution, promotes the absorption of calcium like other sugars and
it is a ready source of energy, providing 30% of the caloric value of bovine
milk. Also, it accounts for 50% of the osmotic pressure of milk, which is
isotonic with blood and hence is essentially constant (Fox & McSweeney,
2009). The minor components present in milk include minerals (calcium,
selenium, iodine, magnesium, and zinc) and vitamins (vitamin A, vitamin
E, riboflavin, folate, and vitamin 12) whose nutritional significance is well
established.
Milk and other dairy products have been undoubtedly considered as
nature’s perfect functional foods owing to the presence of wide myriad of
bioactive components. Milk has been advocated by the food formulators for
the development of novel dairy foods because of its richness in nutrients
and bioactives and molecules that assist in development of excellent sensory
characteristics. Since time immemorial milk and milk nutrients have been
utilized for the commercial manufacture of numerous products like cream,
butter, butter oil, cheese, condensed milk, dried milks, and indigenous dairy
products that contain components only from milk. Besides this, certain other
food products are prepared from milk where milk components form the
major ingredients like kheer, khoa/mawa, rabri, khurchan, kulfi, shrikhand,
ice cream, and so forth. Probably, it is the only raw material that has been
exploited to such a great extent, not only for the manufacture of value added
food products, but also to harness the valuable ingredients for food and phar-
maceutical sector.

7.2 NATURALLY OCCURRING OXIDANTS AND ANTIOXIDANTS
IN MILK AND DAIRY PRODUCTS

The different dairy food components, namely polyunsaturated fatty acids
(PUFA), proteins, vitamins, and pigments undergo oxidative changes, which
could be both desirable and undesirable, during processing and storage.
The rate and extent of oxidation depends on the concentration and activity
of oxidizing agents, which may form the part of food naturally or used in
the food product as ingredient or may be formed during processing and