Page 283 - Natural Antioxidants, Applications in Foods of Animal Origin

262 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir ABSTRACT

Milk, a nature’s perfect food containing high quality of almost all nutri-
ents (proteins, lipids, carbohydrates, vitamins, and minerals), is a polyphasic
secretion of the mammary glands. It is considered to be one of the indis-
pensable ingredients for the preparation of functional foods due to the pres-
ence of myriad bioactive components. Although, besides containing some
antioxidants (like lactoferrin, α-tocopherol, etc.), milk also contains few
oxidants (like polyunsaturated fatty acids (PUFA) of triglycerides, phospho-
lipids, cholesterol ester, riboflavin, ferri-porphyrin, etc.) that may lead to
development of off-flavors in milk and milk products. Some of the oxidation
products especially of lipid oxidation are toxic and reactive. Thus, several
studies have been conducted on the addition of antioxidants, both synthetic
and natural, in milk and milk products. However, natural antioxidants are
gaining wide acceptance as synthetic antioxidants are associated with poten-
tial health hazards. Also, natural antioxidants have positive health implica-
tions and enhance functionality. Several studies have been conducted on the
applications of the natural antioxidants in milk and several dairy products.
These antioxidants can be added either in the form of the essential oil or
in the form of extract (of polar and non-polar solvents) from skins, seeds,
peels, pomace, bark, or leaf of the natural source. This chapter highlights the
applications of these natural antioxidants in dairy foods.

7.1 INTRODUCTION OF MILK AND DAIRY PRODUCTS

Milk and milk products contribute a very significant proportion in our daily
diet. Milk, considered to be closest to the nature’s perfect food, is an excel-
lent source of calcium, a good source of minerals and high-quality proteins,
the only source of lactose, and a source of lipids, the most valuable compo-
nent, which also forms the basis of milk pricing (Upadhyay et al., 2014).
The milk proteins are a good source of essential amino acids and have a high
biological value. The majority of nitrogen in milk is distributed in casein
(around 80%) which is present as colloidal dispersions called as casein
micelles; and whey proteins (around 20%) which are present as true solu-
tion. However, in addition to these proteins, milk also contains two other
groups of proteins or protein-like materials, the proteose-peptone fraction
and the non-protein nitrogen (NPN) fraction (Fox & McSweeney, 1998).
As per the protein quality ranking, casein and whey proteins are reported to
have protein efficiency ratio, biological value, net protein utilization, and