Page 75 - Natural Antioxidants, Applications in Foods of Animal Origin

54 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir understanding the interfacial phenomena is a key to understand the actions

of tocopherols in heterogeneous food systems (Frankel, 1996).

2.8 VITAMIN K (PHYLLOQUINONE)
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Vitamin K is a fat-soluble vitamin that functions as a co-enzyme and is
involved in the synthesis of a number of proteins participating in blood clot-
ting and bone metabolism (Damon et al., 2005). Vitamin K also plays a role
as a co-factor for blood coagulation and coagulation inhibitors in the liver, as
well as a variety of extra hepatic proteins such as the bone protein osteocalcin
(Shearer, 1992). The importance of vitamin K as a blood-clotting agent is
well known. Moreover, it is demonstrated that vitamin K may play a variety
of health-promoting roles. Vitamin K reduces the risk of heart disease, kills
cancer cells, and enhances skin health and have antioxidant properties (Otles
& Cagindi, 2007). A recent study concluded also that high phylloquinone
intakes are markers of a dietary and lifestyle pattern that is associated with
lower CHD risk in men (Erkkilä et al., 2007). Vitamin K (phylloquinone)
1
is a polycylic aromatic ketone which contains a functional naphthoquinone
ring and a phytyl side chain, that is, 2-methyl-1,4-naphthoquinone, with a
3-phytyl substituent (Fig. 2.3). Its molecular formula is C H O and molar
2
31
46
mass is 450.70 g/mol.

0
0 0 0 0 0 0 0 0
0 0

0 0
0 0

FIGURE 2.3 Structure of vitamin K (phylloquinone).
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2.8.1 FOOD APPLICATIONS OF VITAMIN K
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The vitamin K (phylloquinone) level is very low in most foods
1
(<10 mg/100 g), and the majority of the vitamin is obtained from a few green
and leafy vegetables (e.g., spinach and broccoli). Many studies have shown
that some vegetable oils (especially soybean, cottonseed, and rapeseed oils)