Page 297 - Natural Antioxidants, Applications in Foods of Animal Origin

276 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir reported to be lost during frying because of its steam volatility (Gordon &

Kourimska, 1995).

7.7 APPLICATION OF SYNTHETIC ANTIOXIDANTS AND THEIR
EFFECTS

The synthetic antioxidants are lipid soluble and terminate free-radical
chain reactions by donating hydrogen atoms or electrons to free radicals
and thus, converting them to more stable structures (Frankel, 1998). The
use of synthetic antioxidants in the prevention or retardation of autoxida-
tion in lipids and lipid containing food products has been the subject of
numerous investigations. The use of synthetic antioxidants in dairy products
is prohibited in most countries. However, certain studies on the use of these
in dairy products reveal that their effectiveness varies in different products.
While NDGA inhibits the development of oxidized flavor in liquid milk, it
promotes autoxidation in milk fat (Hammond, 1970). Tocopherols are very
effective inhibitors of spontaneous or copper-induced oxidation in liquid
milk (Dunkley et al., 1967; King, 1968) but have little effect in whole milk
powder (Abbot & Waite, 1965). Other antioxidants that have been shown to
exert protective effects are dodecyl gallate in spray-dried whole milk (Abbot
& Waite, 1962), ascorbyl palmitate in lactic butter (Koops, 1964) and propyl
gallate and quercetin in butter oil (Wyatt & Day, 1965). Anhydrous bovine
or buffalo milk fats (ghee) may be stabilized when stored in a hot climate by
combinations of phenolic antioxidants (BHA, BHT, and propyl gallate) and
ascorbic acid (Helal et al., 1976). Wade et al. (1986) reported that BHA and
BHT were effective in retarding oxidation of anhydrous milk fat but DL-α-
tocopherol acted as a pro-oxidant.
There are a number of controversies surrounding the use of synthetic
antioxidants. Since food additives are subjected to the most stringent toxi-
cological testing procedures, only a few synthetic antioxidants have been
used in foods for any length of time. Since the toxicity of some synthetic
antioxidants is not easily assessed, as a result of which, a chemical may be
considered safe by a country, tolerated in another country and forbidden in
a third one (Thorat et al., 2013). For example, TBHQ is authorized as an
antioxidant in the United States, while it is forbidden in the European Union
countries. The legal limit for the addition of BHA and BHT to most foods in
the United States is 200 mg/kg of fat. When added in combination, a total of
200 mg/kg of fat is permitted (CFR, 2001). In India, according to the Food
Safety and Standards Regulations (2011), no antioxidant other than lecithin,