INHIBITORY EFFECTS OF PHYTIC ACID AS A NATURAL ANTIOXIDANT IN PREVENTION OF FISH OIL PEROXIDATION
M.A.H. Sorour, T. Ohshima
Abstract
The inhibitory effects of endogenous phytic acid extracted from wheat bran (PAE), exogenous phytic acid (PA 4mM) and ascorbic acid (A.A) on oxidative stability in 10% cod liver o/w emulsions were investigated. TBARS values, oxygen absorption and total lipid hydroperoxides content were estimated during storage of emulsions treated with antioxidants. PAE and PA 4mM inhibited TBARS formation in cod liver o/w by 67% and 72% of control after 2 weeks of oxidation at 40 °C, respectively. PA 4 mM was highly effective in reducing TBARS values and preventing lipid oxidation compared with ascorbic acid. Residual oxygen content as % in headspace of control vial decreased to about 77% of its initial content (from 20.50 to 4.70%) after 15 days of storage at 40 °C. The rate of oxidation for control sample was about 1% O2/day, while in sample treated with PAE was 0.16% O2/day; which is about 10 times lower. In the headspace air of the vials containing cod liver o/w emulsion treated with PA (4 mM) was significantly lower than that treated with ascorbic acid (0.1%). Total lipid hydroperoxides content in emulsion treated with PAE were significantly lower than that in the control or emulsion treated with WBE stored at 40 °C for 15 days. PA 4 mM inhibited total lipid hydroperoxides formation by 62% of control. Ascorbic acid at concentration 0.1% inhibited hydroperoxidation by 42% at same conditions of storage. In conclusion, phytic acid extracted from wheat bran may be recommended as a food antioxidant that prolongs the stability of fish lipids or fish meats. Moreover, the inhibition of lipid peroxidation by PAE and PA 4 mM, in this investigation was more effective than ascorbic acid.
