83A-25 |
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P. VARELTZIS and H. O. Hultin. Dept. of Food Science, Univ. of Massachusetts,Amherst, Marine Station, P.O. Box 7128, Gloucester, MA 01930 Acid and/or alkali solubilization is a recent method developed to separate muscle proteins with good functional properties. Oxidation of the poly-unsaturated lipids in the membranes is a major cause of quality deterioration. This research reports on a way to stabilize these substrates. The objective of this research was to evaluate the effect of citric acid and calcium chloride on preventing lipid oxidation in minced cod muscle, when membrane phospholipids are the main source of tissue lipids. Thiobarbituric acid-reactive substances and sensory evaluation were employed to follow oxidation. Cod hemoglobin was used to promote lipid oxidation. Citric acid and calcium chloride were more effective in reducing sensitivity to oxidation when added to disrupted whole muscle tissue, rather than when added to disrupted pre-washed tissue, where the soluble constituents have been largely removed. Samples that were incubated with citric acid and calcium chloride for 1h exhibited similar oxidative stability to samples not incubated. No difference was found in resistance to lipid oxidation of the isolated proteins whether the muscle proteins had been solubilized at pH 10.8 or 3. Washed cod samples were oxidized more rapidly than samples that were not washed. Non-solubilized controls if washed started oxidizing after the 2nd day, but were stable until the 7th day if not washed. Increasing the final pH from 7 to 7.4 increased the lag phase of oxidation for the controls from the 2nd day to the 4th. The results suggest that citric acid and calcium chloride provide an effective means of inhibiting lipid oxidation in minced cod.
Session 83A, Aquatic Food Products: Byproducts, mince and surimi
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