89A-12 |
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L. LEBRÓN, Food Science and Technology Department, Univ. of Puerto Rico Mayagüez Campus, PO Box 9030, Mayagüez, PR 00680, E. Díaz, Chemistry Dept., E. Negron, Food Science and Technology, and J. Kubaryk, Marine Sciences Dept. The presence of long-chain, omega 3 polyunsaturated fatty acids is a nutritional benefit in tilapia fish, but double bonds present in fatty acids make them very susceptible to deterioration caused by lipid oxidation and development of off flavors can result. The objective of this research is to evaluate the effect of different concentrations of ascorbic acid in the development of oxidative rancidity in tilapia (Oreochromis niloticus) fish fillets stored at -18°C for a 6 month period. The ascorbic acid was added in the following concentrations: 5ppm, 500ppm and 50,000ppm. The samples were taken monthly and thiobarbituric acid-reactive substances, sensory evaluation and fatty acids composition by GC-MS were employed to follow oxidation development. Through the storage time the oxidative rancidity did not have a significant increase Ascorbic acid was highly effective in inhibiting oxidation at low concentrations: 5 ppm and 500 ppm. The EPA and DHA content in the control and 50,000 ppm had a decreasing pattern. Sensory evaluation found a difference between treatments tested after 6 mo. Panelists found a rancid taste in the control and the 500ppm concentration of ascorbic acid samples. The results show that 5ppm and 500ppm ascorbic acid concentrations are an effective means of inhibiting lipid oxidation in tilapia frozen fish fillets. Further studies about hexanal quantification and aldehydes composition are necessary to investigate the development of oxidation by-products.
Session 89A, Aquatic Food Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |