Effect of Padinaaustralis Alga Extract on Fat Oxidative Degradation in Epinepheluscoioides during Refrigerated Storage

Background and Objectives: Recently, the use of synthetic antioxidants has been limited due to having chemical and toxic compounds, so the use of natural compounds such as algae, as an alternative to synthetic compounds, is important for the storage of fishery products. The aim of this study was to investigate the effect of Padina australis alga extract on controlling the oxidative spoilage of muscle of  Epinephelus coioides during refrigerated storage.  Materials & Methods: Extraction of algae was performed using methanol. The fish were immersed in four different levels of the extract including 0 (control), 150, 300 and 600 mg/L, and were immediately stored in refrigerated polyethylene bags for 12 days. Sampling was carried out on days 0, 3, 6, 9 and 12 to measure lipid oxidative indices. Results: The results showed that the amount of peroxide, thiobarbituric acid, anisidine and Totox value at 300 and 600 mg/l levels of algae extract decreased significantly from day 9 comparing to the control treatment (p <0.05). There was no significant difference between the conjugated diens’ indices in different treatments and days (p> 0.05). The amount of free fatty acids only decreased in the 600 mg/L treatment comparing to the control treatment (p <0.05). Conclusion: Algae extract at 600 mg/L concentration had high antioxidant effect; in this concentration, oxidative degradation indicators were in the standard range until the end of the storage, so it can be used as an alternative to synthetic compounds in food.