Preservation of catfish fat by using polyphenols extracted from green tea (Camellia sinensis)

Abstract

Natural antioxidants have been known worldwide recently and

generally regarded as safe antioxidants for food preservation and human use. The aim of this research is to study possibilities for preservation of catfish fat by using natural antioxidants – green tea polyphenol-rich extracts. Catfish fat was treated with the green tea extracts at different concentrations, and

stored at 3 different temperature conditions: 4oC, room temperature and

60oC, in comparison with the BHT treatment. The total phenolic content (TPC) was determined via Folin-Ciocalteau method and the antioxidant capacity was also determined by the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging assay. The catfish fat was extracted from fish and then treated by adding the polyphenol-rich extracts and BHT. The effects of green tea polyphenols and BHT on improving oxidative stability of catfish fat were investigated. The results showed that the TPC in green tea was found to be 5.17gGAE/100gDW (dry weight). Antioxidant activity of BHT nearly twice as good as green tea polyphenols based on measuring their ability to scavenge stable free radical (DPPH). Compared to BHT at 200ppm, green tea polyphenols showed nearly same strong anti-oxidative capacity on catfish fat with the concentration at 1600ppm at all temperature conditions. Catfish fat treated with the green tea polyphenol-rich extract at 1600ppm can be kept at RT and 60oC up to 30days. However, at the same concentration, catfish fat could be kept at 4oC showed significant lower free fatty acid and peroxide values than the fat samples stored at room temperature and 60oC.

Key words : Total phenolic content (TPC), Butylated Hydroxyltoluene (BHT), Catfish fat, Free fatty acid values (FFAs), Peroxide values (PVs), 1, 1- diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging assay.