Antioxidative Effect of Pineapple Peel Extracts in Refrigerated Storage of Indian Mackerel

Abstract

Natural antioxidants were extracted from pineapple peel (Ananas comosus L, var. queen) waste by cold extraction method [referred as pineapple peel extracts (PPE)] and applied as a preservative against lipid oxidation in Indian mackerel steaks stored at refrigerated condition for 15 days. The antioxidant substances such as total phenols and total flavonoids were determined. The antioxidant potential of PPE was assessed using in vitro assays including, ferric reducing power and DPPH radical scavenging activity. Total phenolic and total flavonoids content were found to be 131 mg GAE 100g-1 and 211.2 mg QE 100g-1 respectively. The IC50 of PPE for DPPH radical scavenging was 0.55 mgml-1. Reducing power (OD=A700nm) of PPE was found to be 0.272 at the concentration of 500µgml-1. Lipid changes during refrigerated storage after treating with PPE were monitored by measuring peroxide value (PV), free fatty acids (FFA) and thiobarbituric acid reactive substance (TBARS). These parameters revealed that the BHA which was used as a standard for comparison was more effective than the PPE. However, when the PPE treated samples were compared with the changes in control samples, PPE was found to offer protective effect to certain degree against lipid oxidation. Thus, it can be concluded that the antioxidant compounds present in the pineapple peel can be extracted and used as natural antioxidants