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.