Assessment of the Effect of Zucchini and Eggplant Peel Extract on the Oxidative Stability of Crude Fish Oil

Fish oil (FO) is a nutritional oil due to its fatty acid composition those riches in polyunsaturated fatty acids. However, these acids makes it susceptible to oxidation at the same time. Owing to oxidation, not only undesired rancid taste and fishy odor and taste occur also the shelf life of FO is shortened; it becomes inconsumable and leads to economic losses. Antioxidants are used not only to prevent FO physicochemical quality but also to nutritional and sensorial quality. The goal of present study was to assess eggplant peel extract (EPE) and zucchini peel extract (ZPE) as an alternative to butylated hydroxyl anisole (BHA) to protect FO against the oxidation. For this purpose, unrefined FO, FO with 200 ppm BHA, and FO enriched with ZPE and EPE at concentrations equivalent to the antioxidant capacity of 200 ppm BHA were used. Oxidative stability of the samples were monitored 60-day storage period at 25 and 35 ºC with viscosity, acid, peroxide, conjugated diene values and total chlorophyll and carotenoid contents. The EPE (84 mgGA/100g) and ZPE (70.24 mgGA/100g) had higher total phenolic contents and antioxidant capacity than BHA (17.5 mgGA/100g). FO with EPE and ZPE showed better oxidative stability compared to the unrefined FO and FO with BHA, until 45 days of storage at both temperatures. In conclusion, findings of this study suggest that EPE and ZPE could be promising natural, green, sustainable and healthier alternatives to artificial antioxidants.