Stabilisation of Soybean Oil with Pod Coat Extracts of Cowpea (Vigna unguiculata)

Abstract

Background: In edible oil processing industry the main reason of lipid deterioration is oxidation. The inclusion of antioxidants is required to preserve colour, flavour and to prevent vitamin destruction. In recent years the discovery of safe antioxidants of plant origin have increased conspicuously and they have been considered as better alternative than synthetic antioxidants such as tert-butyl hydroquinone, butylated hydroxyanisole, propyl gallate etc. This study is an attempt to investigate pod coats of cowpea as potential source of natural antioxidants and to appraise their efficacy for stabilizing soybean oil. Methods: In the laboratory investigation during 2015-2018 the efficacy of cowpea pod coat extracts in stabilizing soybean oil during accelerated storage has been studied. Pod coats of cowpea were extracted with three solvents (acetone, ethyl acetate and chloroform). Soybean oil samples were stabilised by adding different pod coat extracts at 1000 and 2000 ppm concentration. Result: Our investigation allowed us to conclude that rate of oxidative degradation of soybean oil was the lowest in the sample treated with acetone extract (2000 ppm).