Changes in activities of polyphenol oxidase, ascorbate, peroxidase, hydroperoxide and lipid levels during desiccation of Irvingia gabonensis (variety excelsa) seeds

Abstract

Activities of peroxidase (POD), Polyphenol oxidase (PPO), hydroperoxide and lipid contents were investigated during desiccation of cotyledonary tissues of Irvingia gabonensis at ambient temperature (26OC - 30OC), 35OC and 20OC. Activities of POD and PPO increased initially but declined in the latter desiccation period. However, loss of enzymic activity (POD and PPO) occurred generally at moisture content less than 20%. The hydroperoxide and lipid levels increased during desiccation irrespective of stage of seed development. Results suggest that seeds show peroxidation with drying, that is spontaneous oxidation of unsaturated fatty acids. Lipid peroxidation was very pronounced in Irvingia gabonensis seeds indicating the need for rapid drying at relatively high temperature in order to maintain seed quality.

Key Words: POD: Peroxidase; PPO: Polyphenol oxidase; RMC; Relative Moisture Content; Irvingia gabonensis.


(Global Journal of Pure and Applied Sciences: 2003 9(2): 165-170)