Title: In-vitro assay and inactivation kinetics of polyphenol oxidase of some Nigerian banana and plantain cultivars
Authors: Buliyaminu A. Alimi; Taofik A. Shittu
Addresses: Department of Food, Agricultural and Bio-Engineering, Kwara State University, Malete PMB 1530, Ilorin, Nigeria ' Department of Food Science and Technology, Federal University of Agriculture, PMB 2240, Alabata Road, Abeokuta, Nigeria
Abstract: Activity of polyphenol oxidase (PPO) from the pulp of three banana cultivars grown in Nigeria, namely: plantain, light green-skinned banana and red-skinned banana at unripe and ripe states were investigated. The efficiency of extraction of crude PPO enzyme and in-vitro assay of its activity were determined. Polyethylene glycol detergent gave the highest extraction efficiency. Enzyme activity and rate of browning were found to be highest in plantain and least in light green-skinned banana. Enzymes from all the cultivars were specific towards O-diphenolic compounds and not to monophenolics. The optima pH of PPO of the cultivars tends towards neutrality (6.6-7.0). Enzyme activity was destroyed between 2 and 4 min at 80°C. Thermal inactivation kinetic parameters revealed plantain's PPO to be the most thermal stable. Sodium metabisulphite was the most effective chemical inhibitor of the PPO. The electrophoretic patterns of banana PPO showed heterogeneity with greater number of bands in ripe.
Keywords: banana and plantain; browning; polyphenol oxidase; PPO; inactivation; kinetics; electrophoretic pattern.
International Journal of Postharvest Technology and Innovation, 2016 Vol.5 No.3, pp.200 - 214
Accepted: 04 Nov 2015
Published online: 18 Apr 2017 *