Bleaching of Green Peas and Changes in Enzyme Activities of Seeds under Simulated Climatic Conditions

Abstract

ABSTRACT: The effects of simulated climatic conditions on green color loss of peas (Pisum sativum) and related enzyme activities were investigated. Seeds of 2 green pea cultivars showing different resistance to green color bleaching were subjected to light only, soaking in water without light, and soaking in water with light. Green color loss and chlorophyll loss were highest in seeds soaked in water and exposed to light, less in seeds soaked in water under dark conditions, and least in seeds exposed to light only. Increased chlorophyllase activity was associated with loss of green color and chlorophyll, whereas no significant relationship was found between chlorophyll loss and lipoxygenase or chlorophyll‐degrading peroxidase activity. Susceptible and resistant cultivars had significant differences in green color, chlorophyll content, chlorophyll a/b ratio, and chlorophyll degradation kinetics constant when seeds were soaked in water and exposed to light. Enzyme activity was not significantly different between the cultivars. Soaking led to more green color loss, chlorophyll breakdown, and chlorophyllase activity than light exposure. Chlorophyllase may be the key enzyme responsible for green pea bleaching instead of the oxidative chlorophyll degradation pathway with lipoxygenase or chlorophyll‐degrading peroxidase.