Post-Harvest Physiological Deterioration of Cassava Roots (Manihot esculenta Crantz) During Storage Under Different Temperatures

Abstract

Cassava storage roots are highly perishable owing to a phenomenon called post harvest physiological deterioration (PPD). PPD is thought to be result of failed wound response involving various biochemical pathways, reactive oxygen production, changes in phyto-hormones, oxidative enzymes and secondary metabolite production etc,. Storage temperature alter the biochemical processes in root tissue and hence three different storage temperatures such as low (8±2°C), ambient (28±4°C) and high temperature (40±2°C) on the onset of PPD in five different varieties of cassava were studied. Root respiratory rate, oxidative enzymes such as catalase, peroxidase activities were studied for 1, 3 and 6 DAS and correlated with PPD scores. Storage temperatures influenced the respiratory rate as well as the activities of CAT and POX during storage. Varietal variations were noted for respiratory rate and enzyme activities with different storage temperatures. High temperature storage reduced the respiratory rate of roots compared to ambient temperature storage. CAT and POX activities were correlated positively during 1 and 3 DAS and negatively at 6 DAS. PPD positively associated with POX at 6 DAS. Storage of roots under high temperature (40°C) with high RH (80-90%) delayed the onset of PPD and extended shelf-life of cassava roots for a week.