SEASONAL EFFECTS ON THE PHYSICOCHEMICAL PROPERTIES OF STARCH FROM 4 CULTIVARS OF CASSAVA

Four varieties of cassava plants were cultivated at CIAT in Colombia and harvested on four different occasions with a view to evaluating whether there was any relationship between the texture of the cooked roots and the constituent starch. The organoleptic qualities of the cooked roots showed considerable differences in 'glassiness' and hardness of texture, both between varieties and times of harvest. The starch granules were isolated and examined by a variety of techniques. The size of the granules did vary with the seasons but there were only minor differences in the x-ray crystallinity, the elution patterns of iso-amylase-debranched material (including the amylose content), the proximate composition of the starch and the time course of digestion by glucoamylase. None of these provided a basis for explaining the differences in cooked texture.