Effects of cultivar and age at haverst on the dry matter, starch gelatinization properties and the cooking quality of cassava

Abstract

The top-growth, root yield, dry matter and starch contents, swelling power, solubility and the pasting cycle of four cassava varieties harvested at monthly intervals from 7 to 13 months after planting were determined and related to the changes in cooking quality at the onset of the rainy season. The harvesting period coincided with the dry and part of the wet season. All four varieties lost their mealiness and poundability at the onset of the rainy season. Cassava root dry matter (RDMe) was the single most important factor which influenced the changes in cooking quality. The utilization of the stored carbohydrates for vegetative growth at the commencement of the wet season, possibly led to a great drop in RDMC which coincided with the seasonal loss in cooking quality. Local varieties went through the same changes but recovered faster than the introduced varieties. Total starch content did not explain the seasonal loss in cooking quality, but changes in some properties of the starch such as swelling power, solubility and gelatinization range could be related to the changes in cooking quality. Cultivars with high fresh root yield were not necessarily those with high dry matter and starch contents.