Selection of Sweet Potato Variety for High Starch Extraction

Abstract

The basic aim of this work was to determine the reason for the large variances in sweet potato starch yields during extraction. The study was conducted on 19 varieties of sweet potatoes harvested in both the wet and dry season. There was higher starch content (or decreased water content) in sweet potato harvested in the dry season. There seems to be no direct relationship between starch content and starch recovery. This was because the starch present in the tubers was held in different ways in the fiber. As a result different varieties of sweet potato require different amounts of rasping to release the starch. In the choice of the sweet potato variety for starch extraction the amount of tuber harvested per unit area of land, its starch content (which depends on the season of harvest) and most importantly the starch extractability needs to be taken into account. With increased rasping there was increase in the starch extracted from the sweet potato. However, increased in starch extraction levels above 85% require large increase in energy input which might not be economical. It was found that with increase in rasping there was no increase in fiber impurities and that the quality of the starch was acceptable.