Morphology and physicochemical properties of starch isolated from frozen cassava root

Abstract

Spoilage of cassava root begins immediately after harvest, but its shelf-life could be enhanced by adopting freezing as a storage method. This study investigated the physicochemical properties and morphology of starch isolated from cassava roots frozen for 0, 7, 14, 21 and 28 days. Extracted starches can be categorized as compound starches with most granules irregularly shaped, with some oval, round and truncated. The amylose contents (22.05–26.41%) decreased with an increase in the freezing time, but the starches showed similar crystallinity pattern (Type A). Fourier infrared transform spectroscopy showed a reduction in double-helical order structure of starches from frozen cassava roots. Starches from the stored roots were generally less firm, less sticky, more cohesive and had higher peak and trough viscosities compared to starch from freshly harvested roots. Starch from frozen cassava starch may be suited for use in certain types of noodles, such as Japanese noodles due to low amylose content. Future studies are however, required to explore the starches in food applications.