Characterization of acid-thinned cassava starch and its technological properties in sugar solution

Abstract

Cassava is a source of starch but for certain applications the starch needs to be modified. Acid hydrolysis is a type of chemical modification that allows the starch to become suitable for confectionary applications. The objective of this study was to obtain acid-thinned cassava starch, describe its characteristics and investigate the pasting and technological properties in the presence of a mixture of sugars as used in the candy industry (sucrose and glucose syrup). Microscopic analysis did not visualize any alteration in granule form, but some adhered powders was observed on the surface of the granules on the scanning electron microscopy images. Granule size distribution altered from unimodal to bimodal, particle size determination and span detected starch granule agglomeration after acid hydrolysis. X-ray spectrum showed increase of crystallinity from 15.7 to 18.8%. In sugar solution, absorption, swelling power at 90 °C and gelatinization temperature increased, and the rapid viscosity analysis did not detect increase in viscosity in the hot solution, which is a desirable outcome for this type of modification. The acid hydrolysis did not alter granule morphology, the pasting and technological properties changed and provided desirable functional properties for application in confectionary products especially in gum candy.