Effect of hydroxypropylation on the properties of white yam (Dioscorea rotundata) starch.

摘要

Starch isolated from white yam (Dioscorea rotundata) was subjected to hydroxypropylation under various conditions. Corresponding increases were observed between molar substitution (MS) and vol. of propylene oxide added to the reaction mixture. After hydroxypropylation, a slight reduction in the intensity of the peak at 2 theta = 19.6 degrees was observed and the doublet peak at 23.8 degrees , which was present in native starch, was no longer seen. Hydroxypropylation enhanced free swelling capacity (FSC) and solubility. Setback and retrogradation of native starch declined after hydroxypropylation. Turbidity of native starch paste and syneresis were higher with storage time. Results also indicate that enzymic digestibility improved as MS increased, while the reverse was observed for starch paste turbidity, syneresis, setback and retrogradation. This study presents relevant information that could strategically position D. rotundata starch and its hydroxypropylated derivatives for industrial applications.