Crystallinity of Waxy Maize Starch as Influenced by Ambient Temperature Absorption and Desorption, Sucrose Content and Water Activity

Crystallinity of waxy maize starch was determined by X‐ray diffraction. Absorption and desorption over the range 0.33‐0.84 a w , were applied to raw, partially gelatinized, and completely gelatinized starches mixed with0–50% sucrose. Increasing aw and moisture content in‐creased crystallinity in case of all three starch treatments. A critical moisture content was required for recrystallization of starch. Gelatinized starch showed the greatest crystallinity hysteresis which was much greater than water sorption hysteresis. Sucrose had no effect on starch crystallinity with absorption. With desorption of completely gelatinized starch‐sucrose mixtures, the sucrose caused a sharp decrease in crystallinity at0–10% sucrose while, at higher sucrose content, the crystallinity increased.