THERMAL TRANSITIONS IN GELATINIZED WHEAT-STARCH AT DIFFERENT MOISTURECONTENTS BY DYNAMIC-MECHANICAL ANALYSIS

Gelatinized starch was analyzed by DMA and the resulting overlapped ta n delta curve was characterized. At high moisture contents (>30% w/w), transitions around ice melting region of tan delta peak (>50 degrees C wide) showed skewness al the low temperature side. After deconvoluti on, a symmetrical, sharp, main peak was correlated with the ice meltin g endotherm but the cause of the lower temperature asymmetrical peak w as nor identified. Ar <30% moisture, two deconvoluted Gaussian peaks i ndicated at least two separate, broadly distributed domains (slightly frequency dependent). Transitions (other than ice melting), if caused by glassy rubbery transitions, were small in lan delta and broad (50-1 00 degrees C wide).