  2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center  |
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Effect of various sugars and sugar alcohols on thermal transition of starch gel. M. H. BAEK (1), B. S. Yoo (2), B. W. Yoo (3), and S.-T. Lim (1). (1) Korea Univ. Graduate School of Biotechnology; (2) Dongguk Univ. Food Technology; (3) Korea Univ. Dept. of Chemistry.
Cold stability of starch gel or starch-based food can be improved by low molecular weight sugar addition. Various sugars and sugar alcohols were added (10 or 30% based on starch solids) into a corn starch gel (40%, db), and their effect on the thermal transitions of starch and ice in the cold-stored gel was investigated using a differential scanning calorimeter. Melting temperature and enthalpy of starch were increased by the sugar addition. But amylose-lipids complex formation was hindered. Retrogradation while stored at 4°C for 14 days was not retarded by the sugar addition, based on the melting endotherm of recrystallized starch. Ice melting temperature and enthalpy in starch gel decreased as sugar content increased. Glass transition temperature (Tg') of starch gel was also decreased by the sugar addition, and this was more significant with monosaccharides than with disaccharides. For example, with 30% xylose, the Tg' of starch became -17.20°C (-6.83°C without sugar). However, the Tg' of starch gel was seemed to be affected more by the molar ratio of sugar to starch rather than the type of sugars. But, the Tg' increased during the cold storage regardless of sugar presence, as a result of retrogradation. For optimized cryoprotecting effect on starch gel, sugars should be used selectively and in proper amounts.
Copyright 2001
The American Association of Cereal Chemists