Cereal Chem. 71:150-155   |  VIEW ARTICLE


Retrogradation of Amylopectin from Maize and Wheat Starches.

K. E. J. Ward, R. C. Hoseney, and P. A. Seib. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

Differential scanning calorimetry was used to study retrogradation of amylopectin (AP) isolated from corn and wheat starches. Corn AP developed more crystallinity during storage (as demonstrated by higher enthalpy [(Delta)H] values) than did wheat AP; most of the recrystallization occurred during the first week of storage. An increase in onset temperature of melting (To) (annealing of the crystallites) continued during two weeks of storage. As AP concentration was increased from 25 to 45% (w/v), (Delta)H increased and To decreased. Therefore, although more crystallites were formed at higher concentrations, those formed at lower concentrations achieved a higher degree of annealing. Retrogradation effects were determined for some common food additives: NaCl (4%, based on weight of AP); citric acid (3.5%); sodium stearoyl lactylate (0.5%); or sucrose, glucose, and fructose (100%). The (Delta)H of corn AP gels were not affected by any of the additives. The (Delta)H of wheat AP gels were not affected by sodium stearoyl lactylate or the sugars, but the (Delta)H of wheat AP decreased with NaCl. The rate of recrystallization was changed with citric acid. To of corn AP gel was not affected by NaCl or citric acid. The To of wheat AP, however, decreased with NaCl. The rate of annealing decreased with citric acid. To of both amylopectins was decreased by sodium stearoyl lactylate and increased by sugars.