Publication no. C-2004-0325-02R |  VIEW ARTICLE

Changes in Retrogradation Properties of Rice Starches with Amylose Content and Molecular Properties.

Cheng-yi Lii (1,2), Vivian M.-F. Lai (3,4), and Mei-Ching Shen (2). (1) Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan. (2) Graduate Institute of Food Science and Technology, National Taiwan University, Taipei 10764, Taiwan. (3) Dept. of Food and Nutrition, Providence University, Taichung 43301, Taiwan. (4) Corresponding author. E-mail: <mflai@pu.edu.tw> Cereal Chem. 81(3):392-398. Accepted November 19, 2003. Copyright 2004 American Association of Cereal Chemists, Inc.

The increases in storage modulus (G(prime)), retrogradation enthalpy change (DeltaH) and DeltaH-related Avrami kinetic parameters of gelatinized rice starch dispersions at 25% (w/w) were investigated with respect to storage period, amylose content (AC), and molecular properties. Three high-AC and five low-AC rice cultivars were compared for understanding the multiple influences of AC and molecular properties involved. After re­fining the results of correlation analysis, the G(prime) of just-cooled samples changed positively, mainly with AC and additionally with the average chain length of amylose (CL(AM)) and the weight ratio of extra-long plus long chains to short chains of amylopectin (AP) (r(APchain)). The developed DeltaH on short-term storage (10 days) elevated with increasing AC and CL(AM) and decreasing degree of polymerization of AP (DP(AP)), but after long-term aging for one to three months with increasing r(APchain), especially for the low-AC cultivars examined. Greater Avrami rate con­stants for retrogradation could be attributed to the combination of a lower DP(AP) and r(APchain) or AP chain length and a greater CL(AM). The polynomials using these critical factors to describe the retrogradation parameters were elucidated and could account for 85-99.6% of data deviations.