Development of sustainable gel systems with thermo-sensitive properties by enzymatic modification of upcycled rice
Da-Hee Kim1, Tae-Ho Choi1, Ji-Hoon Park1
1Department of Food Science and Nutrition, and the Korean Institute of Nutrition, Hallym University, Hallymdaehak-gil 1, Chuncheon-si, Gangwon-do 24252, Republic of Korea.
Abstract:
Rice cake flour (RCF), obtained by milling byproducts generated during rice cake production, was enzymatically modified using cyclodextrin glucanotransferase (CGTase) to develop thermo-sensitive gels (TSGs). Samples prepared at different CGTase dosages were designated as TSG 40, TSG 60, TSG 80, and TSG 100. CGTase treatment redistributed starch branch-chain lengths, reducing short chains (DP 6-15) while increasing medium chains (DP 16-30), and decreased the weight-average molecular weight from 8.78 × 107 Da to 2.48-4.86 × 107 Da. These structural changes likely contributed to reversible viscoelastic behavior during repeated heating-cooling cycles through modification of starch chain organization. TSG 80 exhibited storage modulus (G') recovery exceeding 109%, while TSG 60 showed improved freeze-thaw stability with reduced syneresis (4.65%) compared to native RCF (9.35%). Texture profile analysis showed reduced hardness with no change in cohesiveness. CGTase-mediated chain rearrangement improved rheological behavior and freeze-thaw stability of upcycled starch gels, highlighting their potential for thermo-processed and frozen food systems.
