Effect of pullulanase debranching on the physical and chemical properties of instant Jasmine rice porridges

Abstract

Gelatinized rice starch was debranched with pullulanase at 60C for 0, 2, 4, 8, 16, and 24 h. Then, freeze/thaw process was applied prior to tray drying, and chemical and physical property evaluations. The starch that was debranched for 16 h showed the highest degrees of hydrolysis and syneresis, namely 18.82 % and 35.40%, respectively. This corresponded to the higher resistant starch (RS) value that slightly increased from 0.32% for 0 h to 0.84% for 16 h. X-ray diffraction and FTIR analyses of 16 h debranched instant rice porridge confirmed the double helix formation and amylose-lipid complexes, which showed increased 12.18% crystallinity and intensity ratios (R) of 1045/1037 cm–1 (0.862) and 1014/995 cm-1 (1.002), respectively. TGA results revealed that enzymatic treatment slightly altered the decomposition temperature by raising it and gave a faster rate of decomposition. Based on this study, improving rice porridge to be suitable food for health-conscious consumers is possible by pullulanase treatment.

Keywords

• pullulanase debranching
• rice porridges
• resistant starch
• amylose-lipid complex