title: Partial beta-amylolysis retards starch retrogradation in rice products.
abstract: Starch retrogradation is the main cause of quality deterioration of starch-containing foods during storage. The current work investigated the effect of partial beta-amylolysis on the retrogradation of rice starch and the potential of beta-amylase in preparing rice products with extended shelf life. Isolated amylopectin, whole rice starch, and rice flour from a regular rice cultivar were partially hydrolyzed by either reagent-grade or food-grade beta-amylase. The degree of beta-amylolysis was expressed as average external chain length () for isolated amylopectin or the degree of hydrolysis (%) for other starch systems. Pulsed nuclear magnetic resonance was used to monitor starch retrogradation during storage at 4 degrees C. The results indicated that partial beta-amylolysis using reagent-grade beta-amylase retarded amylopectin retrogradation by shortening the of amylopectin. When was below DP 11.6, the amylopectin retrogradation was essentially inhibited. Partial beta-amylolysis had a similar effect on the amylopectin retrogradation in the whole starch system. The maltose produced in beta-amylolysis might slightly attenuate the retrogradation-retarding effect of partial beta-amylolysis. The effect of food-grade beta-amylase on starch retrogradation was also evident, although less effective than that of reagent-grade beta-amylase. The retrogradation-retarding effect of food-grade beta-amylase was also demonstrated in rice flour system, indicating a potential method for controlling the starch retrogradation of rice products.
authors.affiliation: Department of Food Science, Wuxi University of Light Industry, Wuxi, Jiangsu 214036, People's Republic of China. yoy1@psu.edu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yao
authors.forename: Jingmin
authors.initials: J
authors.lastname: Zhang
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Ding
mesh_terms: D000687:Amylopectin / Q000737:chemistry / Q000378:metabolism; D005433:Flour; D005524:Food Technology; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008320:Maltose / Q000378:metabolism; D012275:Oryza / Q000737:chemistry*; D013213:Starch / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors; D001614:beta-Amylase / Q000378:metabolism*
chemical_list: D008320:Maltose; D013213:Starch; D000687:Amylopectin; D001614:beta-Amylase