title: Kernel composition, starch structure, and enzyme digestibility of opaque-2 maize and quality protein maize.
abstract: Objectives of this study were to understand how opaque-2 (o2) mutation and quality protein maize (QPM) affect maize kernel composition and starch structure, property, and enzyme digestibility. Kernels of o2 maize contained less protein (9.6-12.5%) than those of the wild-type (WT) counterparts (12.7-13.3%). Kernels of a severe o2 mutant B46o2 also contained less starch (66.9%) than those of B46wt (73.0%). B46o2 and QPM starches contained less amylose (28.0 and 26.0%, respectively) than others (31.9-33.7%). The B46o2 starch also consisted of amylopectin with the fewest branch chains of DP 13-24. Thus, the B46o2 starch was the most susceptible to porcine pancreatic alpha-amylase (PPA) hydrolysis. Starches of the dry-ground o2 maize and QPM were hydrolyzed faster than that of the dry-ground WT maize, resulting from the reduced protein content of the o2-maize kernels and the reduced amylose content of the B46o2 and QPM starch. Starch in the dry-ground maize sample was hydrolyzed faster by PPA (85-91%) than was the isolated starch (62-71%), which could be attributed to the presence of mechanically damaged starch granules and endogenous amylases in the dry-ground maize samples. These results showed that o2 maize and QPM had highly digestible starch and could be desirable for feed and ethanol production.
authors.affiliation: Department of Food Science and Human Nutrition, Iowa State University, and Agricultural Research Service, U.S. Department of Agriculture, Ames, Iowa 50011, USA.
authors.forename: Jovin
authors.initials: J
authors.lastname: Hasjim
authors.forename: Sathaporn
authors.initials: S
authors.lastname: Srichuwong
authors.forename: M Paul
authors.initials: MP
authors.lastname: Scott
authors.forename: Jay-Lin
authors.initials: JL
authors.lastname: Jane
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004063:Digestion; D006868:Hydrolysis; D008954:Models, Biological; D009154:Mutation; D055292:Pancreatic alpha-Amylases / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000737:chemistry* / Q000378:metabolism; D013552:Swine; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors; C067402:opaque-2 protein, Zea mays; D013213:Starch; D055292:Pancreatic alpha-Amylases