title: Insights into molecular structure and digestion rate of oat starch.
abstract: The in vitro digestibility of oat starch and its relationship with starch molecular structure was investigated. The in vitro digestion results showed that the first-order kinetic constant (k) of oat starches (OS-1 and OS-2) was lower than that of rice starch. The size of amylose chains, amylose content and degree of branching (DB) of amylopectin in oat starch were significantly higher than the corresponding parameters in rice starch. The larger molecular size of oat starch may account for its lower digestion rate. The fine structure of amylopectin showed that oat starch had less chains of DP 6-12 and DP>36, which may explain the small difference in digestion rate between oat and rice starch. The biosynthesis model from oat amylopectin fine structure data suggested a lower starch branching enzyme (SBE) activity and/or a higher starch synthase (SS) activity, which may decrease the DB of oat starch and increase its digestion rate.
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science & Technology, Tianjin 300457, China; Institute of Food Science and Technology (IFST), Chinese Academy of Agricultural Science (CAAS), Beijing 100193, China.
authors.forename: Jinchuan
authors.initials: J
authors.lastname: Xu
authors.affiliation: Institute of Food Science and Technology (IFST), Chinese Academy of Agricultural Science (CAAS), Beijing 100193, China.
authors.forename: Qirong
authors.initials: Q
authors.lastname: Kuang
authors.affiliation: College of Food Science, South China Agricultural University, Guangzhou 510640, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: Institute of Food Science and Technology (IFST), Chinese Academy of Agricultural Science (CAAS), Beijing 100193, China.
authors.forename: Sumei
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science & Technology, Tianjin 300457, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Food Science and Technology (IFST), Chinese Academy of Agricultural Science (CAAS), Beijing 100193, China. Electronic address: ytboy652@163.com.
authors.forename: Xingxun
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science & Technology, Tianjin 300457, China. Electronic address: sjwang@tust.edu.cn.
authors.forename: Shujun
authors.initials: S
authors.lastname: Wang
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000378:metabolism; D000687:Amylopectin / Q000737:chemistry; D000688:Amylose / Q000737:chemistry*; D018554:Avena / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D012275:Oryza / Q000737:chemistry; D013213:Starch / Q000737:chemistry*
chemical_list: D013213:Starch; D000688:Amylose; D000687:Amylopectin; D015061:1,4-alpha-Glucan Branching Enzyme
keywords: Amylopectin; Amylose; Fine structure; Oat starch; Starch digestibility