title: The interaction between tea polyphenols and rice starch during gelatinization.
abstract: The interaction between tea polyphenols (TPLs) and rice starch (RS) during gelatinization has been studied. In the RVA analysis, TPLs-fortified RS exhibited no clearly defined peak viscosity and hot paste viscosity. After excluding other factors, irregular viscosity changes were attributed to the strong interactions between RS and TPLs during pasting/gelatinization. Subsequently, the coupling constants of samples A (the gelatinized sample of the blend of 16% TPLs and RS) and B (the blend of 16% TPLs and gelatinized RS sample) in (1)H-NMR measurements were found to be the difference. Sample A had two coupling constants, (26h)J(HH) = 82.08, 100.77 Hz and (6h)J(HH) = 35.57 Hz, whereas Sample B had one larger coupling constant, (9h)J(HH) = 140.24 Hz. This implied that these two samples differed in H-H interaction and interaction strength of sample A may be stronger than that of sample B. More important is, sample A had clearly broadened O-H stretching and frequency red-shifts of C-O-H bending as compared with sample B in quantitative FT-IR analysis. The overall results indicate that TPLs and RS can have hydrogen bonding interaction during gelatinization.
authors.affiliation: National Engineering Laboratory of Rice and By-product Deep Processing, Center South University of Forestry and Technology, 410004 Changsha, Hunan, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wu
authors.forename: Qinlu
authors.initials: Q
authors.lastname: Lin
authors.forename: Zhengxing
authors.initials: Z
authors.lastname: Chen
authors.forename: HuaXi
authors.initials: H
authors.lastname: Xiao
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry*; D055598:Chemical Phenomena; D005503:Food Additives / Q000737:chemistry*; D005782:Gels; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D012275:Oryza / Q000737:chemistry*; D044367:Phase Transition; D059808:Polyphenols / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013213:Starch / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*; D014783:Viscosity
chemical_list: D005503:Food Additives; D005782:Gels; D059808:Polyphenols; D013662:Tea; D002392:Catechin; D013213:Starch; C045651:epigallocatechin gallate