Impact of molecular and crystalline structures on in vitro digestibility of waxy rice starches

• Published in: Carbohydrate polymers Vol. 112; pp. 729 - 735
• Main Authors: You, Su-Yeon, Lim, Seung-Taik, Lee, Ju Hun, Chung, Hyun-Jung
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 04.11.2014; Elsevier
• Subjects: Amylopectin - chemistry; Applied sciences; Biological and medical sciences; Crystalline structure; Crystallins - chemistry; Exact sciences and technology; Food industries; Fundamental and applied biological sciences. Psychology; Glycemic Index; In vitro digestibility; In Vitro Techniques; Molecular Structure; Natural polymers; Oryza - chemistry; Physicochemistry of polymers; Spectroscopy, Fourier Transform Infrared; Starch - chemistry; Starch - metabolism; Starch and polysaccharides; Starch and starchy product industries; Viscosity; Waxy rice starch; X-Ray Diffraction; Asia; South Korea; Korea; In vitro digestibility; Waxy rice starch; Molecular structure; Crystalline structure; Transition temperature; Swelling; Transition heat; Crystallinity; Pasting properties; Experimental study; In vitro; Oside polymer; Chemical composition; Property structure relationship; Rice starch; Comparative study; Glycemia; Cultivar; Digestibility
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2014.06.065

•The influence of molecular and crystalline structures on in vitro digestibility of waxy rice starches was investigated.•Significant differences in the physicochemical properties and digestibility of waxy rice starches were observed.•The crystalline and molecular structures are key factors in controlling starch digestibility. The in vitro digestibility, molecular structure and crystalline structure of waxy rice starches isolated from six Korean cultivars (Shinsun, Dongjin, Baekok, Whasun, Chungbaek, and Bosuk) were investigated. The molecular weight (Mw) of waxy rice starches ranged from 1.1×108g/mol to 2.2×108g/mol. Chungbaek waxy rice starch had the highest average chain length (24.3) and proportion (20.7%) of long branch chains (DP≥37), and the lowest proportion (19.0%) of short branch chains (DP 6–12) among the tested six waxy rice starches. The relative crystallinity and intensity ratio of 1047/1022 ranged from 38.9% to 41.1% and from 0.691 to 0.707, respectively. Chungbaek had the highest gelatinization temperature and enthalpy. Chungbaek had the highest pasting temperature (70.7°C), setback (324cP) and final viscosity (943cP), whereas Baekok showed the highest peak viscosity (1576cP) and breakdown (1031cP). Chungbaek had lower rapidly digestible starch (RDS) content and expected glycemic index (eGI), and higher resistant starch (RS) content, whereas Whasun exhibited higher RDS content and eGI. The slowly digestible starch (SDS) content of Shinsun (38.3%) and Bokok (32.0%) was significantly higher than that of other cultivars (11.3–22.0%).