title: Classification and kinetic analysis of viscosity growth processes for NaOH-gelatinized rice starches.
abstract: Using capillary viscometry, viscosity growth processes were studied for non-glutinous rice starches gelatinized with different NaOH solution concentrations. The viscosity-time data series generally conformed to sigmoid curves with an arbitrary inflection point (IP) for each curve, and were analyzed using a kinetic model that incorporated a first-order reaction rate equation and a mixing rule of a power-law type. The shapes of curves were classified with the exponent ν or the ratio η(*)/ηG, where η(*) and ηG were viscosities at IP and at equilibrium, respectively. It was argued that these parameters were related to the complex formation arising from NaOH-starch interactions. The rate constant K defined uniformly for an entire process increased with NaOH concentration and was power-law dependent. Furthermore, it was suggested that gelatinization evolved non-uniformly over time. A non-uniform analysis was then performed by disassembling the entire process into several elementary stages and revealed the evolutionary process for K.
authors.affiliation: Department of Food Science and Nutrition, Faculty of Human Life and Science, Doshisha Women's College of Liberal Arts, Kamigyo-Ku, Kyoto 602-0893, Japan. hyamamot@dwc.doshisha.ac.jp
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Nozomi
authors.initials: N
authors.lastname: Sawai
authors.forename: Kanako
authors.initials: K
authors.lastname: Seo
mesh_terms: D005782:Gels / Q000737:chemistry*; D007700:Kinetics; D012275:Oryza / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000494:pharmacology*; D013213:Starch / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014783:Viscosity / Q000187:drug effects
chemical_list: D005782:Gels; D012972:Sodium Hydroxide; D013213:Starch
keywords: Gelatinization; Kinetic analysis; NaOH; Starch; Viscosity