title: The effect of moisture content on physicochemical properties of extruded waxy and non-waxy rice flour.
abstract: The properties of waxy rice flour (WRF) and non-waxy rice flour (RF) were modified using an extrusion process with different feeding material moisture contents. WRF was more affected by the thermomechanical stress from extrusion; consequently, it had a lower glass transition temperature but higher water solubility index (WSI) indicating higher molecular degradation than extruded RF. The lower moisture content of the feeding flour caused more severe flour damage (coarser surface of the extruded flour) and lowered relative crystallinity compared to higher moisture content processing. Moreover, low moisture content processing led to complete gelatinization, whereas, partial gelatinization occurred in the higher moisture content extrusion. Consequently, the extruded flours had a lower peak viscosity and gelatinization enthalpy but a higher water absorption index and WSI than native flour. In conclusion, the rice flour type and the moisture content of the extrusion feeding flour affected the physicochemical properties of the extruded flour.
authors.affiliation: Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand.
authors.forename: Ornpicha
authors.initials: O
authors.lastname: Jongsutjarittam
authors.affiliation: Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand. Electronic address: fagisscr@ku.ac.th.
authors.forename: Sanguansri
authors.initials: S
authors.lastname: Charoenrein
mesh_terms: D055598:Chemical Phenomena; D005433:Flour / Q000032:analysis; D006813:Humidity; D012275:Oryza / Q000737:chemistry* / Q000648:ultrastructure; D014783:Viscosity; D014867:Water / Q000032:analysis / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D014867:Water
keywords: Extrusion; Physicochemical properties; Rice flour; Water feed rate; Waxy rice flour