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Effects of Rough Rice Storage Conditions on Gelatinization and Retrogradation Properties of Rice Flours¹

¹Published with the approval of the Director, Arkansas Agricultural Experimental Station, manuscript 99024. ²Former research associate and former associate professor, respectively, Department of Biological and Agricultural Engineering, University of Arkansas. ³Present address: 218 Farrall Hall, Michigan State University, East Lansing, MI 48824-1323. ⁴Corresponding author. Phone: 517-432-7703. Fax: 517-432-2892. E-mail: marksbp@egr.msu.edu

Changes in gelatinization and retrogradation properties of two rice cultivars, Bengal and Kaybonnet, during rough rice storage were studied using differential scanning calorimetry (DSC). The storage variables included two storage moisture contents (12 and 14%), three storage temperatures (4, 21, and 38°C), and four storage durations (0, 3, 9, and 16 weeks). Rough rice cultivar, storage temperature, moisture content, and duration affected (P < 0.05) the enthalpies and temperatures of gelatinization and retrogradation of rice flour. Bengal had a higher gelatinization enthalpy (P < 0.005) but lower gelatinization temperatures (P < 0.0001) than the long-grain Kaybonnet. Rice stored at 38°C exhibited higher gelatinization enthalpy and temperatures (P < 0.05) than those stored at 4 or 21°C. Storage duration affected the gelatinization and retrogradation properties through a higher order, rather than a linear, relationship.