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Effects of Postharvest Parameters on Functional Changes During Rough Rice Storage

¹Graduate assistant, Department of Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK. ²Associate professor, Department of Agricultural Engineering, Michigan State University, East Lansing, MI. ³Corresponding author. Phone: (517) 432-7703. Fax: (517) 432-2892. E-mail: marksbp@msu.edu ⁴Assistant professor, Department of Food Science, University of Arkansas, Fayetteville, AR.

The expansion of value-added uses for rice has created a demand for quantitative models of functional changes during postharvest handling. Consequently, this study evaluated the effects of postharvest parameters on the functional properties of long-grain (cvs. Cypress and Kaybonnet) and medium-grain (cv. Bengal) rice. The experimental treatments included rough rice drying conditions (low vs. high temperature drying), storage moisture content (10, 12, and 14%), storage temperature (4, 21, and 38°C), and storage duration (up to 36 weeks). Milling, cooking, and amylograph pasting properties were analyzed. Polynomial models (up to third-order) were developed to describe the effects of postharvest factors on the functional properties. Drying treatments, storage moisture content, and storage duration affected (P < 0.05) all of the functional properties. Storage temperature influenced (P < 0.01) cooking and pasting properties, but not milling properties. Overall, there were significant interactions among the postharvest parameters. Additionally, these factors were related to the functional properties by higher-order relationships.