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Phil Williams Lecture Award - Applying material state properties to optimize rice drying T. SIEBENMORGEN (1). (1) Univ of Arkansas, Fayetteville, AR, U.S.A. Rice is somewhat unique among cereal grains in that it is predominantly consumed as an intact kernel. While the term “milling yield” applies to various processing quality indices across grains, in rice this term generally refers to the mass percentage of rough that remains as in-tact kernels, after the desired level of bran removal has occurred. Milling yield is a major determinant of the economic value of a rice lot. Thus, most all aspects of rice processing are focused on maintaining kernel physical integrity. The University Arkansas Rice Processing Program has conducted research to better understand not only the physicochemical properties and behavior of individual rice kernels, but also the kernel-to-kernel distributions of these properties. These distributions have been used to explain trends in milling yield levels, during both production and post-harvest processing operations. Perhaps the best example of this individual-kernel approach has been the glass transition hypothesis, which explains endosperm fissure formation during the drying process. The glass transition temperature (Tg) of individual rice kernels was quantified, and a state diagram relating Tg to kernel moisture content was developed. This state diagram has been used to map kernel material states throughout the drying and subsequent tempering processes. Further, the intra-kernel material state differences that can occur due to moisture content and temperature gradients within kernels are hypothesized to initiate fissures that typically result in broken kernels upon subsequent milling. This hypothesis has been validated through a series of laboratory- and commercial-scale experiments. This research is now being used as the basis to explain milling yield reductions during existing drying processes, as well as to improve grain drier designs. View Presentation