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Cocodrie is a long grain rice variety commonly grown throughout the southern United States. Initial industrial scale production of this variety was largely successful, but rice harvested late in the season exhibited lower than expected yield and quality. A pilot scale rice mill was used to determine if rice milling processing parameters could be manipulated to optimize the yield and quality of early and late season Cocodrie rice. A response surface methodology was used to determine rice mill settings of roll gap (husking), feed volume — also known as flow rate — (milling), and water velocity (polishing) to achieve maximal processing outputs including yield, transparency, whiteness, wholeness, and degree of milling. Results showed that milling flow rate significantly affected whiteness and milling degree for early season Cocodrie, and whiteness, milling degree, and wholeness for late season Cocodrie. Roll gap and water velocity did not significantly affect output processing parameters. Though milling quality parameters for late season rice were lower than early season rice, optimal yields and wholeness for both batches were similar. Ridge analysis indicated that machine settings could be manipulated to optimize specific output parameters for early and late season batches of rice. A score variable was developed to determine a unique set of optimal milling settings for each batch based on the relative importance of each of the five parameters. The research presented in this work is intended to be useful to rice processors working with the Cocodrie variety and is presented in terms of optimization.

The feasibility of saving energy by recirculating drying air in batch dehydrators was tested. Peaches and apples received treatments of four constant recirculation rates (0, 25, 50, and 75%). The total energy use for drying was reduced by 53% when drying peaches and 46% when drying apples with 75% recirculated air. Total drying times were almost the same for all recirculation rates. The results also suggested that even higher fixed recirculation rates could further optimize the drying system for greater energy savings.