Date of Graduation

12-2016

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor

Han-Seok Seo

Committee Member

Jean F. Meullenet

Second Committee Member

Terry Siebenmorgen

Third Committee Member

Paul Counce

Abstract

Previous research has demonstrated the extensive impacts of various environmental and processing conditions on rice milling and processing characteristics. Nevertheless, little is known about the influences of these conditions on cooking and sensory qualities of rice. The present study aimed to determine the impact of cultivating location, harvest moisture content (HMC), and thickness fractionation on the physicochemical properties, and cooking and sensory characteristics of long-grain rice. Four long-grain rice cultivars (purelines: Cheniere and V3501, and hybrids: XP760 and XL753) were cultivated at Harrisburg, AR and Alvin, TX, and harvested at three HMC. Rough rice lots were conditioned and a portion was fractionated according to thickness into thin (<1.9 mm) and thick (≥1.9 mm) fractions. Unfractioned rice and thick kernels were used for further comparison. Overall, rice samples cultivated in TX showed higher amount of broken kernels, chalkiness as well as lower amylose contents compared to those cultivated in AR regardless of the cultivar, possibly due to the greater nighttime air temperatures reported in Alvin, TX. Additionally, textural characteristics and flavor attributes were affected by the cultivating location. Increases in broken kernels, lipid content, and protein content were observed with increasing of HMC. However, cooking qualities were mostly unaffected by HMC. Finally, the addition of thickness fractionation in the process stream showed to improve rice physical quality. However, fractioned rice showed longer cooking duration and a greater width kernel expansion than did unfractioned rice. This study demonstrated that cultivating location and HMC affect rice final attributes and that thickness fractionation may have impacts on cooking and textural characteristics of long-grain rice.

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