36D-36 |
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M. I. SALEH, J. -F. Meullenet, T. J. Siebenmorgen, and L. Wang. Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Avenue, Fayetteville, AR 72704 Thickness rice fractions vary in their protein, lipid, crude fiber and starch contents. This variation in chemical composition is expected to lead to differences in functional properties of cooked rice. The objective of this study was to determine the effect of rice thickness fractions, harvested at different moisture contents, on rice texture properties. Wells and Francis rice cultivars from two locations and of high and intermediate Harvest Moisture Content (HMC) were fractionated using a Carter-Day-grader to small, medium, and large thickness fractions. Milled rice dimensions were measured using a Satake rice image-analyzer RIV-1A (Satake-corporation, Japan). Rice was cooked for 20 minutes in a 2:1 water to rice ratio using a heating-mantle controlled by a temperature-controller. A single compression test was performed using a TA-XT2 plus texture analyzer (Texture Technologies, Scarsdale, NY) was used to measure cooked rice texture attributes including hardness and stickiness. Rice fractions thicknesses ranged from 1.77 to 1.86mm and from 1.61 to 1.65mm for large and small fractions respectively. Large thickness fractions resulted in harder cooked rice than small rice fractions. This was a result of higher starch content in the large thickness fraction compared to small fractions. Hardness of small rice thickness fractions harvested at high HMC had values of 87.6 and 76.6 N from the two locations. These values were significantly higher (P<0.05) than small fractions harvested at low HMC. Results indicated that smaller rice fractions were less sticky than larger rice fraction. This variation was explained due to the higher protein content of small rice fractions. Results indicate that large, medium and small thickness fractions differ in texture, especially hardness. Both hardness and stickiness decreased with HMC. Different percentage of large, medium and small rice fraction in a rice bulk could be in part responsible for variations observed in the texture properties of unfractioned-cooked rice.
Session 36D, Food Engineering: Rheology
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |