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Digestibility and physicochemical properties of rice being parboiled combined with heat moisture treatment
A. YEH (1), K. Cheng (1) (1) National Taiwan Univerity, TAIPEI, Other, Taiwan.

Rice is a staple for Taiwanese as well as for Asian people.  However, the consumption of white rice keeps declining recently in Taiwan due to high glycemic index. Brown rice is considered as one kind of whole grain, but is not favored by the market due to rough texture.  Thus, there is a need for rice to develop a process for decreasing glycemic index, but maintaining good texture. Parboiling at 120oC combined with heat-moisture treatment was selected to explore the feasibility of reducing glycemic index by physical treatment.  Sensory and texture profile analysis were employed to examine the texture of products.  Scanning electron microscope was used to observe the morphology of rice after treatments.  <i>In vitro</i> digestibility was utilized to understand the change in slow digestible starch and resistant starch of products.  Some properties of the corresponding rice flours were measured by using differential scanning calorimeter, X-ray diffraction, and rheometers. The data showed that parboiling significantly increase the percentage of resistant starch from 1.95 (untreated rice) to 11% with slightly increase in slightly digestible starch.  The heat-moisture treatment along with parboiling resulted in an increase in slow digestible starch from 37.08 (untreated rice) to 45.83%.  The color of products is brown, but with a texture similar to white rice.  The combination of parboiling and heat-moisture treatment appeared to be a potential method for making rice favorable by the market.