White rice with grains is a nutritious meal that richly contains fiber, vitamin and mineral, but it is difficult for elderly people to masticate some grains and beans due to its hardness. This study was aimed to find the optimal mixing ratio of rice with texture modified grains and beans by comparing rheological properties. Beans were soaked in tap water for 24 hr at 20°C, cooked under pressure (1hr at 121°C), frozen for 24 hr at -18°C, and thawed in water bath for three hr at 30°C. The samples were submerged in macerating enzyme solution, left under vacuum at 60 mmHg for 5 min to infuse the enzyme into the intercellular spaces of samples, and rapidly returned to the atmospheric pressure. The samples were removed from enzyme solution, sealed in plastic bag, placed at 70°C for 20 min for enzyme activation and inactivated at 95°C for 15 min. The grains and texture modified beans were added to white rice with different ratio, soaked for one hr in enzyme solution under warming condition at 70°C, and steamed with electric pressure cooker. Cooked meals were rapidly cooled at -18°C for one hr, placed at 20°C for another one hr, and then rheological properties were measured with texture analyzer. The hardness of texture modified rice with grains was reduced to 2.3 ~ 4.1 × 104 N/m2 and the hardness of rice with beans was reduced to 3.8 ~ 4.8 × 104 N/m2 depending on mixing ratio. The cohesiveness was reduced by 1/3 ~ 2/3 respectively, while adhesiveness was not changed significantly, compared to those of cooked rice. These results suggest that cooked rice mixed with 30 ~ 40% of grain and 6 ~ 10% of bean would be appropriate for elderly people to consume without chewing difficulty.

Grains are nutritious foods that richly contain fiber, vitamins and minerals but it would be difficult to chew for some elderly people with weakened chewing ability. This study was aimed to find the appropriate conditions for reducing hardness of grains by enzyme treatment. To select appropriate enzyme, each grain (white rice, brown rice, barely, sorghum, and job’s tears) was soaked for one hour in enzyme solution at optimum activation temperature. Grains were soaked for one hour in selected enzyme solution at different concentration (0.1, 0.3, 0.5 and 0.7%) under warming condition of cooker at 70℃, steamed in electric rice pressure cooker, rapidly cooled at -18℃ for one hour, placed at 20℃ for another hour, and then hardness was measured by texture analyzer. The initial hardness of white rice, brown rice, barely, sorghum, and job’s tears were 6.5 × 104, 7.1 × 104, 7.0 × 104, 7.8 × 104 and 7.7 × 104 N/m 2 , respectively. The lowest hardness of grains, 4.0 × 104, 5.0 × 104, 4.6 × 104, 5.7 × 104 and 4.7 × 104 N/m 2 were obtained with 0.3% of enzyme D solution while the hardness was not changed significantly with higher concentration. These results suggest that some hard grains treated with enzyme would become softer than white rice, and thus these grains may be used to prepare a healthier meal for elderly people having mastication problem.