Measurement of Hardness and Adhesiveness of Cooked-Rice

밥블록을 이용한 찰밥의 경도 및 부착성 측정법

Hardness and adhessiveness of cooked rice were measured with rice grain and rice block methods by texturemeter. In grain method 3, 4 and 5 grains were arranged and subjected to the texture test with a plastic plunger at 95% strain and 0.5mm/sec speed. The hardness were 7.4kg, 7.5kg and 10.0kg respectively and the coefficient of variation ranged from 37.0% to 25.9%, which was mainly due to the irregular geometry of the grains in each specimen set Adhesiveness could not be measured with this method. A cylindrical rice block($H/D=20mm{\times}15mm$) was made for the texture analysis. The hardness was 2.1 kg with coefficient of variation ranging from 2.8 to 7.0%, and the block method was s more reproducible compared to the grain method. A grooved plastic plunger and platform were designed for the measurement of adhesiveness of cooked rice block. The adhesiveness was 0.68kg sec and the coefficient of the variation was 4.6%.

전기밥솥으로 지은 일반계(Japonica) 쌀밥의 경도와 부착성을 texturemeter를 사용하여 낱알과 밥블록상태에서 측정하였다. 밥알 3, 4, 5개씩을 균등하게 배열하고 95%의 압축비에서 plastic plunger 로 측정한 경우 각각 경도는 7.4, 7.5, 10.0kg이었으며 변이계수가 25.9%에 이르렀다. 원통형 밥블록(15mm diameter, 20mm height)으로 성형한 것을 80% 압축비로 측정한 결과, 경도는 2.1kg이었고 변이계수는 $2.8{\sim}7.0%$의 수준으로 현격히 감소되었다. 밥블록측정법이 정확도와 재현성에서 낱알측정법보다 월등히 좋았으며 밥블록의 성형방법과 측정 방법을 개발하였다. 밥의 부착성은 낱알측정법으로는 불가능하였고, 밥블록을 톱니형의 plunger와 platform을 사용할 경우 가능하였으며 그 값은 0.68kg sec이었고 변이계수는 4.6%이었다.