Abstract
The distribution of mesophilic and thermophilic bacteria in milled rice was not different according to growing land and variety of rice. However, The number of these bacteria were abundant in milled rice of lower milling degree or longer storage period. The growth of thermophilic bacteria in cooked rice of electric rice cooker was rapidly increased during storage of lower temperature below 75 $^{\circ}C$. Thermophilic bacteria were not appeared just after cooking. After cooked rice was stored far 18∼24 hon thermophilic bacterial growth was rapidly increased by changing spore to vegetative cell. The positive relation between cell number of thermophilic bacteria and occurrence of off-odor was slightly observed. The number of thermophilic bacteria in upper cooked rice of oven and was higher than those in inner and lower cooked rice. Major volatile compound of milled rice cooked and stored in electric rice cooker was hexanal oriented from rice. After long storage, it was confirmed that furan was major volatile compound as off-odor.
벼의 산지 및 품종별로는 중온 및 고온성 세균의 분포에 큰 차이가 없었으며, 도정도가 낮을수록 저장기간이 길수록 각각의 균들이 많이 존재하였다. 전기밥솥에서 고온성 세균의 증식은 75$^{\circ}C$이하에서 보온온도가 낮을수록 빠르게 나타났으며, 보온 초기에는 나타나지 않았으나 18∼24시간 사이에 증식속도가 빨라지는 경향을 나타내었다. 전기밥솥 밥의 고온성 세균수와 이상취 발생의 상관성은 있었으며, 고온성 세균수는 오븐내 밥의 표면중앙이 중심이나 밑바닥에 비하여 약간 많게 나타났다. 백미밥의 휘발성 성분은 보온초기에는 쌀로부터 유래되는 hexanal이 주성분이었으며, 장시간보온 후는 이상취를 나타내는 furan을 포함한 고비점 물질이 많았다.
