Abstract
This study was carried out to investigate the effect of germination condition and drying temperature on growth and physicochemical properties of brown rice. Three brown rice seeds of Ilpumbyeo, Dasanbyeo and Heugjinjubyeo were stored at room temperature for six weeks to test the time-sequence germination viability. Relatively stable germination ratio was maintained until 2 weeks after storage. However, 3 weeks after storage, germination ratio of brown rice seeds started to decrease rapidly and their germination ratio was lower than 80%. For this reason, brown rice was recommended for seeding within 2 weeks after hulling. During the initial 5 days, germination ratio of 24 hours pre-soaking brown rice was higher about 2-3% than that of non-soaking brown rice. The $25^{\circ}C$ was considered as the most favorable temperature for brown rice germination, because of the high germination ratio and desirable coleoptile growth of the brown rice, and little seed rotting symptoms. The scanning electron micrographs showed the structural differences between hot-air dried and freeze dried germinated-brown rice kernel. In the freeze dried germinated-brown rice, seed coat (pericarp, tegmen and aleurone layer) was mechanically disrupted from the endosperm, and many cleavages were observed among starch storing cells and starch granules. The endosperm of freeze-dried brown rice kernels formed the sponge-like structures and showed the fragile traits. For this reason, hot-air drying is considered as more suitable method than freeze drying for germinated-brown rice. The crude protein and amylose contents were slightly changed, but there were no significant differences during the germination period. Crude fiber content was decreased, but crude Int and total amino acid contents were increased as seeding days increased. A rapid increase in $\alpha$-amylase activities of germinating brown rice was observed at S days after seeding, and $\alpha$-amylase activities were decreased from 8 days after seeding. Total free sugar contents were decreased during the germination period. There was continuous decline in the contents of sucrose and glucose until 8 days after seeding, but fructose and maltose content were gradually increased from the 5 days after seeding.
1. 현미를 상온저장시 2주까지는 발아율에 차이가 없으나, 저장 3주후부터는 발아율이 급격히 감소되어 발아율이 80%에 미치지 못하기 때문에 발아현미의 재배를 위해서는 도정후 2주 이내의 현미를 사용하는 것이 바람직한 것으로 판단되었다. 2. 24시간 침종처리가 무침종에 비하여 현미의 초기발아율이 약 2-3%증가되었고, $25^{\circ}C$는 현미의 발아율과 생육상태가 좋았을 뿐만 아니라 부패발생도 적었다. 3. 동결건조된 발아현미는 열풍건조된 발아현미와는 달리 호분층 및 내배유부분의 분리현상이 발생되었고, 배유의 전분 저장세포뿐만 아니라 전분립간의 균열현상이 관찰되었다. 4. 열풍건조는 동결건조 보다 유리하였고, 55$^{\circ}C$로 48시간 건조시 발아현미의 불쾌취가 제거되었다. 5. 조단백 및 amylose는 발아일수가 경과함에 따라 함량의 변화가 미미하였으나 조회분, 조섬유 및 유리당은 발아일수가 경과함에 따라 감소되었고, 조지방과 총아미노산의 함량은 증가하였다. 6. $\alpha$-amylase활력은 발아 5일부터 급격히 증가하다가 발아 8일부터 감소되는 경향이었다. 7. 유리당의 함량은 발아기간(0-8일)중 지속적으로 감소되는 경향이었으며 sucrose와 glucose의 감소가 현저하였고 발아 5일 이후 fructose와 maltose는 증가되었다.
