Abstract

This study was carried out at the Chuncheon Substation, National Institute of Crop Science to determine the effect of cold water irrigation on the milling and polished quality of rice, as well as its physicochemical and amylogram characteristics, and palatability Chilling by Irrigation of cold water $(17^{\circ}C)$ induced delay of days to heading, reduction of culm length, inferiority of panicle exsertion and high sterility of panicle. Head rice ratio was decreased, while the percentage of chalky and creak rice increased with increasing sterility over from 20%. Protein content was gained 0.9-2.0% more than, while whiteness and palatability of the milled grain were reduced under cold water irrigation treatment. Significant decrease in maximum viscosity and breakdown viscosity of rice flour was investigated under cold water treatment by amylogram analysis, while the initial gelatinization temperature and setback viscosity were increased. Sensory panel test showed that the palatability of cooked rice was unfavorable and its stickiness was lower compared with that under normal condition. Differences in the aroma of cold-treated and untreated cooked rice were not performed significantly.

고품질 쌀 생산을 위한 기초자료를 얻기 위하여 작물과학원 춘천출장소 냉수처리 포장에서 냉해피해 정도가 다른 시료를 채취하여 벼의 도정특성, 쌀의 이화학적특성, 쌀가루의 아밀로그램특성 및 밥의 식미관능검정을 실시한 결과는 다음과 같다. 1. 냉수관개에 의한 냉해 발생은 불임율이 높을수록 출수 지연일수가 길고, 간장의 단축정도는 심했으며, 이삭의 추출은 불량하였다. 2. 쌀의 외관품질은 불임을 20% 이상부터 완전미율이 낮아지고, 유백미율과 깨어진 쌀이 증가하는 경향이었다. 3. 쌀의 이화학적특성은 냉수관개로 냉해를 유발하고 생산된 쌀이 자연구에 비해 단백질 함량이 $0.9{\sim}2.0%$ 높았으며, 백미의 투명도가 떨어지며, 밥의 윤기치도 낮았다. 4. 쌀가루의 아밀로그램특성은 저온피해를 받은 쌀은 호화개시온도가 높고, 최고점도와 강하점도는 낮았으며, 치반점도는 높았다. 5. 식미관능검정에서는 냉해로 인해 불임율이 높을수록 식미관능이 자연구에 비해 많이 떨어졌다. 평가항목 중에서 밥맛의 차이가 큰 것은 밥의 찰기와 식미총평 이었으며, 차이가 적었던 것은 밥의 냄새였다.

Keywords

• rice;
• chilling injury;
• grain quality;
• amylogram;
• palatability