浸漬對稉米吸水特性及米飯品質影響之探討

Effects of Soaking on the Water Absorption and Quality of Cooked Japonica Rice

汪昆億(Kun-Yi Wang) ； 江伯源(Po-Yuan Chiang)

《臺灣農業化學與食品科學》 49卷5期 (2011/10) Pp. 221-232

https://doi.org/10.6578/TJACFS.2011.025

摘要

臺稉九號是國人常食用之米食（米飯）加工之品種，其浸漬吸水特性對米飯品質之影響是重要研究主題。本試驗以不同浸漬溫度（30、40、50、60℃）探討米粒吸水特性及其吸水動力學，另評估浸漬對米飯品質影響之探討。試驗結果如下（一）隨浸漬溫度提高及時間延長，米粒之吸水率、吸水速率常數及固形物溶出率均隨之增加，米粒硬度則呈下降變化，其吸水活化能13.73kJ/mole；另利用平衡吸水率（35%）時浸漬溫度與時間兩者所呈之函數關係：t=218.33T^(-0.836)（t＝浸漬時間；T＝浸漬溫度）（r^2=0.99），可推算不同浸漬溫度所需之可能浸漬時間；（二）浸漬可增加米粒水分吸收及滲透均勻，可提高米飯之L值、W.I.值、糊化度及降低硬度，以30℃浸漬半小時可得到較佳之感官品評整體接受性，減少烹煮不完全（未熟）情形發生。

關鍵字

稉米 ； 浸漬 ； 吸水率 ； 活化能 ； 米飯 ； 感官品評

並列摘要

TK9 is a rice variety widely preferred by Taiwanese in the form of cooked rice. Its water absorption property and the corresponding impact on the cooked rice quality have always been important research topics in the field of food processing. This study examined the effects of different soaking temperatures (30, 40, 50 and 60℃) on the water absorption properties and kinetics of TK9. The effects of soaking temperature on the cooked rice were also discussed. The research results showed that the amount of water absorbed, the absorption rate constant, and the solid loss percent increased as soaking time and temperature increased. However, grain hardness of the soaked rice decreased with increasing soaking time and temperature. Moreover, the water absorption activation energy was determined to be 13.73 kJ/mole. In addition, we found that the relationship between water absorption of TK9 and soaking temperatures and time was t = 218.33T^(-0.836) (t = soaking time; T = soaking temperature) (r^2 = 0.99). This mathematical relationship can be used to predict the required soaking time at different soaking temperatures. We also observed that pre-soaking could allow better moisture permeability in rice, and improve the gelatinization degree, hardness, L value, and WI value of the cooked rice. The best overall sensory evaluation, with the least amount of incompletely cooked rice, was achieved when the rice was pre-soaked under 30℃ for half hour before cooking.

並列關鍵字

Japonica rice ； soaking ； water absorption ； activation energy ； cooked rice ； sensory evaluation