研究了冷藏条件下不同压力处理大米制得米饭品质的变化。大米在温度40 ℃、米水比（m/m）1:2的条件下浸泡40 min，并在15 ℃下分别经200、400、600 MPa处理10 min，浸泡后未经超高压处理的大米为对照试验组，随后蒸煮15 min制成米饭，保鲜膜密封后置于4 ℃下贮藏7 d，每天对米饭品质相关指标进行测定，并与感官鉴评结果比较。结果表明：超高压米饭的硬度上升较缓慢；黏着性、碘蓝值、pH下降均较快；透光率、白度(W)的上升均较快。400、600 MPa米饭水分含量的变化幅度较大。贮藏期间，200 MPa米饭的W和碘蓝值均最高，pH值最低，感官评分较低。400 MPa米饭的硬度、pH值和W均较低，感官评分接近对照。600 MPa米饭的硬度较高，W较低，碘蓝值的下降和透光率的上升均最快，感官评分最低且下降速率最快。总体来说，大米200、400、600 MPa处理对米饭冷藏品质的影响都是弊大于利。

The quality change, during cold storage, in cooked rice subjected to different pressures prior to cooking was investigated. Rice that had been soaked, with a rice-to-water ratio (m/m) of 1:2, at 40 ℃ for 40 min was treated at 200, 400, or 600 MPa for 10 min at 15 ℃. The soaked rice that had not been subjected to ultrahigh-pressure treatment was used as the control. Subsequently, rice was steamed for 15 min, packaged with plastic wrap, and stored at 4 ℃ for 7 d. Indicators related to rice quality were measured daily and compared with the results of the sensory evaluation. The results showed that compared to the control, the hardness of high-pressure treated rice increased slowly; its adhesiveness, iodine blue value, and pH decreased rapidly; and its light transmittance and whiteness increased quickly. The change range of water content in 400 or 600 MPa treated rice was bigger than others. During the storage period, for rice treated at 200 MPa, the whiteness and iodine blue value were the highest, the pH was the lowest, and the sensory score was lower than that of the control. For rice treated at 400 MPa, the hardness, pH, and whiteness were lower and the sensory score was close to that of the control. Rice treated at 600 MPa had a higher hardness and lower whiteness than the control; additionally, its iodine blue value and light transmittance decreased and increased, respectively at the fastest rate, and its sensory score was the lowest and decreased at the fastest rate. Thus, the effect of ultrahigh-pressure treatment at 200, 400, and 600 MPa on the quality of cooked rice was detrimental rather than beneficial.

辽宁省科技厅重点项目（2008205001）；渤海大学人才引进基金项目（BHU20120301）