Effect of Protein and Lipids on the Retrogradation of Rices

稻米中蛋白質及油脂對老化之影響

張曙明(Shuh-Ming Chang) ； 張采蓮(Tsai-Lean Chang)

《中央研究院化學研究所集刊》 41期 (1994/03) Pp. 113-123

https://doi.org/10.6522/BICAS.1994.41.14

摘要

本實驗係採用高雄秈7，台農67及台中糯70精白米作為材料。其米粉分別以各種溶劑連續除去其中各類蛋白質而得米澱粉，並以甲醇脫油成為脫脂樣品。將各種米粉樣品加熱糊化，同時亦製備以米粒或脫脂米粒或加入dithiothreitol煮成的米飯；分別貯存於5℃或-18℃二星期，以其X-射線繞射圖型及糊化度之變化作為指標，探討精白米中蛋白質及油脂在貯存過程中對老化作用之影響。由實驗結果發現在貯存過程中，於X-射線繞射圖型上有老化晶體之繞射峰出現，稻米中蛋白質及油脂之存在似有延緩老化的作用：貯存後的脫蛋白質米粉樣品及添加dithiothreitol的米飯樣品其糊化度亦較未處理的樣品為低。

並列摘要

Three milled rice varieties (Kaohsiung sen 7, Tainung 67 and Taichung waxy 70) were used as materials in the experiment. The rice flours were deproteinzed by washing with different sol vents successively and defatted with methanol separately. After gelatinization, they were separately stored at 5 °C or -18 °C for 2 weeks. The effects of proteins and lipids on the retrogradation during the aging process of these gels were studied by measuring X-ray diffraction patterns and degree of gelatinization. The retrogradation of the non-defatted and defatted cooked rice with or without dithiothreitol was also studied. From the X-ray diffraction patterns, it was found that some diffraction peaks of retrograded crystal appeared during the aging process. The protein and lipids in the rice may be attributed to retard the retrogradation. Degree of gelatinization of the aged deproteinized samples and the aged cooked rices with dithiothreitol were lower than those of the native samples.