Abstract

Rice is a major crop and the main staple for more than half of the world’s population. With the continuous improvement of the living standard, people pay more attention to the taste, flavor, and nutrition of rice. In this study, a one-step method was used to derivatize the free fatty acids and glyceride fatty acids in rice oil with determination by gas chromatography–mass spectrometry (GC–MS). Rice varieties cultivated in Guangdong and Hunan, including Xiangwanxian 17, Huanghuazhan, Xiangwanxian 13, and Nongxiang 32, were analyzed by this method. The results showed that the main components in rice oil include palmitic acid (29.80–21.41%), oleic acid (33.81–38.29%), and linoleic acid (25.17–31.40%). The content of unsaturated fatty acids (69.41–72.55%) was higher than for saturated fatty acids (27.45–30.59%). Supervised orthogonal partial least squares discriminant analysis (OPLS-DA) was used to identify the differences in the fatty acids in rice oil from different locations and varieties. There are small differences among rice varieties cultivated in the same locations and larger differences between the same varieties from different locations. According to the results from Student’s t-test and variable importance in projection (VIP) value of the OPLS-DA model, the contents of myristic acid, stearic acid, palmitoleic acid, and arachidic acid were significantly affected by the location (p < 0.05 and VIP > 1). These results provide useful information for the further development and utilization of rice resources.

摘要

水稻是一种主要作物，也是世界一半以上人口的主要主食。随着生活水平的不断提高，人们更加注重大米的口感、风味和营养。在本研究中，采用气相色谱-质谱 (GC-MS) 测定的一步法衍生大米油中的游离脂肪酸和甘油酯脂肪酸。采用该方法对广东和湖南栽培的水稻品种向晚县17号、黄花占、向晚县13号、农湘32号等水稻品种进行了分析。结果表明，大米油中的主要成分包括棕榈酸（29.80-21.41%）、油酸（33.81-38.29%）和亚油酸（25.17-31.40%）。不饱和脂肪酸的含量（69.41-72.55%）高于饱和脂肪酸（27.45-30.59%）。监督正交偏最小二乘判别分析（OPLS-DA）用于识别不同地区和品种的米油中脂肪酸的差异。同一地区栽培的水稻品种间差异较小，而不同地区同一品种间差异较大。根据学生的结果t检验和OPLS-DA模型的变量重要性投影（VIP）值，肉豆蔻酸、硬脂酸、棕榈油酸和花生酸的含量受位置影响显着（p  < 0.05和VIP > 1）。这些结果为进一步开发利用水稻资源提供了有益的信息。