GC-MS分析毛霉型、细菌型、曲霉型豆豉中脂肪酸组成

GC-MS analysis of fatty acid composition in mucor-type,bacterial-type and aspergillus-type douchi

采用正己烷提取大豆、毛霉型豆豉、细菌型豆豉和曲霉型豆豉中粗脂肪,通过氢氧化钾-甲醇和硫酸-甲醇对油脂进行甲酯化处理,采用GC-MS分析脂肪酸组成,用外标法对脂肪酸进行定量。结果表明:大豆、毛霉型豆豉、细菌型豆豉和曲霉型豆豉中均含有12种脂肪酸,其中饱和脂肪酸7种,单不饱和脂肪酸3种,多不饱和脂肪酸2种,以亚油酸含量最高,不饱和脂肪酸含量高于饱和脂肪酸含量。不饱和脂肪酸含量(以干基计)从高到低依次是毛霉型豆豉(23.52 g/100 g)、大豆(16.51 g/100 g)、细菌型豆豉(15.35 g/100 g)、曲霉型豆豉(7.00 g/100 g)。大豆经毛霉发酵成豆豉后,其主要脂肪酸含量得到提高,而经细菌和曲霉发酵成豆豉后,主要脂肪酸含量有所降低。

The crude fats in soybean, mucor-type, bacterial-type and aspergillus-type douchi were extracted by hexane and esterified with KOH-CH3OH and H2SO4-CH3OH. The fatty acid composition was analyzed by gas chromatography-mass spectrometry （GC-MS） and quantified by an external standard method. The results showed that twelve kinds of fatty acids were detected in soybean, mucor-type, bacterial-type and aspergillus-type douchi, including seven kinds of saturated fatty acids, three kinds of monounsaturated fatty acids and two kinds of polyunsaturated fatty acids. Among these fatty acids, the content of linoleic acid was the highest and the content of unsaturated fatty acids was higher than that of saturated fatty acids. The contents of unsaturated fatty acids （dry basis） from high to low were mucor-type douchi（23.52 g/100 g）, soybean （16.51 g/100 g）, bacterial-type douchi （15.35 g/100 g） and aspergillus-type douch （7.00 g/100 g）. After soybean fermented into mucor-type douchi, the contents of main fatty acids increased. However, after soybean fermented into bacterial-type and aspergillus-type douchi, the contents of main fatty acids decreased.