摘要:
Cold pressing method,Soxhlet extraction method,organic solvent extraction method and ultrasonic-assis-ted extraction method were used to extract almond oil, respectively. The yield, physicochemical properties and fatty acid composition of almond oil were used to evaluate the four kinds of extraction methods comprehensively. The results showed that the highest yield of almond oil extracted by Soxhlet extraction was 49.00%. By comparing the physicochemical proper-ties,the differences of the smell,transparency,refractive index,specific gravity and iodine value of the almond oil extrac-ted by the four methods were not significant.The differences of acid value,saponification value and peroxide value were sig-nificant. The lowest acid value (0.93 mg/g) was obtained by cold pressing method, the minimum saponification value(169.32 mg/g) was obtained by ultrasonic-assisted extraction method,and the minimum peroxide value(0.09 mmol/kg) was obtained by ultrasonic-assisted extraction method. The contents of oleic acid in almond oil extracted by four methods were above 70%,and the contents of lino-leic acid were more than 21%. The almond oil extracted by Soxhlet extraction method and ultrasonic-assisted extraction method contained small amount of linolenic acid. In con-clusion,ultrasonic-assisted extraction method was the most suitable method for extracting almond oil. Thus,the orthogonal optimization of this method was carried out to obtain the best extraction conditions which were as follows:the ratio of materi-al to liquid 1 : 12, ultrasonic frequency 60 Hz, power 270 W, extraction time 25 min, the yield of almond oil was 45.85%,oil physicochemical indicators were in accordance with national standards.%分别采用冷榨法、索氏提取法、有机溶剂浸提法及超声波辅助提取法提取大扁杏仁油,通过测定大扁杏仁油的提取率、理化特性和脂肪酸组成对4种提取方法进行比较.结果表明:索氏提取法的杏仁油提取率最高,为49.00%.通过比较理化特性发现,4种方法提取的大扁杏仁油的气味、透明度、折光指数、比重值和碘价差异不明显,但酸价、皂化价和过氧化值存在差异,其中冷榨法的酸价最低(0.93 mg/g),超声波辅助提取法的皂化价最低(169.32 mg/g),超声波辅助提取法的过氧化值最低(0.09 mmol/kg).4种方法提取的杏仁油油酸含量都在70%以上,亚油酸含量都在21%以上,索氏提取法和超声波辅助提取法提取的杏仁油中还含有少量亚麻酸.综合比较,超声波辅助提取法是制备大扁杏仁油最合适的方法,因此,进一步对此方法进行了正交优化,最佳提取条件为料液比1 : 12,超声频率60 Hz,功率270 W,提取时间25 min,在此条件下,杏仁油提取率为45.85%,理化指标均符合国家标准.