核桃油的超临界CO_2萃取研究

目的]探讨采用超临界CO2萃取技术萃取核桃油的最佳工艺条件。方法]以新疆产的核桃为原料,去皮后经过液氮冻干处理或烘干处理,然后采用超临界CO2萃取技术萃取核桃油,研究不同萃取时间对核桃油产率的影响,确定最佳工艺条件,并采用气相色谱仪对核桃油的脂肪酸组成进行测定与分析。结果]经试验确定的适宜工艺条件为:原料去皮液氮冻干,萃取温度40℃,萃取压力31MPa,萃取时间4.5 h,分离温度50℃。在此条件下获得的核桃油产率为59.26%。经过液氮处理的原料得到的油颜色比未经液氮处理的浅,且核桃油产率也较高。由气相色谱分析得知,核桃油产品中亚油酸含量为59.83%,油酸含量为21.65%,亚麻酸含量为10.95%。结论]采用超临界CO2萃取技术所得的核桃油体澄清透亮,呈浅黄色。

Research on Extraction of Walnut Oil with Ultra-critical CO2

Objective] The study aimed to discuss the optimum technology conditions for extracting the walnut oil with the ultra-critical CO2.Method] With the walnuts produced from Xinjiang as the raw material,they were treated by the liquid nitrogen freeze-drying processing or by the drying processes after peeling,and the walnut oil were extracted with the ultra-critical CO2 technology.The effects of different extracting time on the yield of the walnut oil were studied to confirm the optimum technology conditions and the fatty acid composition in the walnut oil were determined and analyzed by using the gas chromatography.Result] The proper technology conditions confirmed through the test were as follows: the peeled walnuts were freeze-dried by the liquid nitrogen,the extracting temperature was 40 ℃,the pressure was 31MPa,the extracting time was 4.5 h and the separation temperature was 50 ℃.Under these conditions the yield of walnut oil was 59.26%.The walnut treated by the liquid nitrogen get more light oil color and higher yield than the one without the liquid nitrogen treatment.The gas chromatography analysis showed that the walnut oil contained 59.83% linoleic acid,21.65% oleic acid and 10.95% linolenic acid.Conclusion] The walnut oil obtained by the ultra-critical CO2 extraction technology was clear and bright,showing a light yellow color.