小黄鱼内脏油的提取及其棕榈酸甘油酯低温结晶富集工艺的研究

以小黄鱼内脏为原料,采用稀碱水解法、酶解法和微波辅助法提取鱼油。以提取率为指标,采用气相色谱(GC)检测不同工艺提取的小黄鱼内脏油中脂肪酸组成,比较脂肪酸含量与分布的差异。并以棕榈酸为指标,研究晶体传质模型以及低温富集内脏油中棕榈酸的条件。结果表明:稀碱水解法小黄鱼内脏油的提取率最高,达到84.26%±5.15%;所提鱼油中二十二碳六烯酸(DHA,10.47%±0.28%)、花生四烯酸(ARA,1.16%±0.02%)含量和sn-2位棕榈酸含量(39.94%±1.11%)、相对棕榈酸含量(50.55%±1.06%)均高于酶解法和微波辅助法,适合作为高棕榈酸甘油酯的富集原料。低温结晶富集小黄鱼内脏油的棕榈酸,传质模型预测不同温度下晶体质量方程的决定系数R2>0.97,棕榈酸质量方程的R2>0.94;并确定低温结晶富集棕榈酸的最佳条件为:油/正己烷比例1:6、低温-40℃、结晶时间2.6 h,此时晶体中棕榈酸含量富集至42.62%±2.67%,比内脏油的棕榈酸含量提高了61.01%;sn-2位棕榈酸含量为68.19%±1.47%;棕榈酸得率为80.50%±4.39%。该模型准确模拟了内脏油棕榈酸富集的最佳条件,富集的棕榈酸甘油酯具有应用到婴儿奶粉以提高sn-2棕榈酸的前景。

Extraction of Visceral Oil from Yellow Croaker and Mass Transfer Modeling of Its Palmitic Acid Enrichment by Low Temperature Crystallization

With the lyophilized viscera as material and extraction rate as index,the extraction rate of yellow croaker fish oil by dilute alkali hydrolysis method,enzymatic hydrolysis method and microwave-assisted extraction was studied. The fatty acids composition of fish oil was detected by gas chromatography to analyze the differences in fish oil extracted by three methods,and the differences in the content and distribution of fish oil fatty acid were analyzed. The results showed that the dilute alkali hydrolysis method had the highest extraction rate of viscera oil(accounted for 84.26%±5.15%),and the highest level of DHA,ARA,sn-2 palmitic acid(accounted for 39.94%±1.11%)and relative palmitic acid(accounted for 50.55%±1.06%),which was most suitable as raw material for enrichment in palmitic acid. Then,the best conditions for palmitic acid enrichment were determined with palmitic acid as index by crystal mass transfer model of low temperature crystallization. The correlation coefficients of the predicted crystal mass equation and the palmitic acid mass equation were R2>0.97 and R2>0.94,respectively. The optimal conditions for low temperature crystallization were:Oil-to-hexane ratio 1:6,low temperature -40℃,and crystallization time 2.6 h,in which the yield of palmitic acid was 80.50%±4.39%,the content of palmitic acid was 42.62%±2.67%,and the content of sn-2 palmitic acid was 68.19%±1.47%. The model accurately simulated palmitic acid enrichment of visceral oil and the enriched glyceryl palmitate has the potential to be applied to infant milk powder to increase the sn-2 palmitic acid.