紫苏饼粕的残油醇提工艺及品质分析

为提取紫苏饼粕残油,减少有毒有机溶剂残留和污染,同时获得低脂、高蛋白紫苏饼粕,采用95%乙醇浸提法提取紫苏饼粕残油。在单因素试验的基础上,选出最优浸提温度、浸提次数、液固比、浸提时间。通过正交试验优化获得的工艺条件为:浸提温度75℃、浸提次数5次、液固比3.50:1、时间3 h。在该工艺下对紫苏饼粕残油的提取率可达96.04%,紫苏饼粕含油率降至0.51%,蛋白富集率提升至57.90%。对紫苏籽压榨油、紫苏饼粕乙醇浸提油及石油醚浸提油进行理化性质比较,结果表明三种油在酸值、过氧化值、碘值、皂化值方面均符合国家标准,其中石油醚浸提油的酸值和过氧化值较大分别为3.65 KOH/(mg/g)和5.96 mmol/kg,乙醇浸提油次之,低温压榨油较小为3.30 KOH/(mg/g)和5.22 mmol/kg。碘值无显著差异,而浸提油的皂化值要大于低温压榨油。通过气相色谱(GC)分析,乙醇浸提油的亚麻酸相对含量及不饱和脂肪酸占总脂肪酸比例分别为59.60%和89.31%,略低于低温压榨油的61.09%和90.33%,高于石油醚浸提油的57.29%和86.10%。综合来看乙醇浸提油品质高于石油醚浸提油,略低于低温压榨油。

Alcohol Extraction Process and Quality Analysis of Residual Oil from Perilla Cake Meal

We used 95%ethanol to extract residual oils in perilla cake meal to reduce residues and contamination by toxic organic solvents,as well as to obtain low-fat,high-protein perilla cake meal.Univariate analysis was performed to determine the optimal extraction temperature,number of extractions,liquid-solid ratio,and extraction duration.The processing conditions optimized through orthogonal experimental design were as follows:extraction temperature,75;℃5 extractions;liquid-solid ratio,3.5:1;and time,3 h.Using this process,the extraction rate of residual oil from perilla cake meal was 96.04%,oil content of perilla cake meal was reduced to 0.51%,and protein enrichment rate was increased to 57.90%.The physical and chemical properties of perilla seed pressed oil,perilla cake meal ethanol extract,and petroleum ether extract were compared.The three oils met national standards with respect to acidity,peroxide content,iodine content,and saponification.Among them,the acidity and peroxide content of petroleum ether extract oil were relatively high,with maxima of 3.65(KOH)/(mg/g)and 5.96(mmol/kg),respectively,followed by those for ethanol extract oil and low-temperature pressed oil(3.30(KOH)/(mg/g)and 5.22(mmol/kg),respectively).There was no significant difference in the iodine content,and the degree of saponification of the extract oil was greater than that of the low-temperature pressed oil.Gas chromatography analysis showed that the relative content of linolenic acid and proportion of unsaturated fatty acids in total fatty acids in ethanol extract oil were 59.60%and 89.31%,respectively,which are slightly lower than those observed for low-temperature pressed oil(61.09%and 90.33%,respectively)and higher than those observed for petroleum ether extract oil(57.29%and 86.10%,respectively).Overall,the quality of ethanol extract oil is higher than that of petroleum ether extract oil and slightly lower than that of low temperature pressed oil.