芝麻脱皮对芝麻香油自然沉降过程的影响Effect of peeling on the natural sedimentation process of fragrant sesame oil

在芝麻香油精制过程中，自然沉降规律受诸多因素影响，为探索提升芝麻香油精制效率的技术手段，以脱皮和未脱皮芝麻所得芝麻香油为研究对象，通过测定芝麻原油与沉淀物组成，并结合沉降过程中沉淀物含量、磷脂含量、酸值、过氧化值、沉淀物压缩速度的变化规律，考察芝麻脱皮对芝麻香油自然沉降过程的影响。结果表明：相比未脱皮芝麻香油，脱皮芝麻香油在线性沉降阶段的沉降效率高约5百分点；芝麻香油沉淀物的90%以上是粗脂肪，还有少量水分、磷脂、蛋白质、糖形成的胶杂，水和磷脂发生明显聚集；沉淀物的酸值远高于芝麻香油，但过氧化值变化不明显；芝麻香油磷脂含量与沉淀物含量变化呈现相似的趋势，上、下层油中磷脂含量和酸值在线性沉降阶段后差异较小；脱皮芝麻香油沉淀物初始高度远低于未脱皮芝麻香油，且在线性沉降阶段压缩速度快于未脱皮芝麻香油，最终成品油得率高于未脱皮芝麻香油约3百分点。综上，脱皮有利于芝麻香油的自然沉降以及获得更高的得率。In the refining process of fragrant sesame oil, its natural sedimentation pattern is affected by many factors. In order to explore the technique to improve the refining efficiency of fragrant sesame oil, fragrant sesame oil obtained from peeled and unpeeled sesame was used as the research object, the compositions of crude sesame oil and precipitates were measured, and the changes in precipitates content, phospholipids content, acid value, peroxide value, and compression rate of precipitates during the sedimentation process were analyzed to investigate the effect of sesame peeling on the natural sedimentation process of fragrant sesame oil. The results showed that compared with unpeeled sesame oil, the peeled fragrant sesame oil showed a high sedimentation efficiency of about 5 percentages higher in the linear sedimentation stage. More than 90% of precipitates was crude fat, with small amounts of water, phospholipids, proteins, and sugars forming colloidal impurity, with significant aggregation of water and phospholipids. The acid value of the precipitates was much higher than that of the fragrant sesame oil, but the change of peroxide value was not significant. The changes of phospholipids content showed similar trends with precipitates content, and the differences of phospholipids content and acid value in the upper and lower oil were smaller after the linear sedimentation stage. The initial height of the precipitates of peeled fragrant sesame oil was much lower than that of unpeeled fragrant sesame oil, and the compression rate was faster than that of unpeeled fragrant sesame oil during the linear sedimentation stage as well as the final yield was about 3 percentages higher than that of unpeeled fragrant sesame oil. In conclusion, peeling is beneficial for the natural sedimentation of fragrant sesame oil and achieving higher yield.