3种油脂酸价测定方法的比较

Comparison of three methods for the determination of acid valence of oil

目的研究现行国标中3种油脂酸价测定方法对不同类别植物食用油的检测效果。方法选取花生油、大豆油、玉米油、葵花籽油、菜籽油、橄榄油共6种油样采用这3方法进行酸价测定,通过分析测试结果和存在问题,提出不同测定方法的较佳适用对象和选择依据。结果6种油脂都是冷溶剂自动电位滴定法的平行测定标准差最小,热乙醇指示剂滴定法次之,冷溶剂指示剂滴定法的方差都较大。结论冷溶剂自动电位滴定法通用性最好;冷溶剂自动电位滴定法稳定性最好,热乙醇指示剂滴定法次之,冷溶剂指示剂滴定法的稳定性相对较差。

Objective To investigate the detected results of 3 methods in the current national standard for measuring the oil acid values of different plant edible oils. Methods In this experiment, acid values of 6 kinds of oil samples, such as peanut oil, soybean oil, corn oil, sunflower seed oil, rapeseed oil, and olive oil, were determined by those 3 methods. By analyzing the test results and the existed problems, the preferred application object and selection basis of different measurement methods were proposed. Results Standard deviation of parallel determination of 6 kinds of oils and fats by automatic potentiometric titration with cold solvents was the smallest, thermal ethanol indicator titration followed, while cold solvent indicator titration had a larger variance. Conclusion The method of cold solvent automatic potentiometric titration has the best versatility. The stability of cold solvent automatic potentiometric titration is the best, followed by hot ethanol indicator titration, and the stability of cold solvent indicator titration is relatively poor.