深色食用油脂中过氧化值的测定

目的 比较手动滴定法和电位滴定法对过氧化值的检测结果, 提高过氧化值测定的准确性, 探索测定深色油脂中过氧化值的适宜方法。方法 用手动滴定法和电位滴定法分别测定深色油脂和浅色油脂的过氧化值, 对检测结果进行对比, 选择最优的检测方法, 并进行方法学验证。结果 当样品为浅色样品时, 2种方法测定过氧化值的差异小, 但当样品为深色样品时, 只能用电位滴定的方法来测定, 手动滴定无法判断终点。电位滴定法加标回收实验的回收率为97.55%~104.84%, 相对标准偏差为0.9%~2.2%, 满足实验要求。结论 相比手动滴定法, 电位滴定方法更适用于食用油脂中过氧化值的测定。

Determination of peroxide value in dark edible oils

Objective To compare the results of manual titration and potentiometric titration for determination of peroxide value, improve the accuracy of peroxide value measurement, and explore the suitable method for determination of peroxide value in dark oil. Methods The peroxidation values of dark oil and light oil were determined by manual titration and potentiometric titration, the results were compared, the optimal method was selected, and the methodology was verified. Results When the sample was light color, the difference of peroxide value between the two methods was small, but when the sample was dark color, it could only be determined by potentiometric titration, and manual titration could not determine the end point. The recovery rates of the potential titration method were 97.55%-104.84%, and the relative standard deviations were 0.9%-2.2%, which met the experimental requirements. Conclusion Compared with manual titration, potentiometric titration is more suitable for the determination of peroxide value in edible oils.