电位滴定法测定坚果食品中的酸价和过氧化值

目的建立坚果食品中酸价和过氧化值的电位滴定检测方法。方法本试验采用石油醚对坚果食品试样进行浸提,过滤后用旋转蒸发仪对试剂回收利用,并将浸提出的油脂用电位滴定法测定酸价和过氧化值,计算出坚果食品中酸价和过氧化值结果。结果选择瓜子、花生、杏仁、核桃4类坚果,不同实验室重复测定16次,酸价的电位滴定结果 :0.29~4.09 mg/g,相对标准偏差:0.64%~3.63%;过氧化值的电位滴定结果 :0.011~0.071 g/100 g,相对标准偏差:1.28%~8.77%。电位滴定结果与手动滴定结果相比较,无显著性差异(P0.05)。结论坚果食品中酸价和过氧化值的电位滴定检测方法操作简单,结果准确度能满足国标要求,且灵敏度高,精密度好。

Determination for acid and peroxide value in nuts by potentiometric titration method

Objective To establish a testing method for determination of acid and peroxide value in nuts by potentiometric titration. Methods The nuts samples were extracted by the petroleum ether, the reagent af-ter filtration was recycled with the rotary evaporator, the acid and peroxide value of the extraction of oil were tested by potentiometric titration, and then the results of acid and peroxide value in nuts were calculated. Results The melon-seeds, peanuts, almonds and walnuts as samples were used to detect in different labs, the results of acid value were 0.29~4.09 mg/g, the RSD was 0.64~3.63%, the results of peroxide value were 0.011~0.071 g/100 g, and the RSD was 1.28~8.77%. There is no significant difference between potentiometric titration and manual titration (P>0.05). Conclusion The method is simple, accurate, sensitive, and of high precision. It can be used to detect acid and peroxide value in nuts.