色差加水法测定玉米脂肪酸值研究

Study on Determining Fatty Acid Value in Maize by Chromatism-water Method

在常温下用无水乙醇提取玉米中游离脂肪酸,用氢氧化钾标准滴定液滴定,进行脂肪酸值的测定.结果表明,3个不同脂肪酸值的玉米样品13次平行测试的极差最大为1.53 mgKOH/100g,小于重复性临界值2 mgKOH/100g,标准偏差在0.39～0.60.利用该方法对35个样品进行检测,其结果与国标方法平均值之差大于重复性临界值2 mgKOH/100g,建议对国标进行修订.

The method to determine fatty acid value in maize by judging the titration end point is set up.It can be used m deter- mining dissociated fatty acid extracted from maize in normal temperature with the help of anhydrous ethanol and KOH so- lution.The result shows the limit error of three kinds of maize samples which are different in fatty acid content is as follows （during 13 times tests） ： maximum error： 1.53 mgKOH/100g〈iterative threshold value ： 2 mgKOH/100g.standard deviation： 0.39-0.60（〈1.0）.The result of all the 35 samples are transcend 2 mgKOH/100g compared with the detection result based on the national standard method.So the national standard should be revised as soon as possible.