果蔬中单宁测定技术研究

为研究、建立快速、简便测定蔬菜、水果中单宁含量的方法，选用当前测定单宁应用最为广泛的可见分光光度法为基础进行可行性研究。采用配对t检验，用同一样品对不同单宁提取溶剂、温度和时间及测定的显色时间分别进行比较测定，从而选出最佳单宁提取和测定条件，并对建立的方法进行线性、精密度、准确度等的验证试验。确定了最佳的提取和检测条件为500W超声波提取，超声时间20min，提取溶剂水，温度60℃，显色时间1h。单宁测定线性范围为0~30mg/L，方法检出限0.2mg/g，加标回收率为95.8%~101.9%，相对标准偏差(RSD)1.07%~4.29%。该法具有操作简便、快速、精密度高、重现性好、加标回收率较高、分析成本低等特点。适合于果蔬中单宁酸的快速检测。

Research on Determination of Tannin Content in Vegetable and Fruit

For researching and establishing a fast and convenient method to measure tannins in fruits and vegetables, the author chose the most widely applied method, Folin-Denis spectrophotometric method, as the basis to analyze the feasibility. The author adopted paired t-test, compared the results of experiments that used different tannins extraction solvents, temperature, duration time and coloring time upon the same sample, then did the verifying experiment against the method’ s linearity and accuracy. The experiment confirms that the best extraction and measuring conditions are: 500 W ultrasonic extraction, 20 minutes ultrasonic time, extraction solvent: H2O2, temperature 60℃ and coloring time 1 hour. The linear range of tannins measurement is 0- 30 mg/L; the detection limit is 0.2 mg/g; recovery rate is 95.8%- 101.9% ; RSD (relative standard deviation) is 1.07%- 4.29% . This method has the advantages of simplicity, quickness, high precision, good reproducibility, high recovery rate and low cost. It would be suitable for fast and accurate measurement of tannins in fruits and vegetables.