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| 酸水解法测定淀粉含量的优化与一致性研究 |
| Optimization and consistency study of starch content determination by acid hydrolysis method |
| 投稿时间：2025-03-04 修订日期：2025-04-03 |
| DOI： |
| 中文关键词: 酸水解-斐林试剂滴定法 酸水解-DNS比色法 淀粉测定 方法优化 一致性 |
| 英文关键词:acid hydrolysis-Fehling reagent titration method acid hydrolysis-DNS colorimetric method starch determination method optimization consistency |
| 基金项目:农产品质量安全监管专项(204001/LH007505) |
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| 中文摘要: |
| 目的 优化酸水解-斐林试剂滴定法和酸水解-3,5-二硝基水杨酸（3,5-dinitrosalicylic acid, DNS）比色法，对比粮食作物样品中淀粉含量不同测定方法的一致性。方法 通过对乙醇洗涤量、加酸量、酸解时间、样液pH、检测波长、显色剂加入量、显色时间、显色温度等实验条件的优化，确定测定该类产品淀粉含量的最佳条件。结果 酸水解-斐林试剂滴定法最优条件为称取样品后用适量石油醚、乙醇洗去脂肪及可溶性糖，加入25 mL盐酸，冷凝回流120 min，用氢氧化钠校正试样水解液至中性，过滤后取滤液以1滴/2 s的速度滴定碱性酒石酸铜甲乙液。酸水解-DNS比色法最优条件为脱脂除糖酸解后，校正试样pH为8~9，有颜色且蛋白质含量高的样品加入10 mL乙酸铅以吸附颜色并沉淀蛋白以减少或消除色素干扰质 ，，过滤后取滤液加入2 mL DNS，90~100 ℃水浴12 min进行显色，分光光度计540 nm波长下进行比色，4 h内完成测定。两种方法相对标准偏差（relative standard deviation, RSD）均小于2%，相对误差（relative error, RE）均小于4%，测定结果通过平均值一致性检验与配对样本t检验，具有一致性。结论 优化的两种方法相较国标法更加高效、准确，方法正确度、精密度良好，可适用于粮食作物中淀粉含量的检测。 |
| 英文摘要: |
| Objective The acid hydrolysis-Fehling reagent titration method and the acid hydrolysis-3,5-dinitrosalicylic acid (DNS) colorimetric method were optimized to compareexplore approaches for improving the consistency of different methods for measuring starch content determination in grain crop samples. Methods Experimental conditions, including ethanol washing volume, acid addition volume, acid hydrolysis time, sample solution pH, detection wavelength, chromogenic agent volume, color development time, and color development temperature, were optimized to determine the optimal processing conditions for determining the starch content determination in such products. Results The optimal conditions for the acid hydrolysis-Fehling reagent titration method, the optimized conditions were as follows: after weighing the sample, fats and soluble sugars were removed using an appropriate amount of petroleum ether and ethanol; 25 mL of hydrochloric acid was added, followed by condensation reflux for 120 minutes; the hydrolyzed sample solution was neutralized with sodium hydroxide, filtered, and the filtrate was titrated with alkaline copperpotassium sodium tartrate methyl and ethyl solution at a rate of one drop every 2 seconds. The optimal conditions Ffor the acid hydrolysis-DNS colorimetric method, the optimized conditions were as follows: after removing fat,defatting, sugar removal, and acid hydrolysis, the sample solution pH was adjusted to 8-9; for samples with color and high protein content, 10 mL of lead acetate was added to reduce or eliminate pigment interferenceadsorb color and precipitate proteins; after filtration, 2 mL of DNS was added to the filtrate, followed by color development in a water bath at 90-100 °C for 12 minutes; the absorbance was measured at 540 nm using a spectrophotometer, and the determination was completed within 4 hours. Both methods have a relative standard deviation of less than 2% and a relative error of less than 4%. The measurement results have passed mean consistency test and paired samples t-test. Conclusion The two optimized methods demonstrated consistent results for the same samples and were more efficient and accurate compared to the national standard method, with good accuracy and precision making them suitable for starch content determination in grain crops. |
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