啤酒中有机酸含量的RP-HPLC检测条件优化及其酿造过程中动态分析

Optimization of detection conditions of organic acids contents in beer by RP-HPLC and dynamic analysis in brewing process

该研究对反相高效液相色谱(RP-HPLC)法测定啤酒中有机酸含量的方法进行优化,最终确定了RP-HPLC法测定啤酒中草酸、乳酸、酒石酸、乙酸、苹果酸、α-酮戊二酸、抗坏血酸、柠檬酸、琥珀酸9种有机酸的检测条件,并结合发酵机理对啤酒酿造过程中的有机酸含量动态变化进行分析。结果表明,RP-HPLC优化条件为:检测波长215 nm、流动相缓冲液0.10 mol/L KH_(2)PO_(4)、pH值3.0、流速0.6 mL/min。有机酸在质量浓度0.2~400.0 mg/L范围内线性关系良好(R^(2)均>0.99),加标回收率79.3%~110.0%,精密度试验结果相对标准偏差(RSD)为0.3%~11.5%,表明该方法精密度高、准确性良好。在啤酒酿造过程中有机酸总量及乙酸、琥珀酸、苹果酸、乳酸、柠檬酸、α-酮戊二酸含量呈现先增长后平稳的趋势,草酸、抗坏血酸、酒石酸含量变化相对平稳。

The method for organic acids determination in beer was optimized by reversed phase-high performance liquid chromatography(RP-HPLC).Finally, the determination conditions of 9 kinds of organic acids(oxalic acid, lactic acid, tartaric acid, acetic acid, malic acid, α-ketoglutaric acid, ascorbic acid,citric acid and succinic acid) in beer were determined by RP-HPLC, and combined with fermentation mechanism, the dynamic change of organic acids contents in beer brewing process was analyzed. The results showed that the optimized conditions of RP-HPLC were as follows: detection wavelength 215 nm,mobile phase buffer 0.10 mol/L KH_(2)PO_(4), pH 3.0, flow rate 0.6 ml/min. The linear relationship was good with the mass concentration of organic acids ranging from 0.2-400.0 mg/L(R^(2)>0.99), the recovery rate was 79.3%-110.0%, and the relative standard deviation(RSD) of precision test was 0.3%-11.5%,indicating that the method had high precision and good accuracy. In beer brewing process, the contents of total organic acids, acetic acid, succinic acid,malic acid, lactic acid, citric acid, and α-ketoglutaric acid increased first and then stabilized, while the contents of oxalic acid, ascorbic acid and tartaric acid changed relatively smoothly.