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

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 KH2PO4、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（R2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。

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

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 KH2PO4 , 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 (R2＞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.