液相法测定米香型白酒发酵液中18种有机酸

为给白酒厂建立包括挥发性短链脂肪酸在内的有机酸品控手段，进行了18种有机酸液相定量方法的开发。通过流速和梯度优化，实现了各有机酸的有效分离，色谱条件为:Atlanis T3色谱柱（4.6 mm×250 mm，5 μm），流速0.4 mL/min，梯度洗脱，柱温30 ℃，检测波长210 nm，上样量10 μL。该方法线性范围较宽，R2>0.989，定量限0.280~3.138 mg/L，加标回收率93.03%~107.21%，相对标准偏差<3.70%。米香型白酒发酵跟踪数据表明:各有机酸含量在发酵过程呈现不同的变化趋势。与初始发酵醪液相比，除柠檬酸、L-苹果酸和富马酸外，其它有机酸的含量在12 d发酵醪中均增加。L-乳酸、乙酸、异丁酸、异戊酸、琥珀酸是12 d发酵醪的5种主要有机酸，含量占比均大于10%。发酵过程总有机酸一直增加，且不同发酵进程的有机酸差异较大，暗示着改变发酵周期可以调控米香型白酒有机酸的组成。该方法为米香型白酒有机酸的品控提供了有效手段。

Determination of 18 Organic Acids in Rice Flavored Liquor Fermentation Broth by High Pressure Liquid Chromatography

In order to establish organic acid quality control method including short chain volatile fatty acids for Baijiu distillery, the quantitative method of 18 organic acids was developed by HPLC. Each organic acid was separated effectively by flow rate and gradient optimization. The final optimized analytical conditions were listed as follows: the column was Atlanis T3 column(4.6 mm×250 mm, 5 μm), flow rate was 0.4 mL/min, gradient elution was adopted, column temperature was 30 ℃, detection wavelength was 210 nm, and sample loading volume was 10 μL. This method had a wide linear range, R2>0.989, as well as quantitative limits were from 0.280 to 3.138 mg/L, recovery rates were from 93.03% to 107.21%, relative standard deviations were less than 3.70%. The results of tracking the changes of the contents of organic acids in the ferment broth of rice-flavored liquor during its fermentation process showed that the content of each organic acid showed different changing trends during fermentation. Comparing with those of initial fermented mash, the contents of all the organic acids except citric acid, L-malic acid, fumaric acid increased in the fermented mash of 12th day. L-lactic acid, acetic acid, isobutyric acid, isovaleric acid and succinic acid were the five most abundant organic acids in fermented mash of 12th day, the amounts of them were all more than 10% of total organic acid. In addition to the even increasing of the total organic acid amount, the distributions of organic acids in different stages of fermentation were significantly different. It was suggested that the composition of rice flavor organic acids could be effectively controlled by adjusting the fermentation duration. This method is an effective analysis method for the acidity quality control of rice-flavored liquor production.