葡萄酒、果酒中挥发酸分析方法的研究

Study on the Analytic Methods of Volatile Acids in Grape Wine/Fruit Wine

挥发酸是体现葡萄酒及果酒"健康"状况的一项指标。水蒸气蒸馏法是以蒸馏的方式蒸出样品中的低沸点酸类即挥发酸,然后用碱标准溶液进行滴定,经过计算与修正得出样品中挥发酸的含量。将3种前处理方法进行了对比实验,方法一:在烧瓶中放置10 mL样品进行蒸馏,采集100 mL流出液。加热至沸,迅速冷却至常温。方法二:在烧瓶中放置20 mL样品进行蒸馏,采集250 mL流出液,方法三:在烧瓶中放置20 mL样品和约0.5 g酒石酸进行蒸馏,采集250 mL流出液。通过3种挥发酸的前处理方法的对比,确定方法三能将葡萄酒中的游离态及结合态挥发酸蒸出,而且回收率和重复性都很好,值得推广。

Volatile acid is an indicator reflecting the health status of grape wine/fruit wine. Steam distillation is adopted for the distilla- tion of low-boiling-point acids in wine samples （namely, volatile acids）, then alkali standard solution titration was performed, and vol- atile acids content in wine samples was obtained through calculation and correction. The three pre-treatment methods were adopted in the experiment as follows： （1）10 mL wine sample placed in the flask for distillation, and 100 mL effluent was collected, heated to boiling, and quickly cooled to normal temperature; （2）20 mL wine sample placed in the flask, and 250 mL effluent collected; （3）20 mL wine sample placed in the flask and 0.5 g tartaric acid mixed for the distillation, 250 mL effluent collected. Through the comparison of the three pretreatment methods, pretreatment method No.3 was the best. It could evaporate volatile acids in both free and bound state. Besides, it had good recovery and repeatability.