Determination of Volatile Alcohols in Fruit and Vegetable Juices by an Amperometric Enzyme Electrode Measuring in the Headspace above the Liquid

摘要

The determination of alcohol is relevant to the beverage industry, apparently for liquors, wines, or beers. However, alcohol can also be found in juices e.g. due to starting fermentation during storage of the fruits. We present an amperometric enzyme electrode that determines volatile alcohols (ethanol, methanol) in fruit and vegetable juices (apple, grape, currant, tomato). The biosensor analyses the headspace above the liquid sample. This mode of operation has the advantage that possible interferences are limited to volatile substances and that the biosensor is not contaminated by the sample. For example, no interference by ascorbic acid (vitamin C) can occur. The analysis results of the biosensor are compared to two reference methods, a commercial photometric enzyme test-kit and a HPLC analysis.