Improved performance of the Aromascan A32S electronic nose and its potential for detecting aroma differences in dairy products

The Aromascan A32S, an "electronic nose", was evaluated for its performance under conditions of total humidity control. initially, it was shown that the very high concentration of water vapor in the headspace above a variety of food products used for this study, in comparison with the concentration of their aroma compounds, completely determined the response of the instrument's sensors. Differentiation between the food aromas was impossible. Only when the concentration of a nonaqueous analyte was increased to approximately the water vapor concentration was perfect distinction achieved between air samples with and without analyte. It was obvious that the instrument in its original form would not be capable of distinguishing subtle aroma differences as are encountered within one type of product in quality assurance, storage trials, taint studies etc. However, significant modification of the original version of the instrument and of the sample presentation procedure improved its performance. Now it was possible to distinguish in certain cases, not only between water vapor and food aromas, but also between different samples of the same types of dairy products. These tests were complemented by sensory evaluation by untrained panels. In this form, the Aromascan A32S offers a new vista for successful and reliable application in the food area.