Analytical artifacts caused by the presence of water vapor in the headspace of food products

The aim of the work reported here was to underscore major artifacts appearing during the purge-and-trap step of the volatile fraction analysis of water-rich products. For this purpose we humidified the headspace of dry and lowmoisture products to simulate the artifacts produced during the analysis of naturally moist products. This method implemented with and without dry purge of the trapping adsorbent also enabled us to determine the origin of the observed interference. Materials and methods Samples Two food products of animal origin, namely dehydrated beef stock and powdered Parmesan cheese, were selected for their low water content (respectively 2.3 and 25.0 %) and for the diversity of the chemical families present in their volatile fractions. Description of experiments carried out To target the origin of the water-related artifacts, different analyses were carried out with and without humidification of the headspace of the products, and with and without a dry purge step. In all, eight analyses were performed: two products (dehydrated beef stock and Parmesan cheese) in two moisture states (dry and moist) with two drying states for the Tenax trap (with and without dry purge).