Fractionation of the water-soluble extract of a cheese made from goats' milk by filtration methods: behaviour of fat and volatile compounds

Abstract The intense aroma of goat cheese is mainly due to volatile polar compounds, particularly short- and medium-chain length free fatty acids, contained in its water-soluble extract (WSE). This fraction also contains the taste compounds of the cheese and has been fractionated in order to assess its chemical composition. The aim of the present work was to evaluate the behaviour of the most abundant volatile compounds and fat components in the WSE during multiple successive fractionation steps: i.e. fractionation by 10 and 1 kDa ultrafiltrations and 0.5 kDa nanofiltration. Lipid and volatile components were analysed by TLC-FID and GC–MS methods, respectively, at each filtration step. In the WSE, 43 volatile components were identified and short-chain free fatty acids were the most abundant. Volatile and fat compounds were largely retained during the 10 and 0.5 kDa filtration steps and to a lesser extent during the 1 kDa filtration step. The retention of various volatile compounds could be explained, beside possible interactions with the membranes used, by adsorption or interaction of these compounds with fat or protein material.