Effect of processing conditions on volatile composition of apple jellies and jams

When producing fruit jellies and jams it is intended to preserve as far as possible the presence of the aromatic characteristics of the fresh fruit. In the present work, the influences of sugar content - 6 to 55 degrees Brix - and type of pectin - low methoxyl and medium methoxyl pectin on the volatile composition of apple jellies and jams is studied. Volatile compounds were extracted by Clevenger distillation for 180 min and collected in Is-hexane. All extracts were analysed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GCMS). The influence of jelly structure on flavor release was evaluated by measurement of objective texture. It was observed that the studied parameters quantitatively affected the chromatographic profile, keeping the composition similar. Main compounds identified were 3-methylbutanol, 2-methylbutanol, 1-hexanal, 2-hexanal, hexyl propionate and estragole. The decrease observed in volatile release from jellies and jams seemed to be related to the retention of volatiles in the gel matrix and to sugar bonding.