FLAVOR AND CHEMICAL COMPARISON OF PASTEURIZED AND FRESH VALENCIA ORANGE JUICES

Freshly extracted Florida Valencia orange juice was heated at 98C for 11 s to produce lightly heated juice, and for 37 s to produce heavily heated juice. Sensory panels detected a flavor difference between the fresh, unheated juice and the heavily heated juice. Analyses of these two juice samples by headspace gas chromatography (GC) showed no signi ficant qualitative or quantitative differences. GC analyses of methyle ne chloride extracts of juices and of residues from distillation of th e juices showed only one detectable difference in each case. Extracts of the whole juices showed one GC peak, which was significantly larger in the heavily heated juice, identified as the potential off flavor c ompound, octanoic acid. Extracts of the high-boiling distillation resi due showed one unidentified late-eluting GC peak which appeared only i n the heavily heated juice. These findings supplement previous reports that more severe pasteurization conditions than required for juice pr ocessing cause detectable flavor changes in heated juice.