Influence of off-flavor formed from plasma protein on flavor characteristic of emulsion-type dressing

The off-flavor components formed from the beef plasma protein (PP) were inv estigated by the combined use of solid phase micro-extraction (SPME) and cr yo-focusing GC analysis, with cyclohexanol as an internal standard. The pre sence of 63 peaks was demonstrated in the headspace of the PP solution. The 37 of these peaks were identified by their mass spectra and retention inde x. Hexanal was predominant component (51%), followed by pentanal (51%) and 3-methyl-butanal (3%) in the order of decreasing concentration. The relatio n between odor properties and sensory evaluation was also studied by using the model emulsion consisting of salad oil, water and PP (0.2 similar to2.0 %). The 25 percentage of panelists could distinguish the model emulsion con taining 0.4% PP from that containing 0.2% PP. In 0.4% PP emulsion, the rela tive area ratio of total headspace components (to the internal standard) an d that of hexanal were 79% and 11%, respectively. The addition of vinegar t o an emulsion type salad dressing containing 1% PP as an emulsifier was con sidered to show the masking effect of off-flavor formed from PP.