| Abstract
| - The volatiles (E,Z)-2,6-nonadienal, 1-penten-3-one, (Z)-4-heptenal, and (E,E)-2,4-heptadienal wereadded to milk containing 1.5% fat according to a central composite design, to evaluate the individualand combinatory effects of these volatiles on sensory properties. The milk samples with added volatileswere subjected to sensory descriptive analysis for fishy and metallic off-flavors. The data were analyzedusing partial least-squares regression and multiple linear regression to develop mathematical models.The models revealed significant main effects of (E,Z)-2,6-nonadienal and 1-penten-3-one andhighlighted the importance of two-factor interactions for contribution toward off-flavors. The resultssuggest that (E,Z)-2,6-nonadienal and 1-penten-3-one could be useful markers for fishy and metallicoff-flavors in fish oil and fish oil enriched foods. Within the addition levels of the volatiles there wasa curvature effect of (E,Z)-2,6-nonadienal, a compensatory effect of (Z)-4-heptenal and (E,E)-2,4-heptadienal, and a synergistic effect of (E,Z)-2,6-nonadienal and (Z)-4-heptenal in the developmentof fishy off-flavors. Keywords: (E,Z)-2,6-Nonadienal; 1-penten-3-one; (Z)-4-heptenal; (E,E)-2,4-heptadienal; fishy off-flavor;metallic off-flavor; milk emulsion; PLSR; MLR; response surface plots
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