FACTORS AFFECTING THE THRESHOLD OF METHYL AND ETHYL OLEATE EMULSIONS IN RAISINS AND RAISIN PASTE

Raisins prepared by dipping in methyl or ethyl oleate emulsions and dried in a tunnel dehydrator at 65.5°C for 12 hr had significantly lower off‐flavor thresholds than those in which oleate was added after drying. This indicates that time‐temperature combinations of this magnitude caused oxidative changes or interactions between constituents in the emulsions and raisins yielding a mixture of increased off‐flavor potency. Whole raisins had an apparent lower oleate threshold than the same raisins ground into paste prior to tasting because of the nonuniform distribution of oleates in whole raisins. Consequently, conditions improving the uniform distribution of oleates in whole raisins would reduce off‐flavor detection in oleate‐treated fruit. Emulsifiers used in commercial oleate preparations can be the most significant source of off‐flavor contribution to the dried raisins. Copyright © 1979, Wiley Blackwell. All rights reserved