45C-11 |
Effect of fat level on headspace concentration and sensory threshold of alpha-ionone |
S. GADDAMU1, I. U. Gruen1, K. Adhikari1, L. N. Fernando1, and H. Heymann2. (1) Dept. of Food Science, Univ. of Missouri, Columbia, 256 Eckles Hall - Stringer Wing, Columbia, MO 65211, (2) Dept. of Viticulture & Enology, Univ. of California, Davis, 1 Shields Ave., 3009 Wickson Hall, Davis, CA 95616-8749 Flavor release and perception is greatly influenced by the fat content in a food product. Understanding the interactions between flavor compounds and fat is essential to produce acceptable low fat or nonfat foods. The aromatic ketone alpha-ionone has a violet-like woody odor and is used in bakery, confectionary, frozen dairy products. The objective of the study was to determine the effect of different levels of fat on the headspace concentration and sensory threshold of alpha-ionone. Different concentrations of alpha-ionone were added to 0% (water), 4% and 10% fat emulsions. After 2 h of equilibrium, the vials were sampled by Auto-HS-SPME-GC. The headspace concentration was calculated using an external standard curve. Headspace (HS) concentration of alpha-ionone was very high for water samples and increased exponentially with increasing alpha-ionone concentrations in the solution. HS concentrations in 4% fat emulsion were significantly lower than in water, but were significantly higher than in 10% fat emulsion, indicating a large effect of fat on the release of alpha-ionone into the headspace. For example, a 15ppm alpha-ionone concentration in a 10% fat emulsion resulted in a similar HS concentration as a 5ppm alpha-ionone concentration in a 4% fat emulsion or as a 0.1ppm concentration in water. For the 4% and 10% fat emulsions, the HS concentration of alpha-ionone increased linearly with its concentration in the sample matrix. Alpha-ionone is only slightly soluble in water and very lipophilic, which is consistent with the higher release in water, followed by 4% and the lowest release in 10% fat emulsion, indicating that fat dissolves and retains the flavor compound in the matrix. However, there was little difference in the sensory threshold values of alpha-ionone for the 4% and 10% fat mixes, which were 0.68 and 0.60 ppm respectively. Considering that the threshold concentration was even slightly higher for the 4% fat emulsion than for the 10% emulsion, the sensory thresholds were not well correlated with the HS concentrations. These results indicate an important interaction between fat level, HS concentration and sensory thresholds.
Session 45C, Food Chemistry: Flavor and aroma chemistry
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