12-10 |
Evaluation of the character impact odorants in nonfat dried milk by sensory studies on model mixtures |
Y. KARAGUL-YUCEER, Dept. Food Science, North Carolina State University, Raleigh, NC 27695, M. A. Drake, and K. R. Cadwallader, Dept. Food Science, University of Illinois, Champaign-Urbana, Champaign, IL. Many chemicals can contribute to the aroma and flavor of food. A popular approach in flavor research is to presume that only those compounds that are present in concentrations above their threshold will contribute to aroma. Threshold information is then combined with gas chromatography-olfactometry (GCO) results to create model systems for further study. The objective of this study was to verify aroma-active compounds responsible for the key compounds of NDM aroma using threshold analysis, odor activity values, and model systems. Twelve odor-active compounds were selected based on flavor dilution factors of gas chromatography-olfactometry of NDM. Thresholds for the 12 odor-active compounds were identified using five-set ascending forced choice threshold analysis in odor-free water (n=28 panelists, duplication for each compound). Individual best-estimate values of threshold (BET) were derived from the pattern of correct/incorrect choices with sure/unsure responses produced separately by each panelist. A group threshold was determined for each compound by averaging individual thresholds. Models were prepared using milk ultrafiltrate (MUF) as a base. The compounds were added to MUF in various combinations by addition/subtraction of each chemical. The headspace aroma of each model was evaluated by trained descriptive sensory analysis with that of the original NDM using difference-from-control testing. Models containing a mixture of d-decalactone, methional, o-aminoacetophenone, maltol and 2-acetyl 2-thiazoline were most similar to rehydrated NDM aroma indicating that these compounds constitute the character impact odorants of NDM. The presence or absence of the other seven volatiles had little or no impact on the aroma similarity scores. The combination of GCO, quantitative measurements and model studies is a promising approach for the evaluation of the character impact odorants causing the aroma of a food.
Session 12, Sensory Evaluation: Sensory techniques - Descriptive analysis
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