71A-8 |
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J. M. WRIGHT, M. E. Carunchia Whetstine, and M. A. Drake. Dept. of Food Science, North Carolina State Univ., Schaub Hall, Box 7624, Raleigh, NC 27695-7624 Flavor plays an essential role in consumer purchase decisions. Whey protein isolate (WPI) is a value-added protein with multiple ingredient applications. A bland flavor is expected in WPI and off-flavors can prevent or limit its use in certain foods. Recently, a cabbage off-flavor was noted in some WPI. The objective of this study was to characterize the source of cabbage flavor in WPI. WPI with and without cabbage flavor were collected (n=4), and descriptive sensory analysis was conducted on the rehydrated WPI, using a trained panel and a previously identified sensory language. Volatile compounds were extracted using solvent-assisted flavor evaporation (SAFE), followed by GC-MS and gas chromatography-olfactometry (GC-O), to identify and characterize aroma-active compounds. Selected volatiles were quantified by solid-phase microextration (SPME) with GC-MS. Orthonasal thresholds of selected volatile compounds in deodorized water were evaluated by ascending forced choice analysis, and descriptive analysis of model systems was used to confirm instrumental results. Dimethyl trisulfide (DMTS) (cabbage aroma) was identified by GC-O and GC-MS in WPI with the cabbage flavor. Using SPME GC-MS, DMTS levels were 13 ± 10 parts per trillion (ppt) in WPI with cabbage flavor, and below instrumental detection limits in those without cabbage flavor. The orthonasal threshold for DMTS was less than 3 ppt. Descriptive analysis of model systems containing DMTS added at levels found in WPI with cabbage flavor confirmed the role of DMTS in the cabbage off-flavor. Knowledge of the source of this flavor will aid in identification of ways to minimize or prevent DMTS formation in WPI.
Session 71A, Dairy Foods: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |