18C-24

S. L. SCHWAMBACH and D. G. Peterson. Dept. of Food Science, Pennsylvania State Univ., University Park, PA 16802-2504

Skim milk powder (SMP) is widely utilized by the food industry as an ingredient. However, the flavor stability of milk powders (develop off-flavors) can negatively impact the final product quality. Two primary modes of off-flavor development in skim milk powder have been associated with Maillard-type and lipid oxidation reactions. Recently, epicatechin (EC) has been reported to inhibit aroma-active compounds generated during ultra-high temperature processing of milk samples. It is proposed that EC addition to milk prior to spray drying would also improve the flavor stability of SMP. Our objective was to determine if EC addition to condensed milk prior to spray drying improved the flavor properties and stability of SMP after spray drying and subsequently during storage. Low-heat condensed skim milk and low-heat condensed skim milk with EC added at 0.1% were spray dried using typical commercial conditions. 200g of the control (traditional) and treatment (0.1% EC added) SMP were placed at 37^oC for 4 mo and the remaining powder was frozen (-40^oC). A trained sensory panel was used to compare cooked and stale off-flavor intensities in control and treatment powders in duplicate at time zero and after storage while at the same time aroma extracts of the powders were prepared using solvent assisted flavor evaporation (SAFE). Key aroma compounds were identified and compared using aroma extract dilution analysis (AEDA). The AEDA indicated that addition of EC prior to spray drying reduced the overall formation of key aroma-active compounds in comparison to the control SMP both during the drying process and during storage. Furthermore, the sensory evaluation was also in agreement with the AEDA and reported lower stale flavor intensities in the EC containing milk powders versus the control samples. This work indicated that utilization of phenolic compounds may provide novel control of flavor stability in food ingredients.

Session 18C, Food Chemistry: Food composition, analysis and volatiles
2:00 PM - 5:30 PM, Sunday PM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana