117 Comparison of volatile compounds in fresh white bread crust and popcorn.

R. RENGARAJAN (1), L. M. Seitz (2), and M. S. Ram (1). (1) Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506; (2) USDA, ARS, Grain Marketing and Production Research Center, 1515 College Avenue, Manhattan, KS 66502.

Volatiles from microwave popped popcorn and bread crust separated from freshly baked white wheat bread were analyzed using two different methods. Ethylbenzene-d(10), an internal standard, was added to each sample before the volatiles were purged with helium at 80 C, and collected on Tenax in a purge and trap instrument. Collected volatiles were thermally desorbed from the Tenax and transferred to a gas chromatograph-mass spectrometer for separation and identification. A supercritical fluid carbon dioxide extractor was used in the second method to collect the volatiles in a glass sparger kept at dry ice temperature. Internal standard, napthalene-d(8), was added to the sample before the extraction. The sparger was connected to the purge and trap equipment and purged as mentioned above. Several compounds were observed in common between the two samples. Some pyrazines and other heterocyclics were found in popcorn but not in bread crust. However, 2-acetyl-1-pyrroline, a flavor impact compound that other researchers have reported for both popcorn and bread crust, was observed only in popcorn. This was possibly due to low concentration and small sample size. Supercritical fluid carbon dioxide efficiently extracted carbonyls, pyrazines and some other compounds from 1 g samples of bread crust and popcorn.