Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2007
Publication Date: 9/7/2007
Citation: Schirack, A.V., Drake, M.A., Sanders, T.H., Sandeep, K.P. 2007. Characterization of Aroma-Active Compounds in Microwave Blanced Peanuts. Journal of Food Science 71(9) C513-C520. Interpretive Summary: Great reductions in peanut blanching time may be achieved using planar microwave applicators. Earlier experiments have shown, however, that microwave blanching was sometimes associated with off-flavor formation when internal kernel temperatures became too high during blanching. This paper seeks to establish the identity of compounds responsible for the off-flavor. Several lines of evidence pointed to increases in guaiacol and phenylacetaldehyde due to microwave exposure. Addition of these compounds back to model peanut past systems suggested that they could be responsible for the burnt and stale/floral notes found by the sensory panel.
Technical Abstract: Microwave blanching of peanuts has been explored as an alternative to conventional oven methods based on its speed of operation, energy savings, and efficiency of process control. Although processing times can be greatly reduced,the occurrence of stale/floral and ashy off-flavors has been reported at high process temperatures. This study examined the chemical compounds responsible for this off-flavor using solvent extraction/solvent assisted flavor evaporation (SAFE), gas chromatography-olfactometry (GC/O), gas chromatography-mass spectrometry (GC/MS), and aroma extract dilution analysis(AEDA).Select compounds were quantified based on AEDA results using SAFE and GC/MS. Quantification, threshold testing, and analysis of model systems revealed increased formation of guaiacol and phenylacetaldehyde in the off-flavored peanuts, which resulted in the burnt and stale/floral flavors noted by a trained panel.