Flavor quality evaluation of roasted perilla seed oil by gas chromatography-mass spectrometry and sensory method

Abstract

Roasted perilla seed oil (RPSO) has been widely used in Korea as condiment oil, because it notes a roasted nutty and distinctive aroma reminding of perilla aldehyde. Similar to the sesame seed oil, RPSO is traditionally produced by roasting, mechanical pressing and simple refining of perilla seeds. The sensory attributes and the volatile components of RPSO were affected by the roasting process. Volatile compounds are responsible for the aroma and flavor quality of RPSO and the most important factor in consumer acceptability. Precise objective methods were established in this study for evaluating flavor quality of RPSO based on gas chromatography-mass spectrometry data and sensory method using multivariate statistical analysis. Dynamic headspace purge conditions were investigated to obtain minimum loss of high volatile compounds by breakthrough and maximum recovery of low volatile components of RPSO. A response surface methodology was applied to evaluate the effect of purge temperature, purge time, and sample weight on log (total peak area), breakthrough ratio, and area of perilla ketone the least volatile component of RPSO. All three variables affected the responses selectively and characteristically. The optimum condition was determined by superimposing contour plots at 48℃ for 12 min purge, weight of 0.60 g. Breakthrough compounds were identified as 2-proanone, acetic acid methyl ester, 2-methyl propanal, 2-butanone and acetic acid. Volatile flavor components of RPSO were analyzed by dynamic headspace system-gas chromatography-mass spectrometry. Among one hundred of volatile compounds detected from the RPSO, fifty-eight compounds were tentatively identified by mass spectrum and gas chromatography retention time. Major volatiles of the RPSO were categorized as 10 aldehydes, 6 ketones, 2 alcohols, 7 furans and oxazoles, 18 nitrogen-containing compounds, 7 sulfur-containing compounds, and 8 miscellaneous compounds. Perilla aldehyde and perilla ketone, originat...