HS-SPME-GC–MS characterization of volatile chemicals released from microwaving and conventional processing methods of fenugreek seeds and flours

Abstract

This study was to evaluate the effects of microwave and conventional processing methods on the aroma profiles of fenugreek seeds and flours. The volatiles of raw, sprouted, boiled, roasted, and micro-waved fenugreek grains were evaluated using headspace-solid phase micro-extraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC-MS). 51 and 60 volatiles were detected in the emission bouquets of raw and processed seeds and flours, respectively. Volatiles were divided into seven chemical classes, including monoterpenes hydrocarbons, sesquiterpenes hydrocarbons, phenylpropanoids, non-terpenes derivatives, apocarotenes, nitrogen/sulfur derivative and oxygenated monoterpenes. The data showed that volatiles were significantly affected by the type of processing. All treatments increase the amounts of volatiles including aldehydes, alcohols, esters, and alkanes except for the microwave heating. Indeed, the dominant volatiles in microwaved fenugreek were pyrazines, with chocolate aroma like flavor. The microwave heating is based on an energy-efficient and water-saving technology; it is an interesting and more sustainable technique to be employed in the legume processing. The findings of this study demonstrate that microwave technology has potential for fenugreek processing.