Key odourants in legumes and legume-based foods: evidence from gas chromatography–olfactometry (GC–O) studies

Background Legumes are integral to healthy and sustainable diets, but flavour quality, including both characteristic aromas and undesirable off-odours, strongly influences consumer acceptance. Gas chromatography–olfactometry (GC–O) has been widely applied to identify odour-active compounds in legumes and to evaluate how processing strategies modify aroma profiles. Scope and approach This study intergrated GC–O data across a broad range of legumes and legume-derived foods to identify key odourants. Quantitative GC–O data were standardised using relative odour activity (ROA) values. Statistical and multivariate analyses were applied to summarise odourant profiles of major food legumes (e.g., faba bean, pea and soybean) subjected to laboratory heating and fermentation, as well as commercial legume-based products such as peanut oil, doubanjiang, douchi, soybean paste and soy sauce. Key findings and conclusions Based on the ROA framework, 1-octen-3-ol and hexanal were consistently identified as dominant odour contributors across legumes. In contrast, commercial legume-based foods exhibited distinct signature odourants. Peanut oil was dominated by aldehydes, doubanjiang by alcohols, douchi by acids, soybean paste by esters, and soy sauce by alcohols together with 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HEMF). Multivariate analysis further differentiated odourant patterns amongst the food groups. Overall, these findings provide a practical framework for prioritising target odourants, which may support the formulation of legume-based foods with improved flavour quality.