Evaluation of taste and aroma compounds in oven-roasted broccoli floret and stem as affected by different times using electronic tongue and electronic nose

Roasting processing was commonly applied to enhance flavour characteristics, and thus this study was to investigate the taste and aroma compounds between broccoli floret and stem during oven-roasting processes. In electronic tongue analysis, sourness, saltiness, umami, and sweetness in florets showed an increasing tendency during the roasting, however, decreasing bitterness. Besides, In electronic nose analysis, methanethiol was reduced after the roasting processes and other sulfur compounds were generated in oven-roasted florets and stems. Furthermore, furans were generated after the roasting. Pyridine and pyrazines were only identified in oven-roasted florets, however, pyrrole was only identified in oven-roasted stems. Principal component analysis and cluster analysis were conducted based on combined taste and aroma profiles. Broccoli floret roasted at 15 min was affected by numerous variables compared with the others, and broccoli stems roasted at 15 and 20 min were affected by numerous variables. Additionally, the floret roasted at 15 min was the highest dissimilarity amongst all florets, and the stems roasted at 15 and 20 min were the highest dissimilarity amongst all stems. Accordingly, oven-roasting induced higher changes in taste and aroma characteristics with increasing times. In addition, this research may provide a basis for enhancing the flavour characteristics of broccoli.