Correlation analysis between volatile compounds and α-dicarbonyl compounds in various beans in response to different roasting conditions
Gaeun Lee, Minju Lee, Junghyun Ahn, Yuri Kim, Kwang‐Geun Lee
Abstract
In this study, the content of volatile compounds and α-dicarbonyl compounds (α-DCs; glyoxal, methylglyoxal, and diacetyl) were analysed in various beans (soybeans, black soybeans, and mung beans) roasted at different times and temperatures. Among the volatile compounds detected in unroasted soybeans, 1-octen-3-ol was the most abundant. After roasting, 1-octen-3-ol decreased by up to 86%. In unroasted beans, 3-ethyl-2,5-dimethylpyrazine and 2,3,5-methylpyrazine which are the main volatile compounds after roasting were not detected. Roasting at 180 °C for 25 min produced the highest amount of volatile compounds. Roasting at 200 °C for 25 min produced the highest amount of α-DCs. As the roasting temperature and time increased, the level of α-DCs and volatile compounds showed a positive correlation (spearman correlation, r = 0.878, 0.890, and 0.867 in soybeans, black soybeans, and mung beans, respectively). Volatile compounds and colour values showed a negative correlation (spearman correlation, r = −0.917, −0.967, and −0.850 in soybeans, black soybeans, and mung beans, respectively). The results of this study suggest that the optimal roasting conditions for beans are 180 °C for 25 min, where the generation of flavour compounds is maximised while the generation of α-DCs is relatively small.