Volatile compounds in Chinese steamed bread influenced by fermentation time, yeast level and steaming time

Abstract The aim of this work is to investigate how volatile compounds of Chinese steamed bread (CSB) are influenced by yeast level (0.5, 1 and 1.5%, flour weight basis), fermentation time (20, 40 and 60 min) and steaming time (5, 10, 20 and 30 min). The volatile compounds were extracted by headspace-solid phase microextraction and analyzed by gas chromatography-mass spectrometry. Higher yeast level and longer fermentation time promoted the formation of yeast-metabolism-derived compounds, including 2-methyl-1-propanol, 3-methyl-1-butanol, phenethyl acetate, hexyl acetate and 2-octanone. Increased fermentation time decelerated the generation of lipid oxidation compounds (octanal, nonanal, decanal, (E)-2-nonenal, and (E,E)-2,4-decadienal). Prolonged steaming time facilitated the production of benzaldehyde and 2-pentylfuran and promoted the loss of alcohols and esters. Network analysis showed that 2-pentylfuran contributed to wheat-like aroma of CSB while 3-methyl-1-butanol was related with alcoholic odor. This study was helpful for improving the understanding of CSB aroma evolution profile and may contribute to the aroma improvement of commercial CSB.