Characterization of volatiles and aroma in Chinese steamed bread during elaboration

Effects of different process steps on volatiles and aroma compounds of "Jiaozi" steamed breads (JSBs) fermented by Jiaozi starter were investigated for finding the key process steps related to aroma formation. Thirty aroma active compounds were identified using Gas chromatography-mass spectrometry (GC-MS) and GColfactometry, which provided green, fatty, mushroom, mossy, fruity, sweaty, floral odors to JSBs. GC-MS analysis showed that the concentration of volatiles in JSB dough increased gradually during first-mixing and primary fermentation; decreased after second-mixing, kneading, molding and secondary fermentation; and increased greatly after steaming. Cluster analysis indicated that the aroma profile of fresh cooked JSBs was different from that of JSB dough. Fermentation is an important stage of aroma formation of JSBs. Furthermore, steaming is also a key process step in the formation of JSBs aroma, which endows JSBs unique aroma characteristic that is different from those produced by fermentation.