本文研究了不同发酵类型的乳酸菌发酵对馒头的香气特征的影响，采用电子鼻技术对9株不同乳酸菌分别发酵馒头的香气成分进行检测，对电子鼻10个传感器信号数据进行主成分分析（Principle Component Analysis，PCA）后发现，9株不同乳酸菌发酵的样品能明显区分开，并且按照不同的乳酸发酵类型，在PCA图中能大致划分为三类。采用专性异型菌株发酵制得馒头样品的香气特征与兼性异型菌株发酵制得的样品较近似，却与同型发酵菌株制得的产品存在显著差异，从而说明乳酸菌的发酵代谢类型与馒头的香气物质形成有着紧密的联系。通过气味感官评价及风味模型的构建，探究了不同类型乳酸菌对发酵的馒头的风味贡献特异性，其中异型乳酸发酵菌株发酵的馒头样品同时在麦芽味、水果气味、酒味和酸乳味等风味处都有较高强度表现，更有助于馒头风味的改善，同时为工业化菌种发酵剂的开发奠定了理论研究基础。

In order to better understand the effects of different lactic acid bacteria’ fermentation on the odor characteristics of steamed bread, the flavor components of bread fermented by 9 strains lactic acid bacteria separately were detected by using electronic nose technology. The response values obtained by electronic nose were analyzed by the principal component analysis (PCA). The PCA analysis showed 9 batches of steamed bread samples could be obviously distinguished. According to different lactic acid fermentation type, the samples can be divided into three categories in the PCA diagram. The odor characteristics of the steamed bread samples fermented with obligately homofermentative organisms were significantly different from other two kinds of samples, and the odor characteristic of obligately heterofermentative samples were similar with facultatively heterofermentative samples. Through the sensory evaluation and the establishment of the flavor model, this work aimed to explore the specific odor of steamed bread fermented with different types of lactic acid bacteria, and to provide reference for the quick identification and the odor objectification of steamed breads.

国家自然科学基金资助项目（31471721）；“十二五”国家科技支撑计划项目（2014BAD04B03）