酵子馒头香气形成机理

Aroma of Chinese Jiaozi steamed bread attracts consumers and researchers, but volatile compounds of steamed bread were discussed frequently, and the aroma was not studied systematically. Aroma is the first feature of Chinese Jiaozi steamed bread to attract consumer, but its formation mechanism has not been reported. In the project, negative pressure suction, simultaneous distillation extraction, purge and trap, headspace solid phase microextraction, and etc. will be combined to collect aroma components of Chinese Jiaozi steamed bread; different polar chromatographic column will be used to separate aroma compound in GC system, and mass spectrometer and flame ionization detector will be used to achieve mass spectrometry and retention index, and double qualitative analysis of aroma components; homologues in control system of internal standard will be applied to quantitative analysis of aroma components in GC-FID. Aroma substances of Chinese Jiaozi steamed bread will be found by the organic combination of olfactory perception and precise analysis of aroma compounds, and the key aroma compounds will be excavated through statistical methods. Through collection and analysis of aroma and production process of Chinese Jiaozi steamed bread, production equipment will be designed innovatively to track the key aroma component. The change regulation of aroma substances will be explored in the process of Chinese Jiaozi steamed bread, and the regulation will be simulated and validated. The project has important significance to reveal the formation of aroma from Chinese Jiaozi steamed Bread in the whole process, and it can provide valuable and feasible theoretical reference for maintaining and adding the aroma of steamed bread.

酵子馒头的香味吸引消费者和研究人员，但常常只研究馒头的挥发性物质，并未对其香气进行系统研究。香气是酵子馒头吸引消费者的第一特征，其形成机理未见报道。本项目拟利用负压吸气、同时蒸馏萃取、吹扫捕集、顶空固相微萃取等方法联合使用收集酵子馒头香气组分，通过气相色谱体系种两种不同极性的色谱柱进行分离，再使用质谱仪与氢火焰离子化检测器（FID）获得质谱与气相保留指数，实现双定性；利用GC-FID体系内标法中同系物对照进行准确的定量分析。有机结合人嗅觉感知能力与精准的化合物分析，发现酵子馒头的香气物质，通过统计学方法挖掘出香气关键呈香化合物。结合香气收集分析技术与酵子馒头制作过程，创新设计制作装置实现关键呈香化合物的跟踪分析，探索酵子馒头香气物质在形成过程中的变化规律，并根据此规律进行模拟和验证，揭示酵子馒头香气在整个加工过程的形成机理，为保持或添加馒头香气提供有价值和可行的理论参考。

本项目对酵子馒头香气组分的提取、分析、形成过程进行研究，主要包括以下几点：.（1）自主设计实验装置，使用吹扫捕集法、真空吸收法、同时蒸馏萃取法（SDE）、顶空固相微萃取法（HS-SPME）收集酵子馒头挥发性物质，再利用气质联用（GC-MS）测定，发现SDE和HS-SPME收集的挥发性物质效果较好。.（2）利用GC-MS分析酵子馒头中挥发性化合物，检测出61种挥发性化合物。酵子馒头中醇类物质的种类比商业酵母馒头中少，但是相对含量更高，且醛类物质的相对百分含量较酵母馒头高近三倍。使用气相-嗅闻技术（GC-O）识别香气组分有15个化合物，分别为正己醛、正丁醇、正庚醛、3-甲基-1-丁醇、2-戊基呋喃、正戊醇、(E)-2-庚烯醛、正己醇、壬醛、1-辛烯-3-醇、正庚醇、苯甲醛、萘、(E,E)-2,4-癸二烯醛、乙醇。.（3）对酵子馒头原材料、中间制品和成品挥发物进行分析，共发现78种挥发性化合物，其中醇类20种、醛类15种、酯类9种、酮类5种、碳氢化合物25种、其他化合物4种。经过t检验（P<0.05）筛选出15种具有显著性差异的挥发性成分。其中，醇类和醛类及2-戊基呋喃对酵子馒头的风味从原材料到成品的风味形成起到关键性作用，烃类化合物主要对风味起到修饰性作用。发现正戊醇、3-甲基-1-丁醇、正己醇、正庚醇及正己醛、壬醛是酵子馒头的特征风味。.（4）从民勤、南阳、驻马店、菏泽、泰安、运城、渭南、西安收集8个酵子样品，制作馒头后经过GC-MS和气相-迁移谱检测，建立酵子馒头产地的PCA模型，用于快速区分酵子馒头的地区。陕西西安酵子馒头中挥发性有机物的总体含量最多，风味物质成分最特殊，与其他七个地区的酵子馒头区别最大；山东泰安酵子馒头相对较为接近山西运城；河南驻马店酵子馒头和普通馒头酵子馒头相似度较高；甘肃民勤、河南南阳、山东菏泽和陕西渭南酵子馒头种之间的差异很小。