红枣白兰地风味特征及其形成机理研究

It's a centuries-old tradition in China that the distilled liquor of Chinese date brandy with unique flavor is brewed. However, the traditional brewing process is empirical. The production safety is poor because of its high content of methanol. The flavor quality is out of control because of its unstability. So the scale and industrialisation of production are confined. It's necessary to develop the brewing theory and technique of Chinese date brandy for ensuring its safety and flavor quality. In our previous study, the problem of production safety was resolved. The formation mechanism of methanol was made clear and the methanol content was reduced markedly. Further improving and stabilizing the flavor quality of Chinese date brandy is needed. The flavor components were found more than 90 in Chinese date brandy. However, the characteristic flavor components and its formation mechanism have been unclear. In this work, the methods of GC-MS and GC-O will be used to identify and confirm the characteristic flavor components, and the value of flavor contribution of flavor components will be determined. For making clear about the origin of the characteristic flavor components, the components of alcohol, aldehyde, ketone, ester, etc in the new distilled and aged Chinese date brandy will be separately identified by GC-MS. For making clear about the formation path of the characteristic flavor components, the relevance of the characteristic flavor components to the fermentation materials and ageing course will be investigated by GC-MS. For making clear about the formation path and mechanism of the characteristic flavor components from microorganism, the structure, distribution and evolvement of microflora in distiller's yeast, Zaopei and pit mud will be studied during fermentation by PCR-DGGE combined with the traditional analysis method of microorganism. The developed mechanism will provide the theory basis for the flavor control of Chinese date brandy.

红枣白兰地作为一种传统的蒸馏酒，已经有几千年的历史，由于甲醇含量较高限制了其大规模工业化生产，风味特征及其形成机理不明确影响了风味稳定和产品质量控制。申请人前期研究已经明确了甲醇形成机理，解决了甲醇控制问题，并发现红枣白兰地风味独特，有90多种香气成分，但其特征成分和形成机理不清楚。本项目拟以GC-MS法分析红枣白兰地的风味成分，结合GC-O法分析各成分的风味贡献度，明确其特征风味成分；采用GC-MS分析原料、新蒸酒和陈酿酒中醇、醛、酮、酯等风味物质，明确特征风味物质的主要来源；以GC-MS法分析特征风味物质与原料、陈酿的相关性，明确特征风味物质形成的原料及陈酿途径；利用PCR-DGGE分子生物学技术，结合传统微生物分析方法，研究酒曲、糟醅和窖泥在发酵过程中的微生物菌群结构、分布及演变规律，明确特征风味物质形成的微生物途径及特征香气形成机理，为红枣白兰地香气成分控制提供理论依据。

1．项目背景、主要研究内容和科学意义.红枣白兰地作为一种传统的蒸馏酒，已经有几千年的历史，由于甲醇含量较高限制了其大规模工业化生产，风味特征及其形成机理不明确影响了风味稳定和产品质量控制。本项目采用GC-MS 法分析了红枣白兰地的风味成分；采用 GC-MS 分析原料、新蒸酒和陈酿酒中醇、醛、酮、酯等风味物质，以 GC-MS 法分析特征风味物质与原料、陈酿的相关性；初步明确了特征风味物质形成的微生物途径及特征香气形成机理，为红枣白兰地香气成分控制提供理论依据。.2．重要结果和关键数据.① 建立了红枣白兰地香气形成过程中4种支链氨基酸、8种支链醛和醇、16种酯类类物质的检测方法。该方法线性关系良好，加标回收率较高，可以满足定量分析要求。.② 采用感官组学技术初步确定了原红枣白兰地27种特征香气成分，16种重要香气成分。以气质联用-嗅闻仪技术确定了红枣白兰地55种香气活性成分，OAV超过100的有辛酸乙酯、己酸乙酯、异戊酸乙酯、月桂酸乙酯、等16种。.③ 采用同位素示踪技术初步明确了红枣白兰地乙酸支链酯的生成途径。在发酵基质中添加同位素标记的支链氨基酸，在酒样中检测到同位素标记的支链醛、支链醇及乙酸支链酯，初步证实了乙酸支链酯形成的氨基酸途径。.④ 采用同位素示踪技术初步明确了红枣白兰地双碳酸直链酯的生成途径在发酵基质中添加同位素标记的丙酮酸，在发酵酒样中检测到同位素标记的乙酸乙酯、丁酸乙酯等一系列双碳酸直链酯，证实了丙酮酸是红枣白兰地中双碳酸直链酯的前体物。 .⑤ 研究红枣白兰地特征风味物质形成的发酵途径。以特征风味为导向，研究了发酵过程中微生物菌群结构及演变规律，发现微生物及其代谢与醇、醛、酮、酯、有机酸、芳香族化合物和杂环化合物等特征风味物质形成的关系，初步明确了特征风味物质形成的微生物途径和机理。.⑥ 研究了酿造条件对红枣白兰地特征香气成分的影响，提出了利于红枣白兰地特征香气形成的酿造条件。