新疆蟠桃特征香气指纹图谱构建及基于多重变量解析的香气丧失机制研究

Xinjiang oblate-peach is one kind of regional characteristics fruit resources. Currently, some problems, such as the aging of cultivars, the endangerment of the wild species, and the significant loss of intense aroma during the processing for storage, transportation, and selling, have become the bottleneck of restricting the development of Xinjiang oblate-peaches industry, and then resulting in a substantial reduction in the acreage. In this project, based on the germplasm survey and the analysis of previous research, volatile compounds in oblate-peach samples collected from different producing regions in Xinjiang were analyzed by GC-MS and GC-O. Then, a flavor fingerprint of Xinjiang oblate-peaches was established combined with the clustering analysis and similarity analysis. The flavor fingerprint was validated by using the chemometrics method (PCA and PLS-DA) to determine the accuracy and effectiveness on the quality control of oblate-peaches. Aroma components databases of Xinjiang oblate-peach samples under different storage conditions were established by adopting the above methods for detection and analysis. Meanwhile, differentially fruit proteins databases of those corresponding samples were also created by using the technologies of isotope tagging for relative and absolute protein quantitation (iTRAQ) and liquid chromatography-electrospray ionization mass spectrometry/mass spectrometry (LC-ESI-MS/MS).In order to determine quantitative structure and activity relationships (QSAR), an overview of potential correlations among the samples, odor-active volatiles, and differentially expressed proteins was obtained through partial least square regression (PLSR) on the basis of some indentification joint technologies (eg. preparative high performance liquid chromatography-mass spectrometry, PHPLC-MS). Through the above analysis, it can be determined which effector proteins contribute greatly to each of the characteristic flavor compounds, further revealing the loss mechanism of Xinjiang oblate-peaches characteristic flavor. The anticipated results of this research serve as a theoretical basis for the optimization of planting resources, the improvements of controlled flavor technologies and the upgrading of product quality. The results related with this project and other continuity exploration will play an important role in promoting the development of Xinjiang oblate-peaches industry.

新疆蟠桃为区域特色林果资源，目前其栽培品种结构老化、野生品种趋于濒危及贮藏销售期浓郁香气明显丧失等问题，已成为限制新疆蟠桃产业发展的瓶颈，致使种植面积大幅度减少。本项目在对新疆蟠桃种质资源调查及前期研究成果总结分析的基础上，采用GC-MS-O联用技术分析新疆不同产区蟠桃香气组分，以系统聚类和相似度法构建新疆蟠桃特征香气指纹图谱，结合PCA及 PLS-DA鉴别模型验证其对品质鉴别与监控的准确有效性；利用以上分析手段建立不同贮藏样品香气组分数据库的同时，采用iTRAQ及LC-ESI-MS/MS技术构建相应贮藏样品果实差异蛋白数据库，结合PLSR多重变量回归分析及PHPLC-MS等分离鉴定技术研究不同样本子集中香气物质和差异表达蛋白间的量化与构性关系，挖掘并验证与特征香气相关的效应蛋白，深入解析新疆蟠桃香气丧失的分子机制。预期为新疆蟠桃种植优化、呈香调控等技术改进及产品品质升级提供坚实理论基础。

新疆蟠桃为新疆特色林果资源，目前现有大多数蟠桃品种风味品质不稳定，其浓郁香气在贮藏、运输及销售过程中丧失程度明显，此问题已经成为限制蟠桃产业发展的瓶颈。本项目在对蟠桃种植资源调查统计基础上，采用GC-O-MS对不同主产区蟠桃香气组分进行分析，以系统聚类和相似度法，确认特征香气指纹信息，构建蟠桃特征香气指纹图谱库；同时采用iTRAQ及LC-ESI-MS/MS技术结合PLSR多重变量回归对不同贮藏蟠桃样本中香气物质和差异表达蛋白间的量化与构性关系进行探讨。研究获得的概要成果如下：. 利用SPME-GC-MS对蟠桃鲜果中挥发性成分进行分析，结合聚类分析(CA)优选品质较佳样品，共筛选出15种共有挥发性成分作为蟠桃特征物质构建指纹图谱；通过精密度、重复性和稳定性实验及相似度分析对所建立的蟠桃指纹构建方法进行验证，结果显示该方法符合指纹图谱建立的要求。在此基础上，依据所建立的指纹信息，采用主成分分析(PCA)及偏最小二阶回归(PLS)对不同水果样品进行对照研究，显示PCA和PLS基本能将蟠桃鲜果与其它果品明显区分，结合PLS载荷分析，确定了蟠桃与其它果品间风味差异重要组分，为蟠桃鲜果品质控制和系列风味产品的开发提供科学依据。. 筛选建立适应蟠桃蛋白质的提取方法，在不同贮藏条件基础上，筛选5个风味差异显著的样本，以新鲜蟠桃样本为对照，采用差异蛋白质组学技术，对不同香气丧失程度的果实蛋白质表达谱进行比较，并对差异表达蛋白质进行分析鉴定。. 结合差异蛋白表达模式聚类法从1101种极显著差异表达蛋白中筛选获得了共性差异蛋白。通过差异蛋白作用通路结合PLSR模型，挖掘并验证与特征香气相关的效应蛋白，明晰了蟠桃香气物质变化与差异蛋白之间存在可预见的多重相关性，初步解析了新疆蟠桃香气丧失的分子机制。预期为新疆蟠桃种植优化、呈香调控等技术改进及产品品质升级提供坚实理论基础。