基于组学方法研究益生菌干酪成熟过程微生态变化及品质形成机制

With increased awareness of human health and demands for probiotic products, research and processing of probiotic cheese also increased constantly. However, there is still little knowledge about the mechanism of probiotic survival and functionality in the cheese matrix, and the effect of probiotics on microecological changes and quality formation mechanism during cheese ripening. In the present study, several probiotic lactobacillus and bifidobacterial strains previously isolated in our lab will be used as adjunct cultures to manufacture probiotic Cheddar cheese. Metagenomics methods will be used to study the effect of the probiotic strains on microbial flora changes and functional genes in cheese matrix, in order to elucidate the intrinsic factors influencing the probiotic survival, and the stress effect on probiotics during cheese processing process and in the microenvironment of cheese matrix. Proteomics methods will be used to study various enzymes produced in the cheese matrix by the probiotics, starter and nonstarter microbes, the enzymatic hydrolysis of proteins and lipids, and their effects on cheese microstructure and quality. By studying deeply the cheese functionality and quality formation mechanism, the results of this study will provide scientific basis for effective control of probiotic cheese quality, and for establishment of probiotic cheese product and technical standards. The present study will be of both theoretical and practical significance in enhancing the processing technology of cheese products suitable for Chinese consumers, and in developing probiotic cheese products, as well as promoting the development of cheese industry in China.

随着人们健康意识及对益生菌产品需求的增强，有关益生菌干酪的研究和加工也不断增多。但是对于干酪成熟阶段益生菌的存活机制及其功能性、以及益生菌作用下的干酪微生态变化和品质形成机制仍然了解甚少。本研究利用课题组分离筛选的数株益生性乳杆菌和双歧杆菌作为辅助发酵剂制作切达干酪。采用宏基因组学方法研究干酪成熟阶段基于益生菌作用下的微生物菌群变化及功能基因，揭示影响益生菌存活的内在因素，以及加工过程和干酪基质微环境对益生菌的胁迫效应。采用蛋白质组学方法研究干酪成熟阶段益生菌、主发酵剂和非发酵剂微生物所产生的各种酶及酶促蛋白质分解和脂解、及其对干酪微观结构和品质的影响。深入研究益生菌干酪的功能性和品质形成机制，为有效地控制益生菌干酪的品质,建立益生菌干酪产品和技术标准提供科学依据。本项研究对于提升适于我国消费特点的干酪加工技术水平和益生菌干酪产品的研制、以及促进我国干酪产业的发展具有重要的理论和实际意义。

干酪成熟阶段益生菌的存活及其功能性、以及益生菌作用下的干酪微生态变化和品质是益生菌干酪研究的热点。本研究利用课题组分离筛选的数株益生性植物乳杆菌作为辅助发酵剂制作切达干酪，采用宏基因组学方法，明确了干酪中微生物的多样性及在成熟过程中的微生物群落演替过程，定量确定了成熟干酪中发酵剂优势菌群不断衰落的过程，Streptococcus（9.22%->4.19%）和Lactobacillus（1.49%->0.46%）；采用基于HPLC-MS-MS的肽组学技术，对干酪成熟过程中的肽的多样性进行了全面分析，获得了干酪成熟过程的肽的种类、构成及益生菌对干酪功能性肽形成的影响，共获得肽段2365条，其中已报道的具有活性的肽段28条，益生菌可以显著增加干酪中活性肽的种类和含量（α<0.05）；研究还明确了益生菌干酪成熟过程中品质的动态变化过程，确定了益生菌添加方式、数量对干酪质构、风味、理化等品质的影响，为开发益生菌干酪新产品，明确益生菌干酪的功能标称提供了理论和技术支撑。项目相关研究内容共发表SCI收录论文8篇，中文核心期刊收录论文20篇，项目负责人出版学术专著一部（主编），获授权发明专利一项，完成全部预期指标。