Structure - texturizing function relationship of exopolysaccharides in fermented dairy specialities

尽管乳制品消费量总体下降，但2004年至2013年期间，加拿大酸奶消费量的平均年增长率为2.2%（MAPAQ，2014）。酸奶市场份额的增长预计将至少持续到2023年（加拿大，2014年）。酸奶是通过乳酸菌发酵牛奶以获得酸性凝胶的传统产品，其可以作为凝固、搅拌或可饮用的形式商业化。许多因素控制酸性凝胶的性质，如细菌的类型（酸化性质，胞外多糖的产生），乳制品混合物的组成和加工步骤。酸奶中产生胞外多糖（EPS）的乳酸菌菌株已被研究，因为它们天然产生稳定剂，有助于发酵乳制品的质地和保水性。然而，它们对酸奶的物理和感官特性的影响取决于酸奶的类型（凝固或搅拌）和EPS特性。其他乳酸菌也能产生EPS，如双歧杆菌和魏氏菌，但它们在乳制品中的应用很少报道，也没有建立结构-功能关系。我们建议在这个为期一年的项目中展示使用酸奶EPS生产菌株与辅助EPS生产菌株的混合物的真实的潜力，以扩大发酵乳制品的功能，并提供多样化和开发新的创新产品的机会。该项目是一个长期项目之前的第一步，该项目旨在研究使用基于EPS结构-功能关系的创新方法生产EPS菌株及其在混合物中的使用，以建立选择适当菌株的基本原理，从而能够扩大酸性凝胶的功能特性范围。这方面的知识是至关重要的，使乳制品多样化，更基本的支持控制质量属性实际波动的商业产品。除了培训乳制品行业的学生外，这还可以支持该行业的发展，并增加该行业的有价值的工作岗位。

Despite an overall decrease of dairy products consumption, between 2004 and 2013 market trends depicted an average annual growth rate of 2.2% for yogurt consumption in Canada (MAPAQ, 2014). Growth of market share for yogurt is expected to continue at least up to 2023 (Canada, 2014). Yogurt is a traditional product obtained through a fermentation process of milk by lactic acid bacteria to obtain an acidic gel that can be commercialized as set, stirred or drinkable version. Many factors control the properties of acidic gels as the type of bacteria (acidifying properties, exopolysaccharide production), dairy mix composition and processing steps. Yogurt's lactic acid bacteria strains producing exopolysaccharide (EPS) have been studied as they naturally produce stabilizers that could contribute to texture and water retention in fermented dairy products. However, their effect on physical and sensory properties of yogurt depends on the type of yogurt (set or stirred) and on EPS characteristics. Other lactic acid bacteria are also able to produce EPS as Bifidobacteria, and Weissella but their use in dairy products has been seldom reported and no structure-function relationship has been established. We propose in this one year project to demonstrate the real potential of using yogurt EPS producing strains in mixture with adjunct EPS producing strains to widen the functionality of the fermented dairy products and offer diversification and opportunities to develop new innovative products. This project is a first step before a longer term project to investigate use of EPS-producing strains with an innovative approach based on the structure-function relationship of their EPS and their use in mixture to establish a rationale to choose the adequate strains to be able to enlarge the range of functional properties of acidic gels. This knowledge is crucial to allow dairy product diversification and more basically support the control of quality attributes actually fluctuating in commercial products. In addition to training of students available for the dairy industry, this could support the growth of this industry and increase the number of valuable jobs in the sector.