Structure - texturizing function relationship of exopolysaccharides in fermented dairy specialities

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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.