Exopolysaccharide production and degradation by lactic acid and probiotic bacteria: a functional approach to improve their applications in food and health

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Exopolysaccharides (EPS) are carbohydrate polymers that can improve food texture and influence the microbial community of the intestine. The aim of this research program is to understand how the structural characteristics determine the functional properties of EPS. By manipulating composition and molecular mass, we will be able to investigate the effect of these parameters on the functional properties of EPS in food, in models of the gastrointestinal microbiota and in interactions with human mucosal and immune cells. However, EPS yield varies greatly among the strains we have studied, indicating possible differences in regulation and degradation. The first theme of this research program is to elucidate the mechanisms of gene and protein regulation to understand how exopolysaccharide production is coordinated by environmental signals and metabolism. The second theme is to investigate the mechanisms determining the molecular mass of EPS with the aim of manipulating EPS size distribution for testing in dairy food systems and in interactions with human cells. EPS with lower molecular mass will be produced using enzymes. This will contribute to the development of viscosifying ingredients that can influence the rheological properties of fermented milk products. The third theme is to investigate the interactions of EPS with the gut microbiota (pathogens and probiotic bacteria) and with host cells (mucosal and immune modulating cells) in order to comprehend functional mechanisms and the impact of polymer structure on these interactions. Understanding gene function and regulation in probiotic and lactic acid bacteria is essential for improving yogurt and cheese starter microorganisms, as well as for preventing food spoilage and developing functional foods and ingredients that have a beneficial impact on human health. This research will stimulate innovation by the Canadian dairy and functional food industries to improve dairy processing and develop functional food ingredients. In 2013, Canada produced 78 million hectolitres of milk and Canadian milk and dairy products worth $15.7 billion represent 16% of the total value of manufactured food and beverages. The dairy processing industry employs close to 23,000 people across Canada in 465 dairy processing establishments. There are over 750 Canadian companies specialized in functional foods and natural health products, generating more than $11 billion in revenues, which is about 2.5% of global sales. Continued future growth is projected, given the significant consumer demand for products related to health and wellness. These sectors require support in knowledge base and personnel. From a Statistics Canada survey in 2013, scientific R&D, technical or engineering staff were identified as the critical competencies for reaching strategic goals by functional food establishments while representing the greatest needs in unfilled positions.