USE OF EPS PRODUCING BIFIDOBACTERIUM AESCULAPII STRAINS TO IMPROVE TEXTURE AND QUALITY OF SOY MILK BASED FERMENTED MILKS

Functional foods represent one of the fastest growing areas in the food industry because considered a dietary strategy to reduce illness. The development of dairy functional products has become an important subject. Consumers have increased the demand for low/fat-free, but also smooth and creamy, functional dairy products. Since milk fat contributes to flavour and texture of the dairy products, its removal leads to textural defects. So several attempts have been made to increase the textural and quality properties of these products. Among the strategies, the use of strains able to produce exopolysaccharides (EPS) has been suggested as an alternative to additives such as xanthan, pectin and carrageenan. So, the use of EPS-producing Bifidobacterium aesculapii strains was proposed for to obatain functional fermented milks from soy milk. Seven strains of B. aesculapii, recently described, able to ferment lactose and producing an exocellular gelling matrix, were employed for the fermentation of soy-milk. The strains were inoculated (7.5 log cfu/ml) and incubated at 37°C. The resulting fermented milks were subjected to EPS and volatile molecule profiles (GC/MS-SPME) analysis and Texture Analyzer. Also the survival of B. aesculapii in the products was checked during the refrigerated storage. The results showed all the strains were able to grow in soymilk and to reach a final concentration of 9.0 log cfu/ml. The strains produced large amount of EPS in products. The fermented milks were characterized by specific volatile molecule profiles. Generally, the strains able to produce the major amount of EPS resulted in more viscous products. The results obtained have highlighted the chance to exploit EPS producing Bifidobacterium aesculapii strains to produce fermented milks characterized by specific “aromagramma and texture properties. These results could be exploited also to expand the market of fermented soy-milk products by using a biotechnological approach enhancing also the overall product quality.