Use of selected Strains of Lactic Acid Bacteria to improve the technological characteristics and quality of Fermented Goat Milk

In recent years, goat’s milk has gained increasing importance in human nutrition due to its numerous positive properties, such as the lower allergenic characteristics and the greater digestibility compared to cow’s milk. On the other hand, the production of fermented milk from goat’s milk shows, from a technological point of view, a critical aspect due to obtaining clots with consistency and viscosity not comparable to that of cow’s milk, or in any case poorly acceptable by the consumer. This issue can be overcome by using tailor-made microbial starters capable of producing thickening and gelling substances such as exopolysaccharides (EPS). In this study 12 strains of lactic acid bacteria, i.e. Lactobacillus bulgaricus and Streptococcus thermophilus previously isolated from homemade dairy products, were selected for their ability to produce EPS in synthetic medium, their growth and acidification kinetics in goat’s milk. Finally, 4 strains were used for the production of fermented goat and cow milks which were characterized for their EPS content, texture, profile in soluble proteins (by SDS-page electrophoresis) and in volatile molecules (by SPME/GC-MS analysis). The results of this study showed that the combination of all the selected strains led to acidification kinetics comparable to those of cow’s milk, giving rise to products with acceptable texture thanks to the production of EPS. Furthermore, the fermented goat milks were characterized by a balanced profile in aromatic molecules with some volatiles frequently identified also in commercial products. This biotechnological intervention, based on the use of appropriately selected starters able to produce EPS, represents an innovative strategy consistent with the increasing consumers’ demand for products without additives and preservatives