CHARACTERISTICS OF THE BULGARIAN YOGURT LACTIC-ACID BACTERIA-METABOLISM OF LACTOSE

The investigation was made with more than 200 selected strains of lact ic acid bacteria isolated from home-made yoghurt produced in tile high -mountains regions of Bulgaria. 94% of them (LBD strains) were attribu ted to L. bulgaricus spicies and only 6% (KBL strains) were attributed to the species S. thermophilus. The results showed that the LED strai ns utilize glucose completely. The LBL strains partially utilize galac tose and most (or all) glucose derived from lactose hydrolysis. The st arters for Bulgarian yoghurt contain selected strains of L. bulgaricus and S. thermophilus, and the starters for Yana yoghurt contain select ed strains L. helveticus and S.thermophilus. So the symbiotic starters used for production of Bulgarian yoghurt, as well as those used for t he production of Yana yoghurt, guarantee the obtaining of a product wh ich contains over 80% L(+) lactate, and some cases over 93% L(+) lacta te. According to the references of WHO these kinds of yoghurt could be used in child's nutrition.