Determination of probiotic potential of selected lactic acid bacteria strains

Probiotici su živi mikroorganizmi čijom se uporabom u prehrani, u odgovarajućim količinama, javljaju pozitivni učinci kod korisnika. Potrebno je prilikom karakterizacije bakterija mliječne kiseline (BMK) kao probiotika ispitati niz selekcijskih kriterija koje moraju zadovoljiti kako bi bili djelotvorni. Kriteriji obuhvaćaju održivost bakterija u gastrointestinalnom sustavu te njihovu sigurnost i djelotvornost u organizmu. Cilj ovog rada bila je izolacija i karakterizacija dvaju sojeva BMK kao probiotika, te je u tu svrhu ispitano nekoliko selekcijskih kriterija. Izmjeren je stupanj preživljenja u simuliranom soku želuca i tankog crijeva, sposobnost formiranja biofilma, sposobnost autoagregacije, te hemolitička aktivnost. Izmjeren je i antioksidativni kapacitet preko sposobnosti uklanjanja DPPH slobodnih radikala i određivanjem ukupne unutarstanične koncentracije glutationa.Probiotics are living microorganisms that are used in diet and who, in an appropriate concentration, bring positive effects for the user. When characterizing lactic acid bacteria (LAB) as probiotics, they have to satisfy a number of selection criteria in order to be effective. The criteria include viability of bacteria in the gastrointestinal system, their safety and their effectiveness in an organism. The aim of this study was to isolate and characterize two strains of LAB as probiotics. Several selection criteria were tested for this purpose. The degree of survival in simulated gastric and small intestinal juice, biofilm-forming ability, autoaggregation ability and hemolytic acivity were measured. Antioxidant capacity was measured through the ability to remove DPPH free radicals and by determining total intracellular glutathione concentration