Functionality of probiotic bacteria in lyophilized probiotic preparations

Cilj ovog rada bio je ispitati funkcionalna svojstva bakterijskih sojeva izoliranih iz probiotičkih pripravaka prisutnih na hrvatskom tržištu. Tijekom izlaganja simuliranim uvjetima gastrointestinalnog trakta broj živih stanica svih ispitanih sojeva, osim kod soja Bifidobacterium sp. 3, se održao iznad 106 CFU/ml, pri čemu je najbolje preživljavanje pokazao soj Lactobacillus sp. 1 čiji se broj živih stanica smanjio za samo 1,1 log jedinica. Svi su ispitani sojevi pokazali autoagregacijska svojstva, pri čemu je autoagregacija soja Lactobacillus sp. 8a iznosila 70%, autoagregacija sojeva Lactobacillus sp. 1, Lactobacillus sp. 4, Bifidobacterium sp. 5a i Bifidobacterium sp. 8b oko 50%, a soja Bifidobacterium sp. 3 oko 20%. Bakterijski sojevi Lactobacillus sp. 1, Lactobacillus sp. 8a i Bifidobacterium sp. 8b su koagregirali u najvećem postotku s test-mikroorganizmom Escherichia coli 3014 (cca 40%), a sojevi Lactobacillus sp. 1 i Lactobacillus sp. 8a, i s test-mikroorganizmom Salmonella enterica serovar Typhimurium FP1. Visoki postotak adhezije stanica sojeva Bifidobacterium sp. 3, Lactobacillus sp. 8a i Bifidobacterium sp. 8b na heksan upućuje na njihovu hidrofobnost, a afinitet svih ispitivanih sojeva za kloroform, na elektron-donorska svojstva površine bakterijskih stanica. Svi sojevi pokazuju slabu aktivnost hidrolaze žučnih soli jer su dekonjugirali svega 10-15% taurokolata dodanog u hranjivu podlogu.The purpose of this study was to investigate the functional properties of bacterial strains isolated from probiotic products present on the Croatian market. During exposure to simulated conditions of gastrointestinal tract, the number of living cells of all tested strains, except of strain Bifidobacterium sp. 3, held above 106 CFU/ml, where strain Lactobacillus sp. 1 has shown the best survival since the number of viable cells was decreased only by 1.1 log units. All tested strains have shown autoaggregation properties, whereby strain Lactobacillus sp. 8a autoaggregated 70%, strains Lactobacillus sp. 1, Lactobacillus sp. 4, Bifidobacterium sp. 5a and Bifidobacterium sp. 8b around 50% and strain Bifidobacterium sp. 3 around 20%. Bacterial strains Lactobacillus sp. 1, Lactobacillus sp. 8a and Bifidobacterium sp. 8b have coaggregate relatively high with test-microorganism Escherichia coli 3014 (around 40%), and strains Lactobacillus sp. 1 and Lactobacillus sp. 8a have coaggregate also with test-microorganism Salmonella enterica serovar Typhimurium FP1. A high percentage of adhesion of Bifidobacterium sp. 3, Lactobacillus sp. 8a and Bifidobacterium sp. 8b cells on hexane points to their hydrophobicity, and high affinity of all tested strains to the chloroform points on electron-donor properties of the surface of bacterial cells. All strains showed weak bile salt hydrolase activity since they have deconjugate only 10-15% of taurocolate in the media