Production of fermented probiotic beverages from milk permeate enriched with whey retentate and identification of present lactic acid bacteria

U ovom radu istražena je mogućnost primjene bakterijskih sojeva Lactobacillus helveticus M92, Lactobacillus plantarum L4 i Enterococcus faecium L3 za proizvodnju probiotičkih napitaka od permeata mlijeka, obogaćenih sa 10 % (v/v) retentata sirutke. U prethodnim istraživanjima, sklopu probiotičkog koncepta, definirana su probiotička svojstva navedenih sojeva bakterija mliječne kiseline. Nakon kntrolirane fermentacije permeata mlijeka obogaćenih sa 10 % (v/v) retentata sirutke, probiotički sojevi su proizveli cca 7,4 g/L mliječne kiseline, pH-vrijednost iznosila je oko 4,7, a broj živih stanica je bio cca 108 CFU/mL. Broj živih stanica primijenjenih probiotičkih sojeva, identificiranih RAPD (Random Amplified Polymorphic DNA) metodom, održao se na cca 107 CFU/mL tijekom 28 dana čuvanja pri temperaturi od 4 °C. Nadalje, provedena je i spontana fermentacija permeata mlijeka, obogaćenog sa 10 % (v/v) retentata sirutke, tijekom koje su izolirane bakterije mliječne kiseline prisutne u ovim supstratima. Svi bakterijski izolati su brzo zakiselili hranjivu podlogu i pokazali antibakterijsko djelovanje prema odabranim test-mikroorganizmima, što su važna svojstva potencijalnih starter kultura za fermentaciju mliječnih proizvoda. Rezultati biokemijskih API testova pokazali su da je riječ o dvije različite vrste bakterija mliječne kiseline koje su identificirane kao Lactococcus lactis subsp. lactis i Lactobacillus helveticus.In this research the application of bacterial strains Lactobacillus acidophilus M92, Lactobacillus plantarum L4 and Enterococcus faecium L3 in the production of fermented probiotic beverages from milk permeate enriched with 10 % (v/v) whey retentate, was investigated. In the previous researches of probiotic concept, probiotic properties of these three strains of lactic acid bacteria have been defined. At the end of controlled fermentation, probiotic strains have produced 7.4 g/L lactic acid, pH was decreased to 4.7, and number of live cells was around 108 CFU/mL. Number of viable count of probiotic bacteria, which were identified with RAPD (Random Amplified Polymorphic DNA)method, was maintained at around 107 CFU/mL during 28 days of the preservation at 4 °C. Furthermore, a spontaneous fermentation of milk permeate enriched with 10 % (v/v) of whey retentate was carried out and lactic acid bacteria present in these substrates were isolated. All of these bacterial strains have rapidly acidified the growth media and have shown antibacterial activity against chosen test-microorganisms, what are important properties of potential starter cultures for the fermentation of dairy products. The results of biochemical API analysis have identified isolated strains as Lactococcus lactis subsp. lactis and Lactobacillus helveticus