Application and viability of autochthonous spray dried potential probiotic lactic acid bacteria in food and gastrointestinal conditions

Abstract

Increasing consumer concerns about health, as well as inadequate nutrition, have led to great interest in foods enriched with additional functional components, referred to as functional foods. Particular importance is devoted to the functional food with probiotic bacteria. Autochthonous lactic acid bacteria isolated from traditional cheeses represent an endless source of new strains with various metabolic activities, which allows the selection of potential probiotic strains. In addition, spray drying of probiotic strains is frequently used due to significantly better survival during storage of product, as well as through the passage in the gastrointestinal tract. The aim of this doctoral thesis is the isolation and selection of potential probiotic bacteria from traditional cheeses, testing their viability and probiotic characteristics after microencapsulation by spray drying, application in the production of yogurt, cheese from ultrafiltered (UF) milk and dark chocolate, the viability of probiotics and sensory quality of products, as well as establishing the ability of potential probiotic bacteria to survive gastrointestinal conditions. From 5 samples of Pirot‗s kashkaval and 2 samples of Sjenica cheese, there were 61 isolates. Based on morphological, physiological and technological characteristics, 9 isolates were selected for identification and testing of potential probiotic characteristics. Based on the ability to survive simulated gastrointestinal conditions, antibiotic resistance and antimicrobial activity, two potential probiotic bacteria, Lactobacillus plantarum 564 and Lactobacillus paracasei Z8 were selected for further testing. The selected strains were microencapsulated by spray drying technique, after which the viability of potential probiotic cells and ability to survive simulated gastrointestinal conditions were examined. Viability was assessed by the plate-counting method and real time PCR combine with propidium monoazide (PMA) - treatment...

Sve veća briga potrošača o zdravlju, kao i neadekvatna ishrana, doveli su do velikog interesovanja za hranu obogaćenu dodatnim funkcionalnim komponentama, pri čemu je uveden pojam funkcionalne hrane. Poseban značaj se pridaje funkcionalnoj hrani sa probiotskim bakterijama. Autohtone bakterije mlečne kiseline izolovane iz tradicionalnih sireva predstavljaju neiscrpan izvor novih sojeva, različitih metaboličkih aktivnosti, što daje mogućnost selekcije novih potencijalnih probiotskih sojeva. Pored toga, sprej sušenje probiotskih sojeva ima sve veću primenu, usled značajno bolje odrţivosti probiotika tokom skladištenja proizvoda, kao i tokom prolaza kroz gastrointestinalni trakt. Cilj ove doktorske disertacije jeste izolacija i selekcija potencijalnih probiotskih bakterija, ispitivanje njihove vijabilnosti i probiotskih karakteristika nakon mikroinkapsulacije sprej sušenjem, primena u proizvodnji jogurta, sira od ultrafiltriranog (UF) mleka i crne čokolade, utvrĎivanje vijabilnosti probiotika i senzornog kvaliteta navedenih proizvoda, kao i sposobnost preţivljavanja potencijalnih probiotskih bakterija u gastrointestinalnim uslovima. Iz 5 uzoraka Pirotskog kačkavalja i 2 uzorka Sjeničkog sira, izolovano je ukupno 61 izolat. Na osnovu morfoloških, fizioloških i tehnoloških karakteristika, 9 izolata je selektovano za identifikaciju i ispitivanje potencijalnih probiotskih karakteristika. Na osnovu rezultata sposobnosti preţivljavanja simuliranih gastrointestinalnih uslova, rezistencije na antibiotike i antimikrobno delovanje, za dalja ispitivanja selektovane su dve potencijalne probiotske bakterije, Lactobacillus plantarum 564 i Lactobacillus paracasei Z8. Selektovani sojevi su inkapsulisani tehnikom sprej sušenja, gde je nakon mikroinkapsulacije ispitivana vijabilnost sprej sušenih potencijalnih probiotskih ćelija i sposobnost preţivljavanja simuliranih gastrointestinalnih uslova...