Research on Some Factors Influencing Acid and Exopolysaccharide Produced by Dairy Propionibacterium Strains Isolated from Traditional Homemade Turkish Cheeses

Abstract

<jats:p>In this study, a total of 32 isolated strains and 5 reference strains of dairy propionibacteria were analyzed for acid and exopolysaccharide (EPS) production in skim milk and yeast extract–lactate broth (YEL) media in order to investigate the physiological background and preservative role of acid and EPS. The effects of final culture pH and optical density on acid and EPS production were also determined. On average, all strains produced more acid and reached lower final pH values in skim milk than in YEL medium. While the correlations obtained between the acid produced by propionibacterium strains and their final culture pH in skim milk medium were significant (P &amp;lt; 0.01), no correlations were found between optical density, final pH, and produced acid in YEL medium. Sixteen isolated and five reference strains of propionibacteria were tested further for the ability to produce propionic and acetic acids. On average, Propionibacterium freudenreichii subsp. shermanii and P. freudenreichii subsp. freudenreichii strains produced higher amounts of propionic and acetic acids than did Propionibacterium jensenii in YEL medium. The acid produced by these strains may be used as a preservative in the food industry for replacement or reduction of the increasing use of chemical additives. The EPS production by propionibacterium strains during growth in YEL medium was 72 to 168 mg/liter, while in skim milk it was 94 to 359 mg/liter. The monomer compositions of the EPSs formed by the six selected dairy propionibacteria strains were analyzed. The EPSs may have applications as food grade additives and viscosity-stabilizing agents.</jats:p>

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods

“…Yogurt, Swiss-type, and Cheddar cheeses represent suitable food matrices for the delivery of the hypocholesterolemic EPS-producer strain L. mucosae DPC 6426 (Ryan et al, 2015). Other microorganisms with potential to produce EPS in cheese are P. freudenreichii KG15/KG6, Lactococcus lactis SMQ-461 or S. thermophilus MR-1C (Dabour et al, 2005; Darilmaz and Gumustekin, 2012). Significant levels of EPS can also be produced in kefir by L. plantarum YW11 (Wang et al, 2015).…”

Bile salt deconjugation activity of Propionibacterium strains and their cholesterol co‐precipitation abilities

“…In this study, all the strains of propionibacteria used were isolated from traditional home‐made Turkish cheeses. Although important probiotic characteristics of these strains have been studied (Onal Darilmaz et al ; Onal Darilmaz and Gumustekin ; Onal Darilmaz and Beyatli , b; Onal Darilmaz ; Yuksekdag et al ), their abilities to deconjugate bile salts and co‐precipitation of cholesterol activities were unknown. We aimed to determine bile salt deconjugation activities and co‐precipitation of cholesterol of these strains before further in vivo studies.…”

“…In our previous studies, Propionibacterium spp. strains (SP3, DO8, BSM1, BDP11, BDP6, DO6 and AKP1) showed viability at pH 2, 3 and 4 and 0.06, 0.15 and 0.3% bile salts (Onal Darilmaz and Gumustekin ; Onal Darilmaz ). These findings demonstrate that these seven strains will not only survive the low pH of the stomach but also may be able to grow and colonise in the high bile conditions of the intestine.…”

“…freudenreichii DO8, SP3, P. freudenreichii subsp. shermanii BSM1, Propionibacterium jensenii BDP6, BDP11, DO6 and Propionibacterium thoenii AKP1), which were identified and selected from 61 strains isolated from six different kinds of traditional home‐made Turkish cheese samples (Table ), exhibited the highest exopolysaccharide production, resistance to different pH conditions and bile salt concentrations, and gastrointestinal transit tolerance (Onal Darilmaz et al ; Onal Darilmaz and Gumustekin, ; Onal Darilmaz and Beyatli, , ; Onal Darilmaz, ). To prepare active cultures for the experiments, Propionibacterium spp.…”

Relationship between gastrointestinal tolerance and exopolysaccharide production of propionibacteria strains under different pH and bile conditions

“…freudenreichii SP4, P. freudenreichii subsp. shermanii BSM1 and P. jensenii MP7, BDP11) EPS production and resistance to different pH conditions and bile salt concentrations (Darilmaz and Beyatli ,b and Darilmaz and Gumustekin ). Prior to experimental use, organisms were subcultured at least three times in yeast extract lactate broth (YEL; 1% peptone, 1% yeast extract, 1% sodium lactate, 0.025% w/v K 2 HPO 4 , 0.05% w/v MnSO 4 , pH 7.0) at 30 °C for 48 h (exponential growth phase) under anaerobic conditions (Malik et al .…”