Unraveling the probiotic efficiency of bacterium Pediococcus pentosaceus OBK05 isolated from buttermilk: An in vitro study for cholesterol assimilation potential and antibiotic resistance status.

The present study describes the probiotic potential and functional properties of the lactic acid bacterium Pediococcus pentosaceus OBK05 isolated from buttermilk. The isolate OBK05 was assessed for its probiotic properties. The isolate showed notable tolerance to pH 2.0 and 3.0 (8.44, 8.35 log CFU/mL), oxbile of 0.5% at 2 and 4 h of incubation (6.97, 6.35 log CFU/mL) and higher aggregation (auto-aggregation, adhesion to hydrocarbons) than the referral strain, Lactobacillus acidophilus MTCC 10307. The adhesion efficiency to HT-29 cells was found to be maximum, corresponding to 93.5% and 97% at 1 and 2 h incubation, respectively. In addition, the isolate OBK05 showed antagonistic solid activity against bacterial pathogens like Pseudomonas aeruginosa MTCC 424 and Bacillus subtilis MTCC 1133. The phenotypic antibiotic resistance of the isolate was examined before and after curing plasmids. Among the known five structural genes responsible for different antibiotic resistance, four genes indicating antibiotic resistance to kanamycin-Aph (3´´)-III, streptomycin-strA, vancomycin-vanA and ciprofloxacin-gyrA were detected by PCR amplification of genomic DNA. Further, the horizontal gene transfer from OBK05 isolate to pathogens was not found for these antibiotic resistance markers when filter and food mating were carried out as no transconjugants developed on media plates containing respective antibiotics. This indicates that the intrinsic resistance is harbored on chromosomal genes, and hence it is nontransferable to other microbes. In addition, strain OBK05 exhibited good DPPH scavenging activity of 56 to 77% and liberated free amino acid from conjugated bile acid. The strain OBK05 demonstrated a strong ability to reduce cholesterol at 12 h (17%), 24 h (27%) and 48 h (67%) of incubation.

Analysis of the Ability to Produce Pleasant Aromas on Sour Whey and Buttermilk By-Products by Mold Galactomyces geotrichum: Identification of Key Odorants.

Currently, there is a growing demand for flavorings, especially of natural origin. It is worth paying attention to the biotechnological processes of flavor production, characterized by simplicity, high efficiency and relatively low cost. In this study, we analyzed the ability of the Galac tomyces geotrichum mold to transform by-products of the dairy industry: sour whey and buttermilk to complex flavour mixtures with pleasant, honey-rose aroma. Furthermore, the aroma complexity of the fermentation product has been carefully identified applying a sensomic approach involving the use of gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and stable isotope dilution assay (SIDA) to identify and quantify aroma compounds. Based on the calculation of odor activity value (OAV), 13 key aroma compounds were present in both tested variants. The highest OAVs were found for phenylacetaldehyde (honey-like) in the buttermilk variant (912) and 2-phenylethanol (rose-like) in the sour whey variant (524). High values of this indicator were also recorded for phenylacetaldehyde (319) and 3-methyl-1-butanol with a fruity aroma (149) in the sour whey culture. The other compounds identified are 3-methylbutanal (malty), 2,3-butanedione (cheesy), isovaleric acid (cheesy), 3-(methylthio)-propanal (boiled potato), butanoic acid (vinegar), (E)-2-nonenal (fatty), ethyl furaneol (burnt sugar), dimethyl trisulfide (cabbage), and acetic acid (vinegar).

Production of Functional Buttermilk and Soymilk Using Pediococcus acidilactici BD16 (alaD+).

Functional foods or drinks prepared using lactic acid bacteria (LAB) have recently gained considerable attention because they can offer additional nutritional and health benefits. The present study aimed to develop functional drinks by the fermentation of buttermilk and soymilk preparations using the Pediococcus acidilactici BD16 (alaD+) strain expressing the L-alanine dehydrogenase enzyme. LAB fermentation was carried out for 24 h and its impact on the physicochemical and quality attributes of the fermented drinks was evaluated. Levels of total antioxidants, phenolics, flavonoids, and especially L-alanine enhanced significantly after LAB fermentation. Further, GC-MS-based metabolomic fingerprinting was performed to identify the presence of bioactive metabolites such as 1,2-benzenedicarboxylic acid, 1-dodecene, 2-aminononadecane, 3-octadecene, 4-octen-3-one, acetic acid, azanonane, benzaldehyde, benzoic acid, chloroacetic acid, colchicine, heptadecanenitrile, hexadecanal, quercetin, and triacontane, which could be accountable for the improvement of organoleptic attributes and health benefits of the drinks. Meanwhile, the levels of certain undesirable metabolites such as 1-pentadecene, 2-bromopropionic acid, 8-heptadecene, formic acid, and propionic acid, which impart bitterness, rancidity, and unpleasant odor to the fermented drinks, were reduced considerably after LAB fermentation. This study is probably the first of its kind that highlights the application of P. acidilactici BD16 (alaD+) as a starter culture candidate for the production of functional buttermilk and soymilk.

Fermented probiotic beverages based on acid whey.

BACKGROUND: Production of fermented probiotic beverages can be a good method for acid whey usage. The obtained products combine a high nutritional value of whey with health benefits claimed for probiotic bacteria. The aim of the study was to define quality properties of beverages based on fresh acid whey and milk with addition of buttermilk powder or sweet whey powder. METHODS: Samples were inoculated with two strains of commercial probiotic cultures: Lactobacillus acidophilus La-5 or Bifidobacterium animalis Bb-12. After fermentation, samples were stored at refrigerated conditions. After 1, 4, 7, 14 and 21 days sensory characteristics, hardness, acetaldehyde content, titratable acidity, pH acidity and count of bacteria cells were evaluated. RESULTS: Throughout all storage period, the number of bacteria was higher than 8 log cfu/ml in the all samples. Beverages with La-5 strain had higher hardness and acidity, whilst samples with Bb-12 contained more acetaldehyde. Samples with buttermilk powder had better sensory properties than with sweet whey powder. CONCLUSIONS: Obtained products made of acid whey combined with milk and fortified with buttermilk powder or sweet whey powder, are good medium for growth and survival of examined probiotic bacteria strains. The level of bacteria was sufficient to provide health benefits to consumers.