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    The effect of flours of different immature cereal grains on sourdough and sourdough bread: Microbiological, rheological, textural and sugar profiles
    (Wiley, 2022) Alkay, Zuhal; Yilmaz, Mustafa Tahsin; Can, Asli Muslu; Ispirli, Humeyra; Dertli, Enes
    In this study, the utilization of LAB (Lactiplantibacillus plantarum, Levilactobacillus brevis, Furfurilactobacillus rossiae, Weissella cibaria) cultures with selected flours of different immature cereal grains (wheat, barley, oat and rye) on sourdough and sourdough bread was investigated. In total, 16 different sourdough breads were produced and microbiological, pH, TTA and rheological properties of sourdoughs at 0, 8 and 24 h were determined. At the beginning of the fermentation, while sourdoughs showed elasticity, they showed viscoelastic properties after 24 h of fermentation. The sugar profile of cereal grains at the stage of milk formation and the sugar groups presented in EPSs isolated from sourdoughs were revealed by HPLC analysis. The sugar groups in sourdoughs were glucose, xylose and arabinose, while the sugars in the immature cereal grains were glucose, fructose and mannose. The highest EPS production level (1882.69 +/- 8.16) was observed in immature barley flour and Lpb. plantarum containing sourdough and all sourdoughs were found to contain glucan type EPSs. It was observed that the amount of EPS produced by the related species differed significantly under different grain conditions. Besides, it was observed that the sourdough breads produced were harder than the control bread. Novelty Impact Statement Wheat, barley, oat and rye immature grains and four distinct LAB strains were used during sourdough fermentation. Immature grain type and LAB strain used were determinants for in situ exopolysaccharide (EPS) production. Viscoelastic properties of sourdough and textural properties of sourdough bread were affected by grains and LAB strain utilized.
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    Physicochemical and structural characterisation of a branched dextran type exopolysaccharide (EPS) from Weissella confusa S6 isolated from fermented sausage (Sucuk)
    (Elsevier, 2024) Ozpinar, Fatma Beyza; Ispirli, Huemeyra; Kayacan, Selma; Korkmaz, Kader; Dere, Sevda; Sagdic, Osman; Alkay, Zuhal
    Exopolysaccharide (EPS) producing Lactic Acid Bacteria (LAB) species can be presented in distinct environments. In this study, Turkish fermented sausage (sucuk) was tested for the presence of EPS producer LAB strains and slimy-mucoid colonies were selected for further tests. Among the isolates, Weissella confusa strain S6 was identified and tested for the physicochemical characterisation of its EPS. This strain was found to produce 0.74 g L-1 of EPS in modified BHI medium conditions. Structural characterisation of EPS S6 by 1H and 13C NMR demonstrated that EPS S6 was a highly branched dextran type glucan formed by mainly (1 -* 2)-linked alpha-D- glucose units together with low levels of (1 -* 3)-linked alpha-D-glucose units as branching points. This structure was further confirmed by methylation analysis detected by GC-MS. An average molecular weight of 8 x 106 Da was detected for dextran S6. The FTIR analysis supported the dextran structure and revealed the presence of distinct functional groups within dextran S6 structure. A strong thermal profile was observed for dextran S6 detected by DSC and TGA analysis and dextran S6 revealed a degradation temperature of 289 degrees C. In terms of physical status, dextran S6 showed amorphous nature detected by XRD analysis. SEM analysis of dextran S6 demonstrated its rough, compact and porous morphology whereas AFM analysis of dextran S6 detected in its water solution showed the irregularity with no clear cross -link within the dextran chains. These technological features of dextran S6 suggests its potential to be used for in situ or ex situ application during meat fermentations.
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    VIRULENCE FACTORS, ANTIBIOTIC RESISTANCE, AND ANTIMICROBIAL ACTIVITY OF ENTEROCOCCUS SPP. ISOLATED FROM DIFFERENT SOURCES IN ALGERIA
    (Slovak Univ Agriculture Nitra, 2021) Houicher, Abderrahmane; Alkay, Zuhal; Bourahla, Mahdi; Dertli, Enes
    This study aimed to isolate and identify different Enterococcus spp. from diverse sources including dromedary raw milk, rhizospheric soil and natural saline water samples and to determine their antimicrobial activities and safety aspects. From these sources, distinct strains of E. faecium, E. durans, E. hirae, and E. gallinarum species were detected. No virulence factors were observed for six Enterococcus strains while none of the tested Enterococci harboured the genes encoding cytolysin and aggregation substance. All tested strains showed a high sensitivity to many antibiotics, particularly vancomycin, and exhibited a remarkable antagonist activity toward Salmonella typhimurium, Fusarium graminearum and Penicillium expansum. PCR testing of enterocins revealed the co-presence of entA and entB among all tested Enterococci. No hemolytic reaction was also detected in Enterococci isolates, except for six strains. Based on these findings, potential candidates for use as biocontrol agents or probiotic starters were selected for further studies.