Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 5Production of Food Grade Ss-Galactosidase From Artisanal Yogurt Strains(Taylor and Francis Ltd., 2010) Tarı, Canan; Üstok, Fatma Işık; Harsa, ŞebnemSuperior artisanal isolates of thermophilic lactic acid bacteria producing high lactic acid and β-galactosidase were isolated from traditional Turkish yogurt samples from the Toros mountain region from a highly bio-diverse environment. A full factorial statistical design, with the factors of types of strains and medium formulations under static and agitation conditions, were applied to investigate the effects on β-galactosidase and lactic acid production. Streptococcus thermophilus 95/2 and Lactobacillus delbrueckii subsp. thermophilus 77 exhibited remarkable potential as promising starter culture candidates valuable to various applications in the dairy industry. The efficiency of cell disruption methods was investigated on the extraction of intracellular β-galactosidase enzyme. Lysozyme enzyme treatment was determined as the most effective method, which resulted in approximately 1.5 and 10 times higher enzyme activity than glass bead and homogenization treatment, respectively. © Taylor & Francis Group, LLC.Article Citation - WoS: 19Citation - Scopus: 22Optimization of the Associative Growth of Novel Yoghurt Cultures in the Production of Biomass, Ss-Galactosidase and Lactic Acid Using Response Surface Methodology(Elsevier Ltd., 2009) Tarı, Canan; Üstok, Fatma Işık; Harsa, Hayriye ŞebnemThe associative growth of Streptococcus thermophilus 95/2 (St 95/2) and Lactobacillus delbrueckii ssp. bulgaricus 77 (Lb 77) isolated from the Toros mountain region of Turkey was investigated with respect to lactic acid, biomass and β-galactosidase enzyme production using response surface methodology (RSM). The ratio (St 95/2:Lb 77) of the strains and media formulation had significant effect on all responses (p < 0.001). The predicted enzyme activity (2.14 U mL-1), lactic acid (22.50 g L-1) and biomass (7.11 g L-1) production at optimum conditions were very close to the actual experimental values (2.14 U mL-1, 22.94 g L-1 and 7.86 g L-1, respectively). The optimum conditions were to use these cultures in a ratio of 1.66:1.62 (St 95/2:Lb 77) in a medium containing whey (5%), corn steep liquor (4%), potassium phosphate (2%) and peptone (2%) at 43 °C for 8 h. The associative growth provided 6.4% and 39% more β-galactosidase activity and 8.73% and 44% more lactic acid compared with the results obtained using pure St 95/2 and Lb 77 strains, respectively.