Food Engineering / Gıda Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/12

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Author: search.filters.author.Tarı, CananSubject: search.filters.subject.Streptococcus thermophilus

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  • Article
    Citation - WoS: 3
    Citation - Scopus: 5
    Production of Food Grade Ss-Galactosidase From Artisanal Yogurt Strains
    (Taylor and Francis Ltd., 2010) Tarı, Canan; Üstok, Fatma Işık; Harsa, Şebnem
    Superior 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: 48
    Citation - Scopus: 59
    Biochemical and Thermal Properties of Ss-Galactosidase Enzymes Produced by Artisanal Yoghurt Cultures
    (Elsevier Ltd., 2010) Üstok, Fatma Işık; Tarı, Canan; Harsa, Şebnem
    β-Galactosidases, produced by pure and mixed cultures of Streptococcus thermophilus 95/2 (St 95/2) and Lactobacillus delbrueckii ssp bulgaricus 77 (Lb 77) isolated from the Toros mountain region of Turkey, were characterised with respect to their biochemical and thermal properties. Optimum pH and temperature for maximum activity were determined and these enzymes were stable in the pH range 7-9 and in the temperature range 20-37 °C, retaining 80-90% of their initial activities. The inactivation energies of β-galactosidase from Lb 77, St 95/2 and mixed culture (Lb 77 and St 95/2) were 51.3, 44.0 and 48.3 kcal mol-1, respectively. Moreover, thermodynamic (ΔG, ΔS, ΔH) and kinetic constants (Km and Vmax) were determined and effects of metal ions were investigated. As a result, these enzymes could be considered as potential candidates for lactose hydrolysis of milk and milk products. © 2009 Elsevier Ltd. All rights reserved.