TR Dizin İndeksli Yayınlar / TR Dizin Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7149

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2014 - 20203

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Department: search.filters.department.İzmir Institute of Technology. Food EngineeringPublisher: search.filters.publisher.Türk Biyokimya Derneği

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    In Vitro Assessment of Food-Derived Bioaccessibility and Bioavailability in Bicameral Cell Culture System
    (Türk Biyokimya Derneği, 2020) Özel Taşcı, Cansu; Pilatin, Gözde; Edeer, Özgür; Güleç, Şükrü
    Background: Functional foods can help prevent metabolic diseases, and it is essential to evaluate functional characteristics of foods through in vitro and in vivo experimental approaches. Objective: We aimed to use the bicameral cell culture system combined with the in vitro digestion to evaluate glucose bioavailability. Materials and methods: Cake, almond paste, and pudding were modified by adding fiber and replacing sugar with sweeteners and polyols. Digestion process was modeled in test tubes. Rat enterocyte cells (IEC-6) were grown in a bicameral cell culture system to mimic the physiological characteristics of the human intestine. The glucose bioaccessibility and cellular glucose efflux were measured by glucose oxidase assay. Results and discussion: The glucose bioaccessibilities of modified foods were significantly lower (cake: 2.6 fold, almond paste: 9.2 fold, pudding 2.8 fold) than the controls. Cellular glucose effluxes also decreased in the modified cake, almond paste, and pudding by 2.2, 4, and 2 fold respectively compared to their controls. Conclusion: Our results suggest that combining in vitro enzymatic digestion with cell culture studies can be a practical way to test in vitro glucose bioaccessibility and bioavailability in functional food development.
  • Article
    Kinetic and Structural Characterization of Interaction Between Trypsin and Equisetum Arvense Extract
    (Türk Biyokimya Derneği, 2014) Uslu, Mehmet Emin; Bayraktar, Oğuz; Ceylan, Çağatay
    Objective: In this study the inhibitory effect of E. arvense extract on trypsin activity and the effect of trypsin on E. arvense extract were studied. In addition the nature of the interaction between the extract and trypsin was investigated. Methods: The inhibitory effect ethanol extract of E. arvense on trypsin activity was determined using trypsin enzyme assay. The structural effects of the extract-trypsin interaction for the extract were analyzed by FTIR. Finally, the HPLC analyses were carried out to analyze the individual components of the extract and the supernatant and soluble precipitate phases. Results: E. arvense extract was found to decrease total percent activity of trypsin to 5% in 24 hour at 24 °C. FTIR analyses indicated that the interaction between trypsin and E. arvense extract caused changes in the structure and hydrogen bonding behavior and composition of the extract proteins. These interactions also caused the extract lipids to accumulate in the insoluble precipitate phase. Most of the phenolics remained in the supernatant phase enhancing the inactivation of trypsin. However, the precipitated compounds were shown to be of apolar in nature as shown in the HPLC chromatograms. Conclusion: The methods that were used showed that the high phenolic content of E. arvense was the main reason for the inhibition of trypsin enzyme activity by denaturing the enzyme.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 2
    Structural and Functional Characterization of Solution, Gel, and Aggregated Forms of Trypsin in Organic Solvent-Assisted and Ph-Induced Phase Changes
    (Türk Biyokimya Derneği, 2015) Ceylan, Çağatay; Karaçiçek, Bilge
    In this study the effect of three different physicochemical parameters on pHtriggered gelation and aggregation of bovine pancreatic trypsin changes and structural and functional changes in these changes in alcohol-water mixtures were studied. Methods: Trypsin gelation times were studied using inverted tube method. Trypsin stability was studied using trypsin enzyme assay. Protein secondary structural changes were monitored using FTIR spectroscopy. Gel and aggregate macrostructures and morphologies were viewed using Scanning Electron Microscopy. Results: The solution phase was observed in the absence of both NaOH and CaCl2. The gel phase was observed in the absence of the either. The aggregate phase was observed in the presence of the both agents all depending on trypsin concentrations used. Trypsin stability studies showed that there were a nearly 53 and 32% specific activity losses after the gelation and aggregation processes. According to FTIR studies β–sheet structure in 1637 cm-1 band disappeared in trypsin gel and trypsin aggregates. Increases in α–helix structure in 1651 cm-1 in trypsin gel and aggregates were observed. Iodoacetamide delayed the gelation and prevented the aggregation indicating the importance of intermolecular disulfides in the both processes. Conclusion: Trypsin gelation was caused by the denaturation of the protein three dimensional structures. The gel and aggregate formation indicates a secondary structural change towards α–helix structure formation at the expense of β–sheet structure and formation of intermolecular disulfide bonds.