Browsing by Author "Ceylan, Çağatay"

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The effect of enzyme use on the formation of carbonyls and structural properties of cakes
(01. Izmir Institute of Technology, 2021-12) Er, Ayşe Ege; Ceylan, Çağatay; Şanlı Mohamed, Gülşah
Enzymes are used as additives to improve the quality parameters of cakes. However, high temperature conditions produce carbonyl-containing compounds as precursors of toxic maillard reaction products. In this study three food grade enzymes were used as agents to decrease the formation of carbonyl-containig compounds while preserving the cake quality factors. For this purpose transglutaminase, lipase and amylase enzymes were used. All of the three enzymes lowered the amounts of carbonyls with the largest decrease by lipase of 31.83% (p<0.05) with respect to the control cake. Transglutaminase and lipase addition changed the carbonyl profile of cakes. Both transglutaminase and lipase caused important changes in protein secondary structures with large increases in alpha helix, turns and anti-parallel beta structures, however, amylase did not cause such large changes. The three enzymes used caused the lipid/protein ratio to decrease. The level of lipid unsaturation did not change for transglutaminase and lipase, however, the level unsaturation decreased in the case of amylase indicating the formation of dicarbonyls was via Maillard reaction not due to lipid peroxidation. However, the GC-MS analysis results indicated that there was no change in the formation of neither the Maillard reaction products nor the lipid oxidation products in the head space analysis. The amorphous structure of the starch in cake samples increased depending on the enzyme concentration used.
The evaluation of antiproliferative and structural effects of statins on non-small-cell lung cancer cell line A549
(Izmir Institute of Technology, 2019-07) Aksoy, Hatice Nurdan; Ceylan, Çağatay; Çağır, Ali
Statins are commonly prescribed anti-lipidemic and anti-cholesterol class of drugs. In addition to their major role, they have been found to have anti-cancer effects on in vitro, animal and clinical studies. The aim of this study was to investigate the structural effects of 6 different statins (rosuvastatin, pravastatin, simvastatin, lovastatin, fluvastatin and atorvastatin) on A549 cells by a spectroscopic method. MTT viability tests were carried out to detect the half maximal inhibitory concentrations (IC50) of each statin on A549 cells. The IC50 values were 50 μM for simvastatin, 150 μM for atorvastatin and pravastatin, and 170 μM for fluvastatin, 200 μM for rosuvastatin and lovastatin on A549 cells. The cells were treated with IC5, IC10 and IC50 values of each statins concentration and their whole cell extracts and lipid extracts were compared using FTIR spectroscopy which is one of the most useful techniques to evaluate the structural changes at the macromolecular functional group level. The results indicated that different statins have different prominent effects on A549 cells. All the statins studied caused observable conformational changes on DNA and proteome of A549 cells. Whereas atorvastatin led to lipidation, lovastatin and pravastatin indicated enormous lipid-lowering properties. Based on the cell lipid extracts it was found that hydrocarbon chain length, unsaturation index, phospholipid containing lipids and carbonyl index showed increasing except for rosuvastatin-treated A549 cells. This study indicated that statins caused significant structural and compositional changes on A549 cells based on a spectroscopic evaluation.
Investigation of structural and biological activities of D-glucose-L-glycine, D-glucose-L-arginine, and bread melanoidins
(Izmir Institute of Technology, 2022-07) Elci, Ferhat; Ceylan, Çağatay; Şahin, İpek
As a result of Maillard reactions, high molecular weight compounds known melanoidins are formed from the proteins and sugars in food. Amino acids and reducing sugars combine, making them common ingredients in meals, fruit juices, coffee, and baked products that are consumed on a regular basis. Food melanoidins can affect human health, thus it's critical to assess and understand their chemical composition. Understanding the relationship between melanoidins' structural analysis and their activity was the main objective of this work. According to our observations, melanoidins have an antibacterial effect on the microorganisms E. coli and S. aureus. Melanoidins demonstrated excellent antibacterial action against E. coli at low doses, whereas S. aureus was more resistant at higher concentrations. These data suggested that melanoidins have a significant level of activity against gram-negative bacteria. The antioxidant capacity of melanoidins was assessed using the ABTS test. The bread melanoid exhibited the lowest antioxidant value, whereas the Gly - Glc melanoid model system had the strongest antioxidant property. Fourier transform Infrared (FTIR) spectroscopy was utilized to identify the functional groups of melanoidins and to analyze these groups. HPLC was used to identify melanoidins. We investigated the structural and functional properties of melanoidins utilizing spectroscopic methods such as FTIR spectroscopy, UV-Visible Spectroscopy, Scanning Electron Microscopy, and biochemical approaches. Studies on their biological activities and structures have enhanced our understanding of them; yet the complexity of the structures and variety of melanoidins provide the greatest obstacle to the knowledge.
Structural investigation of isopropanol and alkaline pH-induced trypsin gel and thin flim and its biotechnological applications
(Izmir Institute of Technology, 2011) Karaçiçek, Bilge; Ceylan, Çağatay
Trypsin is a biologically and industrially important member of serine protease family. Gelation forms a three dimensional network structure through the interaction of protein molecules among themselves and also with the environment. The aim of the study was the investigation of structural and the functional properties of bovine pancreatic trypsin after gelation and aggregation processes. The phase behaviour of trypsin was determined for different protein concentration, NaOH concentration and CaCl2 concentrations. In addition, the effect of sucrose addition to gelation time was observed. Increasing protein concentrations caused a decrease in gelation time. Increasing NaOH concentrations resulted in a decrease in gelation time. In low CaCl2 concentrations gelation was observed but in high CaCl2 concentrations aggregation was observed. The gels were resolubilized in water. Trypsin stability studies showed that there was a nearly 50% specific activity loss after the gelation process. 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 with sucrose and aggregate with and without sucrose were observed. Iodoacetamide was shown to delay in gelation indicating the importance of intermolecular disulfides in the gelation process. The QCM studies showed that the film formed after gelation had absorbtion ability to different gases (benzene, carbon monoxide, carbon dioxide, dichloromethane, hydrogen peroxide and propanol) and can be used for gas sensing purposes. GI-XRD studies showed that trypsin thin film did not contain any crystalline structures.