Browsing by Author "Okutan, Gulistan"

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Edible Films Based on Plant and Animal Origin Proteins: Comparison of Some Mechanical and Physicochemical Characteristics
(Wiley, 2025) Okutan, Gulistan; Koc, Gunes; Cansu, Umran; Boran, Gokhan
Edible films were manufactured from three different proteins to evaluate their mechanical strength and some physicochemical features. Wheat gluten (WG), cow hide gelatin (CHG), and cow milk casein (CMC) were used at three different concentrations (5%, 6%, and 7% w/v for WG or 2%, 3%, and 4% w/v for both CHG and CMC) for the film samples. Water activity of the film samples varied within a rather narrow gap, which was between 0.26 and 0.36, with the highest values for WG films and the lowest for CMC. WG and CMC gave basic films while CHG resulted in acidic films with a pH value between 5.6 and 5.7. CHG films showed the highest conductivity while pH and conductivity increased as CHG concentration increased. WG resulted in opaque and dark colored films while CHG and CMC led to almost transparent and light colored films. Water vapor permeability of CMC films was slightly higher compared to CHG and WG counterparts with values around 2.0 x 10-14 g m/s Pa m2. In addition, tensile strength of CHG films was significantly higher than CMC and WG counterparts with values over 25 N/mm2 and more flexible with higher values of Young's modulus and elongation at break. It is concluded that CHG may be utilized by the food industry to manufacture edible films with superior mechanical features along with ease of dissolving and transparent visual characteristics, while WG and CMC might be preferred for more rigid, opaque, and dark colored films as needed.
Effect of Gelatin Based Edible Coatings on Quality of Surimi From Pearl Mullet (Alburnus Tarichi,guldenstadt, 1814) During Cold Storage
(Soc Brasileira Ciencia Tecnologia Alimentos, 2022) Okutan, Gulistan; Boran, Gokhan
A two-phase study was designed to investigate the effects of pH and salt concentration of washing solution on quality and yield of surimi from pearl mullet fillets and edible coatings on quality of the resultant surimi during cold storage. In the first phase, higher salt concentration increased gel strength of surimi and improved some other textural attributes. Surimi obtained by conventional method was found to be superior as higher yield, dry matter and protein contents were achieved. In the second phase of the study, surimi samples coated by 4 different coating formulations were stored at 4 degrees C for 10 days along with fish mince and uncoated surimi as control. TVB-N values of coated samples were not significantly increased during storage while that of fish mince reached to 53.6 mg/100 g sample on the 7th day of storage. Acidity of all samples increased leading to lower ultimate pH values while ultimate pH of coated samples was not significantly different from that of control. In general, gelatin and chitosan based edible coatings were found not meaningfully effective in extending the shelf life of surimi under conditions studied and coating formulations used with while surimi itself showed prolonged shelf life compared to fish mince.