Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Department: search.filters.department.Thesis (Master)--İzmir Institute of Technology, BioengineeringSubject: search.filters.subject.Edible coatings

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Now showing 1 - 3 of 3
  • Master Thesis
    Development of Antimicrobial Protective Food Coating Materials From Edible Alginate Films
    (Izmir Institute of Technology, 2007) Yener, Fatih Yalçın Güneş; Korel, Figen; Korel, Figen; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Consumer interests in high quality, healthy, convenient and safe food continue to increase, presenting food processors with new challenges to which functional edible coating and film concepts offer potential solutions. The interest in the research of edible film which has many advantages and applications has increased during last decade.There is a particular interest in the use of antimicrobial biopreservatives in edible films and to increase food safety without application of chemical preservatives. In this study,we have developed antimicrobial or protective edible films by incorporation of antimicrobial enzyme lactoperoxidase or protective cultures (Lactobacillus delbrueckii subsp. lactis and Lactobacillus plantarum) into alginate films, respectively. The main objective of this research was to increase food safety by using lactoperoxidase or lactic acid bacteria incorporated into alginate films. The results obtained in the study showed that in reaction mixtures, the lactoperoxidase system has antimicrobial activity against E. coli, L. innocua, and P. fluorescens. The developed lactoperoxidase incorporated antimicrobial films also reduced the total microbial load of a selected seafood during cold storage. The lactic acid bacteria, used in edible films for the first time, also successfully incorporated into alginate films. The bacteria showed sufficient stability in alginate films and at surface of red meat during cold storage. The results of this study clearly showed the good potential of using lactoperoxidase and lactic acid bacteria incorporated alginate films in food packaging. The developed films can be used in antimicrobial packaging or protective packaging. However, further studies are needed to show the beneficial effects of developed films on different food systems.
  • Master Thesis
    Water vapour permeable edible membranes
    (Izmir Institute of Technology, 2005) Alyanak, Didem; Balköse, Devrim; Balköse, Devrim; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, polysaccharide based edible films were prepared and characterized. Also water vapour sorption, diffusion and permeability characteristics of these films were studied. For these purposes cellulose ethers such as sodium salt of carboxymethyl cellulose (NaCMC) and hydroxypropylcellulose (HPC) were used as a film forming materials. Distilled water and glycerin were used as solvent and plasticizer respectively. To determine the effect of polymer concentration of the film forming solution on the film properties, NaCMC and HPC films were prepared from three different concentrations (3, 4, 5g polymer/100ml distilled water) of film forming solutions. During the characterization studies of the films, to determine the elements and structural composition of the films, energy dispersive X-Ray and scanning electron microscopy analyze were applied to NaCMC and HPC based edible films. Also, X-Ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry analysis were applied to determine the form of elements, functional groups and glass transition temperature.Water vapour sorption capacities of NaCMC and HPC based films were measured nearly 70%w and 25%w respectively. GAB and Halsey models were found to give the best fit for the water vapour sorption data of both NaCMC and HPC films. Diffusion coefficient of water vapour in vacuum microbalance test was higher than that determined using the humidity chamber, this case could be result of the structural changes of films such as formation of porous structure in microbalance tests due to the fast drying of films by high vacuum. NaCMC based edible films showed higher diffusion coefficient values than HPC based films, due to the heterogeneous structure and bigger pore dimensions of the NaCMC films that was observed in the scanning electron micrographs. Water vapour permeability (WVP) of both films increased with increasing thickness and increasing film forming solution concentration and WVP values of NaCMC based films were higher than the WVP values of HPC films. In mechanical properties, while NaCMC films have brittle, stronger and stiffer structure, HPC films show elastic and ductile property.
  • Master Thesis
    Production of Functional Packaging Materials by Use of Biopreservatives
    (Izmir Institute of Technology, 2005) Mecitoğlu Güçbilmez, Çiğdem; Yemenicioğlu, Ahmet; Yemenicioğlu, Ahmet; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, partially purified lyophilized lysozyme (LSZ) and lactoperoxidase (LPS) from chicken egg white and bovine whey were incorporated into zein and alginate films, respectively. The LSZ showed very low affinity to zein films. Thus, when zein films incorporated with 63-455 .g/cm2 (187-1318 U/ cm2) LSZ was exposed to release tests in distilled water, the enzyme released rapidly from the films with release rates of 9 to 29 U/cm2/min. The ethanol used in film making caused significant activation of the LSZ. Therefore, the released LSZ activity from zein films was mostly 130-300 % higher than the activity incorporated into films. On the other hand, the LPS incorporated into alginate films showed a very high affinity to these films and immobilized.The incorporation of 0.53 or 1.06 mg/cm2 proteins such as crude thermally processed chick-pea proteins (TP-CP) and sericine in combination with LSZ and LPS into zein or alginate films increased the antioxidant activity of edible films significantly.In zein films, the incorporation of antioxidant proteins reduced the total activity of LSZ released from the films between 50 % and 75 %, but increased the immobilized enzyme activity 3.5-15 fold. On the other hand, incorporation of antioxidant proteins into alginate films enhanced LPS activity slightly to moderately. The results of this study clearly showed the good potential of edible films and natural biopreservatives in active packaging.