Food Engineering / Gıda Mühendisliği

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

Browse

Filters

2009 - 20103

Settings

Author: search.filters.author.Alsoy Altınkaya, Sacide

Search Results

Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 153
    Citation - Scopus: 192
    Development of Cellulose Acetate Based Antimicrobial Food Packaging Materials for Controlled Release of Lysozyme
    (Elsevier Ltd., 2009) Gemili, Seyhun; Yemenicioğlu, Ahmet; Alsoy Altınkaya, Sacide
    Antimicrobial packaging materials were obtained by incorporation of lysozyme into cellulose acetate (CA) films. In order to achieve controlled release of lysozyme, the structure of the films was changed from highly asymmetric and porous to dense by modulating the composition of the initial casting solution. The highest release rate, soluble lysozyme activity and antimicrobial activity were obtained with the film prepared from 5% CA solution including 1.5% lysozyme. Increasing CA content in the casting solution decreased the porosity of the films, hence, reduced the release rate, maximum released lysozyme activities and the antimicrobial activities of the films. In contrast, immobilized lysozyme activities and the tensile strength of the films increased. The incorporation of lysozyme did not cause significant reductions in tensile strength and elongation at break values except in films prepared with 15% CA. This study showed the good potential of asymmetric CA films to achieve controlled release in antimicrobial packaging.
  • Article
    Citation - WoS: 87
    Citation - Scopus: 111
    Development of Antioxidant Food Packaging Materials With Controlled Release Properties
    (Elsevier Ltd., 2010) Gemili, Seyhun; Yemenicioğlu, Ahmet; Alsoy Altınkaya, Sacide
    In this study, cellulose acetate (CA) films with different morphological features were prepared in order to control the release rates of low molecular weight natural antioxidants, L-ascorbic acid and L-tyrosine. Increasing CA content in the casting solution decreased the average pore size and porosity of the films, thus, reduced the diffusion rates of both antioxidants through the films. Although both antioxidants have similar molecular weights, L-tyrosine released into water much more slowly than L-ascorbic acid. The highest antioxidant activity in release test solutions was observed with highly porous L-tyrosine containing films. However, when the porosity of the films reduced, the antioxidant activity of L-ascorbic acid released into solution was found to be higher due to trapping of significant amount of L-tyrosine in dense films. The use of different antioxidants caused different changes in morphological and mechanical properties of the CA films. Varying the structural features of the films with the preparation conditions or using different surfaces of the films allowed the controlled release of each antioxidant. © 2009 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 46
    Citation - Scopus: 52
    Effect of Enzyme Location on Activity and Stability of Trypsin and Urease Immobilized on Porous Membranes by Using Layer-By Self-Assembly of Polyelectrolyte
    (Elsevier Ltd., 2010) Guedidi, Sadika; Yürekli, Yılmaz; Deratani, André; Déjardin, Philippe; Innocent, Christophe; Alsoy Altınkaya, Sacide; Roudesli, Sadok; Yemenicioğlu, Ahmet
    The layer-by-layer (LbL) self-assembly of polyelectrolyte is one of the simplest ways to immobilize enzyme on membrane. In this paper, the immobilization of trypsin (TRY) and urease (URE) on polyacrylonitrile based membranes using the LbL assembly technique was presented. The studied systems consisted in bilayered assemblies with the enzyme layer as the outer layer and trilayered assemblies with the enzyme layer as the inner sandwiched layer. The membrane pore size was chosen so that the smaller enzyme TRY was mainly immobilized within the membrane and confined in the porous membrane structure while URE immobilization mainly took place at the membrane surface. No dramatic difference on reactivity was evidenced between these two enzyme locations. The catalytic activity of immobilized enzymes was found to be lower than the free ones in solution but their stability was dramatically enhanced. The higher activity was observed when the enzyme is deposited as the outer layer of the LbL assembly. On the other hand, the more stable catalytic membranes were obtained when the outer layer consists of a polyelectrolyte covering the enzyme layer. © 2010 Elsevier B.V.