Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 36Citation - Scopus: 50Development of Activate-At Edible Antimicrobial Films: an Example Ph-Triggering Mechanism Formed for Smoked Salmon Slices Using Lysozyme in Whey Protein Films(Elsevier Ltd., 2016) Boyacı, Derya; Korel, Figen; Yemencioğlu, AhmetThe aim of the present study was to develop the first generation of a novel natural antimicrobial packaging system which could be activated by consumers at home. For this purpose, antimicrobial films having a pH-triggering mechanism which could be activated by acidification were developed by exploiting isoelectric properties and pH induced charge-charge interactions between whey proteins (WP) and lysozyme (LYS). The release tests of films in buffers and on coated smoked salmon slices at 4 °C showed the immobilization of positively charged LYS by the negatively charged WP films at pHs ≥ 5.5. The LYS release initiated when pH was reduced below 5.5 where WP started to gain positive charges. The amount of LYS released and LYS release rate increased as pH reduced gradually from 5.5 to 3.0. The preparation of composite films of WP with beeswax (BW) and oleic acid (OLE) increased the total released LYS from films. WP, WP-OLE and WP-BW films showed antimicrobial activity against Listeria innocua in laboratory media. The smoked salmon slices coated by activated LYS containing WP-OLE films showed significantly lower (almost 0.6 decimal) L. innocua counts than controls after 1 week at 4 °C. This study clearly showed that the antimicrobial films could be activated by consumers to improve safety of opened packed food stored in home type refrigerators.Article Citation - WoS: 48Citation - Scopus: 64Active Packaging of Ground Beef Patties by Edible Zein Films Incorporated With Partially Purified Lysozyme and Na 2edta(John Wiley and Sons Inc., 2011) Uysal Ünalan, İlke; Korel, Figen; Yemencioğlu, AhmetIn this study, antimicrobial activity of zein films incorporated with partially purified lysozyme and disodium ethylenediaminetetraacetic acid (Na 2EDTA) has been tested on selected pathogenic bacteria and refrigerated ground beef patties. The developed films containing 700μgcm -2 lysozyme and 300μgcm -2 Na 2EDTA showed antimicrobial activity on Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhimurium. The application of lysozyme and Na 2EDTA incorporated zein films on beef patties significantly decreased total viable counts (TVC) and total coliform counts after 5days of storage compared to those of control patties (P<0.05). Zein films incorporated with lysozyme and Na 2EDTA or Na 2EDTA alone significantly slowed down the oxidative changes in patties during storage (P<0.05). Redness indices of patties coated with zein films were significantly lower than those of uncoated control patties during storage (P<0.05). This study demonstrated the potential usage of zein films containing lysozyme and Na 2EDTA for active packaging of refrigerated meat products. © 2011 The Authors. International Journal of Food Science and Technology.Article Citation - WoS: 20Citation - Scopus: 23Antimicrobial Potential of Polylysine in Edible Films(Japanese Society for Food Science and Technology, 2011) Uysal Ünalan, İlke; Arserim Uçar, Dılhun Keriman; Arcan, İskender; Korel, Figen; Yemenicioğlu, AhmetThe antimicrobial activity of edible films from whey proteins, alginate, zein and chitosan incorporated with polylysine (PL) and PL- ethylenediaminetetraacetic acid (Na 2EDTA) combination have been tested on different bacteria including Escherichia coli, Listeria innocua, Salmonella Typhimurium and Stapylococcus aureus. The PL-containing films of whey proteins, alginate and chitosan were effective on L. innocua, but had limited effect on E. coli. On the other hand, the PL-containing zein films showed good antimicrobial activity on both E. coli and L. innocua as well as on S. aureus. PL-Na 2EDTA combination also gave zein films effective on S. Typhimurium. The incorporation of PL alone or PL-Na 2EDTA combination did not cause any significant change in mechanical properties of zein films. Zein has a good potential to develop novel antimicrobial packaging materials incorporated with PL.Article Citation - WoS: 36Citation - Scopus: 38Antimicrobial Activity of Lactoperoxidase System Incorporated Into Cross-Linked Alginate Films(John Wiley and Sons Inc., 2009) Yener, Fatih Yalçın Güneş; Korel, Figen; Yemenicioğlu, AhmetIn this study, the antimicrobial effect of lactoperoxidase (LPS) incorporated alginate films was investigated on Escherichia coli (NRRL B-3008), Listeria innocua (NRRL B-33314), and Pseudomonas fluorescens (NRRL B-253) in presence of different concentrations of H2O2 (0.2, 0.4, and 0.8 mM) and KSCN (1, 2, and 4 mM). The incorporation of 70 nmol ABTS/min/cm2 LPS into alginate films gave 0.66 to 0.85 nmol ABTS/min/cm2 enzyme activity at 0.2 to 0.8 mM H2O 2 concentration range. The antimicrobial activity of LPS system on target bacteria changed according to the concentrations of KSCN and H 2O2. The growth of all tested bacteria was prevented for a 6-h period by applying LPS system in presence of 0.4 or 0.8 mM H 2O2 and 4 mM KSCN. At 0.8 mM H2O2 and 4 mM KSCN, the LPS system also inhibited growth of L. innocua and P. fluorescens for a 24-h incubation period, whereas E. coli growth could not be inhibited for 24 h under these conditions. At 0.2 mM H2O2 and 1 to 4 mM KSCN, a considerable inhibitory effect was obtained only on P. fluorescens. The decreasing order of the resistance of studied bacteria to LPS system is as follows: E. coli, L. innocua, and P. fluorescens. The developed antimicrobial system has a good potential for use in meat, poultry, and seafood since alginate coatings are already used in these products. Further studies are needed to test the LPS incorporated edible films in real food systems.Article Citation - WoS: 125Citation - Scopus: 147Incorporation of Partially Purified Hen Egg White Lysozyme Into Zein Films for Antimicrobial Food Packaging(Elsevier Ltd., 2006) Mecitoğlu, Çiğdem; Yemenicioğlu, Ahmet; Arslanoğlu, Alper; Elmacı, Zehra Seda; Korel, Figen; Çetin, Ali EmrahLysozyme, partially purified from hen egg white by precipitation of non-enzyme protein with ethanol and lyophilized after dialysis, was incorporated into zein films. The recovery and specific activity of the enzyme after partial purification varied between 45% and 72% and 2173 and 3448 U/mg, whereas the activity of the lyophilized enzyme varied between 2900 and 3351 U/mg. The partially purified enzyme was very stable and lost almost no activity in lyophilized form or in zein films stored at -18 and 4°C for up to 8 and 4 months, respectively. During partial purification and in zein film preparation, ethanol treatment caused 123-137% and 132-315% activation of the enzyme, respectively. In zein films incorporated with 187-1318 U/cm2 (63-455 μg/cm2) lysozyme, the release rates at 4°C, changed between 7 and 29 U/cm2/min, increased at high lysozyme concentrations. Zein films incorporated with partially purified lysozyme showed antimicrobial effect on Bacillus subtilis and Lactobacillus plantarum. By the addition of disodium EDTA, the films also became effective on Escherichia coli. The results of this study showed that the partially purified lysozyme may be used in antimicrobial packaging to increase food safety.