Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 5Citation - Scopus: 9Antilisterial Effects of Lysozyme-Nisin Combination at Temperature and Ph Ranges Optimal for Lysozyme Activity: Test of Key Findings To Inactivate Listeria in Raw Milk(Academic Press Inc., 2021) Sözbilen, Gözde Seval; Yemenicioğlu, AhmetThis study aimed to determine antilisterial potential of lysozyme (LYS)-nisin (NIS) combination at temperatures and pHs optimal for LYS activity. Tests in buffers at pH 4.5 and 6.0 showed that heating at 50 or 60 °C combined with LYS-NIS caused higher Listeria innocua inactivation (- 6.2 to >6.6 log) than heating alone (- 0.05 to 5.5 log), or heating combined with LYS (- 4.34 to 6.0 log) or NIS (3.9 to >6.6). The antimicrobial performance of LYS-NIS in buffer at 50 °C was not pH-dependant (5.8–5.9 logs) while heating at 60 °C with LYS-NIS at pH 6.0 (>6.6 logs) caused higher Listeria reduction than that at pH 4.5 (5.7 logs). Heating at 50 °C for 45 min alone or in combination with LYS-NIS caused 0 and 5.5 logs Listeria reduction in milk, respectively. In contrast, Listeria inactivation in milk at 60 °C occurred mainly by heat (5.5 logs) with limited contribution of LYS and/or NIS. Milk heated at 50 °C maintained 73% of NIS and 63% of LYS activity. Application of LYS-NIS at 50 °C provides an opportunity to improve milk safety with less destruction of milk enzyme and microbial flora necessary to obtain desired ripening periods, and aroma and flavour in traditional cheeses. © 2020 Elsevier LtdArticle Citation - WoS: 9Citation - Scopus: 10Decontamination of Seeds Destined for Edible Sprout Production From Listeria by Using Chitosan Coating With Synergetic Lysozyme-Nisin Mixture(Elsevier, 2020) Sözbilen, Gözde Seval; Yemenicioğlu, AhmetThis study aimed at decontamination of seeds destined for edible sprout production from Listeria using chitosan (CS) coatings incorporated with synergetic lysozyme-nisin (LYS-NIS) mixtures. Low molecular weight (LMW) CS coating showed the highest potency against Listeria innocua, followed by medium molecular weight (MMW) and high molecular weight (HMW) CSs. The LMW CS film with LYS-NIS also caused almost 1.5-fold greater log reduction (similar to 5 log) in initial L. innocua load of broth culture than MMW and HMW CS films with LYS-NIS within 6 days. Moreover, LMW CS coating with LYS-NIS reduced the initial Listeria loads of inoculated mung beans, lentils, and wheats by 3.3, 3.4 and 4.1 log, respectively. Antimicrobial coating did not affect seed germination rates considerably. The LYS-NIS addition increased yellowness and opacity of films, and caused limited changes in their mechanical and morphological properties. LMW CS coating with LYS-NIS reduces risk of listeriosis from sprouted seeds.Article Citation - WoS: 5Citation - Scopus: 9Development of Gel-Based Pads Loaded With Lysozyme and Green Tea Extract: Characterization of Pads and Test of Their Antilisterial Potential on Cold-Smoked Salmon(Academic Press, 2020) Boyacı, Derya; Yemenicioğlu, AhmetThe objective of this work is to develop antilisterial gel-based pads (g-pad) for active packaging of cold-smoked salmon. Lysozyme (LYS) and/or green tea extract (GTE) (1% w/w) were incorporated into g-pads of gelatin (GEL), and its mechanically improved composite g-pads obtained by mixing GEL with rice starch (GEL/RS) or candelilla wax (GEL/CW). GEL g-pad with LYS and GEL/RS g-pad with LYS or LYS + GTE, and GEL/CW g-pad with LYS + GTE caused >= similar to 1.8 and similar to 1.7 log reduction in broth media against Listeria innocua within 11 and 15 days, respectively. All g-pads with LYS or LYS + GTE inhibited L. innocua growth, and gave cold-smoked salmon with 1.5-1.9 log lower Listeria load than controls after 15 days at +4 degrees C. GEL g-pad with LYS was the most potent on salmon surface since it achieved faster LYS release (1.3-1.8-fold) than other g-pads. Sustained release of GEL/RS g-pads for LYS, and GEL/CW g-pads for GTE was promising for extended storage. Composite g-pads were more compatible with GTE than GEL g-pads since they prevented discoloration of polyphenols. Water absorption capacities showed that GEL/RS g-pads (75%) could prevent drip-loss better than GEL (59%) and GEL/CW (57%) g-pads. Active g-pads provide alternative to active edible films to reduce listeriosis from processed high-risk food.Article Citation - WoS: 6Citation - Scopus: 7An Innovative Design and Application of Natural Antimicrobial Gelatin Based Filling To Control Risk of Listeriosis From Caramel Apples(Elsevier, 2020) Kavur, Pelin Barış; Yemenicioğlu, AhmetThe aim of this study is to design and apply antimicrobial gelatin based filling with an innovative method in production of safe caramel apples that caused deadly listeriosis cases. For this purpose, water holding capacity and mechanical stability of gelatin (GEL) gels were improved by incorporation of soy proteins (SP) and inulin (IN), respectively. The water activity (a(w)) of gels were also reduced < 0.9 by addition of sucrose (SUC). The application was conducted by coring of apples, filling void core with GEL-SP-IN-SUC blend gel solution containing synergetic antimicrobials, nisin and lysozyme, and antibrowning agent ascorbic acid (each at 1% in gel). Candy sticks were then placed into gel-filled void cores of apples, and apples were kept at 4 degrees C for 20 h for gelation of filling before they were dip-coated with caramel. The inoculated caramel apples with antimicrobial GEL-SP-IN-SUC filling showed 2.4-2.9 D lower Listeria count than traditional inoculated caramel apples during 7-day cold storage. The active blend gel-filling also successfully prevented the discoloration of apple core and accumulation of apple juice between apple surface-caramel coating interface. Mechanical tests showed strong binding of candy sticks by GEL-SP-IN-SUC gel-filling. Active blend gel-filling applied in an innovative way showed good potential to improve safety of candied apples.Article Citation - WoS: 14Citation - Scopus: 23Expanding Horizons of Active Packaging: Design of Consumer-Controlled Release Systems Helps Risk Management of Susceptible Individuals(Elsevier Ltd., 2018) Boyacı, Derya; Yemenicioğlu, AhmetThe objective of this study was the development of zein based antilisterial films that contain a consumer-controlled and pH-triggered release mechanism for lysozyme (LYS). For this purpose, composite films were formed by mixing hydrophobic zein with hydrophilic soy protein isolate (SPI) or lentil protein isolate (LPI). Active property of films was formed by maintaining 30 to 50% of total LYS in free form (LYSfree). On the other hand, the pH-triggered release mechanism was formed by exploiting attractive charge-charge interactions between LYS (pI: 11.4) and SPI or LPI (pI values ≈ 4.5), and binding remaining LYS (LYSbound) in film matrix. The pH-triggered release mechanism of composite films worked in buffers that had pHs varying between 4.3 and 7.3. The composite films bound majority of LYS between pH 5.3 and 7.3, but they released LYS at pH ≤ 4.5. The pH-triggered release of LYS was achieved with zein-LPI films activated by acidification in packed cold-stored beef, lamb and smoked salmon. The zein-SPI films performed pH-triggered LYS release in packed food with the exception of packed smoked salmon. The LYSfree and LYSbound released from pH-triggered films showed antimicrobial activity on Listeria innocua. Consumer-controlled release mechanisms enable increasing antimicrobial stress over pathogens during transfer from market to home and cold storage at home. Thus, such films could initiate personalized packaged food to help risk management of susceptible individuals.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: 30Citation - Scopus: 33Preparation and Characterization of Polyacrylonitrile Membranes Modified With Polyelectrolyte Deposition for Separating Similar Sized Proteins(Elsevier Ltd., 2012) Yaşar Mahlıçlı, Filiz; Alsoy Altınkaya, Sacide; Yürekli, YılmazOne of the challenges faced by ultrafiltration membranes is to separate proteins with a small difference in their molecular weights. Recently, some researchers tried to overcome this problem by using charged membranes. This study examined the use of layer by layer deposition of polyelectrolytes on the chemically-modified polyacyronitrile membrane to increase the selectivity of the ultrafiltration. The membranes were prepared by wet-phase inversion technique and polyethylenimine (PEI) and alginate (ALG) were chosen as cationic and anionic polyelectrolytes for the modification of the surfaces. Sieving coefficient data were obtained with myoglobin and lysozyme as model proteins. The influences of solution pH, ionic strengths of the protein and polyelectrolyte solution and the number of polyelectrolyte bilayers on both selectivity and throughput were investigated. The highest selectivity and throughput were achieved with the 1-bilayer PEI-ALG coated polyacrylonitrile (PAN) membrane. Increasing the number of coating bilayers or the ionic strength of the protein solution or adding salt into the polyelectrolyte coating solution decreased both the maximum selectivity and throughput of the modified membranes.Article Citation - WoS: 35Citation - Scopus: 43Controlled Release Properties of Zein-Fatty Acid Blend Films for Multiple Bioactive Compounds(American Chemical Society, 2014) Arcan, İskender; Yemenicioğlu, AhmetTo develop edible films having controlled release properties for multiple bioactive compounds, hydrophobicity and morphology of zein films were modified by blending zein with oleic (C18:1)Δ9, linoleic (C18:2)Δ9,12, or lauric (C12) acids in the presence of lecithin. The blend zein films showed 2-8.5- and 1.6-2.9-fold lower initial release rates for the model active compounds, lysozyme (LYS) and (+)-catechin (CAT), than the zein control films, respectively. The change of fatty acid chain length affected both CAT and LYS release rates while the change of fatty acid double bond number affected only the CAT release rate. The film morphologies suggested that the blend films owe their controlled release properties mainly to the microspheres formed within their matrix and encapsulation of active compounds. The blend films showed antilisterial activity and antioxidant activity up to 81 μmol Trolox/cm2. The controlled release of multiple bioactive compounds from a single film showed the possibility of combining application of active and bioactive packaging technologies and improving not only safety and quality but also health benefits of packed food.Article Citation - WoS: 76Citation - Scopus: 95Development of Flexible Zein-Wax Composite and Zein-Fatty Acid Blend Films for Controlled Release of Lysozyme(Elsevier Ltd., 2013) Arcan, İskender; Yemenicioğlu, AhmetThe aim of this study was controlled release of lysozyme by modification of hydrophobicity and morphology of zein films using composite and blend film making methods. The incorporation of beeswax, carnauba or candelilla wax into films at 5% (w/w) of zein gave composite films containing amorphous wax particles, while incorporation of oleic acid into film at 5% of zein caused formation of blend films containing many spherical zein capsules within their matrix. The lysozyme release rates of composites reduced as the melting point of waxes increased. The composites and blends showed 2.5 to 17 fold lower lysozyme release rates than controls. The films were effectively plasticized by using catechin. The catechin also provided antioxidant activity of films (up to 69 mu mol Trolox/cm(2)) and contributed to their controlled release properties by reducing film porosity. The films showed antimicrobial activity against Listeria innocua. This work showed the possibility of obtaining advanced edible films having flexibility, antimicrobial and antioxidant activity and controlled release properties.Article Citation - WoS: 153Citation - Scopus: 192Development of Cellulose Acetate Based Antimicrobial Food Packaging Materials for Controlled Release of Lysozyme(Elsevier Ltd., 2009) Gemili, Seyhun; Yemenicioğlu, Ahmet; Alsoy Altınkaya, SacideAntimicrobial 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.