Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 22Citation - Scopus: 27Layer-By Assembly of Lysozyme With Iota-Carrageenan and Gum Arabic for Surface Modification of Food Packaging Materials With Improved Barrier Properties(Elsevier, 2022) Koca, Nazan; Bayramoğlu, BesteThe study aimed to investigate the surface modification of biaxially oriented polypropylene (BOPP) by layer-by-layer (LbL) assembly of lysozyme (LZ) with two different polysaccharides, iota-carrageenan (IC) and gum arabic (GA), for food packaging applications. The effects of solution pH, adsorption time, elimination of intermediate drying steps were investigated. The LbL film growth was monitored up to 10 deposition steps by UV–Vis spectroscopy and in situ surface plasmon resonance (SPR). The most successful processing conditions for both types of coatings were pH 7–7 combination with intermediate drying and 20 min adsorption time. SPR pointed out a ‘dissolution/reconstruction’ mechanism in film formation. The thickness and surface morphology of the coatings were characterized by Atomic force microscopy (AFM). The surface roughnesses of LZ/IC coatings were higher than that of LZ/GA coatings indicating a denser matrix in the latter. Deposition of 5 bilayers of LZ/IC and LZ/GA on BOPP resulted in 66.15% and 56.89% reduction in oxygen transmission rate (OTR) of the film, respectively. The corresponding reductions in water vapor transmission rate (WVTR) were 28% and 33.52%, respectively. Elimination of intermediate drying steps resulted in less overall deposition, rougher surfaces, diminished oxygen and water barrier properties. The edible LbL coatings obtained in this study possess good gas barrier properties, which is very promising for their use in the preservation of fresh/fresh-cut produce in combination with modified atmosphere packaging applications. The results promise reduced use of plastic films in food packaging.Article Citation - WoS: 5Citation - Scopus: 5Physicochemical and Active Properties of Gelatine-Based Composite Gels Loaded With Lysozyme and Green Tea Polyphenols(University of Zagreb, 2021) Boyacı, Derya; Barış Kavur, Pelin; Güleç, Şükrü; Yemenicioğlu, AhmetResearch background. The use of gel-based systems as a novel method for the delivery of natural antimicrobial, antioxidant and bioactive compounds is a developing innovative solution for the food industry. This research aims to develop multifunctional active edible gels based on gelatine and its composites with improved mechanical properties. Experimental approach. Antilisterial and bioactive composite gels showing different physical and active properties from classical gelatine gel were developed by loading lysozyme and green tea extract into gelatine/starch and gelatine/wax composite gels. Mechanical properties, swelling profiles, colour, release profiles, and antimicrobial and bioactive properties of the gels were characterised. Results and conclusions. Gelatine/wax gels showed 1.3-to 2.1-fold higher firmness and cutting strength than gelatine and gelatine/starch composite gels that had similar firmness and cutting strengths. Work to shear of both composite gels was 1.4-to 1.9-fold higher than that of gelatine gel. The gelatine/starch gel showed the highest water absorption capacity. Green tea extract reduced soluble lysozyme in all gels, but composite gels contained higher amount of soluble lysozyme than gelatine gel. All the gels with lysozyme inhibited Listeria innocua growth in the broth media, while green tea extract showed antilisterial activity only in gelatine/wax gels. Gels with green tea extract showed antioxidant, antidiabetic (?-glucosidase and ?-amylase inhibition), antihypertensive (angiotensin-converting enzyme inhibition) and antiproliferative activities (on Caco-2 human colon carcinoma cells). However, gelatine and gelatine/wax gels showed the highest antioxidant and antidiabetic activity. The gelatine/wax gels prevented phenolic browning, while green tea extract in other gels showed moderate or extensive browning. Novelty and scientific contribution. This work clearly showed the possibility of improving mechanical properties and modifying water absorption and controlled release profiles of gelatine gels using gelatine/starch and gelatine/wax composites. The novel composite gels reduced browning of incorporated polyphenols and showed antilisterial and bioactive properties. © 2021, University of Zagreb. All rights reserved.Article 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: 12Citation - Scopus: 16Control of Lactic Acid Bacteria in Fermented Beverages Using Lysozyme and Nisin: Test of Traditional Beverage Boza as a Model Food System(Wiley, 2018) Sözbilen, Gözde Seval; Korel, Figen; Yemenicioğlu, AhmetThe objective of this study was to increase quality and limited shelf-life of boza (3–15 days), a traditional Balkan origin fermented beverage using lysozyme (LYS) and/or nisin (NIS). For this purpose, the effectiveness of NIS, LYS and LYS:NIS combinations was first tested in a broth medium at 4 °C for 3 weeks on Lactobacillus plantarum, one of the frequently isolated lactic acid bacteria in boza. Stability of LYS and NIS in boza, their effects on LAB counts, and chemical and sensory properties of boza were then evaluated during cold storage at 4 °C. Results of LAB counts as well as pH, d- and l-lactic acid, and titratable acidity measurements showed that LAB in boza containing NIS (250 μg g−1) or LYS:NIS (500:250 μg g−1) could be controlled without reducing LAB counts below 6 log CFU mL−1 during 2 weeks shelf-life. In contrast, LYS (500 μg g−1) alone could not control LAB in boza to delay its acidic spoilage. Positive effects of NIS and LYS:NIS application on quality of boza were also proved with sensory analysis by panelists and e-nose measurements. This work showed that use of natural GRAS agents in preservation of fermented beverages containing probiotic LAB is possible without affecting their characteristic aroma and flavour.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: 49Citation - Scopus: 55Effects of Nisin and Lysozyme on Growth Inhibition and Biofilm Formation Capacity of Staphylococcus Aureus Strains Isolated From Raw Milk and Cheese Samples(International Association for Food Protection, 2012) Sudağıdan, Mert; Yemenicioğlu, AhmetEffects of nisin and lysozyme on growth inhibition and biofilm formation capacity of 25 Staphylococcus aureus strains isolated from raw milk (13 strains) and cheese (12 strains) were studied. Nisin was tested at concentrations between 0.5 and 25 μg/ ml; the growth of all strains was inhibited at 25 μg/ml, but the resistances of strains showed a great variation at lower nisin concentrations. In contrast, lysozyme tested at concentrations up to 5.0 mg/ml showed no inhibition on the growth of strains. Nisin used at the growth inhibitory concentration prevented the biofilm formation of strains, but strains continued biofilm formation at subinhibitory nisin concentrations. Lysozyme did not affect the biofilm formation of 19 of the strains, but it caused a considerable activation in the biofilm formation capacity of six strains. Twelve of the strains contained both biofilm-related protease genes (sspA, sspB, and aur) and active proteases; eight of these strains were nisin resistant. These results suggest a potential risk of S. aureus growth and biofilm formation when lysozyme is used in the biopreservation of dairy products. Nisin can be used to control growth and biofilm formation of foodborne S. aureus, unless resistance against this biopreservative develops. Copyright ©, International Association for Food Protection.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.