Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 17Citation - Scopus: 18Incorporation of Organic Acids Turns Classically Brittle Zein Films into Flexible Antimicrobial Packaging Materials(Wiley, 2022) Sozbilen, G.S.; Çavdaroğlu, E.; Yemenicioglu, A.This study aimed to turn classically brittle zein films into flexible antimicrobial ones by the use of lactic (LA), malic (MA) and tartaric acids (TA). The most effective plasticizer was LA (400% elongation at break [EB] at 4%), while MA (189% EB at 4.5%) and TA (68% EB at 5%) showed moderate and limited plasticizing effects, respectively. The LA- and MA-loaded films maintained their flexibility during 30-day storage at 4°C or 25°C. Fourier transform infrared (FTIR) analysis suggested that the plasticization of LA and MA could be related to secondary structural changes in zein such as increased α-helix and random coils (mainly by MA) and spaced/modified intermolecular (only by LA) and intramolecular (mainly by MA) β-sheets. Atomic force and scanning electron microscopy showed that LA and MA gave more homogenous and smoother films than TA. Films with LA showed the highest water vapour permeability followed by those of control, MA- and TA-loaded films. Films with 3%–4% LA or MA formed clear zones on Listeria innocua and Klebsiella pneumonia, but only films with LA formed clear zones on Escherichia coli. All OA-loaded films gave unclear zones on Staphylococcus aureus in disc-diffusion tests, but this bacterium was inactivated rapidly in antimicrobial tests based on surface inoculation tests. LA is the best OA to develop flexible antimicrobial films from zein, an industrial by-product that films could not have been utilized as a widespread packaging material due to their brittleness. © 2021 John Wiley & Sons, Ltd.Article Citation - WoS: 64Citation - Scopus: 77Development of Flexible Antimicrobial Zein Coatings With Essential Oils for the Inhibition of Critical Pathogens on the Surface of Whole Fruits: Test of Coatings on Inoculated Melons(Elsevier, 2019) Boyacı, Derya; Iorio, Gianmarco; Sözbilen, Gözde Seval; Alkan, Derya; Trabattoni, Silvia; Pucillo, Flavia; Yemenicioğlu, AhmetThis study aimed to develop essential oil (EO)-containing antimicrobial coatings for the inhibition of pathogenic bacteria contamination on fruit peels. Incorporation of eugenol (EUG), carvacrol (CAR), and thymol (THY) into films at > 1% (w/w) eliminated the typical brittleness of zein films. However, EUG outperformed CAR and THY in terms of mechanical properties. Films with >= 2% (w/w) CAR and THY and >= 3% EUG showed clear zones against L. innocua and E. coli in agar medium at 37 degrees C. All EO-containing films also inhibited L. innocua and E. coli inoculated at their surfaces by minimum 3.9 and 2.7 decimal (D) within 1 day at 10 degrees C. Moreover, 2% EUG-containing zein coatings caused 2-3 decimal reduction in L. innocua and E. coli counts of inoculated melon surfaces at 10 degrees C. Unlike the bare zein coatings, flexible EUG-containing films on melons did not show cracking or detachment. Zein films loaded with EUG showed a highly hydrophilic surface. The best oxygen barrier performance was observed for the EUG-richest formulation (i.e., EUG at 3%), and this was attributed to a homogenizing effect of the EO that eventually led to a denser and hole-free network. This work suggested that flexible coatings of zein containing EOs could inhibit pathogens embedded in the rough peel surface of melons.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: 80Citation - Scopus: 107Application of Active Zein-Based Films With Controlled Release Properties To Control Listeria Monocytogenes Growth and Lipid Oxidation in Fresh Kashar Cheese(Elsevier Ltd., 2013) Uysal Ünalan, İlke; Arcan, İskender; Korel, Figen; Yemenicioğlu, AhmetThe antimicrobial and antioxidant potential of zein and zein-wax composite films having different release profiles for lysozyme and mixture of lysozyme, catechin and gallic acid were tested on cold-stored fresh Kashar cheese inoculated with Listeria monocytogenes ATCC 7644. All lysozyme containing films prevented the increase of L. monocytogenes counts in Kashar cheese for 8 weeks at 4°C, but it was only the zein-wax composite films with sustained lysozyme-release rates which caused a significant reduction (- 0.4 decimals) in initial microbial load of inoculated cheese samples. The mixture of catechin and gallic acid improved the in vitro antimicrobial effect of films against L. monocytogenes, but showed no considerable antimicrobial effect in cheese. However, the films containing catechin and gallic acid were effective in preventing oxidative changes in cheese. This study showed the possibility of increasing safety and quality of fresh cheeses by use of active packaging employing natural antimicrobial compounds and controlled release technology. Industrial relevance There has been a growing interest to develop the functional properties of packaging materials and to obtain packed foods with better shelf-life and quality. Active packaging incorporating antimicrobials is one of the most promising areas since application of this method can improve safety of foods by inhibiting pathogenic bacteria or controlling spoilage flora by using minimum amounts of active compounds. Recently, health concerns of consumers and environmental problems related to plastics increased the popularity of using natural antimicrobial substances in edible films and coatings. This work employs a GRAS status natural antimicrobial lysozyme and zein a major by-product of rapidly growing oil and bioethanol industries which can form self-standing films, coatings or casings. The results of this study showed the possibility of using flexible antimicrobial and antioxidant films with controlled release properties in diary industry.Article Citation - WoS: 180Citation - Scopus: 208Incorporating Phenolic Compounds Opens a New Perspective To Use Zein Films as Flexible Bioactive Packaging Materials(Elsevier Ltd., 2011) Arcan, İskender; Yemenicioğlu, AhmetTo eliminate their classical brittleness and flexibility problems zein films were plasticized by incorporation of different phenolic acids (gallic acid (GA), p-hydroxy benzoic acid (HBA) or ferulic acids (FA)) or flavonoids (catechin (CAT), flavone (FLA) or quercetin (QU)). The use of GA, CAT, FA and HBA at 3mg/cm2 eliminated the brittleness of films and gave highly flexible films showing elongations between 135% and 189%, while FLA and QU caused no considerable effect on film elongation. The films containing FA and HBA showed extreme swelling and lost their structural integrity when hydrated in distilled water. In contrast, CAT and GA containing films maintained their integrity following hydration. Most of the GA (up to 93%) and a considerable portion of CAT (up to 60%) in the films existed in soluble form. Therefore, the films showed antioxidant and/or antimicrobial activity. The TEACs of soluble phenolic compounds in 3mg/cm2 CAT and GA containing films were 21.0 and 86.2μmoltrolox/cm2, respectively. The GA containing films showed antimicrobial activity on Listeria monocytogenes and Campylobacter jejuni, while CAT showed no antimicrobial activity on these bacteria at the studied concentration. This work opens a new perspective for using zein in flexible bioactive packaging.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: 125Citation - Scopus: 156Antimicrobial and Antioxidant Activity of Edible Zein Films Incorporated With Lysozyme, Albumin Proteins and Disodium Edta(Elsevier Ltd., 2007) Mecitoğlu Güçbilmez, Çiğdem; Yemenicioğlu, Ahmet; Arslanoğlu, AlperIn this study, partially purified lysozyme was incorporated into zein films in combination with chickpea albumin extract (CPAE), bovine serum albumin (BSA) and disodium EDTA. The zein films showed an inherent free radical scavenging activity. Incorporation of lysozyme did not contribute to soluble free radical scavenging activity of zein films. However, the incorporation of lysozyme in combination with CPAE increased the soluble and immobilized free radical scavenging activity of zein films 17% to 25% and almost 84%, respectively. The incorporation of CPAE also improved the distribution of partially purified lysozyme preparation in zein films and enabled the controlled release of lysozyme by reducing its release rate from zein films between 1.5- and 3.5-fold, depending on the concentration of incorporated CPAE. In contrast, the BSA incorporation made distribution of lysozyme more heterogeneous and it did not contribute to the free radical scavenging activity of films significantly. The combinational incorporation of partially purified lysozyme with disodium EDTA · 2H2O or CPAE and disodium EDTA · 2H2O gave zein films effective on Escherichia coli and Bacillus subtilis. This study clearly showed the benefits of using functional protein extracts to control lysozyme distribution and release rate and to improve antioxidant activity in zein films.