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    Antimicrobial Edible Cellulose-Based (CB) Films and Coatings for Enhancing Microbial Safety of White Cheese During Storage
    (United Arab Emirates Univ, 2022) Yildirim, Seval Cing; Ates, Firat
    In this research, the antioxidant and antibacterial characteristics of edible cellulose-based film (CBEF) coating incorporated with (3-carotene, Hesperedin and Propolis on the quality of the white cheese at 4 degrees C were investigated. Samples evaluated were: Control, CBE films with 8 different contents containing natural or non-natural antimicrobial agents for 15 days at 5 day intervals. The antimicrobial effects of edible cellulosic films prepared with antimicrobial agents against Staphylococcus aureus and Escherichia coli, which are important food pathogens, were directly evaluated with artificially contaminated food samples under cold storage conditions. Fresh white cheese samples, which are one of the semi-hard traditional Turkish cheeses, were used for artificial contamination. The antimicrobial activity of the tested antimicrobial substances was measured by the paper disc method. The DPPH free radical scavenging activities, the total phenolic content, and the characteristics (FT-IR, DSC and TGA) of the CBEFs were investigated. All of the samples significantly reduced E. coli, S. aureus and total viable counts, as compared with control during the storage time. Specifically, it was determined that hesperidin sprayed films showed an antimicrobial effect on E.coli growth and carotene sprayed films showed an antimicrobial effect on S. aureus growth. Growth of both bacterial species was highly inhibited (>50%) in the presence of 20% propolis. It was concluded that (3 -carotene, hesperidin and propolis can be substituted as natural preservatives in white cheese. With this advanced packaging technology, food safety can be ensured, the shelf life of the product can be extended and food losses in this sector can be reduced.
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    Characterization and Antimicrobial Activity of Spice Extract-Loaded Algal Microcomposites Based on the Microemulsion Technique
    (Wiley-V C H Verlag Gmbh, 2022) Yildirim, Seval Cing; Dincer, Aslihan Seyma; Kivilcim, Fadime Nulufer
    In recent years, with the increase in knowledge and awareness, people's efforts to return to nature have increased in the field of medical science and cosmetics industry. Spices, sumac and coriander, grown and frequently used in Turkey, have different bioactive effects. Microalgae are preferred in the treatment of skin problems. The aim of this study was to synthesize algae microcomposites that were effective against bacterial infections, prepared based on microemulsion technique and loaded with spice extract. Microemulsion formulations were prepared by the titration method. Aqueous and ethanolic extractions of sumac/coriander were carried out using the ultrasonic-assisted extraction method. Twenty-four different algal microcomposites loaded with extracts were synthesized. The disk diffusion method was used to determine the antimicrobial activity. The DPPH free radical scavenging activities, the total phenolic content (TPSC), and the characteristics (FT-IR) of the microcomposites were investigated. In addition, the chemical contents of extracts were determined by the GC/MS method. Aqueous extracts of both sumac and coriander were highly effective against Escherichia coli (ES DII). The highest antimicrobial activity against Staphylococcus aureus (F6 III) was obtained with M9 (microcomposite containing ethanolic extract of sumac) and M15 (microcomposite containing aqueous extract of coriander). The highest TPSC value (6.025 mg GAE/gr) was detected in the aqueous extract of coriander. The DPPH radical scavenging activities of coriander extracts were lower than those of sumac extracts. It has been determined that the spices contain organic (propanoic, butanoic, malic and benzoic) acids and fatty (palmitic, oleic and myristic) acids. According to the results of FT-IR spectroscopy, microcomposites prepared with sumac and coriander extracts were successfully synthesized. The synthesized algae-based microcomposites have properties that could be in the green-labeled bio-based category.
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    A comparative study on decolorization of reactive azo and indigoid dyes by free/immobilized pellets of Trametes versicolor and Funalia trogii
    (Triveni Enterprises, 2015) Yildirim, Seval Cing; Yesilada, Ozfer
    The objective of the present study was to investigate decolorization of Acid Blue 74 and Reactive Blue 198 dyes by free and immobilized white rot fungal pellets in order to confirm the possibility of practical application via repeated-batch cultivation. Decolorization studies were conducted using free pellets (FP), fungal cells immobilized on activated carbon (IFCAC) and pinewood (IFCP), and also fungal cells entrapped in alginate beads (FCEAB). No additional nitrogen and carbon source was used and high decolorization rates were achieved in only dye-contained media without pH adjustment. Acid Blue 74 was decolorized 96 and 94% within 2 hr by Trametes versicolor and Funalia trogii free pellets, respectively. These values were 87 and 84% for Reactive Blue 198, in this respect. Immobilization of fungal cells on pinewood increased the usability of pellets and the average decolorization efficiency of both dyes. The micro environment changed in the presence of pinewood and increased the stability of immobilized pellets. Decolorization was performed rapidly and efficiently. Laccase activity enhanced with availability of pinewood, and high laccase production with F trogii was obtained. After separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), the molecular weight of Trametes versicolor and F trogii laccase bands was determined 64 and 61 kDa approximately. Green bands were obtained by the activity staining process with laccase substrate (ABTS) after gel renaturation step.
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    The evaluation of pre-grown mycelial pellets in decolorization of textile dyes during repeated batch process
    (Springer, 2010) Yesilada, Ozfer; Yildirim, Seval Cing; Birhanli, Emre; Apohan, Elif; Asma, Dilek; Kuru, Filiz
    This study was undertaken for the possibility of application of pre-grown pellets for biotechnological treatment of dyes and textile industry waste waters. Mycelial pellets of five different white rot fungi were tested for their dye decolorization activity. The pellets of Funalia trogii, Phanerochaete chrysosporium and Trametes versicolor were determined as the most effective ones. The decolorization ability of viable pellets was compared with the decolorization (adsorption) ability of dead pellets during repeated batch studies. Astrazon Black dye was decolorized effectively, about 90%, by viable pellets of all fungi during the first use. Viable F. trogii pellets were found as the most effective pellets. Upon pellet treatment not only a high decolorization but also reduced toxicity (antimicrobial activity) of the Astrazon Black dye was recorded. This type of decolorization activity with commercial or crude laccase was partially observed. Growing cells of F. trogii in batch system showed lower efficiency in color removal of mixed dyes compared to the pre-grown pellets in repeated batch system. The results in this study showed that mycelial pellets could effectively be used as an alternative to traditional physicochemical processes.