الفهرس 
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Abstract
This work provides details regarding physicochemical and antimicrobial properties of Carboxymethyl Cellulose (CMC)-based film containing nanosized Pg/ Cat/ OPQ-loaded chitosan-alginate. The incorporation of NPs considerably affected the thermal, mechanical and optical properties of the films. Antimicrobial activity against food pathogens (Salmonella Typhimurium, Campylobacter jejuni, Staphylococcus aureus and Listeria monocytogens) was evaluated.
Pg extract was obtained from Peels extract solution (PES) and Pg juice and revealed an abundance of phenolics compounds which proved by the HPLC.Extraction of catechin from green tea occurred by simple aqueous method which confirmed by HPLC. Quercetin was extracted by ultrasound-assisted extraction which performed in an ultrasound bath.
Preparation of polymers nanocapsules containing phenolics was carried out in aqueous conditions using ionic gelation method and then a layer of chitosan was coated on the Nps surface. The particle size of Pg/ Cat/ OPQ -loaded nanoparticles was 233 nm, 219 nm, and 276 nm and the formation of nanoparticle was proved by TEM technique, FTIR and XRD.
The selected plant extractsincorporated into nanocarrier polymers were tested for antimicrobial properties both in-vitro and in model systems.
The antibacterial activity of nanoparticles was evaluated using agar diffusion method and the result revealed that Pg-Nps was effective against all testedfoodborne strains included Camp. jejuni S.Typhimurium,Staph.aureus and L. monocytogens. On the other hands OPQ -Nps was effective against Staph.aureus and L. monocytogens but Cat-Nps was showed antibacterial properties against Camp. jejuni andS.Typhimurium.
The Pg-Nps showed maximum growth inhibition 88.49%, against L. monocytogens and Staph. aureusat a concentration of 1.15 mg/ml also showed inhibition growth of 86 %against S. TyphimuriumandC. jejuni.Cat-Nps showed a maximum growth inhibition of S. Typhimuriumof 87.8 %by 2.5 mg/ml. OPQ-Nps inhibited the growth of L. monocytogenes and Staph. aureus at a concentration of 0.625 mg/ml and 5 mg/ml by 85.54 and 85.51 %, respectively.
The nanocomposite film was prepared after synthesis of the nanoparticles by 2 %wt. CMC and in presence of glycerol as a common plasticizer. As-prepared film was firstly investigated on the physical properties. The film had nice mechanical performance and water/CO2 permeability. Optical properties of the film were subsequently determined by UV-Vis.
The addition of Pg-Nps/OPQ–Nps/ Cat-Nps into the CMC film exert a selection effect towards spoilage microorganisms of the fresh beef and poultry meat stored in refrigerated condition (4 ⁰C) to at least 12, 10 and 7 days.
Also, our studies reported that CMC- nanocomposite film possessed strong antimicrobial activity against the most common food-borne pathogens such as S. Typhimurium, C. jejuni, Staph. aureus and L. monocytogens.
Due to the unique properties and results of Pg against foodborne pathogens and food spoilage microorganisms, we prepared more advanced nanocomposite film by using hyperbranchednanoparticles. Antimicrobial properties of Pg were increased in the presence of PAMAM which increased effective binding on the outer membrane and cell membranes of organisms.
The prepared packaging film with HB-Nps allow longer storage at refrigerated temperatures (4 °C) reach to 14 days.
Moreover, our results were supported by microbiological, physicochemical and sensory evaluation andit can be concluded that the nanocomposite film has the ability to delay microbial and chemical changes, extend the shelf-life and exhibit desirable sensory attributes including taste, color, odor, texture and overall acceptability in beef and chicken breast meat.
Results showed that the CMC-nanocomposite film was proved to be highly effective to inhibiting bacterial growth and extending both beef and poultry meat. Therefore, these results are promising evidence to possibly aid in the prevention of microbial dissemination in foods and can be used in the industrial scale as a novel method to improve fresh beef and poultry meat by preventing microbial spoilage as well as oxidation during refrigerated storage.
A developed simple colorimetric sensor based on 2, 6-Dichlorophenolindophenol (DCPIP) to monitorthe bacterial growth patterns in chicken meat samples thus enabling the “real-time” monitoring of spoilage.
DCPIP was immobilized onto PES membrane attached as a label on the packaging material to provide information about the quality of food. DCPIP couples directly microbial electron chain and subsequently the color of the sensor will change from blue to pale violet for spoilage indication, which is easily visible to the naked eye.
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