الفهرس 
Introductionيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
Summary and conclusion
English summary
This thesis focuses on the following points:
Preparation and characterization of pectin, microcrystalline Cellulose (MCC), TEMPO-cellulose nanofibers (CNF), cellulose nanocrystals (CNC) extracted from citrus sinensis peel, nanomaterials like: i) Zinc oxide nanoparticales [ZnO-NPs] ii) Titanium dioxide nanoparticales [TiO2-NPs], as well as antimicrobial Bio-Nanocomposites films: a) pectin/HEC/ZnO Bio-Nanocomposites films b) pectin/HEC/TiO2 Bio-Nanocomposites films, using best techniques, Resulting in bio-nanocomposite films for usage in applications for smart packaging. These biofilms will have the biological activity to inhibit the growth of microorganisms and therefore prevent the spoil of preserved materials. So they may increase the shelf life of them and reduce the need for a lot of energy for the process of cooling these preserved materials.
The present study divided into three chapters: Chapter (I) Introduction and literature review, chapter (II) Materials and methods and chapter (III) Results and discussion.
The first chapter is divided into two sections: introduction and literature review. The chapter provided detailed information and previous studies findings regarding the non-renewable resources, global warming, food packaging and environmental pollution. Effective food packaging and its use as a barrier to external contaminants, preventing microbial growth and oxidation that could compromise the safety and integrity of the contents within, As well as microcrystalline cellulose (MCC), cellulose nanocrystals (CNC), cellulose nanofiber (CNFs) and nanomaterials, such as (ZnO -TiO2) and its effect on the usage of different polymers in combination to create antimicrobial food packaging materials (biofilms). The main categories of pectin include natural, source, chemistry, chemical, gel formation properties and different types of pectin, its application and various extraction of pectin were illustrated in the literature review.
Chapter (II) ”Materials and methods” that partitioned into: The natural and modifying chemical materials to be used in this study for pectin, nanocellulose [microcrystalline cellulose (MCC), cellulose nanocrystals (CNC), cellulose nanofiber (CNFs)] and nanomaterials, such as (ZnO -TiO2)] preparation, methods exhibited to prepare the nanocomposite biofilms [pectin/HEC/ZnO or TiO2], Instruments utilized to identify the synthetic product and measuring its efficiency, The characterization techniques which included eight approaches were used to accomplish this characterization: (1) Fourier-transform infrared spectroscopy (FTIR), (2) X-ray diffraction (XRD) analysis, (3) Mechanical properties, (4) Water vapor permeability (WVP), (5) Scanning electron microscopy (SEM) & EDX measurement, (6) Thermal gravimetric analysis (TGA), (7) Transmission electron microscopy (TEM), (8) Antimicrobial activity and determination of degree of esterification of pectin, this techniques utilized to identify the synthetic material and measuring of its efficiency in food packaging.
Chapter (III) ”Results and discussion” This chapter is divided into two main sections. (I) The characterization results of pectin and micro/nanocellulose which include determination of degree of esterification (DE) of pectin. (II) The characterization results of Bio-Nanocomposites films and Nanomaterials. It was found through our study that different parameters such as temperature, pH and time effect on the pectin yield, where temperature (80, 90, 100 °C) , time (60, 90, 120 min) and pH (1.5 or 2.0), So we found that the pectin yield at its best result was 16.9 %, At which (temp 90 °C ,time 90 min, pH 1.5). Determination of degree of esterification of extracted pectin recorded 83 which is suitable value. The surface morphology, chemical structure, and the crystal structure characteristics of the nanocellulose were also studied. (II) The characterization results of Bio-Nanocomposites films pectin/HEC/ZnO or TiO2, which were prepared in an aqueous solution at room temperature using solvent casting method, were characterized by different techniques. Its antimicrobial activity against Gram negative bacteria (E. coli, Pseudomonas aeruginosa and Salmonella enterica Typhimiurium) and two Gram positive bacteria (Listeria monocytogenes and Staphylococcus aureus) and also has antifungal activity against Candida albicans was assessed. The results demonstrated that the ZnO or TiO2 nanoparticles were well dispersed in the biofilms, and it showed high transparency and flexibility, with enhanced tensile properties. Tensile properties of pectin/HEC were enhanced with addition of ZnO or TiO2 nanoparticles. The study revealed that the synthesized Bio-Nanocomposites films had excellent qualities such as transparency, flexibility, low cost, and being environmentally friendly. The Pectin/HEC/ZnO or TiO2 b Bio-Nanocomposites film was found to be an ideal biofilm for food packaging due to its safety and affordability, which is able to prolong food shelf-life.