Potential application of hydroxypropyl methylcellulose/shellac embedded with graphene oxide/TiO2-Nps as natural packaging film.

Graphene oxide (GO), TiO2-NPs, HPMC, and shellac are environmentally green polymers and nanocomposites. This work aimed to create biodegradable composite films made of HPMC/shellac, HPMC/shellac-GO, and HPMC/shellac-GO/TiO2-NPs by film casting. TiO2-HPMC/shellac-GO matrix's dispersibility and mixing ability were characterized and observed using FTIR and XRD. XRD analysis shows that the crystallinity decreased within the composites due to breaking H-bonding. Compared to HPMC/shellac, TGA/DTG demonstrated the composite films' superior thermal stability. TiO2 (0.08-0.16 %) was cast into a composite film comprising HPMC, shellac, and GO. The homogeneity of TiO2 distribution in the composite film was shown using a SEM, which was also used to display the morphology of nanocomposite films. Nanocomposite films' thickness, air permeability, tensile strength, Young's modulus, and burst strength were examined. The results demonstrated that natural films prepared by a combination of shellac/GO with HPMC enhanced the fabricating of films' properties, the tensile strength increased by 231 % (from 16 to 53 MPa) in HPMC and HPSG2 (HPMC 1.9 g/shellac 0.25 g/GO 0.125 g in 100 mL) respectively, whereas the contact angle did not change. And after addition of TiO2-NPs, there were high enhancements in HPMC films' properties, such tensile strength increased by 212 % (from 16 to 50 MPa), burst strength increased by 20.96 % (3.1 to 3.75 Kg/cm2), and the contact angle by 60.86 % (48 to 74°) in HPMC and HPSGT2 respectively. Compared to HPMC films, films exhibited the highest levels of antibacterial activity against E. coli, B. mycoides, and C. albicans. So, the composite films from HPMC/shellac/GO/TiO2-NPs are promising potential packaging materials.

Polysaccharides, Protein and Lipid -Based Natural Edible Films in Food Packaging: A Review.

Polysaccharides, such as pectin, starch, alginate, carrageenan, and xanthan gum, have been used as biopolymer materials to create coatings and edible films to reduce traditional plastic packages. Petrochemical polymers, extensively used for food packaging, are non-renewable and non-biodegradable and need landfills. Thus, there is a requirement to find alternative packaging materials that are easily degradable and renewable. Natural edible polymers are the materials made from natural edible constituents that can be consumed by animals or human beings with no health risk. Since they are directly consumed with food, nothing is left for disposal. Polysaccharides, Protein and Lipid-Based Natural edible polymers are used to make coatings and edible films surrounding the surface of the food. These natural edible polymers are generally categorized into polysaccharides, lipids and proteins. This review article summarizes the importance of various natural polymers used for making coatings and edible films.

Novel natural composite films as packaging materials with enhanced properties.

The present work was devoted to prepare novel natural composite films based on carboxymethyl cellulose (CMC), gelatin and/or shellac. Four composites films series were prepared by altering the film compositions from CMC and gelatin or shellac. The composite films were prepared by solution casting in presence of glycerol (30% weight). Films were characterized by SEM, air permeability (porosity), tensile strength, burst strength, TGA and WVP. Antimicrobial activity in opposition to E. coli, B. mycoides and C. albicans were also investigated. The results revealed that, films exhibit flexibility with good antimicrobial, tensile strength, homogeneity, transparency, elongation properties, reduce porosity & air permeability and without signs of particles aggregation. Gelatin/CMC (50/50%) film was the most important one with respect to thermal stability, which exhibit a high thermal stability up to 800 °C. This study opens the door to use cellulosic composite materials to produce environmentally friendly, low-cost and sustainable packaging materials.

Carboxymethyl cellulose prepared from mesquite tree: New source for promising nanocomposite materials.

In the current article cellulose pulp extracted from mesquite tree was characterized and used as a raw material for preparation of carboxymethyl cellulose (CMC) which further used for preparing nanocomposite. CMC/Fe3O4 nanocomposite was synthesized by co-precipitation of iron (II) and (III) salts by aqueous ammonia in CMC solution. Cellulose pulp, CMC and CMC/Fe3O4 materials were characterized by using FTIR, XRD, TGA, SEM and TEM analysis. The results showed that homogenous spherical magnetic nanoparticles with diameter ∼25 nm were formed. The nanocomposite was further applied to remove methylene blue (MB) from aqueous solutions. The adsorption experiments showed the maximum adsorption capacity at pH 7. The adsorption results were analyzed by different isotherm and kinetic models and the results were fitted well with the Langmuir model and pseudo second-order model respectively. The current article showed that mesquite tree is a new resource for cellulose pulp which could be employed for preparing sustainable and environmentally friendly composite materials.

Synthesis of hybrid paper sheets with enhanced air barrier and antimicrobial properties for food packaging.

Paper sheets made from bagasse pulp have been modified using nanocellulose (NC) obtained from the same raw material. Modification of paper sheets have been carried out either through loading of paper with different concentrations of NC and antibacterial agent, Chitosan (Ch) during making sheets, or by surface coating of the paper. Crystals of NC extracted using concentrated sulfuric acid from bagasse pulp were found to have crystallinity index (CrI) 90%. Morphology of obtained NC has been confirmed by TEM and images revealed formation of NC crystals with large size distribution ranges from 4 to 60nm. Mechanical properties and air permeability of paper sheets loaded with different ratios of NC and Ch have been investigated. The results showed that presence of NC did not negatively affect the obtained modified paper sheets, while air permeability decreased with adding 8% NC to paper matrix. On the other hand, surface coverage of paper sheets with NC greatly reduced air permeability. Antimicrobial investigations carried out by optical density method indicated that presence of Ch in the paper sheets as an additive or in a coating formulation enhanced paper resistance to different microorganisms especially those causing food poisoning. The current study confirms that the modified paper can have potential application in food packaging.