Starch/chitosan nanoparticles bionanocomposite membranes for methylene blue dye removal

This research aims to develop relatively new membranes from starch biopolymer incorporated with different concentrations (0, 5, 10, 15, 20% w/w of solid starch) of chitosan nanoparticles (CNP) that can be used for water treatment. The membranes were fabricated using the solvent casting method while the CNP was produced using the ionic gelation method. The membranes were characterized in terms of morphology, porosity, water vapor permeability (WVP), and water contact angle. The application of the membranes to treat water was demonstrated on methylene blue solution because methylene blue is a commonly used dye in many industries. It was found that the starch/10% CNP membrane was the optimum membrane for methylene blue dye treatment because the membrane exhibits a smooth surface, high WVP (1.67 × 10-10g Pa-1h-1m-1), high porosity (59.92%), low water contact angle value (44.8°), and resulted in the highest percentage removal of methylene blue (94.0%) after the filtration. After filtration, the starch/10% CNP membrane was still in good condition without breakage. In conclusion, the starch/CNP membranes produced in this study are promising for sustainable and environmentally friendly water treatment, especially for water containing methylene blue dye. This research aligns with current thematic trends in bionanohybrid composite materials utilization, offering innovative solutions for addressing water pollution challenges.

Combining Chitosan Nanoparticles and Garlic Essential Oil as Additive Fillers to Produce Pectin-Based Nanocomposite Edible Films

Edible films were produced by combining a pectin (PEC) matrix with chitosan nanopar-ticle (CSNP), polysorbate 80 (T80), and garlic essential oil (GEO) as an antimicrobial agent. CSNPs were analyzed for their size and stability, and the films, throughout their contact angle, scanning electron microscopy (SEM), mechanical and thermal properties, water vapor transmission rate, and antimicrobial activity. Four filming-forming suspensions were investigated: PGEO (control); PGEO@T80; PGEO@CSNP; PGEO@T80@CSNP. The compositions are included in the methodology. The average particle size was 317 nm, with the zeta potential reaching +21.4 mV, which indicated colloidal stability. The contact angle of the films exhibited values of 65°, 43°, 78°, and 64°, respec-tively. These values showed films with variations in hydrophilicity. In antimicrobial tests, the films containing GEO showed inhibition only by contact for S. aureus. For E. coli, the inhibition occurred in films containing CSNP and by direct contact in the culture. The results indicate a promising al-ternative for designing stable antimicrobial nanoparticles for application in novel food packaging. Although, it still shows some deficiencies in the mechanical properties, as demonstrated in the elongation data.

Antimicrobial and biodegradable chitosan/cellulose acetate phthalate/ZnO nano composite films with optimal oxygen permeability and hydrophobicity for extending the shelf life of black grape fruits

Film-forming biopolymers possessing antimicrobial activity and biodegradability are of great interest on account of their potential use in food packaging applications. The present study deals with the fabrication and characterisation of chitosan (CS) - cellulose acetate phthalate (CAP) films incorporated with ZnO nanoparticles (nano ZnO). CS-CAP films with varying ratios of nano ZnO reinforcement were prepared by solvent casting method. The thermal stability and barrier properties of the fabricated films increased with increasing amount of nano ZnO in the range of 2-7.5% (w/w). CS-CAP film loaded with 5% (w/w) nano ZnO showed the most optimal tensile strength and stiffness to be utilized as a food packaging material. Water contact angle measurements showed the prepared nano composite films to have low surface wettability and high contact angle value up to 90°. Biodegradability of the nano composite films ranged from 30 to 50% in 28 days. The CS-CAP film loaded with 5% (w/w) nano ZnO had extended the shelf life of black grape fruits up to 9 days. The demonstrated barrier and food protection characteristics of the CS-CAP-ZnO films attested its suitability as a primary food packaging material that can be used to increase the shelf life of black grape fruits.