Search Results (4)

Mechanical damage and microbial contamination are major challenges in the postharvest logistics of perishable fruit. In this study, two types of functionally modified chitosan-based aerogel pads were developed to enhance cushioning and preservation of wax apples. A chitosan/polyvinyl alcohol (CP) aerogel was first optimized by adjusting solid content, CS:PVA ratio, and crosslinker concentration. The optimal formulation (2% solids, 1:1 CS: PVA, 3% glutaraldehyde) exhibited a uniform porous structure and improved compressive strength. A chitosan/montmorillonite (CM) aerogel with 5% montmorillonite (MMT) showed high porosity, low density, and excellent cyclic stability. Incorporating 10% copper nanoparticle-loaded antibacterial fibers (CuNPs-TNF) into CM aerogels yielded CM-Cu aerogels with enhanced cushioning and antimicrobial properties. Under simulated transport and cold storage conditions, all aerogel-packaged groups reduced mechanical damage and decay of wax apples. Compared to the control, the CM-Cu group showed 66% lower decay, 5% less weight loss, 6 N greater firmness, 7% less juice yield, and a 13% reduction in relative electrical conductivity. Additionally, it better preserved fruit color and total soluble solids, extending shelf life by 4 d at 20 °C. These results demonstrate the potential of chitosan-based aerogels as multifunctional packaging materials that combine mechanical protection with antimicrobial activity for perishable fruit preservation. Full article

Dandelion extract is a reducing agent, and CuSO₄∙5H₂O was used as a carrier to create copper nanoparticles (CuNPs). A novel polyvinyl alcohol–chitosan–dandelion–CuNP (PVA/CTS/DAN/CuNP) gel was acquired by cross-linking Polyvinyl alcohol (PVA) and chitosan (CTS) solution. Its structure was analyzed using Fourier transform infrared spectroscopy, Scanning electron microscopy, and X-ray diffraction. The PVA/CTS/DAN/CuNP gels manifested good stability, recycling ability, swelling properties, and biocompatibility. Using the agar diffusion method, the diameters of the inhibition zone of the composite gel against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa could be over 21 mm. In conclusion, the PVA/CTS/DAN/CuNP composite gel had good antibacterial performance, which has a high potential for application in microbial contamination treatment and environmental protection. Full article

The objective of this work was to formulate PVA films with the addition of modified phenols, chitosan, silver, or copper nanoparticles with fungistatic and bacteriostatic activity. The films were characterized by Fourier transform infrared spectroscopy, thermogravimetry analysis, differential scanning calorimetry, and scanning electron microscopy. The bacteriostatic activity against Salmonella gallinarum and Lactobacillus acidophilus, and the fungistatic activity against Penicillium acidophilus were determined. The results indicated that the addition of phenols enhanced the effect on the stability of the chemical structure of the PVA film. PVA films with modified bioactives and nanoparticles inhibited the colonization of the microorganisms tested, indicating germicidal control. Full article

A chitosan/poly(vinyl alcohol)-stabilized copper nanoparticle (CP@Cu NPs) was used as a heterogeneous catalyst for the borylation of α, β-unsaturated ketones, MBH alcohols, and MBH esters in mild conditions. This catalyst not only demonstrated remarkable efficiency in synthesizing organoboron compounds but also still maintained excellent reactivity and stability even after seven recycled uses of the catalyst. This methodology provides a gentle and efficient approach to synthesize the organoboron compounds by efficiently constructing carbon–boron bonds. Full article