Emulsion polymerized latex-based pressure-sensitive adhesives (PSAs) are more environmentally benign because they are synthesized in water but often underperform compared to their solution polymerized counterparts. Studies have shown a simultaneous improvement in the tack, and peel and shear strength of various acrylic PSAs upon the addition of cellulose nanocrystals (CNCs). This work uses atomic force microscopy (AFM) to examine the role of CNCs in (i) the coalescence of hydrophobic 2-ethyl hexyl acrylate/-butyl acrylate/methyl methacrylate (EHA/BA/MMA) latex films and (ii) as adhesion modifiers over multiple length scales.
View Article and Find Full Text PDFThe edible coating has been used for covering fruits and vegetables, bringing surface protection, and extending product shelf-life. Due to the outstanding properties, nanomaterials have become a part of the packaging/coating new generation, demonstrating improvements in the barrier capacity of materials starting from construction products to the food industry. In the food industry, on the other hand, Agaricus bisporus mushrooms have a limited shelf-life from 1 to 3 days because of their high respiration rate and enzymatic browning.
View Article and Find Full Text PDFUV barrier properties and the oxygen permeability (OP) of alginate based films loaded from 0 to 30% CNCs (w/w polymer, dry basis) were evaluated at 0, 50, and 70% RH. The best performing film was used to coat chicken breasts and lipid oxidation was assessed during storage through lipid peroxide value (PV), thiobarbituric acid reagent substances (TBARS) quantification and color variability measurements. Results showed promising UV barrier effects and 25% decrease of OP at 70% RH when 30% CNCs were loaded in alginate films.
View Article and Find Full Text PDFThis work describes the development of membrane based on chitosan (CHI), cellulose nanocrystals (CNCs), and glycerol (GLY), and optimization of the formulation for immobilization of monoclonal anti-Shiga toxin 2B antibody (mAnti-stx2B-Ab) for E. coli O157:H7 detection. The effect of CHI deacetylation degree & viscosity, CNCs and GLY concentrations on Anti-stx2B-Ab immobilization efficiency was evaluated.
View Article and Find Full Text PDFThe aim of this study was to develop a novel approach allowing simultaneous enrichment as well as specific and fast detection of Escherichia coli O157:H7 by indirect ELISA using optimized support membrane based on chitosan (CHI), cellulose nanocrystals (CNCs), and glycerol (GLY). Therefore, combining the step of the capture of the pathogen and enrichment steps for the microbial growth led to a high detection signal at a low inoculation level without cross-reaction with Pseudomonas and Salmonella strains. The detection was performed by varying incubation periods and different level of inoculations.
View Article and Find Full Text PDFThis paper presents the effects of the composition of different media (i.e., Tryptic soy broth (TSB), Brain heart infusion (BHI), Listeria enrichment broth (LEB), Fraser broth (FB) and University of Vermont medium (UVM)) on the detection of a short peptide fragment PepD specific to the p60 protein (p60) of L.
View Article and Find Full Text PDFCellulose nanocrystals (CNCs) reinforced chitosan based antifungal films were prepared by encapsulating essential oils (EOs) nanoemulsion. Vapor phase assays of the chitosan-based nanocomposite films loaded with thyme-oregano, thyme-tea tree and thyme-peppermint EO mixtures showed significant antifungal activity against Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus, and Penicillium chrysogenum, reducing their growth by 51-77%. Combining the bioactive chitosan films loaded with thyme and oregano EOs produced ~2 log reduction in fungal growth in inoculated rice during 8 weeks of storage at 28 °C.
View Article and Find Full Text PDFSurface-initiated atom transfer radical polymerization was used to graft hydrophobic poly(butyl acrylate) from cellulose nanocrystals (CNCs) resulting in compatibilized CNCs that were successfully incorporated inside the core of polymer latex particles. CNCs are anisotropic nanoparticles derived from renewable resources and have potential as reinforcing agents in nanocomposites. However, challenges due to the incompatibility between cellulose and hydrophobic polymers and processing difficulties, such as aggregation, have limited the performance of CNC nanocomposites produced to date.
View Article and Find Full Text PDFProbiotic (Lactobacillus rhamnosus ATCC 9595) was encapsulated in alginate-CNC-lecithin microbeads to produce nutraceutical microcapsules. Addition of CNC and lecithin in alginate microbeads (ACL-1) improved the viability of L. rhamnosus during gastric passage and storage.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2014
Cellulose nanocrystal (CNC) reinforced chitosan based antimicrobial films were prepared by immobilizing nisin on the surface of the films. Nanocomposite films containing 18.65 μg/cm(2) of nisin reduced the count of L.
View Article and Find Full Text PDFNanocrystalline cellulose (NCC) reinforced alginate-based nanocomposite film was prepared by solution casting. The NCC content in the matrix was varied from 1 to 8% ((w/w) % dry matrix). It was found that the nanocomposite reinforced with 5 wt% NCC content exhibits the highest tensile strength which was increased by 37% compared to the control.
View Article and Find Full Text PDFStereocomplexes between poly(D-lactide) (PDLA) and poly(L-lactide) (PLLA) have been extensively studied, including, in recent years, several reports on the stereocomplexation of PDLA with small molecules such as peptides. Here, the possible complexation between PDLA and luteinizing hormone releasing hormone (LHRH), a l-configured decapeptide, is considered for which several observations were made: (1) in calorimetry an additional endothermic peak appears at a lower temperature than the melting temperature of pure PDLA; (2) in Raman analyses a band splitting of the C=O stretching mode (not present in pure PDLA) shows up; (3) in X-ray diffraction, however, no change is observed after mixing the two species, indicating no crystal structure modification (and the absence of any stereocomplex crystal structure). The calorimetric double melting peak is merely explained by the presence of two distinct morphological forms of PDLA, whereas the spectroscopic band splitting can be due to simple differences of crystallinity.
View Article and Find Full Text PDFRegioselectively substituted maltooligosaccharides were prepared by enzymatic transformation of modified cyclodextrins by using simultaneously two different enzymes: cyclodextrin glucanotransferase (CGTase) and amyloglucosidase. Oligosaccharides were obtained in very good yields and their structures were identified by 1D and 2D NMR spectroscopy. These results provided new information about the specificity of the catalytic sites of CGTase and amyloglucosidase.
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