Search

Bionanocomposite films of three biopolymers including chitosan, gelatin, and pectin incorporated with rosemary essential oil (REO) were developed and characterized in terms of their physical, structural, mechanical, morphological, antioxidant, and antimicrobial properties. Incorporation of REO showed an increased hydrophobic nature thus, improved water vapor transmission rate (WVTR), tensile strength (TS), elongation-at-break (EAB), and thermal stability significantly (P ≤ 0.05) as compared to the control films. The addition of REO leads to more opaque films with relatively increased microstructural heterogeneity, resulting in an increase in film opacity. Fourier transform infrared spectroscopy (FTIR) and particle size revealed that REO incorporation exhibits high physicochemical stability in chitosan, gelatin, and pectin bionanocomposite films. Incorporation of REO exhibited the highest inhibitory activity against the tested pathogenic strains (Bacillus subtilis and Escherichia coli). Furthermore, the addition of REO increased the inhibitory activity of films against ABTS and DPPH free radicals. Therefore, chitosan, gelatin, and pectin-based bionanocomposite films containing REO as food packaging could act as a potential barrier to extending food shelf life., Competing Interests: Declaration of competing interest The authors have no conflict of interests or personal relationships to be declared for the work reported in this manuscript., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Planetary ball milling of chitosan microparticles (CMP) for 8 h produced chitosan nanoparticles (CNP) having hydrodynamic diameter of 615.18 nm. The ζ-potential decreased from 56.48 mV (CMP) to 31.52 mV (CNP). High resolution transmission electron microscopy (HRTEM) revealed nanosize, irregular shape and surface roughening of CNP. CNP was whiter than CMP having higher water absorption capacity and decreased flow ability. Both CMP and CNP showed negligible swelling and no water solubility. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) revealed no chemical changes and X-ray diffraction (XRD) showed decreased crystallinity in CNP. In CNP, thermogravimetric analysis (TGA) revealed increased thermal degradation; differential thermogravimetric (DTG) revealed increased rate of thermal degradation; and high temperature differential scanning calorimetry (HDSC) revealed broadening of endothermic and exothermic phases and reduction in glass transition temperature as compared to CMP. In conclusion, planetary ball milling for 8 h produces bright, amorphous and rough CNP with improved functional and comparable thermal properties., Competing Interests: Declaration of competing interest The authors have no conflict of interest to be declared., (Copyright © 2020. Published by Elsevier B.V.)

Rosemary (REO), mint essential oil (MEO), nisin and lactic acid were incorporated at 0.5% to develop a novel functional packaging film including chitosan pectin and starch polymers (0.75:1.5:0.75 w/w). Inclusion of REO and nisin significantly (p ≤ 0.05) improved water barrier properties (0.014 g.mm/m224h), tensile strength (25.95 MPa) and thermal stability as compared to control. ATR-FTIR spectra and XRD pattern elucidated structural interaction between EO's and biocomposite films. Addition of REO of and nisin increased microsctructural heterogeneity and opacity (2.78). Incorporation of REO and nisin exhibited the highest inhibitory activity against all tested pathogenic strains (Bacillus subtilis , Escherichia coli , and Listeria monocytogenes). The antioxidant properties of biocomposite films were analyzed using reducing power, metal chelation, DPPH and ABTS radical scavenging assays, which enhanced significantly (p ≤ 0.05) with the addition of MEO and REO. This study validated that incorporation of natural additives in active biocomposite films offers promising functional ingredients for packaging materials for various food applications. [ABSTRACT FROM AUTHOR]

• Chtosan polymer produces nanocapsules through ionic gelation with sodium bisulfate. • The nanocapsules were amorphous with spherical to irregular shape. • Hydroxytyrosol (HT) was nanoencapsulated using ultrasonication in tandem. • Nanoencapsulated HT was protected during the gastrointestinal simulations. • Drug release was slow and took place mainly during the intestinal simulation. This research includes production of chitosan nanocapsules through ionic gelation with sodium bisulfate for nanoencapsulation of hydroxytyrosol (HT) using ultrasonication in tandem. The resulting nanocapsules encapsulating HT were analyzed for particle size, ζ-potential, packaging characteristics, FESEM, ATR-FTIR, XRD, DSC, in vitro release, antioxidant potential and antiproliferative properties. The nanocapsules (size 119.50–365.21 nm) were spherical to irregular shaped with positive ζ-potential (17.50–18.09 mV). The encapsulation efficiency of 5 mg/g HT (HTS1) and 20 mg/g HT (HTS2) was 77.13% and 56.30%, respectively. The nanocapsules were amorphous in nature with 12.34% to 15.48% crystallinity and crystallite size between 20 nm and 27 nm. Formation of nanocapsules resulted in increasing the glass transition temperature. HTS2 delivered 67.12% HT (HTS1 58.89%) at the end of the simulated gastrointestinal digestion. The nanoencapsulated HT showed higher antioxidant and antiproliferative (against A549 and MDA-MB-231 cancer cell lines) properties than the free HT. [ABSTRACT FROM AUTHOR]

Chitosan flakes (CF) were modified to chitosan nanopowder (CP), using planetary ball milling for 8 h. Dynamic light scattering (DLS) revealed and high resolution transmission electron microscopy (HRTEM) confirmed the nano size of CP. Least gelation capacity (LGC) of CF (3%) and CP (4%) was manipulated to fabricate gels with 1.5, 2, and 3 fold increase in LGC. The total color difference was higher in CP than CF gels and depended on concentration. Dynamic rheometry under temperature ramping (20–80 °C and 80-20 °C) showed stable viscoelasticity. Besides, optimal structural network was observed in CP8 and CF6. During temperature ramping, the damping factor (tan δ) for all the gels was >0.1 < 1, which confirmed the elastic behavior of the gels. Power law model revealed maximum shear thinning behavior in CP8 and CF6. Rapid increase in temperature of gels during thermogravimetric analysis (TGA) and high temperature differential scanning calorimetry (HDSC) revealed more thermal stability in CP than CF gels. The interconnecting gap of polymer gel matrix revealed through scanning electron microscopy (SEM) was higher in CF than in CP gels. In conclusion, the CP gels have comparable rheology but better thermal and matrix properties that could be explored for food and pharmaceutical applications. • Chitosan powder gels at higher concentration than chitosan flakes. • Chitosan gels remain viscoelastic even under cyclic temperature ramping. • Chitosan powder gels dehydrate faster than chitosan flake gels. • Chitosan powder gels have more thermal stability to rapid heating. • Increase in solvent–particle interaction decreases the interconnecting gap of polymer matrix in powder gels. [ABSTRACT FROM AUTHOR]