tannins and triphosphoric-acid

Orange essential oil was microencapsulated by complex coacervation with whey protein isolate (WPI): carboxymethylcellulose (CMC), WPI:sodium alginate (SA) and WPI:chitosan (CH). Effect of pH, protein:polysaccharide ratio and solid concentration on coacervation efficiency were selected for the best coacervation conditions. Tannic acid (TA), sodium tripolyphosphate, oxidised tannic acid and transglutaminase enzyme (TG) were used as cross-linking agents. Highest encapsulation efficiency (EE) for wet coacervated microcapsules ranged from 88% to 94%. Microcapsules were freeze and spray dried to evaluate their effect on its integrity. EE was higher than 80% in freeze dried coacervated microcapsules with and without cross-linking agent, but they formed a solid cake. Spray-dried samples formed a free fluid solid (10-20 µm), where the systems WPI:CMC and WPI:CH cross-linked with TA and TG, respectively showed the highest EE (47% and 50% respectively), representing 400% improvement compared to the samples without cross-linking.

Topics: Capsules; Citrus sinensis; Cross-Linking Reagents; Desiccation; Drug Compounding; Freeze Drying; Oils, Volatile; Oxidation-Reduction; Plant Oils; Polyphosphates; Polysaccharides; Tannins; Transglutaminases; Whey Proteins

The tannin acid/chitosan/tripolyphosphate nanoparticles were encapsulated in polyvinyl alcohol (PVA)/poly-acrylic acid (PAA) electrospinning films by electrostatic spinning technology. To optimize the prepared condition, properties and morphology of nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The optimized initial concentration of tannin, chitosan and tripolyphosphate solutions were 1, 1, 0.5mg/ml, respectively, with adding proportion for 5:5:1. The average diameter of tannin acid/chitosan/tripolyphosphate nanoparticles was ∼80nm. The electrospinning films showed an excellent water-resistant property with 0.5wt%N,N'-Methylenebisacrylamide (MBA). Due to the antioxidant and antibacterial of tannic acid, the films possessed these properties. The antioxidant and antibacterial of these fibers significantly improved after in situ formation of silver nanoparticles (AgNPs). Electrospun films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).

Topics: Anti-Bacterial Agents; Chitosan; Electricity; Escherichia coli; Free Radical Scavengers; Metal Nanoparticles; Polyphosphates; Silver; Staphylococcus aureus; Structure-Activity Relationship; Surface Properties; Tannins

Electrospun chitosan fibers have numerous potential in biomedical, food, and pharmaceutical applications. However, the mats formed are often not chemically stable in a wide range of pHs unless crosslinked. Here, we report on the use of glycerol phosphate (GP), tripolyphosphate (TPP) and tannic acid (TA) as a new set of non-covalent crosslinkers for electrospun chitosan fibers. Crosslinking with or without heat or base activation were performed either prior to (one-step or activated one-step) or after (two-step or activated two-step) electrospinning with either GP or TA. TPP crosslinking was performed in two-step and activated two-step. FESEM, FTIR and UV-vis transmittance at 600 nm were used to determine fiber surface morphology, chemical interactions and solubility in 1M AA (pH 3), water (~pH 6) and 1 M NaOH (pH 13), respectively. Crosslinking of chitosan with GP and TA yields fibers with a mean diameter range of 145-334 nm and 143-5554 nm, respectively. TPP crosslinking produced branched fibers with mean diameters of 117-462 nm range. Two-step chitosan-TA did not dissolve in 1M AA even after 72 h while all chitosan-TPP, activated two-step chitosan-TA and two-step heat activated chitosan-GP fibers survived in water after 72 h.

Topics: Chitosan; Cross-Linking Reagents; Glycerophosphates; Hydrogen-Ion Concentration; Microscopy, Electron, Scanning; Polyphosphates; Solubility; Spectroscopy, Fourier Transform Infrared; Tannins; Viscosity