Levels Of Chitosan Research Articles

Effect of chitosan concentration on physicochemical properties of starch-based straws

China’s 2021 ban on disposable (single-use) plastic straws and bags has necessitated the invention of more biodegradable straws. However, the application of starch-based straws is limited by their poor mechanical properties. Under high-temperature and high-pressure conditions, starch becomes a paste and its molecular hydrogen bonds are broken. After adding chitosan (CH), the CH and starch can form new hydrogen bonds. Biodegradable starch-based straws were made from cassava starch and rice starch (weight ratio = 1:1; CR) by using the extrusion technique. CH (0, 5, 10, 15 and 20%) was added to improve the mechanical properties of the straws, and the effect of CH on the chemical, mechanical and water resistance properties of the starch-based straws was investigated. The color, transparency and water resistance of CR/CH straws containing different levels of CH were superior to those of CR straws. The best mechanical properties and water resistance of starch-based straws were obtained when the CH addition was 5%. The addition of CH flattened the appearance of the starch-based straws and improved the mechanical properties and water resistance of the straws. The aforementioned structure can provide a reference for the application of starch-based materials.

Chitosan-gum Arabic complex nanocarriers for encapsulation of saffron bioactive components

Evaluating the proficiency of complex based polymers in order to increase the bioavailability and protection of bioactive compounds through nanoencapsulation has been studied during last years. The present work reports on preparation of saffron extract included-nanocomplexes of chitosan (CS) and gum Arabic (GA) through ionic gelation (IG). Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed the formation of bonds between functional groups (−COO− and –NH3+) of the two biopolymers and the creation of an amorphous structure. Transmission electron microscopy (TEM) illustrated the spherical and smooth shapes and approximately uniform particle size distribution of final nanocapsules. The size, PDI and zeta potential of produced nanoparticles was in the range of 183–295 nm, 0.272-0.612 and 20.5–50.5 mV, respectively. The levels of CS, GA, and saffron extract significantly influenced the properties of nanocomplexes and their encapsulation efficiency. An increase in CS and GA within complexes gave rise to the encapsulation efficiency from 29.12 to 52.34%, by increasing the attractive forces between the positive and negative groups of these two biopolymers on one hand, and by raising zeta potential on the other hand. The release profiles of saffron bioactive components (picrocrocin) in acidic and neutral environments were significantly different due to changes in chitosan solubility, brought about ˜ 40% difference in the first 60 min of release. To conclude, nanoencapsulation of saffron extract through ionic gelation of CS and GA was an efficient protective method in order to produce a stable form of saffron.

Effects of reaction pH on self-crosslinked chitosan-carrageenan polyelectrolyte complex gels and sponges

Macromolecular biomaterials often require covalent crosslinking to achieve adequate stability for their given application. However, the use of auxiliary chemicals may be associated with long-term toxicity in the body. Oppositely-charged polyelectrolytes (PEs) have the advantage that they can self-crosslink electrostatically and those derived from marine organisms such as chitosan (CS) and carrageenan (CRG) are inexpensive non-toxic alternatives to glycosaminoglycans present in the extracellular matrix of human tissues. The aim of this study was to explore the properties of crosslinker-free PEC gels and freeze-dried PEC sponges based on CS and CRG precursors. We offer new insights into the optimisation of conditions and mechanisms involved in the process and offer a systematic study of property changes across a full range of pH values. Zeta-potential measurements indicated that the PECs produced at pH 2–6 had a high strength of electrostatic interaction with the highest being at pH 4–5. This resulted in strong intra-crosslinking in the PEC gels which led to the formation of higher yield, viscosity, fibre content and lower moisture content. The weaker interaction between CS and CRG at pH 7–12 resulted in higher levels of CS incorporated into the complex and the formation of more inter-crosslinking through entanglements and secondary interactions between PEC units. This resulted in the production of stable PEC sponge materials compared with the PEC materials produced at pH 6 and below. From the range of samples tested, the PECs produced at pH 7.4 appeared to show the optimum combination of yield, stability and homogeneity.

Solvent strength and biopolymer blending effects on physicochemical properties of zein-chitosan-polyvinyl alcohol composite films

The aim of this research was to optimise and develop edible films made from zein (ZN), chitosan (CS), poly(vinyl alcohol) (PVOH) and poly(ethylene glycol) (PEG400) using Box Behnken Design (BBD). Four factors viz. ZN:CS ratio (w/w) (1:3, 1:1, 3:1), PVOH wt.% (in dry film) (0, 0.25, and 0.5), PEG400 wt% (0.13, 0.21, 0.31) and ethanol (40–80% v/v in water), were investigated. The effects on tensile strength (TS), Young's modulus of elasticity (EM), elongation at break (%EAB), water vapour permeability (WVP), solubility in water (Ws), and optical properties were evaluated. The films were further characterised using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), x-ray diffraction (XRD) and swelling behaviour. SEM micrographs showed that high levels of ZN and PEG400 resulted in rough surfaces with major film defects, but these were minimised at high levels of CS or PVOH. XRD analysis indicated potential interactions through hydrogen bonding between the polar groups of ZN and hydroxyl moieties of PVOH and CS. Stress-strain curves showed that ZN and CS composite films possessed high TS but were brittle. Incorporation of PVOH increased the ductility of the composite films. Optimum films were obtained using ZN/CS/PVOH/PEG400 ratio of 0.35/0.29/0.13/0.23 (wt.%) and 60% ethanol, giving dry state properties of TS, EM, and EAB as 24.21 MPa, 356.62 MPa and 84.23%. respectively. This study demonstrated the influence of critical interactions between solvent features (polarity) and interfacial properties of ZN, CS, PVOH and PEG400. The observed crosslinking behaviour suggested the effectiveness of blending technique in improving the compatibility of biopolymers and overall functionality of edible films.