Bioactive Pectin-Murta (Ugni molinae T.) Seed Extract Films Reinforced with Chitin Fibers

This study investigated the biocomposite pectin films enriched with murta (Ugni molinae T.) seed polyphenolic extract and reinforced by chitin nanofiber. The structural, morphological, mechanical, barrier, colorimetric, and antioxidant activity of films were evaluated. The obtained data clearly demonstrated that the addition of murta seed extract and the high load of chitin nanofibers (50%) provided more cohesive and dense morphology of films and improved the mechanical resistance and water vapor barrier in comparison to the control pectin film. The antioxidant activity ranged between 71% and 86%, depending on the film formulation and concentration of chitin nanofibers. The presented results highlight the potential use of chitin nanofibers and murta seed extract in the pectin matrix to be applied in functional food coatings and packaging, as a sustainable solution.

Chitin Fiber from Mushroom as Reinforcement for Biobased Polymer

This project aimed to study the reinforcement effect of fungal chitin at different loading on chitin/PLA composite. The chitin nanofibers were extracted from three mushroom species (oyster mushroom Pleurotus ostreatus, shiitake mushroom Lentinula edodes, enoki mushroom Flammulina velutipes) and used as a reinforcement element in PLA. The chitin/PLA composite was fabricated using a solvent-casting method followed by the hot-compress molding method. In the solvent-casting method, the chitin nanofibers were dispersed in PLA/chloroform mixture and the mixture was left for solvent evaporation. The solvent-free chitin/PLA thin film was then filled in dog bone mold before proceeded with hot-compress molding at 190°C and 70 bar. The samples with different chitin loading were tested with tensile test to study the mechanical performance of nanocomposite. The chitin/PLA composite from oyster mushroom shows the optimum result (σ= 43 MPa, E= 12 MPa) at 5% chitin loading. The increment of the chitin loading leads to a decrease in both strength and strain. However, for the samples from enoki and shitake mushrooms, the optimum chitin loading is 10% with 55 MPa and 56 MPa tensile strength, respectively. This study suggests the potential of fungal chitin as reinforcement in PLA.

Isolation and Characterization of Chitin Nanofibers from Calocybe indica and its Applications

In this study, chitin nanofibers are isolated from Calocybe indica (Milky White Mushroom), and they are further characterized using various analytical techniques such as UV-VIS, FTIR, TGA, Fe - SEM, and XRD. Antioxidant activity of the chitin nanofibers was studied by performing various assays such as DPPH, ABTS, H2O5 Scavenging Activity, Hydroxyl Radical Activity, Superoxide Assay, and Reduced Glutathione Activity. Isolated Chitin nanofibers were then chemically treated to form hydrogels. The hydrogels formed were further characterized.

Preparation of Composite Materials from Self-Assembled Chitin Nanofibers

Although chitin is a representative abundant polysaccharide, it is mostly unutilized as a material source because of its poor solubility and processability. Certain specific properties, such as biodegradability, biocompatibility, and renewability, make nanofibrillation an efficient approach for providing chitin-based functional nanomaterials. The composition of nanochitins with other polymeric components has been efficiently conducted at the nanoscale to fabricate nanostructured composite materials. Disentanglement of chitin microfibrils in natural sources upon the top-down approach and regeneration from the chitin solutions/gels with appropriate media, such as hexafluoro-2-propanol, LiCl/N, N-dimethylacetamide, and ionic liquids, have, according to the self-assembling bottom-up process, been representatively conducted to fabricate nanochitins. Compared with the former approach, the latter one has emerged only in the last one-and-a-half decade. This short review article presents the preparation of composite materials from the self-assembled chitin nanofibers combined with other polymeric substrates through regenerative processes based on the bottom-up approach.

Effect of mixing ratio on mechanical properties of mixture of chitin nanofibers and microfibrillated cellulose reinforced PVA hybrid nanocomposites

In order to explore the possibility of polyvinyl alcohol (PVA) reinforced by mixture of chitin nanofibers (ChNFs) and microfibrillated cellulose (MFC) instead of a single reinforcing phase, mechanical properties of PVA based hybrid nanocomposites reinforced with combination of ChNFs and MFC in various mixing ratios were investigated. For comparison, two different experiments were conducted to prepare nanocomposite films by casting technical processing, where ratios of ChNFs to MFC were mixed varying from 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, and 0:1 in both projects, while in Project 1 the weights of PVA and ChNFs were always kept constant and the weight of PVA only was kept constant in Project 2. The results were as follows: (1) The hybrid ternary nanocomposites acquired the highest Young’s modulus and tensile strength when ratio of ChNFs to MFC was 1:1, which exhibited higher Young’s modulus and higher tensile strength than PVA/ChNFs composites, but delivered higher Young’s modulus and similar tensile strength comparing to PVA/MFC composites; (2) Aggregations and voids inside nanocomposites were detrimental to mechanical properties of PVA based hybrid nanocomposites. In some industries such as food packing, PVA based hybrid nanocomposites at mixing ratio 1:1 of ChNFs to MFC are applied presumably with ChNFs partly instead of MFC in the future.