Encapsulation of polyketide colorants in chitosan and maltodextrin microparticles.

This study aimed to encapsulate Talaromyces amestolkiae colorants in maltodextrin and chitosan microparticles using the spraydrying technique and to evaluate the biopolymers' capacities to protect the fungal colorant against temperature (65 °C) and extreme pH (2.0 and 13.0). The compact microparticles exhibited smooth or indented surfaces with internal diameters ranging between 2.58-4.69 µm and ζ ~ -26 mV. The encapsulation efficiencies were 86 % and 56 % for chitosan and maltodextrin microparticles, respectively. The shifted endothermic peaks of the free colorants indicated their physical stabilization into microparticles. The encapsulated colorants retained most of their absorbance (compared to the 0 h) even after 25 days at 65 °C. Contrary, the free colorant presented almost no absorbance after 1 day under the same conditions. Colorants in chitosan and maltodextrin matrices also partially maintained their colorimetric and fluorometric properties at acidic pH. However, only maltodextrin improved the resistance of the red colorant to alkaline environments. For the first time, the potential of polysaccharide-based microparticles to preserve polyketide colorants was demonstrated using 3D fluorescence. Therefore, this study demonstrated an alternative in developing functional products with natural color additives.

Insect residues as an alternative and promising source for the extraction of chitin and chitosan.

This work aimed to obtain and characterize chitin and chitosan extracted from the rearing residues of Tenebrio molitor, Zophobas morio, and Blaptica dubia insects in different growth stages in the same rearing cycles chitin and chitosan yielded 11.21 %-20.89 % and 6.26 %-7.07 %, respectively. The deacetylation degrees of chitosan ranged from 75.75 %-89.21 %, and the solubilities from 69.88 %-94.39 %. Infrared spectroscopy corroborated the acquisition of chitin and chitosan and can be used as a semi-quantitative technique for determining the degree of chitosan deacetylation. The X-ray diffraction profiles revealed the presence of α-chitin, and the relative crystalline indices ranged from 65.9 %-89.2 %. Typical TG profiles with two thermal events are observed for chitin and chitosan samples with different residue contents from the extraction procedure. The chitosan solutions exhibited pseudoplastic behavior, with apparent viscosities ranging from 195.96 to 249.86 mPa.s. The characterization results of the biopolymers extracted from insect residues were similar to those obtained from conventional sources. The growth stage influenced the chitin yield and crystallinity index. The results of this study reinforce the feasibility of using alternative sources of chitin and chitosan, providing the use of waste from insect farms and contributing to sustainability and a circular economy.

Effect of Addition of Cross-Linked Starch on the Properties of Degraded PBAT Poly(butylene adipate-co-terephthalate) Films.

This work aimed to evaluate the properties of butylene adipate-co-terephthalate (PBAT) degraded after 1800 days of storage (DPBAT) by preparing blends (films) with crosslinked starch (Cm) through extrusion and thermocompression. Different ratios of DPBAT:Cm (70:30, 60:40, and 50:50 m/m) were prepared. The incorporation of Cm into DPBAT significantly changed the properties of the films by making them stiffer (increasing Young's modulus by up to 50%) and increasing the thermal resistance of DPBAT. The presence of crosslinked starch in the films made them less hydrophobic (with decreased contact angle and increased moisture content), but these parameters did not vary linearly with changes in the content of crosslinked starch in the blend (DPBAT:Cm). The microscopic images show an inhomogeneous distribution of Cm granules in the DPBAT matrix. Thus, the films prepared with PBAT show a significant decrease in their mechanical parameters and heat resistance after long-term storage. However, the preparation of blends of degraded DPBAT with crosslinked starch promoted changes in the properties of the films prepared by thermocompression, which could be useful for disposable packaging.