Ambient plasma treatment of pectin in aqueous solution to produce a polymer used in packaging.

Water resistance, mechanical behavior and coloration of pectin needs to be tuned for packing utilization. Plasma was used for the treatment of natural products, but there is no research on its effect on the biomass in the presence of ammonia. Though the reaction of pectin (PE) and ammonia was known to impart the ammonolysis and de-esterification, the plasma treatment on PE solution containing ammonia was explored to exemplify the amination and polymerization of the carbohydrate at the ambient condition. The plasma treatment increased the coloration of the solution due to the deprotonation of PE for the production of more sp2 carbon. The film from the amination of PE showed higher hydrophobicity and water stability than the bare PE. The plasma treatment alone decreased the Young's modulus (4.3 MPa versus 22 MPa), while the nitrogen addition enhanced the Young's modulus to 160 MPa and increased the tensile strength (28.7 MPa versus 25.8 MPa of PE). The hydrogen bonds from the amine group induced a glass-to-rubber transition at 77.9 °C by the increasing the crosslinking. This work provided a facile way of aminating and conjugating the biomass in solution to produce polymer with improved mechanical properties using plasma and ammonia incorporation.

Tuning the physicochemical properties of apple pectin films by incorporating chitosan/pectin fiber.

Various biodegradable or edible films were designed to deal with the environmental threats from plastic films. To overcome the defects of pectin film, the feasibility for the incorporation of CH/PE fiber was explored. Micron-scale novel artificial CH/PE fibers in needle, spindle or whisker shape with a diameter around 25 µm were fabricated via a shearing regime in virtue of electrostatic complexing. The incorporation of CH/PE fiber (mixture) and its size-fractioned portions (small and large) substantially changed PE films in diverse ways. Structurally, the fiber-incorporated films were heterogeneous with the fibers concentrated in the upper layer, although they presented similar FT-IR spectra and XRD pattern to PE film. Regarding the film performance, the incorporation of CH/PE fibers, especially the small portion, rendered the PE film with higher values in water-proof ability, thermal stability, break resistibility, stretchability and UV blocking capacity. More importantly, this work provided an innovative strategy to improve the performance of edible films.

Physicochemical properties of the edible films from the blends of high methoxyl apple pectin and chitosan.

Chitosan (CH) and pectin (PE) are considered as promising biomaterials in developing eco-friendly films due to their film-forming, biodegradable, and non-toxic characteristics, the films from pure CH or PE have obvious defects such as poor barrier and mechanical properties. In this study, the blend films of CH and PE at varying mass ratios were characterized. Structurally, numerous small pores evenly distributed in PE film while big caves unevenly scattered in CH film. CH film is semicrystalline but PE and blend films are totally amorphous, the two individual films presented comparable values in water content and solubility to blend films. The CH film showed lower water vapor permeability and surface wettability and these parameters of the blend films decreased with CH level, the blend films exhibited high transparence as PE film did, which is much higher than that of CH film. Mechanically, the PE film presented higher values in stretchability and tensile strength than CH film. Moreover, in a different blending ratios, synergistic effects were found with several characters of the CH/PE blend film, especially in transparence and mechanical properties. These synergistic effects were ascribed to the intermolecular electrostatic interactions between CH and PE.

Aggregates of octenylsuccinate oat ß-glucan as novel capsules to stabilize curcumin over food processing, storage and digestive fluids and to enhance its bioavailability.

Self-aggregates of octenylsuccinate oat ß-glucan (AOSG) have been verified as nanocapsules to load curcumin, a representative of hydrophobic phytochemicals. This study primarily investigated the stability of curcumin-loaded AOSGs over food processing, storage and digestive fluids. Curcumin in AOSGs showed better stability over storage and thermal treatment than its free form. Curcumin loaded in AOSGs stored at 4 °C in the dark exhibited higher stability than that at higher temperatures or exposed to light. Approximately 18% of curcumin was lost after five freeze-thaw cycles. Curcumin in AOSG was more stable than its free form in mimetic intestinal fluids, attesting to the effective protection of AOSG for curcumin over digestive environments. When curcumin-loaded AOSG travelled across mimetic gastric and intestinal fluids, curcumin was tightly accommodated in the capsule, while it rapidly escaped as the capsule reached the colon. Interestingly, the curcumin loaded in AOSG generated higher values of Cmax and area under the curve than did its free counterpart. These observations showed that AOSG is a powerful vehicle for stabilizing hydrophobic phytochemicals in food processing and storage, facilitating their colon-targeted delivery and enhancing their bioavailability.