Improving chitosan properties through ionic and chemical cross‐linking and their impact on emulsified systems

Abstract

Chitosan (CS) nanoparticles were formed by two different methodologies: ionic (with sodium tripolyphosphate -TPP) and chemical (with genipin -GN) cross-linking. CS-TPP and CS-GN nanoparticles showed positive zeta potential (+46.24 and +62.86 mV, respectively) and sizes ranging from 83.70 to 835.91 nm, respectively. Ionic cross-linking (with TPP) resulted in particles smaller than those formed by chemical cross-linking (with GN). The in vitro antibacterial activity revealed an efficient inhibitory effect, especially regarding CS-TPP. In situ, antibacterial and antioxidant studies were carried out on O/W emulsions. The mesophilic and psychrotrophic counts, peroxide value and quantification of conjugated dienes and trienes during time revealed that nanoparticles tend to improve the microbiological and oxidative stability of emulsions. These findings underline the direct relationship between the reduction of particle size and the increase in biopolymer functional properties and expand the possibilities of CS application as a natural preservative of emulsified systems.

Magnetic Nanoparticle Support with an Ultra-Thin Chitosan Layer Preserves the Catalytic Activity of the Immobilized Glucose Oxidase

“…This method uses the least expensive chemicals and allows for the conservation of energy compared to the thermal decomposition methods of metal compounds frequently used for syntheses of magnetic NPs [ 59 , 60 , 61 ]. Here, the magnetic NP aggregates (MNAs) were then coated with an ultrathin layer of CS cross-linked with a most benign compound—TPP—which is allowed for use in the food and pharmaceuticals industries [ 62 ]. In addition, the attachment of GOx was carried out with benign 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) [ 63 , 64 ].…”