Interactions between κ-carrageenan and chitosan in nanolayered coatings—Structural and transport properties

Abstract

The interactions between-carrageenan and chitosan, two oppositely charged polysaccharides, have been investigated through microcalorimetric and quartz crystal microbalance measurements. Microcalorimetric measurements show that-carrageenan/chitosan interaction is an exothermic process and that the alternate deposition of-carrageenan and chitosan results in the formation of a nanolayered coating mainly due to the electrostatic interactions existing between the two polyelectrolytes (though other types of interactions may also be involved). Quartz crystal microbalance measurements confirmed that the alternating deposition of-carrageenan and chitosan resulted in the formation of a stable multilayer structure. The-carrageenan/chitosan nanolayered coating, assembled on a polyethylene terephthalate (PET) support, was characterized in terms of its surface (contact angle measurements) and gas barrier properties (water vapor and O 2 permeabilities) and analyzed by scanning electron microscopy (SEM). The water vapor permeability (WVP) and the oxygen permeability (O 2 P) of the-carrageenan/chitosan nanolayers were found to be 0.020 ± 0.002 × 10 −11 and 0.043 ± 0.027 × 10 −14 g m −1 s −1 Pa −1 , respectively. These results contribute to a better understanding of the type of interactions that play role during the construction of this type of nanostructures. This knowledge can be used in the establishment of an approach to produce edible, biodegradable multilayered nanostructures with improved mechanical and barrier properties for application in, e.g. food and biomedical industries.

Perspectives on Utilization of Edible Coatings and Nano-laminate Coatings for Extension of Postharvest Storage of Fruits and Vegetables

“…Table 3 shows the permeabilities to oxygen and water vapor of conventional and nano-laminate coatings. It is suggested that barrier properties of nano-laminate coatings are improved due to their nano-structure, which has an increased tortuosity resulting from the electrostatic interactions between the nano-laminate's components and also from the interpenetration of the successively deposited layers that hampers gas molecules migration through the structure [61,79,94]. The application of LbL technique in fruits and vegetables is very recent, and few studies showed its effect on shelf-life parameters.…”

Active Packaging Coatings

“…In one recent work published by Pinheiro et al, κ-carrageenan (polyanion) and chitosan (polycation) were applied onto aminated PET resulting in improved gas barrier properties (reduced oxygen and water vapor transmission rates) [74]. In other work presented by Carneiro-da-Cunha et al [75], alginate was employed as the polyanion, suggesting it as an attractive alternative as there was not significant difference in water vapor permeability between the aminated PET film used and its coated counterpart.…”

Nanostructuring Biopolymers for Improved Food Quality and Safety

“…Another technique with great potential in the development of nanoscopically structured new materials is the sequential LbL adsorption of polymer of solid substrates (Pinheiro et al, 2012;Weis et al, 2006). By means of this procedure, several biopolymers with opposite charges can be used to produce nanolayered films assembled through LbL.…”