Self-assembled gelatin-ι-carrageenan encapsulation structures for intestinal-targeted release applications

Abstract

In this work, natural biopolymeric encapsulation structures were developed through the self-assembly of gelatin and ι-carrageenan in aqueous solutions. The interactions of this binary system and of a ternary system containing a polyphenol-rich extract were deeply explored for the development of intestinal delivery systems. The processing of the structures (extrusion vs. freeze-drying) greatly influenced release properties, explained by the specific interactions between gelatin and polyphenols, thus allowing for tuning the processing conditions depending on the desired target application. Release was further controlled by incorporating a divalent salt, giving raise to extract-loaded ι-carrageenan/gelatin capsules with adequate release profiles for intestinal targeted delivery. These results demonstrate the potential of exploiting biopolymer interactions for designing bioactive delivery systems using environmentally friendly processes which do not involve the use of toxic or harsh solvents or cross-linkers.

Development of gelatin-coated ι-carrageenan hydrogel capsules by electric field-aided extrusion. Impact of phenolic compounds on their performance

“…However, the size of the obtained capsules (~ 5-6 mm) was too large for their practical application. Therefore, electric field-aided extrusion was used in this work to obtain ι-carrageenan/gelatin hydrogel capsules with reduced sizes, using the same biopolymers employed in our previous work, which had been previously characterized (Gómez-Mascaraque, et al, 2018). The obtained capsules are shown in Figure 1A.…”

“…When CaCl 2 was incorporated to the system, it was dissolved at a concentration of 50 mM in the gelatin solution. This optimal concentration had been previously determined (Gómez-Mascaraque, et al, 2018).…”

“…The release of the phenolic compounds from the capsules in different food simulants was assessed following a method adapted from Gómez-Mascaraque, et al (2018).…”

“…In our previous work, quasi-spherical ι-carrageenan/gelatin capsules were obtained by extrusion of ι-carrageenan onto a gelatin solution in the presence of a divalent salt, and were used to encapsulate a polyphenol-rich grape juice extract, showing almost ideal release properties for intestinal targeted delivery purposes (Gómez-Mascaraque, et al, 2018). However, the size of the obtained capsules (~ 5-6 mm) was too large for their practical application.…”

“…On the other hand, biopolymers and, in particular, proteins, have been described to strongly interact with natural polyphenols through different mechanisms, including hydrophobic interactions and hydrogen bonding (Jakobek, 2015;Siebert, Troukhanova, & Lynn, 1996). These intermolecular interactions are responsible, at least partially, of the stabilization effect and the release properties of polyphenol-loaded encapsulation structures (Atay, et al, 2017;Gómez-Mascaraque, et al, 2018). Most research works focus on the impact of microencapsulation on the stabilization of the bioactive ingredients to be protected (Gómez-Mascaraque & López-Rubio, 2016;Kong, Bhosale, & Ziegler, 2018;Pérez-Masiá, Lagaron, & Lopez-Rubio, 2015;Torres-Giner, Martinez-Abad, Ocio, & Lagaron, 2010).…”