Influence of Sodium Alginate Concentration on Microcapsules Properties Foreseeing the Protection and Controlled Release of Bioactive Substances

Abstract

To understand the abilities of Ca-alginate microcapsules and their specific applications in different fields, it is necessary to determine the physicochemical and structural properties of those formulated microcapsules. In this work, we aimed to study the effect of alginate concentration in the improvement of the encapsulation efficiency (EE) and on the release of phenolic and flavonoid substances. The relationship between the structure of the encapsulated bioactive substance and Ca-alginate network and their effect on the EE and release kinetics have been investigated. The incorporation, structure, morphology, and phase properties of all elaborated materials were characterized by UV-spectroscopy, Fourier transform infrared (ATR-FTIR), scanning electron microscope (SEM), and X-ray diffraction (DRX). The results indicate that increasing the polymer concentration increases the EE and decreases the loading capacity (LC), whereas the effect of alginate polymer concentration on the release was not observed. The release study of bioactive substances showed that the release kinetics is relatively dependent on the structure and the physicochemical characteristics of the bioactive substance, which became clear when the encapsulated compounds were released from the core of calcium alginate microcapsules. Thus, it could be concluded that the pores size of the Ca-alginate network is smaller than the volume of the crocin molecule (2794.926 Å3) and higher than the volume of the gallic acid molecule (527.659 Å3). For the same microcapsules system, the release mechanism is affected by the structure and physicochemical properties of the encapsulated molecules.

Preparation, Physicochemical Characterization, and Antioxidant Activity of Naringin–Silk Fibroin–Alginate Microspheres and Application in Yogurt

“…As an amorphous excipient, the SA did not show sharp crystal diffraction peaks. This phenomenon was also observed by Essifi et al [ 32 ]. The naringin diffraction peaks could still be observed in the PM, indicating the crystalline structure of naringin was not changed.…”

Donut-Shaped Microparticles Prepared from Different C-Type Starch Sources: Characterization and Encapsulation of Gallic Acid

“…The percentage of encapsulated phenolic compounds did not depend on the native starch precursor, and the efficiency values ranged from 38 to 45%. Essifi et al 40 described similar results after evaluating the encapsulation of GA in alginate microcapsules using the ionotropic gelation method. However, Goncalves da Rosa et al 11 reported that the encapsulation efficiency of GA in β-cyclodextrin was 80%.…”

Hybrid Microcapsules for Encapsulation and Controlled Release of Rosemary Essential Oil

“… where m t / m ∞ is the percentage of the drug released at time t and for all time; k is the description of the macromolecular network system and n is the release exponent indicating the release mechanism. A linear form of the equation can be acquired through plotting ln ( m t / m ∞ ) against ln(t), whose linear coefficient is k and whose angular coefficient is n. The determined n value is used to discover which of the three mechanisms can describe the release behaviour: the n value is less than 0.43; the release follows the Fickian law and the n value is between 0.43 and 0.85; the non-Fickian release mechanism is established, and when the n value is greater than 0.85 it indicates the case II of transport release with a polymer chain relaxation [ 28 ]. Using OriginPro 2018 software, we calculated the squared correlation coefficient (R 2 was used to confirm the accuracy of the model).…”