A critical review on approaches to regulate the release rate of bioactive compounds from biopolymeric matrices.

Recently, there has been a growing interest in novel food formulations and packaging materials using controlled release systems in order to enhance the functional performance of food bioactive ingredients and to prolong the shelf-life of food products. Correspondingly, numerous types of matrices (polymers, biopolymers, synthetic materials) could be implemented as carriers based on their compatibility with the bioactive ingredients and the type of releasing medium. A plethora of applications of controlled release can be identified in the pharmaceutical, agriculture, cosmetics, and particularly the food industries. Moreover, several physical and chemical stimuli are applied to regulate the release behavior of a bioactive molecule in the desired medium, which is under development. This review highlights the strategies applied to regulate the release rate of biopolymeric networks mainly including mixing of biopolymers, physical and chemical crosslinkers along with encapsulation systems, furthermore, the future prospects of release concept are discussed.

Strategies of confining green tea catechin compounds in nano-biopolymeric matrices: A review.

Catechins are polyphenolic compounds which abundantly occur in the plants, especially tea leaves. They are widely used in nutraceutical and pharmaceutical formulations due to their capability of lowering the risk of developing various diseases. Nevertheless, low stability, loss of antioxidant and antimicrobial activities hinder the direct application of catechins in food formulations. To surmount this pervasive challenge, bioactive ingredients should be entrapped in a biopolymeric matrix. Thus, nanoencapsulation technology would be an appropriate strategy to improve the stability of these bioactive compounds and to protect them against degradation. Among different types of nanocarriers, biopolymer-based nanovehicles has captured a lot of attention in both industry and academia due to their safety and biocompatibility. This revision enlarges upon the various types of biopolymeric nanostructures used for accommodation of catechins, namely nanogels, nanotubes, nanofibers, nanoemulsions and nanoparticles. Last but not least, the applications of the entrapped catechins in the food industry are highlighted.

Production and characterization of catechin-loaded electrospun nanofibers from Azivash gum- polyvinyl alcohol.

In this study, Response Surface Methodology was used to optimize the electrospinning process parameters including voltage, distance, and flow rate in order to obtain catechin-loaded electrospun nanofibers from Azivash (Corchorus olitorius. L) gum-polyvinyl alcohol with the minimum diameter of nanofibers. The optimum electrospinning conditions were applied for catechin encapsulation at different loading concentrations (500, 1000, 2000 and 3000 mg L-1). According to the results, increase in catechin concentration led to increment in polymer solution viscosity. However, electrical conductivity decreased and mean diameter of nanofibers increased from 89 nm to 371 nm. There was a robust interaction between the catechin and polymer matrix; also addition of catechin improved thermal stability of nanofibers. In general, at higher catechin levels, despite increasing loading capacity, encapsulation efficiency was significantly reduced (p < 0.05). Optimum nanofibers loaded with 500 and 1000 mg L-1 catechin can be considered to apply in active food packaging and pharmaceutical applications.