Stability and release of an encapsulated solvent-free lycopene extract in alginate-based beads

W/O/W emulsion-filled sodium alginate hydrogel beads for co-encapsulation of vitamins C and E: Insights into the fabrication, lipolysis, and digestion behavior

In this study, vitamins C and E were simultaneously encapsulated in water-in-oil-in-water (W/O/W) emulsion-filled sodium alginate (SA) hydrogel beads, as well as the effects of SA concentrations (0.5%, 1.0%, 1.5%, and 2.0%) on the structures and lipolysis the of hydrogel beads were investigated. With increasing SA concentration, the beads showed larger sizes, denser structures and better textures. The droplets tightly penetrated the gel network at high SA concentrations. Digestion behavior revealed the disintegrated intramolecular structure at low SA concentrations. The beads with 0.5% SA were fragmented, losing the initial shape during digestion in the intestinal fluid. Additionally, lipid phases were released as W/O/W and O/W emulsion droplets after digestion. However, the high SA concentration-containing beads exhibited a well-preserved morphological structure after digestion, and the release profiles of lipid phase were mainly O/W emulsion droplets. Furthermore, vitamins C and E encapsulated in the beads exhibited high bioaccessibility (vitamin C: 90.20% and vitamin E: 95.19%).

Alginate Gel-Based Carriers for Encapsulation of Carotenoids: On Challenges and Applications

Sodium alginate is one of the most interesting and the most investigated and applied biopolymers due to its advantageous properties. Among them, easy, simple, mild, rapid, non-toxic gelation by divalent cations is the most important. In addition, it is abundant, low-cost, eco-friendly, bio-compatible, bio-adhesive, biodegradable, stable, etc. All those properties were systematically considered within this review. Carotenoids are functional components in the human diet with plenty of health benefits. However, their sensitivity to environmental and process stresses, chemical instability, easy oxidation, low water solubility, and bioavailability limit their food and pharmaceutical applications. Encapsulation may help in overcoming these limitations and within this review, the role of alginate-based encapsulation systems in improving the stability and bioavailability of carotenoids is explored. It may be concluded that all alginate-based systems increase carotenoid stability, but only those of micro- and nano-size, as well as emulsion-based, may improve their low bioaccessibility. In addition, the incorporation of other biopolymers may further improve encapsulation system properties. Furthermore, the main techniques for evaluating the encapsulation are briefly considered. This review critically and profoundly explains the role of alginates in improving the encapsulation process of carotenoids, suggesting the best alternatives for those systems. Moreover, it provides a comprehensive cover of recent advances in this field.

Recent advances in microbeads-based drug delivery system for achieving controlled drug release

Novel drug delivery system endows a beneficial method for achieving a desired drug concentration at the appropriate site in the body. The concept of targeted drug delivery has been emerged to localize the drug in the targeted tissue of interest while reducing the relative concentration of the medication in the surrounding tissues. This could be easily accomplished by using different multi-particulate dosage forms like pellets, granules, microcapsules, liposomes, beads. But the major drawbacks associated with them are the use of harsh chemicals and an elevated temperature for their preparation. Preparation of microbeads by ionotropic gelation and emulsion gelation method overcomes these problems by neither using harsh chemicals nor elevated temperature for their preparation. Thus, this can be proved to be a better alternative over other dosage forms. Several parameters were studied in terms of their morphology, particle size, encapsulation efficiency, swelling ratio, mucoadhesivity, etc. The endeavor of present article is toward presenting a wider perspective of the comprehensive knowledge available in the field of microbeads. Thus, the intent of this review is to recapitulate the relevance of microbeads.

The impact of pH on mechanical properties, storage stability and digestion of alginate-based and soy protein isolate-stabilized emulsion gel beads with encapsulated lycopene

In alginate-based emulsion gels containing protein-coated droplets, pH can influence the gelation mechanism of alginate gels, and the interactions between alginate molecules and protein-coated droplets, and thus properties of emulsion gels. This study investigated the impact of pH 3-7 on the properties (e.g., surface structures of droplets, mechanical properties, storage stability, digestion behavior) of alginate gel beads containing soy protein isolate(SPI)-stabilized oil droplets. Emulsion droplets were SPI-coated droplets at pH 6-7 and alginate/SPI-coated droplets at pH 3-5. Emulsion droplet flocculation only occurred in emulsions at pH 7.0. Emulsion gel beads at pH 3.0 had lower mechanical strength, higher storage stability, faster release of encapsulated lycopene during in-vitro digestion, and higher bioaccesibility of lycopene after 2 h of intestinal digestion than those at pH 7.0 and 5.0. The findings of this study are crucial to emulsion gel beads with controlled release and improved storage stability of encapsulated compounds by changing the pH of emulsions.

New Sensor to Measure the Microencapsulated Active Compounds Released in an Aqueous Liquid Media Based in Dielectric Properties in Radiofrequency Range

In recent years, the general and scientific interest in nutrition, digestion, and what role they play in our body has increased, and there is still much work to be carried out in the field of developing sensors and techniques that are capable of identifying and quantifying the chemical species involved in these processes. Iron deficiency is the most common and widespread nutritional disorder that mainly affects the health of children and women. Iron from the diet may be available as heme or organic iron, or as non-heme or inorganic iron. The absorption of non-heme iron requires its solubilization and reduction in the ferric state to ferrous that begins in the gastric acid environment, because iron in the ferric state is very poorly absorbable. There are chemical species with reducing capacity (antioxidants) that also have the ability to reduce iron, such as ascorbic acid. This paper aims to develop a sensor for measuring the release of encapsulated active compounds, in different media, based on dielectric properties measurement in the radio frequency range. An impedance sensor able to measure the release of microencapsulated active compounds was developed. The sensor was tested with calcium alginate beads encapsulating iron ions and ascorbic acid as active compounds. The prediction and measurement potential of this sensor was improved by developing a thermodynamic model that allows obtaining kinetic parameters that will allow suitable encapsulation design for subsequent release.

A review of encapsulation of carotenoids using spray drying and freeze drying

Carotenoids are potent antioxidants, but they are highly unstable and susceptible during processing and storage. Encapsulation technologies protect against degradation and are capable of releasing individual or combination of bioactive substances during processing as well as development of various functional food products. Moreover, encapsulating agents can be used to increase the stability of carotenoids and form a barrier between the core and wall materials. Suitable encapsulating agents, temperature, and drying methods are the most important factors for the encapsulation process. In this report, we reviewed the current status of encapsulation of carotenoids from different fruits, vegetables, spices, seaweeds, microorganisms, and synthetic sources using various types of encapsulating agents through spray drying and freeze drying. We also focused on the degradation kinetics and various factors that affect the stability and bioavailability of encapsulated carotenoids during their processing and storage.

Freezing and drying of pink grapefruit-lycopene encapsulated in Ca(II)-alginate beads containing galactomannans

Lycopene extracted from pink grapefruit was encapsulated on Ca(II)-alginate beads with the addition of trehalose and galactomannans to improve its stability against freezing and drying. Three galactomannans of different physicochemical properties were studied since their inclusion affects both loading efficiency and release of lycopene in wet beads; however, there is no information about their performance during freezing and dehydration operations. The remaining lycopene and its stability towards isomerization were analyzed in beads subjected to continuous freezing, freezing/thawing cycles and vacuum- and freeze-drying. Isothermal crystallization studies were conducted by LF-NMR and related to beads formulation and lycopene stability. In the absence of excipients, lycopene was severely affected by all the treatments, retaining less than 20% of the original content. Alginate beads containing trehalose with guar gum protected more than 80% of the lycopene regardless of the employed freezing or drying methods. These beads concomitantly showed higher solid fraction than the other two galactomannans-containing systems, displaying guar gum ability to associate water. On the other hand, the addition of vinal gum affected lycopene stability (between 40 and 60% were recovered after treatments), even compromising the positive effect of a well-established cryoprotectant as trehalose. Thus, the addition of secondary excipients should be carefully conducted. The differences among galactomannans could be related to the substitution degree of the polymer chains, affecting the overall systems interactions. These results can contribute to excipients selection for the encapsulation of labile biomolecules in Ca(II)-alginate beads subjected to freezing and drying.