Wall Materials for Encapsulating Bioactive Compounds via Spray-Drying: A Review

Spray-drying is a continuous encapsulation method that effectively preserves, stabilizes, and retards the degradation of bioactive compounds by encapsulating them within a wall material. The resulting capsules exhibit diverse characteristics influenced by factors such as operating conditions (e.g., air temperature and feed rate) and the interactions between the bioactive compounds and the wall material. This review aims to compile recent research (within the past 5 years) on spray-drying for bioactive compound encapsulation, emphasizing the significance of wall materials in spray-drying and their impact on encapsulation yield, efficiency, and capsule morphology.

Enhancing the functional properties of rice starch through biopolymer blending for industrial applications: A review

Rice starch has been used in various agri-food products due to its hypoallergenic properties. However, rice starch has poor solubility, lower resistant starch content with reduced retrogradation and poor functional properties. Hence, its industrial applications are rather limited. The lack of comprehensive information and a holistic understanding of the interaction between rice starch and endo/exogenous constituents to improve physico-chemical properties is a prerequisite in designing industrial products with enhanced functional attributes. In this comprehensive review, we highlight the potentials of physically mixing of biopolymers in upgrading the functional characteristics of rice starch as a raw material for industrial applications. Specifically, this review tackles rice starch modifications by adding natural/synthetic polymers and plasticizers, leading to functional blends or composites in developing sustainable packaging materials, pharma- and nutraceutical products. Moreover, a brief discussion on rice starch chemical and genetic modifications to alter starch quality for the deployment of rice starch industrial application is also highlighted.

Encapsulation of bioactive compounds from byproducts of two species of passionflowers: evaluation of the physicochemical properties and controlled release in a gastrointestinal model

This study aimed to evaluate the release of active components with antioxidant and antihypertensive capacity from encapsulated extracts of the peel and seeds of Gulupa (Passiflora edulis f. edulis) and Cholupa (Passiflora maliformis) in an in vitro gastrointestinal digestion model. Microencapsulated extracts were prepared with enzymatically modified rice starch as the encapsulating material and ethanol extracts of seeds and peel of P. edulis f. edulis and P. maliformis as encapsulated material. Microcapsule characterization was performed by scanning electron microscopy with values of 4.54-5.13 μm and ξ potential values of -6.34 mV and -6.66 mV. Dynamic light scattering (DLS) analysis was conducted with polydispersion values from 1.33 to 1.51, and dispersion stability analysis was also conducted. The total phenol content and antioxidant activities (ABTS, DPPH, and FRAP) and ACE inhibitory activity (in vitro antihypertensive activity) were evaluated after each stage of digestion, with values greater than 80% of activity before gastrointestinal transit and with values greater than 55% activity after the end of gastrointestinal transit. Gastrointestinal evaluation of the encapsulated extracts was performed with an ex vivo model using pig intestines and simulating the conditions of digestion in three phases: the gastric (pH 2.0 with 1.0 M HCl +0.5 g/L pepsin), enteric (pH 8.0 with Krebs solution +1.0 mL/L bile) and final enteric (pH 7.5 Krebs solution only) phases. The microencapsulation of passionflower extracts showed good behavior against changes in pH and enzymatic activities throughout digestion, thus promoting a controlled release and targeted delivery of bioactive compounds, undergoing a paracellular mechanism through the intestinal barrier to preserve the antioxidant activity and ACE inhibitory that was shown by the extracts before encapsulation of the material.

Effect of pH adjustment and ratio of oppositely charged polymers on the mechanistic performance and sustained release of volatile perfume in interpolyelectrolyte complex microcapsules

In this study, volatile perfume was encapsulated in microcapsules (MCs) via interpolyelectrolyte complexes (IPECs) of oppositely charged polymers, with high encapsulation efficiency, to be delivered in a sustained manner. Positively charged chitosan (CTS) and negatively charged Eudragit® S100 (ES100) were used as eco-friendly biopolymers. Limonene (LMN) was selected as the model perfume. First, the solution of LMN in ethyl acetate and poloxamer 407 (POX407) in acidic solution was emulsified using ultrasonication. CTS and ES100 were added in that particular order to form o/w emulsion. LMN-loaded microcapsules (LMN-MCs) were prepared by adjusting the pH and freeze-drying for solidification. The electrostatic interactions of CTS and ES100 to form IPECs were highly dependent on pH, changing in the microscopic images of emulsion droplets and zeta potential. The NH₃⁺ group of CTS and the COO^- group of ES100 caused the electrostatic interactions at a specific pH. The formation mechanism of LMN-MCs was successfully validated using instrumental analysis, charge density, and energy dispersive X-ray spectrometer (EDS) mapping. Encapsulation efficiency, loading content, and release rates of LMN-MCs varied according to the ratios of CTS and ES100, demonstrating optimal performance at a 1:1 ratio. The current LMN-MCs could provide a simple manufacturing process with high performance in terms of encapsulation efficiency (>94%), drug loading, yield and sustained release of volatile perfume for 120 h.

Gum arabic and collagen hydrolysate extracted from hide fleshing wastes as novel wall materials for microencapsulation of Origanum onites L. essential oil through complex coacervation

Renewable resource-based biodegradable materials attract more attention than petroleum-based biodegradable materials to support the sustainable development of ecology. Obtaining collagen hydrolysate (CH) from hide fleshing wastes of leather industry is an environmentally friendly way to develop multifunctional materials that can contribute to technological advances in different industries. In this study, 2:1, 1:1, and 1 2 ratios of gum arabic (GA) and CH extracted from hide fleshing waste were used as wall materials to encapsulate Origanum onites L. essential oil (OOEO) using the complex coacervation method. The encapsulation yield and efficiency, functional group composition, particle size, morphology, and thermal stability of the obtained OOEO microcapsules were characterized. The results showed that the obtained microcapsules had high encapsulation yield and efficiency, as well as good functional properties such as uniform morphology and low water activity. The best mass ratio for the biopolymers (GA:CH) was 1:1. Scanning electron microscopy analysis showed that OOEO microcapsule samples had a spherical shape. FTIR analysis was performed on obtained microcapsules, confirming the molecular interactions between GA and CH. These findings can be useful in designing an ideal wall material using GA and CH for microencapsulation of essential oils by the complex coacervation method.

Microencapsulation of Vanilla Oleoresin (V. planifolia Andrews) by Complex Coacervation and Spray Drying: Physicochemical and Microstructural Characterization

Vanilla is one of the most popular species in the world. Its main compound, vanillin, is responsible for its characteristic aroma and flavor and its antioxidant and biological properties. Vanillin is very unstable in the presence of oxygen, light, and humidity, which complicates its use and preservation. Therefore, to solve this problem, this study aimed to develop vanilla oleoresin microcapsules. Vanilla oleoresin was obtained with supercritical carbon dioxide and microencapsulated by complex coacervation and subsequent spray drying (100 °C/60 °C inlet/outlet temperature). The optimal conditions for the complex coacervation process were 0.34% chitosan, 1.7% gum Arabic, 5.29 pH, and an oleoresin:wall material ratio of 1:2.5. Fourier Transform Infrared Spectroscopy (FT-IR) analysis of the coacervates before and after spray drying revealed the presence of the functional group C=N (associated with carbonyl groups of vanillin and amino groups of chitosan), indicating that microencapsulation by complex coacervation-spray drying was successful. The retention and encapsulation efficiencies were 84.89 ± 1.94% and 69.20 ± 1.79%. The microcapsules obtained from vanilla oleoresin had high vanillin concentration and the presence of other volatile compounds and essential fatty acids. All this improves the aroma and flavor of the product, increasing its consumption and application in various food matrices.