Novel Technologies Based on Supercritical Fluids for the Encapsulation of Food Grade Bioactive Compounds

Comparative Study of Cinnamon and Paprika Oleoresins Encapsulated by Spray Chilling and Particles from Gas Saturated Solutions Techniques: Evaluation of Physical Characteristics and Oleoresins Release in Food Simulated Media

In this study, cinnamon and paprika oleoresins were encapsulated by two technologies, respectively, spray chilling and particles from gas saturated solutions. Both technologies used palm oil as wall materials. The physical characteristics of the microparticles were compared as well as the oleoresins release behavior in high- and low-fat simulated food media. The spray chilling microparticles had an average diameter of 143.7 ± 1.5 µm, spherical shape, smooth surface, and passable flow property. In contrast, microparticles obtained by particles from gas saturated solutions (PGSS) showed an average diameter of 105.7 ± 0.6 µm, irregular shape, porous surface, poor flow property but higher encapsulation efficiency. In evaluating the compounds released in a simulated food medium, the spray chilling particles delivered 30.7%, while PGSS reached 23.1% after 1 h. Both microparticles well fitted the Kosmeyer-Peppas (R2 = 0.98 and 0.96 for spray chilling and PGSS) and Peppas-Sahlin models (R2 = 0.98 and 0.97 for spray chilling and PGSS). However, spray chilling microparticles showed a diffusion mechanism, while for PGSS ones erosion was the main mechanism. Despite the different physical characteristics, both microparticles proved to be possible facilitators in delivering oleoresins in food products.

Valorisation of Micro/Nanoencapsulated Bioactive Compounds from Plant Sources for Food Applications Towards Sustainability

The micro- and nanoencapsulation of bioactive compounds has resulted in a large improvement in the food, nutraceutical, pharmaceutical, and agriculture industries. These technologies serve, on one side, to protect, among others, vitamins, minerals, essential fatty acids, polyphenols, flavours, antimicrobials, colorants, and antioxidants, and, on the other hand, to control the release and assure the delivery of the bioactive compounds, targeting them to specific cells, tissues, or organs in the human body by improving their absorption/penetration through the gastrointestinal tract. The food industry has been applying nanotechnology in several ways to improve food texture, flavour, taste, nutrient bioavailability, and shelf life using nanostructures. The use of micro- and nanocapsules in food is an actual trend used mainly in the cereal, bakery, dairy, and beverage industries, as well as packaging and coating. The elaboration of bio capsules with high-value compounds from agro-industrial by-products is sustainable for the natural ecosystem and economically interesting from a circular economy perspective. This critical review presents the principal methodologies for performing micro- and nanoencapsulation, classifies them (top-down and/or bottom-up), and discusses the differences and advantages among them; the principal types of encapsulation systems; the natural plant sources, including agro-industrial by-products, of bioactive compounds with interest for the food industry to be encapsulated; the bioavailability of encapsulates; and the main techniques used to analyse micro- and nanocapsules. Research work on the use of encapsulated bioactive compounds, such as lycopene, hydroxytyrosol, and resveratrol, from agro-industrial by-products must be further reinforced, and it plays an important role, as it presents a high potential for the use of their antioxidant and/or antimicrobial activities in food applications and, therefore, in the food industry. The incorporation of these bioactive compounds in food is a challenge and must be evaluated, not only for their nutritional aspect, but also for the chemical safety of the ingredients. The potential use of these products is an available economical alternative towards a circular economy and, as a consequence, sustainability.

Encapsulation of Bioactive Compounds for Food and Agricultural Applications

This review presents an updated scenario of findings and evolutions of encapsulation of bioactive compounds for food and agricultural applications. Many polymers have been reported as encapsulated agents, such as sodium alginate, gum Arabic, chitosan, cellulose and carboxymethylcellulose, pectin, Shellac, xanthan gum, zein, pullulan, maltodextrin, whey protein, galactomannan, modified starch, polycaprolactone, and sodium caseinate. The main encapsulation methods investigated in the study include both physical and chemical ones, such as freeze-drying, spray-drying, extrusion, coacervation, complexation, and supercritical anti-solvent drying. Consequently, in the food area, bioactive peptides, vitamins, essential oils, caffeine, plant extracts, fatty acids, flavonoids, carotenoids, and terpenes are the main compounds encapsulated. In the agricultural area, essential oils, lipids, phytotoxins, medicines, vaccines, hemoglobin, and microbial metabolites are the main compounds encapsulated. Most scientific investigations have one or more objectives, such as to improve the stability of formulated systems, increase the release time, retain and protect active properties, reduce lipid oxidation, maintain organoleptic properties, and present bioactivities even in extreme thermal, radiation, and pH conditions. Considering the increasing worldwide interest for biomolecules in modern and sustainable agriculture, encapsulation can be efficient for the formulation of biofungicides, biopesticides, bioherbicides, and biofertilizers. With this review, it is inferred that the current scenario indicates evolutions in the production methods by increasing the scales and the techno-economic feasibilities. The Technology Readiness Level (TRL) for most of the encapsulation methods is going beyond TRL 6, in which the knowledge gathered allows for having a functional prototype or a representative model of the encapsulation technologies presented in this review.

Pharmaceutical Applications of Supercritical Fluid Extraction of Emulsions for Micro-/Nanoparticle Formation

Micro-/nanoparticle formulations containing drugs with or without various biocompatible excipients are widely used in the pharmaceutical field to improve the physicochemical and clinical properties of the final drug product. Among the various micro-/nanoparticle production technologies, emulsion-based particle formation is the most widely used because of its unique advantages such as uniform generation of spherical small particles and higher encapsulation efficiency (EE). For this emulsion-based micro-/nanoparticle technology, one of the most important factors is the extraction efficiency associated with the fast removal of the organic solvent. In consideration of this, a technology called supercritical fluid extraction of emulsions (SFEE) that uses the unique mass transfer mechanism and solvent power of a supercritical fluid (SCF) has been proposed to overcome the shortcomings of several conventional technologies such as solvent evaporation, extraction, and spray drying. This review article presents the main aspects of SFEE technology for the preparation of micro-/nanoparticles by focusing on its pharmaceutical applications, which have been organized and classified according to several types of drug delivery systems and active pharmaceutical ingredients. It was definitely confirmed that SFEE can be applied in a variety of drugs from water-soluble to poorly water-soluble. In addition, it has advantages such as low organic solvent residual, high EE, desirable release control, better particle size control, and agglomeration prevention through efficient and fast solvent removal compared to conventional micro-/nanoparticle technologies. Therefore, this review will be a good resource for determining the applicability of SFEE to obtain better pharmaceutical quality when researchers in related fields want to select a suitable manufacturing process for preparing desired micro-/nanoparticle drug delivery systems containing their active material.

Preparation and Characterization of Instant Casein Phosphopeptide by Supercritical Fluid Assisted Atomization

Casein phosphopeptide (CPP) has been widely used as micronutrient supplementation for certain populations. However, its solubility performance is far from satisfying. In this work, instant CPP powders with micropore structures were fabricated by supercritical fluid-assisted atomization (SAA) using supercritical CO₂ fluid (SC-CO₂) as an atomizing agent. The effects of the processing parameters (temperature, time, and pressure) on SC-CO₂ absorption rate and dissolution rate were systematically evaluated and studied. The viscosity of the CPP solution increased with increased pressure of SC-CO₂ as pressure increased its solubility. The processing conditions are optimized as follows: 40 °C, 40 min, and 8.27 MPa, with an SC-CO₂ absorption rate of about 8 wt.%. The dissolution time of the SAA-CPP powders was significantly decreased from 1800 s to 54 s at room temperature, due to the micropore structures and almost 10 times increase in the specific surface area of SAA-CPP. The bioactivities of the instant SAA-CPP, especially the calcium-binding capacity, were also evaluated and showed no observable difference. Among the four CPPs prepared in different ways in this work, SAA-CPP had better dissolution performance. The results show that SAA technology is a promising way to prepare instant polypeptide powders.

Biopesticide Encapsulation Using Supercritical CO2: A Comprehensive Review and Potential Applications

As an alternative to synthetic pesticides, natural chemistries from living organisms, are not harmful to nontarget organisms and the environment, can be used as biopesticides, nontarget. However, to reduce the reactivity of active ingredients, avoid undesired reactions, protect from physical stress, and control or lower the release rate, encapsulation processes can be applied to biopesticides. In this review, the advantages and disadvantages of the most common encapsulation processes for biopesticides are discussed. The use of supercritical fluid technology (SFT), mainly carbon dioxide (CO₂), to encapsulate biopesticides is highlighted, as they reduce the use of organic solvents, have simpler separation processes, and achieve high-purity particles. This review also presents challenges to be surpassed and the lack of application of SFT for biopesticides in the published literature is discussed to evaluate its potential and prospects.