Combined plant protein modification and complex coacervation as a sustainable strategy to produce coacervates encapsulating bioactives

Recent advances in modification of plant-based proteins for improved encapsulation performance

Encapsulation is a useful technique for protection, stabilization and controlling the release of bioactive compounds and food ingredients particularly sensitive to environmental factors such as heat, light and temperature. A wide variety of biopolymers can be used as wall materials in encapsulation, among which proteins are an essential group. In recent years, with the increasing interest in concepts such as plant-based nutrition and sustainability, the use of plant proteins in encapsulation has also increased. Proteins obtained from plant sources are sustainable, easily accessible, and low cost compared to animal-based counterparts; additionally, they are biodegradable, renewable, and biocompatible. However, there are some limitations regarding their functional properties such as solubility, emulsifying, gelling, and film-forming abilities. Various physical, chemical and enzymatic modification methods are used to improve the functional properties of plant proteins and to expand their use in encapsulation technologies. In this review, plant-based proteins (PBPs) and their use in encapsulation are discussed. Different modification techniques can improve the encapsulation performance of plant proteins; however, process parameters should be optimized. The most commonly studied physical, chemical, enzymatic and combined modification methods are sonication, Maillard conjugation, enzymatic hydrolysis and pH-shifting combined ultrasonication, respectively. The use of combined modification methods is a promising approach for improvement of the encapsulation performance of PBPs.

Bioactive compound encapsulation: Characteristics, applications in food systems, and implications for human health

Nanotechnology plays a pivotal role in food science, particularly in the nanoencapsulation of bioactive compounds, to enhance their stability, bioavailability, and therapeutic potential. This review aims to provide a comprehensive analysis of the encapsulation of bioactive compounds, emphasizing the characteristics, food applications, and implications for human health. This work offers a detailed comparison of polymers such as sodium alginate, gum Arabic, chitosan, cellulose, pectin, shellac, and xanthan gum, while also examining both conventional and emerging encapsulation techniques, including freeze-drying, spray-drying, extrusion, coacervation, and supercritical anti-solvent drying. The contribution of this review lies in highlighting the role of encapsulation in improving system stability, controlling release rates, maintaining bioactivity under extreme conditions, and reducing lipid oxidation. Furthermore, it explores recent technological advances aimed at optimizing encapsulation processes for targeted therapies and functional foods. The findings underline the significant potential of encapsulation not only in food supplements and functional foods but also in supportive medical treatments, showcasing its relevance to improving human health in various contexts.

The Effects of Ultrasound on the Rehydration of Konjac Glucomannan/Soy Protein Isolate Gel and Simulation of Gas-Liquid Interface Evolution During the Rehydration Process

Soy protein isolate (SPI) possesses potential gelling properties, making it suitable for gel-based applications. However, the gel network stability and mechanical properties of SPI are relatively poor and can be improved through modifications or by combining it with other polymers, such as Konjac Glucomannan (KGM). Combining SPI with KGM can overcome the poor gel network stability and mechanical properties of SPI, but it reduces the water-absorbing capacity of the gel network after drying, which affects the quality characteristics of plant-based protein rehydrated foods and limits the economic feasibility of soy protein foods. In this study, SPI and KGM are the main research objects. By using the alkali method to construct SPI/KGM dry gels with good gel properties, the influence of different ultrasonic powers on the rehydration kinetics and performance changes of SPI/KGM dry gels is examined. The speed and state of water entering the pores are simulated by constructing different pore-size capillary filling models, and the rehydration mechanism of the gel is elucidated. This study provides research ideas and a theoretical basis for the application of ultrasonic wave technology in the study of dry product rehydration performance.

Complexation with Alginate in Pumpkin Leaf Protein Solutions for the Encapsulation of Folic Acid: The Effect of Extraction Protocols

This study aimed to assess pumpkin leaves as a protein source and determine the feasibility of these proteins to form complexes with alginate for the encapsulation of folic acid. Different isolation protocols, two based on isoelectric precipitation (one with thermal pretreatment and the other with alkali pre-extraction) and one based on stepwise precipitation with ammonium sulfate, were compared regarding the yield and structural properties of the obtained leaf protein concentrates (LPC). The highest purity of protein was achieved using the thermal-acid protocol and the salting-out protocol at 40% saturation. RuBisCO protein was detected by SDS-PAGE in all LPCs, except for the fractions obtained through salting-out at saturation level ≥ 60%. Complexation of the LPC solutions (1 mg/mL) and sodium alginate solution (10 mg/mL) was monitored as a function of LPC:alginate ratio (2:1, 5:1, and 10:1) and pH (2-8) by zeta-potential measurements and confirmed by FT-IR analysis. Based on the results, the strongest interaction between LPCs and alginate occurred at a pH between 2.20 and 2.80 and an LPC:alginate ratio of 10:1. Complexation resulted in particle yields of 42-71% and folic acid entrapment of 46-92%. The LPC-folic acid interactions elucidated by computational protein-ligand docking demonstrated the high potential of RuBisCO as a biocarrier material for folic acid. The in vitro release study in the simulated gastrointestinal fluids indicated that complexes would be stable in gastric conditions, while folic acid would be gradually released in the intestinal fluids.

Microencapsulation of natural products using spray drying; an overview

AIMS

This study examines microencapsulation as a method to enhance the stability of natural compounds, which typically suffer from inherent instability under environmental conditions, aiming to extend their application in the pharmaceutical industry.

METHODS

We explore and compare various microencapsulation techniques, including spray drying, freeze drying, and coacervation, with a focus on spray drying due to its noted advantages.

RESULTS

The analysis reveals that microencapsulation, especially via spray drying, significantly improves natural compounds' stability, offering varied morphologies, sizes, and efficiencies in encapsulation. These advancements facilitate controlled release, taste modification, protection from degradation, and extended shelf life of pharmaceutical products.

CONCLUSION

Microencapsulation, particularly through spray drying, presents a viable solution to the instability of natural compounds, broadening their application in pharmaceuticals by enhancing protection and shelf life.

Toward Diverse Plant Proteins for Food Innovation

This review highlights the development of plant proteins from a wide variety of sources, as most of the research and development efforts to date have been limited to a few sources including soy, chickpea, wheat, and pea. The native structure of plant proteins during production and their impact on food colloids including emulsions, foams, and gels are considered in relation to their fundamental properties, while highlighting the recent developments in the production and processing technologies with regard to their impacts on the molecular properties and aggregation of the proteins. The ability to quantify structural, morphological, and rheological properties can provide a better understanding of the roles of plant proteins in food systems. The applications of plant proteins as dairy and meat alternatives are discussed from the perspective of food structure formation. Future directions on the processing of plant proteins and potential applications are outlined to encourage the generation of more diverse plant-based products.

Encapsulation of β-carotene in gelatin-gum Arabic-sodium carboxymethylcellulose complex coacervates: Enhancing surimi gel properties and exploring 3D printing potential

This study investigates the utilization of functional additives (β-carotene microcapsules) and 3D printing technology for the production of innovative surimi products. The β-carotene microcapsules were prepared using different ratios of gelatin (Ge), gum Arabic (Ara), and carboxymethylcellulose sodium (CMC). Among these ratios, the ratio of 5:5:1 (Ge:Ara:CMC) resulted in more stable microcapsules spherical structures and better environmental stability. Subsequently, different concentrations (5-20 %) of the obtained β-carotene microcapsules were added to surimi samples. As the concentration increased, there was an improvement in the gel strength of the surimi. However, no significant changes were observed when the concentration was 15 % (p > 0.05). All samples exhibited shear thinning behavior. The addition of microcapsules improved the resilience and thixotropy of surimi, making it more suitable for 3D printing applications. The inclusion of β-carotene microcapsules in surimi products not only meets the nutritional needs of consumers, but also provides valuable insights for the development of functional surimi products.

The molecular picture of the local environment in a stable model coacervate

Complex coacervates play essential roles in various biological processes and applications. Although substantial progress has been made in understanding the molecular interactions driving complex coacervation, the mechanisms stabilizing coacervates against coalescence remain experimentally challenging and not fully elucidated. We recently showed that polydiallyldimethylammonium chloride (PDDA) and adenosine triphosphate (ATP) coacervates stabilize upon their transfer to deionized (DI) water. Here, we perform molecular dynamics simulations of PDDA-ATP coacervates in supernatant and DI water, to understand the ion dynamics and structure within stable coacervates. We found that transferring the coacervates to DI water results in an immediate ejection of a significant fraction of small ions (Na+ and Cl-) from the surface of the coacervates to DI water. We also observed a notable reduction in the mobility of these counterions in coacervates when in DI water, both in the cluster-forming and slab simulations, together with a lowered displacement of PDDA and ATP. These results suggest that the initial ejection of the ions from the coacervates in DI water may induce an interfacial skin layer formation, inhibiting further mobility of ions in the skin layer.

Impact of wall materials and DHA sources on the release, digestion and absorption of DHA microcapsules: Advancements, challenges and future directions

Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, offers significant health benefits but faces challenges such as distinct odor, oxidation susceptibility, and limited intestinal permeability, hindering its broad application. Microencapsulation, widely employed, enhances DHA performance by facilitating controlled release, digestion, and absorption in the gastrointestinal tract. Despite extensive studies on DHA microcapsules and related delivery systems, understanding the mechanisms governing encapsulated DHA release, digestion, and absorption, particularly regarding the influence of wall materials and DHA sources, remains limited. This review starts with an overview of current techniques commonly applied for DHA microencapsulation. It then proceeds to outline up-to-date advances in the release, digestion and absorption of DHA microcapsules, highlighting the roles of wall materials and DHA sources. Importantly, it proposes strategies for overcoming challenges and exploiting opportunities to enhance the bioavailability of DHA microcapsules. Notably, spray drying dominates DHA microencapsulation (over 90 % usage), while complex coacervation shows promise for future applications. The combination of proteins and carbohydrates or phospholipids as wall material exhibits potential in controlling release and digestion of DHA microcapsules. The source of DHA, particularly algal oil, demonstrates higher lipid digestibility and absorptivity of free fatty acids (FFAs) than fish oil. Future advancements in DHA microcapsule development include formulation redesign (e.g., using plant proteins as wall material and algal oil as DHA source), technique optimization (such as co-microencapsulation and pre-digestion), and creation of advanced in vitro systems for assessing DHA digestion and absorption kinetics.

The potential of carboxylmethyl cellulose from empty fruit bunch as versatile material in food coating: A review

The rising demand for food packaging has led to a growing interest in sustainable and eco-friendly food coatings. Carboxymethyl cellulose (CMC), being a versatile cellulose derivative produced from various lignocellulosic sources, has emerged in edible food coatings. This review evaluates the research trends on CMC production from empty fruit bunch (EFB) as a potential edible food coating material by systematic review approach. It explores sustainable pre-treatment for green cellulose and different CMC synthesis methods. The review compares CMC-based coatings to other materials, focusing on formulation processes, coating quality, safety, and commercial feasibility. The bibliometric analysis is performed to correlate food coating and CMC. As a result, the study discovered the rapid growth in research on edible food coatings made from CMC for various food industry applications. The green approach such as ozone pre-treatment appear as promising method for cellulose isolation from EFB to be used as raw material for CMC. The synthesis conditions of the treatment would affect the CMC characteristics and usage. Herein, utilizing CMC from cellulose EFB in coating formulation and on coated food shows different benefits. This review provides a road map for future research with potential to make important contributions to the food industry's long-term evolution.

New perspective on protein-based microcapsules as delivery vehicles for sensitive substances: A review

Sensitive substances have attracted wide attention due to their rich functional activities, such as antibiosis activities, antioxidant activities and prevent disease, etc. However, the low stability of sensitive substances limits their bioavailability and functional activities. Protein-based microcapsules can encapsulate sensitive substances to improve their adverse properties due to their good stability, strong emulsifying ability and wide source. Therefore, it is necessary to fully elaborate and summarize protein-based microcapsules to maximize their potential benefits in nutritional interventions. The focus of this review is to highlight the classification of protein-based microcapsules. In addition, the principles, advantages and disadvantages of preparation methods for protein-based microcapsules are summarized. Some novel preparation methods for protein-based microcapsules are also emphasized. Moreover, the mechanism of protein-based microcapsules that release sensitive substances in vitro is elucidated and summarized. Furthermore, the applications of protein-based microcapsules are outlined. Protein-based microcapsules can effectively encapsulate sensitive substances, which improve their bioavailability, and provide protective effects during storage and gastrointestinal digestion. In addition, microcapsules can improve the sensory quality of food and enhance its stability. The performance of protein-based microcapsules for delivering sensitive substances is influenced by factors such as protein type, the ratio between protein ratio and the other wall material, the preparation process, etc. Future research should focus on the new composite protein-based microcapsule delivery system, which can be applied to in vivo research and have synergistic effects and precise nutritional functions. In summary, protein-based microcapsules have broader research prospects in the functional foods and nutrition field.

Advances in protein-based microcapsules and their applications: A review

Due to their excellent emulsification, biocompatibility, and biological activity, proteins are widely used as microcapsule wall materials for encapsulating drugs, natural bioactive substances, essential oils, probiotics, etc. In this review, we summarize the protein-based microcapsules, discussing the types of proteins utilized in microcapsule wall materials, the preparation process, and the main factors that influence their properties. Additionally, we conclude with examples of the vital role of protein-based microcapsules in advancing the food industry from primary processing to deep processing and their potential applications in the biomedical, chemical, and textile industries. However, the low stability and controllability of protein wall materials lead to degraded performance and quality of microcapsules. Protein complexes with polysaccharides or modifications to proteins are often used to improve the thermal instability, pH sensitivity, encapsulation efficiency and antioxidant capacity of microcapsules. In addition, factors such as wall material composition, wall material ratio, the ratio of core to wall material, pH, and preparation method all play critical roles in the preparation and performance of microcapsules. The application area and scope of protein-based microcapsules can be further expanded by optimizing the preparation process and studying the microcapsule release mechanism and control strategy.

Simple and complex coacervation in systems involving plant proteins

Plant-based foods are gaining popularity as alternatives to meat and dairy products due to sustainability and health concerns. As a consequence, there is a renewed interest in the phase behaviour of plant proteins and of mixtures of plant proteins and polysaccharides, in particular in the cases where coacervation is found to occur, i.e., liquid-liquid phase separation (LLPS) into two phases, one of which is rich in biopolymers and one of which is poor in biopolymer. Here we review recent research into both simple and complex coacervation in systems involving plant proteins, and their applications in food- as well as other technologies, such as microencapsulation, microgel production, adhesives, biopolymer films, and more.

Plant protein solubility: A challenge or insurmountable obstacle

Currently, there is an increasing focus on comprehending the solubility of plant-based proteins, driven by the rising demand for animal-free food formulations. The solubility of proteins plays a crucial role in impacting other functional properties of proteins and food processing. Consequently, understanding protein solubility in a deeper sense may allow a better usage of plant proteins. Herein, we discussed the definition of protein solubility from both thermodynamic and colloidal perspectives. A range of factors affecting solubility of plant proteins are generalized, including intrinsic factors (amino acids composition, hydrophobicity), and extrinsic factors (pH, ionic strength, extraction and drying methods). Current methods to enhance solubility are outlined, including microwave, high intensity ultrasound, hydrostatic pressure, glycation, pH-shifting, enzymatic hydrolysis, enzymatic cross-linking, complexation and modulation of amino acids. We base the discussion on diverse modified methods of nitrogen solubility index available to determine and analyze protein solubility followed by addressing how other indigenous components affect the solubility of plant proteins. Some nonproteinaceous constituents in proteins such as carbohydrates and polyphenols may exert positive or negative impact on protein solubility. Appropriate protein extraction and modification methods that meet consumer and manufacturers requirements concerning nutritious and eco-friendly foods with lower cost should be investigated and further explored.

Current and New Insights on Delivery Systems for Plant Sterols in Food

Plant sterols are minor bioactive components of food lipids, which are often used for the formulation of functional foods due to their cholesterol-lowering properties. However, they have low solubility and tend to crystallize, which may affect their biological effects, the sensory profile of the sterol-enriched food, and its consumer acceptability. Moreover, due to the unsaturated structure of sterols, they are susceptible to oxidation, so different encapsulation systems have been developed to improve their dispersibility/solubility, stability, delivery, and bioaccessibility. This chapter provides an overview of the main encapsulation systems currently used for plant sterols and their application in model and food systems, with a particular focus on their efficiency and impact on sterol bioaccessibility.

Emulsifying properties of O/W emulsion stabilized by soy protein isolate and γ-polyglutamic acid electrostatic complex

In order to improve the emulsifying properties of soy protein around isoelectric point, soy protein isolate (SPI) and γ-polyglutamic acid (γ-PGA) complexes were prepared by electrostatic interaction. The formation of SPI-γ-PGA electrostatic complex and emulsifying properties were investigated by monitoring turbidity, zeta potential, intrinsic fluorophores, emulsion characterization, and microstructure observation. The results showed that the formation of SPI-γ-PGA electrostatic complex was identified through turbidimetric analysis and zeta-potential measurement. Intrinsic fluorescence spectrum indicated internal structure changes of electrostatic complexes. Furthermore, SPI-γ-PGA complex-stabilized emulsions showed better stability with small droplet sizes and slow growth as well as the uniform microstructure around the isoelectric point (pH 4.0-5.0) than SPI-formed emulsions. Under the different thermal treatments and ionic strengths, emulsions stabilized by SPI-γ-PGA-soluble complex resulted in improved emulsion stability to environmental stresses. This may be attributed to the increased steric repulsion and electrostatic repulsion by SPI-γ-PGA complexes at oil-water interfaces. The findings derived from this research would provide theoretical reference about SPI-γ-PGA electrostatic complex that can be applied in acid beverages and developed a novel plant-based sustainable stabilizer for emulsions. PRACTICAL APPLICATION: The electrostatic interaction between SPI and γ-PGA improved the emulsifying characteristics of soy protein around isoelectric point. The results derived from this research would expand applications of SPI-γ-PGA-soluble electrostatic complex that can be applied in acid beverages, as well as a novel plant-based sustainable stabilizer for emulsions.

Research Advances in Plant Protein-Based Products: Protein Sources, Processing Technology, and Food Applications

Plant proteins are high-quality dietary components of food products. With the growing interest in sustainable and healthy food alternatives, plant proteins have gained significant attention as viable substitutes for animal-based proteins. Understanding the diversity of protein sources derived from plants, novel processing technology, and multiple applications is crucial for developing nutritious and sustainable plant protein-based products. This Review summarizes the natural sources of traditional and emerging plant proteins. The classifications, processing technologies, and applications of plant protein-based products in the food industry are explicitly elucidated. Moreover, the advantages and disadvantages of plant protein-based food products are revealed. Strategies such as protein fortification and complementation to overcome these shortcomings are critically discussed. We also demonstrate several issues that need to be addressed in future development.

Research progress of starch as microencapsulated wall material

Starch is non-toxic, low cost, and possesses good biocompatibility and biodegradability. As a natural polymer material, starch is an ideal choice for microcapsule wall materials. Starch-based microcapsules have a wide range of applications and application prospects in fields such as food, pharmaceuticals, cosmetics, and others. This paper firstly reviews the commonly used wall materials and preparation methods of starch-based microcapsules. Then the effect of starch wall materials on microcapsule properties is introduced in detail. It is expected to provide researchers with design inspiration and ideas for the development of starch-based microcapsules. Next the applications of starch-based microcapsules in various fields are presented. Finally, the future trends of starch-based microcapsules are discussed. Molecular simulation, green chemistry, and solutions to the main problems faced by resistant starch microcapsules may be the future research trends of starch-based microcapsules.

Protein-Stabilized Emulsion Gels with Improved Emulsifying and Gelling Properties for the Delivery of Bioactive Ingredients: A Review

In today's food industry, the potential of bioactive compounds in preventing many chronic diseases has garnered significant attention. Many delivery systems have been developed to encapsulate these unstable bioactive compounds. Emulsion gels, as colloidal soft-solid materials, with their unique three-dimensional network structure and strong mechanical properties, are believed to provide excellent protection for bioactive substances. In the context of constructing carriers for bioactive materials, proteins are frequently employed as emulsifiers or gelling agents in emulsions or protein gels. However, in emulsion gels, when protein is used as an emulsifier to stabilize the oil/water interface, the gelling properties of proteins can also have a great influence on the functionality of the emulsion gels. Therefore, this paper aims to focus on the role of proteins' emulsifying and gelling properties in emulsion gels, providing a comprehensive review of the formation and modification of protein-based emulsion gels to build high-quality emulsion gel systems, thereby improving the stability and bioavailability of embedded bioactive substances.

Allergenicity of wheat protein in diet: Mechanisms, modifications and challenges

Wheat is widely available in people's daily diets. However, some people are currently experiencing IgE-mediated allergic reactions to wheat-based foods, which seriously impact their quality of life. Thus, it is imperative to provide comprehensive knowledge and effective methods to reduce the risk of wheat allergy (WA) in food. In the present review, recent advances in WA symptoms, the major allergens, detection methods, opportunities and challenges in establishing animal models of WA are summarized and discussed. Furthermore, an updated overview of the different modification methods that are currently being applied to wheat-based foods is provided. This study concludes that future approaches to food allergen detection will focus on combining multiple tools to rapidly and accurately quantify individual allergens in complex food matrices. Besides, biological modification has many advantages over physical or chemical modification methods in the development of hypoallergenic wheat products, such as enzymatic hydrolysis and fermentation. It is worth noting that using biotechnology to edit wheat allergen genes to produce allergen-free food may be a promising method in the future which could improve the safety of wheat foods and the health of allergy sufferers.

Characterization of coacervation behavior between whey protein isolate and gum Arabic: Effects of heat treatment

Currently, the effect of heat treatment on the complex coacervation behavior of whey isolate protein (WPI) with gum arabic (GA) is undiscussed. In this work, the complex coacervation behavior of WPI with or without heat treatment and GA in different environments was investigated. The results showed that coacervates were formed at a mass ratio of 2:1 and a pH of 3.5, which was confirmed by the fluorescence spectroscopy results. Heat treatment increased the surface charge of WPI, reduced the saturated adsorption concentration of GA, and enhanced the sensitivity of the complex coacervation reaction to salt ions. Fourier infrared spectroscopy, intermolecular force analysis and molecular docking results confirm that the formation of coacervates is the result of electrostatic interactions. From the scanning electron microscope and differential scanning calorimetry results, it is clear that the whey isolate protein combined with gum arabic forms a gel-like conjugate with higher thermal stability and a dense structure. This study provides more in-depth theoretical guidance for the application of WPI and GA based coacervation and more advanced theoretical data for the study of hWPI.

Updates on Plant-Based Protein Products as an Alternative to Animal Protein: Technology, Properties, and Their Health Benefits

Plant-based protein products, represented by "plant meat", are gaining more and more popularity as an alternative to animal proteins. In the present review, we aimed to update the current status of research and industrial growth of plant-based protein products, including plant-based meat, plant-based eggs, plant-based dairy products, and plant-based protein emulsion foods. Moreover, the common processing technology of plant-based protein products and its principles, as well as the emerging strategies, are given equal importance. The knowledge gap between the use of plant proteins and animal proteins is also described, such as poor functional properties, insufficient texture, low protein biomass, allergens, and off-flavors, etc. Furthermore, the nutritional and health benefits of plant-based protein products are highlighted. Lately, researchers are committed to exploring novel plant protein resources and high-quality proteins with enhanced properties through the latest scientific and technological interventions, including physical, chemical, enzyme, fermentation, germination, and protein interaction technology.

Complex coacervation and freeze drying using whey protein concentrate, soy protein isolate and arabic gum to improve the oxidative stability of chia oil

BACKGROUND

Chia oil (CO) is popular for being the richest vegetable source of α-linolenic acid (60-66%). However, this content of polyunsaturated fatty acids (PUFA) limits the incorporation of bulk CO in food products due to its high probability of oxidation. This justifies the study of alternative wall materials for microencapsulation. No reports regarding the use of dairy protein/vegetable protein/polysaccharide blends as wall material for the microencapsulation of CO have been published. Therefore, this work analyzed the behavior of a whey protein concentrate (WPC)/soy protein isolate (SPI)/arabic gum (AG) blend as wall material. The complex coacervation (CC) process was studied: pH, 4.0; total solid content, 30% w/v; WPC/SPI/AG ratio, 8:1:1 w/w/w; stirring speed, 600 rpm; time, 30 min; room temperature.

RESULTS

The oxidative stability index (OSI) of CO (3.25 ± 0.16 h) was significantly increased after microencapsulation (around four times higher). Furthermore, the well-known matrix-forming ability of AG and WPC helped increase the OSI of microencapsulated oils. Meanwhile, SPI contributed to the increase of the encapsulation efficiency due to its high viscosity. Enhanced properties were observed with CC: encapsulation efficiency (up to 79.88%), OSIs (from 11.25 to 12.52 h) and thermal stability of microcapsules given by the denaturation peak temperatures of WPC (from 77.12 to 86.00 °C). No significant differences were observed in the fatty acid composition of bulk and microencapsulated oils.

CONCLUSION

Microcapsules developed from complex coacervates based on the ternary blend represent promising omega-3-rich carriers for being incorporated into functional foods.

Microencapsulation of tomato seed oil using phlorotannins-adducted pea protein isolate-chitosan and pea protein isolate-chitosan complex coacervates

Pea protein isolates (PPI)/phlorotannins (PT)/chitosan (CS) ternary complex and PPI/CS binary complex were synthesized to prepare tomato seed oil (TSO) microcapsules. The concentration of PT was determined to be 0.025% (w/w) based on the solubility, emulsification, and UV-visible spectrum of PPI-PT complex. Subsequently, the optimal pHs associated with the formation of PPI/CS and PPI-PT/CS complex coacervates were determined to be pH 6.6 and 6.1, while the optimal ratios were 9:1 and 6:1, respectively. The coacervate microcapsules were successfully produced by freeze-dried method and those formulated with PPI-PT/CS displayed significantly lower surface oil content (14.57 ± 0.22%), higher encapsulation efficiency (70.54 ± 0.13%), lower particle size (5.97 ± 0.16 μm), and PDI (0.25 ± 0.02) than PPI/CS. The microcapsules were characterized by scanning electron microscopy and Fourier Transform infrared spectroscopy. Furthermore, the encapsulated TSO exhibited enhanced thermal and oxidative stability than that of free oil, along with microcapsules fabricated with PPI-PT/CS ternary complex showed better protection than that of free PT. Overall, PPI-PT/CS complex as an effective wall material in delivery system presented great potential.

Effect of Enzymatic Hydrolysis on Solubility and Emulsifying Properties of Lupin Proteins (Lupinus luteus)

Solubility and emulsifying properties are important functional properties associated with proteins. However, many plant proteins have lower techno-functional properties, which limit their functional performance in many formulations. Therefore, the objective of this study was to investigate the effect of protein hydrolysis by commercial enzymes to improve their solubility and emulsifying properties. Lupin protein isolate (LPI) was hydrolyzed by 7 commercial proteases using different E/S ratios and hydrolysis times while the solubility and emulsifying properties were evaluated. The results showed that neutral and alkaline proteases are most efficient in hydrolyzing lupin proteins than acidic proteases. Among the proteases, Protamex® (alkaline protease) showed the highest DH values after 5 h of protein hydrolysis. Meanwhile, protein solubility of LPI hydrolysates was significantly higher (p < 0.05) than untreated LPI at all pH analyzed values. Moreover, the emulsifying capacity (EC) of undigested LPI was lower than most of the hydrolysates, except for acidic proteases, while emulsifying stability (ES) was significantly higher (p < 0.05) than most LPI hydrolysates by acidic proteases, except for LPI hydrolyzed with Acid Stable Protease with an E/S ratio of 0.04. In conclusion, the solubility, and emulsifying properties of lupin (Lupinus luteus) proteins can be improved by enzymatic hydrolysis using commercial enzymes.

Microencapsulation of Carvacrol by Complex Coacervation of Walnut Meal Protein Isolate and Gum Arabic: Preparation, Characterization and Bio-Functional Activity

As a natural phenolic compound, carvacrol has attracted much attention due to its excellent antibacterial and antioxidant activities. However, its application is limited due to its instability, such as easy volatilization, easy oxidation, etc. Protein-polysaccharide interactions provide strategies for improving their stability issues. In this study, the plant-based carvacrol microcapsules via complex coacervation between walnut meal protein isolate (WMPI) and gum Arabic (GA) has been fabricated and characterized. The formation conditions of WMPI-GA coacervates were determined by some parameters, such as pH, zeta-potential, and turbidity. The optimum preparation conditions were achieved at pH 4.0 with a WMPI-to-GA ratio of 6:1 (w/w). The mean particle size, loading capacity (LC), and encapsulation efficiency (EE) of the microcapsules were 43.21 μm, 26.37%, and 89.87%, respectively. Fourier transform infrared spectroscopy (FT-IR) and fluorescence microscopy further confirmed the successful microencapsulation of carvacrol. The microencapsulation of carvacrol improved the thermal stability of the free carvacrol. The swelling capacity results indicated that it could resist gastric acid, and facilitate its intestinal absorption. Meanwhile, the carvacrol molecules trapped within the microcapsules could be continuously released in a concentration-dependent manner. Furthermore, the microcapsules presented good antioxidant activity and antibacterial activity against the Gram-negative (E. coli) and the Gram-positive (S. aureus) bacteria. These results indicated that the obtained carvacrol microcapsules have a potential application value as a food preservative in the food industry.

Recent advances in essential oil complex coacervation by efficient physical field technology: A review of enhancing efficient and quality attributes

Although complex coacervation could improve the water solubility, thermal stability, bioavailability, antioxidant activity and antibacterial activity of essential oils (EOs). However, some wall materials (such as proteins and polysaccharides) with water solubility and hydrophobic nature limited their application in complex coacervation. In order to improve the properties of EO complex coacervates, some efficient physical field technology was proposed. This paper summarizes the application and functional properties of EOs in complex coacervates, formation and controlled-release mechanism, as well as functions of EO complex coacervates. In particular, efficient physical field technology as innovative technology, such as high pressure, ultrasound, cold plasma, pulsed electric fields, electrohydrodynamic atomization and microwave technology improved efficient and quality attributes of EO complex coacervates are reviewed. The physical fields could modify the gelling, structural, textural, emulsifying, rheological properties, solubility of wall material (proteins and polysaccharides), which improve the properties of EO complex coacervates. Overall, EOs complex coacervates possess great potential to be used in the food industry, including high bioavailability, excellent antioxidant capacity and gut microbiota in vivo, masking the sensation of off-taste or flavor, favorable antimicrobial capacity.

Encapsulation of tannins and tannin-rich plant extracts by complex coacervation to improve their physicochemical properties and biological activities: A review

As a major class of dietary polyphenols, tannins are demonstrated to have various health-promoting properties. Although tannins have been widely utilized in food, pharmaceutical and many other industries, the applications of tannins are quite limited due to their poor stability, sensory attributes and bioavailability. Encapsulation helps improve all of these properties. Complex coacervation, one of the most effective encapsulation techniques, is known for its simplicity, low cost, scalability and reproducibility in encapsulation of functional components. In recent years, complex coacervation has been successfully used for encapsulation of tannins and tannin-rich plant extracts. In this article, the research progress in encapsulating tannins and tannin-rich plant extracts by complex coacervation to improve their physicochemical properties and biological activities is critically reviewed for the first time. Encapsulation of tannins and tannin-rich plant extracts can effectively improve their sensory characteristics, stabilities, bioavailability, anti-hypercholesterolemia, anti-diabetic, antioxidant, anticancer and antimicrobial activities. In particular, the enhancement of biological activities of tannins and tannin-rich plant extracts is usually correlated to their improved physicochemical properties imparted by the encapsulation technique. Moreover, we introduce the issues that need to be further resolved in future studies on encapsulation of tannins and tannin-rich plant extracts by complex coacervation.

Effect of crosslinking and drying method on the oxidative stability of lipid microcapsules obtained by complex coacervation

The crosslinking and drying method of microcapsules prepared by complex coacervation has been investigated in order to reach a better control of the oxidative stability of final powder product. Methyl...