Chitosan hydrochloride/carboxymethyl starch complex nanogels stabilized Pickering emulsions for oral delivery of β-carotene: Protection effect and in vitro digestion study

High internal phase pickering emulsions stabilized by zein/whey protein nanofibril complexes: Preparation and lycopene loading

High internal phase Pickering emulsions (HIPPEs) prepared from natural polymers have attracted much attention in the food manufactures. However, single zein-stabilized HIPPEs are poorly stable and prone to flocculation near the isoelectric point. To address this issue, in this study, zein and whey protein nanofibrils (WPN) complex nanoparticles (ZWNPs) were successfully prepared using a pH-driven method, and ZWNPs were further used as HIPPEs stabilizers. The results showed that zein and WPN were combined together through hydrogen bonding and hydrophobic interaction to form ZWNPs, and the HIPPEs stabilized by ZWNPs had excellent stability, which could effectively protect the internally encapsulated lycopene and improve the bioaccessibility of lycopene. In conclusion, this study provides a new strategy for the preparation of stable hydrophobic protein-based HIPPEs, represented by zein.

Walnut protein isolate based emulsion as a promising delivery system enhanced lutein bioaccessibility

Lutein, a natural pigment with multiple beneficial bioactivities, faces limitations in food processing due to its instability. In this study, we constructed four modified walnut protein isolate (WNPI) based emulsions as emulsion-based delivery systems (EBDS) for lutein fortification. The modification treatments enhanced the encapsulation efficiency of the WNPI-based EBDS on lutein. The modified WNPI-based EBDS exhibited improved storage and digestive stability, as well as increased lutein delivery capability in simulated gastrointestinal conditions. After in vitro digestion, the lutein retention in the modified WNPI-based EBDS was higher than in the untreated WNPI-based EBDS, with a maximum retention of 49.67 ± 1.10 % achieved after ultrasonic modification. Furthermore, the modified WNPI-based EBDS exhibited an elevated lutein bioaccessibility, reaching a maximum value of 40.49 ± 1.29 % after ultrasonic modification, nearly twice as high as the untreated WNPI-based EBDS. Molecular docking analysis indicated a robust affinity between WNPI and lutein, involving hydrogen bonds and hydrophobic interactions. Collectively, this study broadens WNPI's application and provides a foundation for fortifying other fat-soluble bioactive substances.

Emulsion gels prepared from Longzhua mushroom polysaccharides with self-gelling properties as β-carotene carriers: Stability and in vitro digestibility of β-carotene

β-Carotene is widely used in food systems because of its biological activity; however, β-carotene has poor chemical stability and low bioavailability. Thus, researchers use encapsulated delivery systems to overcome these disadvantages. In this study, we prepared emulsion gels to encapsulate β-carotene, using Longzhua mushroom polysaccharide (LMP), which can autonomously form weak gels. The LMP emulsion gel (LEG) exhibited a high water-holding capacity of up to 95.06 %. All samples showed adequate storage stability for 28 days. Increasing the polysaccharide content in the emulsion gel enhanced the encapsulation efficiency of β-carotene (96.76 %-98.27 %), the release of free fatty acids (68.21 %-81.44 %), and the photostability (80.65 %-91.27 %), thermal stability (73.84 %-97.08 %), and bioaccessibility (18.28 %-30.26 %) of β-carotene. In conclusion, LEG is a promising fat-soluble material that can be used for food-grade encapsulated delivery systems.

Characterization of modified starch-based complexes-stabilized linolenic acid emulsions and their enhanced oxidative stability in vitro gastrointestinal digestion

A new approach of fabricating α-linolenic acid emulsions with enhanced oxidative stability in vitro digestion was established, using covalent octenyl succinic anhydride starch (OSAS)-soy protein (SP)-epigallocatechin-3-gallate (EGCG) complexes as emulsifiers. The physicochemical characteristics and surface morphology of emulsions were mainly characterized by rheological measurements, laser scanning microscope (CLSM) and cryo-scanning electron microscopy (Cryo-SEM). Results indicated that emulsions had dense interfacial layers and strong network structures. As a result, the stability and antioxidant ability of emulsions were improved significantly. In addition, the oxidative stability of emulsions in vitro gastrointestinal digestion was explored. Results showed that emulsions could maintain better oxidative stability owing to antioxidant activity of covalent OSAS-SP-EGCG complexes under gastrointestinal conditions. In particular, lipid hydroperoxide and malondialdehyde contents of emulsions prepared by 1:4 complexes were lower than 0.35 mmol/L and 20.5 nmol/mL, respectively, approximately half those of emulsions stabilized by OSAS (0.65 mmol/L and 39.5 nmol/mL). It was indicated that covalent OSAS-SP-EGCG complexes could effectively inhibit α-linolenic acid oxidation in emulsions during vitro gastrointestinal digestion. This work will provide a theoretical basis for the development of α-linolenic acid emulsions, which will help to broaden application of α-linolenic acid in food industry.

Design, characterization and digestibility of β-carotene-loaded emulsion system stabilized by whey protein with chitosan and potato starch addition

The physicochemical properties and gastrointestinal fate of β-carotene-loaded emulsions and emulsion gels were examined. The emulsion was emulsified by whey protein isolate and incorporated with chitosan, then the emulsion gels were produced by gelatinizing potato starch in the aqueous phase. The rheology properties, water distribution, and microstructure of emulsions and emulsion gels were modulated by chitosan combination. A standardized INFOGEST method was employed to track the gastrointestinal fate of emulsion systems. Significant changes in droplet size, zeta-potential, and aggregation state were detected during in vitro digestion, including simulated oral, stomach, and small intestine phases. The presence of chitosan led to a significantly reduced free fatty acids release in emulsion, whereas a slightly increasing released amount in the emulsion gel. β-carotene bioaccessibility was significantly improved by hydrogel formation and chitosan addition. These results could be used to formulate advanced emulsion systems to improve the gastrointestinal fate of hydrophobic nutraceuticals.

The evaluation of mixed-layer emulsions stabilized by myofibrillar protein-chitosan complex for delivering astaxanthin: Fabrication, characterization, stability and in vitro digestibility

Muscle protein based functional foods have been attracted great interests in novel food designing. Herein, myofibrillar protein (MP)-chitosan (CH) electrostatic complexes were employed to fabricate mixed-layer emulsions to protect and deliver astaxanthin. The MP/CH complex fabricated mixed-layer emulsions displayed higher stability against pH and temperature changes, exhibiting smaller droplet and homogenous distributions. After UV-light irradiation for 8 h, the mixed-layer emulsions had higher astaxanthin retention (69.11 %, 1:1 group). During storage, a lower degree of lipid oxidation, protein oxidation and higher astaxanthin retention were obtained, indicating desirable protections of mixed-layer emulsions. The vitro digestion reveled the mixed-layer emulsions could decrease the release of free fatty acids. Meanwhile, the bioaccessibility of astaxanthin was higher (30.43 %, 2:1 group) than monolayer emulsion. In all, the MP/CH prepared mixed-layer emulsions could protect and deliver fat-soluble bioactive compounds, and contributed to develop muscle protein based functional foods to meet the needs of slow and controlled release.

General approaches to biopolymer-based Pickering emulsions

Pickering emulsion is a type of emulsion that uses solid particles or colloidal particles as emulsifiers rather than surfactants to adhere at oil-water interface. Pickering emulsions have gathered significant research attention recently due to their excellent stability and wide range of potential uses compared to traditional emulsions. Major advancements have been made in development of innovative Pickering emulsions using different colloidal particles by various techniques including homogenization, emulsification and ultrasonication. Use of biopolymer particles gives Pickering emulsions a more escalating possibilities. In this review paper, we seek to present a critical overview of development in food-grade particles that have been utilized to create Pickering emulsions with a focus on techniques and application of Pickering emulsions. Particularly, we have evaluated protein, lipid, polysaccharide-based particles and microalgal proteins that have emerged in recent years with respect to their potential to stabilize and add novel functionalities to Pickering emulsions. Some preparation methods of Pickering emulsions in brief, applications of Pickering emulsions are also highlighted. Encapsulation and delivery of bioactive compounds, fat substitutes, film formation and catalysis are potential applications of Pickering emulsions. Pickering double emulsions, nutraceutical and bioactive co-delivery, and preparation of porous materials are among research trends of food-grade Pickering emulsions.

Synergistic stabilization of high internal phase Pickering emulsions by peanut isolate proteins and cellulose nanocrystals for β-carotene encapsulation

In this study, high internal phase Pickering emulsions (HIPPEs) were stabilized by the complexes of peanut protein isolate (PPI) and cellulose nanocrystals (CNCs) for encapsulation β-carotene to retard its degradation during processing and storage. CNCs were prepared by H2SO4 hydrolysis (HCNCs), APS oxidation (ACNCs) and TEMPO oxidation (TCNCs), exhibiting needle-like or rod-like structures with nanoscale size and uniformly distributed around the spherical PPI particle, which enhanced the emulsifying capability of PPI. Results of optical micrographs and droplet size measurement showed that Pickering emulsions stabilized by PPI/ACNCs complexes exhibited the most excellent stability after 30 days of storage, which indicated that ACNCs had the most obvious effect to improve emulsifying capability of PPI. HIPPEs encapsulated β-carotene (βc-HIPPEs) were stabilized by PPI/ACNCs complexes and showed excellent inverted storage stability. Moreover, βc-HIPPEs exhibited typical shear thinning behavior investigated by rheological properties analysis. During thermal treatment, ultraviolet radiation and oxidation, the retentions of β-carotene encapsulated in HIPPEs were improved significantly. This research holds promise in expanding Pickering emulsions stabilized by proteins-polysaccharide particles to delivery systems for hydrophobic bioactive compounds.

Body temperature responsive capsules templated from Pickering emulsion for thermally triggered release of β-carotene

In recent years, functional foods with lipophilic nutraceutical ingredients are gaining more and more attention because of its potential healthy and commercial value, and developing of various bioderived food-grade particles for use in fabrication of Pickering emulsion has attracted great attentions. Herein, the bio-originated sodium caseinate-lysozyme (Cas-Lyz) complex particles were firstly designed to be used as a novel interfacial emulsifier for Pickering emulsions. Pickering emulsions of various food oils were all successfully stabilized by the Cas-Lyz particles without addition of any synthetic surfactants, while the fluorescence microscopy and SEM characterizations clearly evidenced Cas-Lyz particles were attached on the surface of emulsion droplets. Additionally, the Cas-Lyz particles stabilized emulsion can also be used to encapsulate the β-carotene-loaded soybean oil, suggestion a potential method to carry lipophilic bioactive ingredients in an aqueous formulation for food, cosmetic and medical industry. At last, we present a Pickering emulsion strategy that utilizes biocompatible, edible and body temperature-responsive lard oil as the core material in microcapsules, which can achieve hermetic sealing and physiological temperature-triggered release of model nutraceutical ingredient (β-carotene).

Fabrication and characterization of anthocyanin-loaded double Pickering emulsions stabilized by β-cyclodextrin

Anthocyanins, one of the important water-soluble pigments, are sensitive to environmental factors, which limits the application of anthocyanins in food field. In order to overcome this limitation, double Pickering emulsions stabilized by β-cyclodextrin were developed. The optimum preparation conditions of the emulsions were determined firstly and the performance and structure of emulsions were investigated. Results showed that the optimum preparation conditions of emulsions were the ratio of (W1/O): W2 = 6:4 and 4 % β-cyclodextrin concentration. Optical microscope and confocal laser scanning microscope results confirmed that β-cyclodextrin adsorbed onto the surface of droplets forming stable double Pickering emulsions structure. In vitro gastrointestinal digestion experiments proved that double Pickering emulsions played a controlled-release effect in the small intestine. Rheological analysis proved that the emulsions exhibited elastic properties and demonstrated shear thinning behavior. The emulsions showed excellent stability under centrifugation and thermal conditions. These findings will promote anthocyanins' application in daily diet.

Preparation and properties of pH-sensitive cationic starch nanoparticles

Environmentally friendly and outstanding pH responsiveness cationic starch nanoparticles (CSNP) were prepared through ethanol precipitation from pH-sensitive starch, which preparation of cationic starch (CS) by grafting copolymerization with dimethylaminoethyl methacrylate (DMAEMA). In this work, CSNP showed a nanometer size and regular sphere, highly free-flowing molecular chains, and outstanding pH responsiveness which was proved by the high stability of its stabilized emulsion through 6 emulsification/ demulsification transition. The result of the SEM and particle size distribution indicated that the size of the CSNP-0 was about 800 nm, and decreased with the DMAEMA increased. Moreover, the CSNP-stabilized emulsion was stable at pH = 7 and pH = 12. However, this emulsion exhibited breakage at pH = 2. In addition, the CSNP-stabilized Pickering emulsion achieved an emulsification/demulsification switching by cycling the pH at least 6 times, during which the average droplet size gradually increased. At pH ≥ 7, the emulsions exhibit shear thinning behavior.

Starch-based particles as stabilizers for Pickering emulsions: modification, characteristics, stabilization, and applications

The potential utilization of starch as a particle-based emulsifier in the preparation of Pickering emulsions is gaining interest within the food industry. Starch is an affordable and abundant functional ingredient, which makes it an excellent candidate for the stabilization of Pickering emulsions. This review article focuses on the formation, stabilization, and properties of Pickering emulsions formulated using starch-based particles and their derivatives. First, methods of isolating and modifying starch-based particles are highlighted. The key parameters governing the properties of starch-stabilized Pickering emulsions are then discussed, including the concentration, size, morphology, charge, and wettability of the starch-based particles, as well as the type and size of the oil droplets. The physicochemical mechanisms underlying the ability of starch-based particles to form and stabilize Pickering emulsions are also discussed. Starch-based Pickering emulsions tend to be more resistant to coalescence than conventional emulsions, which is useful for some food applications. Potential applications of starch-stabilized Pickering emulsions are reviewed, as well as recent studies on their gastrointestinal fate. The information provided may stimulate the utilization of starch-based Pickering emulsions in food and other industries.

In vitro gastrointestinal digestion and colonic fermentation of media-milled black rice particle-stabilized Pickering emulsion: Phenolic release, bioactivity and prebiotic potential

This is a pioneer study that investigated the digestive characteristics of Pickering emulsions stabilized by media-milled black rice particles during in vitro digestion and colonic fermentation. Free fatty acid release of the emulsions improved from 28.42 ± 3.13% to 33.68 ± 4.05% after media milling. The phenolics released from media-milled sample were close to those from unground sample. Media-milled sample exhibited higher DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging ability and α-glucosidase inhibition rate than unground sample. Media milling increased the generation of short-chain fatty acids (SCFAs) during colonic fermentation, especially acetic acid (23% improvement in media-milled sample over unground sample). It also inhibited the growth of harmful bacteria namely Escherichia Shigella and Streptococcus, and promoted the growth of beneficial bacteria including Bifidobacterium and Blautia. These findings revealed that media-milled black rice particle-stabilized Pickering emulsions possessed intrinsic bioactivity and prebiotic potentials in the gastrointestinal tract for the first time.

Zein/hyaluronic acid nanoparticle stabilized Pickering emulsion for astaxanthin encapsulation

Pickering emulsions have attracted considerable attention owing to the stability and functionality. In this study, zein/hyaluronic acid (ZH) nanoparticles were prepared and applied for stabilizing astaxanthin encapsulated Pickering emulsions. By non-covalent interaction between Zein and hyaluronic acid (HA), the conformation of zein changed and therefore improved the wettability of ZH nanoparticles. Unlike the spherical zein nanoparticles, ZH nanoparticles possessed a cross-linked structure with rough surface. Confocal laser scanning microscopy indicated that the nanoparticles accumulated at the oil-water interface. The Pickering emulsion stabilized by ZH nanoparticles exhibited high viscoelasticity and a solid-like behavior, as well as excellent stability during the storage. In vitro digestion results revealed that the presence of HA coating prevented the emulsion from pepsin hydrolysis and achieved efficient delivery of astaxanthin. This work confirmed that Pickering emulsion stabilized by ZH nanoparticles could be used as an effective deliver system for bioactive substances.

Edible polysaccharide-based oleogels and novel emulsion gels as fat analogues: A review

Polysaccharide-based oleogels and emulsion gels have become novel strategies to replace solid fats due to safe and plentiful raw material, healthier fatty acid composition, controllable viscoelasticity, and more varied nutrition/flavor embedding. Recently, various oleogelation techniques and novel emulsion gels have been reported further to enrich the potential of polysaccharides in oil structuring, in which a crucial step is to promote the formation of polysaccharide networks determining gel properties through different media. Meanwhile, polysaccharide-based oleogels and emulsion gels have good oil holding, nutrient/flavor embedding, and 3D food printability, and their applications as fat substitutes have been explored in foods. This paper comprehensively reviews the types, preparation methods, and mechanisms of various polysaccharide-based oleogels and emulsion gels; meanwhile, the food applications and new trends of polysaccharide-based gels are discussed. Moreover, some viewpoints about potential developments and application challenges of polysaccharide-based gels are mentioned. In the future, polysaccharide-based gels may be flexible materials for customized nutritional foods and molecular gastronomy. However, it is still a challenge to select the appropriate oleogels or emulsion gels to meet the requirements of the products. Once this issue is addressed, oleogels and emulsion gels are anticipated to be used widely.

Development of Emulsion Gels Stabilized by Chitosan and Octenyl Succinic Anhydride-Modified β-Cyclodextrin Complexes for β-Carotene Digestion and 3D Printing

β-cyclodextrin (β-CD)-based emulsion gels encapsulated with nutrition for three-dimensional (3D) printing are promising, while obstacles such as low bioaccessibility of bioactive compounds and the molding process in food manufacturing hinder their application. This study intended to develop stable composite emulsion gels using the complexes of chitosan (CS) and octenyl succinic anhydride (OSA)-modified β-CD (OCD) to conquer these challenges. The esterification of OSA generated more negatively charged OCD and ester groups, which aided in the combination of OCD and CS through enhanced electrostatic and hydrogen bonding interactions. The addition of CS improved the emulsification properties of the complexes and acted as a bridge link in the aqueous phase, thereby increasing the gel strength of the composite emulsion gels. Moreover, the encapsulation of β-carotene destabilized the strength of the emulsion gels by lowering the interfacial tension. The emulsion gel stabilized by OCD3/CS-0.75% at an initial pH not only successfully encapsulated β-carotene and presented the highest bioaccessibility of 41.88 ± 0.87% in the in vitro digestion but also showed excellent 3D printability. These results provided a promising strategy to enhance the viscoelasticity of β-CD-based emulsion gels and accelerate their application in bioactive compound delivery systems and 3D food printing.

The colloid and interface strategies to inhibit lipid digestion for designing low-calorie food

Although fat is one of the indispensable components of food flavor, excessive fat consumption could cause obesity, metabolism syndromes and an imbalance in the intestinal flora. In the pursuit of a healthy diet, designing fat reducing foods by inhibiting lipid digestion and calorie intake is a promising strategy. Altering the gastric emptying rates of lipids as well as acting on the lipase by suppressing the enzymatic activity or limiting lipase diffusion via interfacial modulation can effectively decrease lipolysis rates. In this review, we provide a comprehensive overview of colloid-based strategies that can be employed to retard lipid hydrolysis, including pancreatic lipase inhibitors, emulsion-based interfacial modulation and fat substitutes. Plants-/microorganisms-derived lipase inhibitors bind to catalytic active sites and change the enzymatic conformation to inhibit lipase activity. Introducing oil-in-water Pickering emulsions into the food can effectively delay lipolysis via steric hindrance of interfacial particulates. Regulating stability and physical states of emulsions can also affect the rate of hydrolysis by altering the active hydrolysis surface. 3D network structure assembled by fat substitutes with high viscosity can not only slow down the peristole and obstruct the diffusion of lipase to the oil droplets but also impede the transportation of lipolysis products to epithelial cells for adsorption. Their applications in low-calorie bakery, dairy and meat products were also discussed, emphasizing fat intake reduction, structure and flavor retention and potential health benefits. However, further application of these strategies in large-scale food production still requires more optimization on cost and lipid reducing effects. This review provides a comprehensive review on colloidal approaches, design, principles and applications of fat reducing strategies to meet the growing demand for healthier diet and offer practical insights for the low-calorie food industry.

Soy Protein Isolate-Chitosan Nanoparticle-Stabilized Pickering Emulsions: Stability and In Vitro Digestion for DHA

The purpose of the study was to investigate the stability and oral delivery of DHA-encapsulated Pickering emulsions stabilized by soy protein isolate-chitosan (SPI-CS) nanoparticles (SPI-CS Pickering emulsions) under various conditions and in the simulated gastrointestinal (GIT) model. The stability of DHA was characterized by the retention rate under storage, ionic strength, and thermal conditions. The oral delivery efficiency was characterized by the retention and release rate of DHA in the GIT model and cell viability and uptake in the Caco-2 model. The results showed that the content of DHA was above 90% in various conditions. The retention rate of DHA in Pickering emulsions containing various nanoparticle concentrations (1.5 and 3.5%) decreased to 80%, while passing through the mouth to the stomach, and DHA was released 26% in 1.5% Pickering emulsions, which was faster than that of 3.5% in the small intestine. After digestion, DHA Pickering emulsions proved to be nontoxic and effectively absorbed by cells. These findings helped to develop a novel delivery system for DHA.

Research progress on chitin/chitosan-based emulsion delivery systems and their application in lipid digestion regulation

Excessive lipid intake is linked to an elevated risk of health problems. However, reducing lipid contents may influence food structure and flavor. Some alternatives are needed to control the lipid absorption. Emulsions are common carriers for lipids, which can control the hydrolysis and absorption of lipids. Chitin (Ch) and chitosan (CS) are natural polysaccharides with good biodegradability, biocompatibility, and unique cationic properties. They have been reported to be able to delay lipolysis, which can be regarded as one of the most promising agents that regulates lipid digestion (LiD). The application of Ch/CS and their derivatives in emulsions are summarized in this review with a focus on their performances and mechanisms for LiD regulation, aiming to provide theoretical guidance for the development of novel Ch/CS emulsions, and the regulation of LiD. A reasonable design of emulsion interface can provide its resistance to the external environment and then control LiD. The properties of emulsion interface are the key factors affecting LiD. Therefore, systematic study on the relationship between Ch/CS-based emulsion structure and LiD can not only instruct the reasonable design of emulsion interface to accurately regulate LiD, but also provide scientific guidelines for applying Ch/CS in functional food, medicine and other fields.

Application of Pickering emulsions stabilized by corn, potato and pea starch nanoparticles: Effect of environmental conditions and approach for curcumin release

To apply octenyl succinic anhydride (OSA)-modified corn, potato and pea starch nanoparticles (OCSNPs, OPtSNPs and OPSNPs, respectively) as Pickering emulsion stabilizers, effect of environmental conditions such as 30 days of storage period, pH of 1-11, ionic strength of 0.1-0.9 mol/L and heat of 30-90 °C on the stability of the emulsions was evaluated. Compared with emulsions stabilized by starch nanoparticles (SNPs), the emulsions stabilized by OSA-modified SNPs (OSNPs) kept stable against different environmental stresses (pH, ionic strength and heat) as well as for a storage period of 30 days, especially for OPtSNPs. Additionally, oiling-off was not observed in OSNPs emulsions over the storage time. OSNPs emulsions also showed improved protection on curcumin during storage and controlled release during in vitro digestion. These findings enlarged the application of OCSNPs, OPtSNPs and OPSNPs stabilized-Pickering emulsion in food systems and deliver system.

Oral bioavailability of bioactive compounds; modulating factors, in vitro analysis methods, and enhancing strategies

Foods are complex biosystems made up of a wide variety of compounds. Some of them, such as nutrients and bioactive compounds (bioactives), contribute to supporting body functions and bring important health benefits; others, such as food additives, are involved in processing techniques and contribute to improving sensory attributes and ensuring food safety. Also, there are antinutrients in foods that affect food bioefficiency and contaminants that increase the risk of toxicity. The bioefficiency of food is evaluated with bioavailability which represents the amount of nutrients or bioactives from the consumed food reaching the organs and tissues where they exert their biological activity. Oral bioavailability is the result of some physicochemical and biological processes in which food is involved such as liberation, absorption, distribution, metabolism, and elimination (LADME). In this paper, a general presentation of the factors influencing oral bioavailability of nutrients and bioactives as well as the in vitro techniques for evaluating bioaccessibility and is provided. In this context, a critical analysis of the effects of physiological factors related to the characteristics of the gastrointestinal tract (GIT) on oral bioavailability is discussed, such as pH, chemical composition, volumes of gastrointestinal (GI) fluids, transit time, enzymatic activity, mechanical processes, and so on, and the pharmacokinetics factors including BAC and solubility of bioactives, their transport across the cell membrane, their biodistribution and metabolism. The impact of matrix and food processing on the BAC of bioactives is also explained. The researchers' recent concerns for improving oral bioavailability of nutrients and food bioactives using both traditional techniques, for example, thermal treatments, mechanical processes, soaking, germination and fermentation, as well as food nanotechnologies, such as loading of bioactives in different colloidal delivery systems (CDSs), is also highlighted.

Tuning egg yolk granules/sodium alginate emulsion gel structure to enhance β-carotene stability and in vitro digestion property

In this study, emulsion gels were constructed by ionic gelation method using egg yolk granules/sodium alginate bilayers emulsion. In particular, the main driving force of the emulsion gels was controlled by adjusting pH. Compared with pH 7.0, the mechanical properties of EYGs emulsion gel were enhanced at pH 4.0 (G' > G″). The interfacial protein aggregation that occurred at pH 4.0 promoted the compactness of the EYGs emulsion gel structure along with enhanced capillary effect. The emulsion gel structure tended to be complete at 1 % SA of pH 4.0, for the electrostatic interaction required more SA molecules involved in maintaining emulsion gel structural stability. The denser emulsion gel structure of pH 4.0 than pH 7.0 improved storage stability, FFA releasing, and chemical stability of β-carotenes. Bioaccessibility of β-carotenes also decreased to achieve sustained release. This study provides a theoretical basis for tuning emulsion gel structure to adjust encapsulation stability and in vitro digestion characteristics of active ingredients.

High internal phase emulsion gels stabilized by phosphorylated perilla protein isolate for protecting hydrophobic nutrients: Adjusting emulsion performance by incorporating chitosan-protocatechuic acid conjugate

The delivery vehicles based on protein-polysaccharide-polyphenol are promising methods to encapsulate bioactive components with the aim of improving their solubility and bioavailability. In this study, chitosan-protocatechuic acid (CSPA) conjugate interacted with phosphorylated perilla protein isolate (LZPI) to engineer a composite antioxidant interfacial architecture to delay lipid oxidation and regulate the stability and digestion profiles of β-carotene loaded in high internal phase emulsions (HIPEs). Compared to LZPI, the LZPI-CSPA complexes formed by hydrogen bond and electrostatic interaction showed improved wettability and reduced interfacial tension, which facilitated their adsorption at the interface. Furthermore, the addition of CSPA conjugate promoted the formation of interconnected network structure of LZPI-stabilized HIPEs, thereby endowing them with excellent viscoelasticity and storage stability. Moreover, the denser interfacial film based on LZPI-CSPA complexes effectively decreased the contents of lipid hydroperoxide and malondialdehyde in HIPEs, thus improving their oxidation stability. The encapsulation of β-carotene by LZPI-CSPA complex-stabilized HIPEs could further enhance its retention rate against different environmental stresses. After in vitro simulated digestion, the bioaccessibility of β-carotene also improved, reaching the highest value in HIPEs containing 1.5 % CSPA conjugate. These findings will give a reference for the fabrication of delivery vehicles to enhance the stability and bioaccessibility of bioactive components.

Comparison of properties and application of starch nanoparticles optimized prepared from different crystalline starches

Starch nanoparticles (SNPs) were produced by nanoprecipitation combined with ultrasonication with the use of different starches (corn, potato and sago starch) and used to stabilize Pickering emulsions. The orthogonal experiment was used to optimize preparation conditions of gelatinization pretreatment duration of 30 min, ultrasonic power of 600 W, and ultrasonic time of 40 min. Compared with native starch, the SNPs were spherical in shape and displayed a V-type crystalline structure with low relative crystallinity and higher degree of double-helix. Compared with native starch-Pickering emulsion, the SNP-Pickering emulsion had a smaller droplet size, more uniform distribution, clearer oil/water interface, and higher static stability of droplets. The sago SNP-Pickering emulsion had the great gelatinous structure and emulsion stability. In addition, the SNP-Pickering emulsion had the better loading efficiency and controlled release performance of curcumin. Meanwhile, the bioavailability of curcumin in sago SNP-Pickering emulsion was highest.

Encapsulating biocontrol bacteria with starch as a safe and edible biopolymer to alleviate plant diseases: A review

Healthy foods with few artificial additives are in high demand among consumers. Preserving conventional pesticides, frequently used as chemicals to control phytopathogens, is challenging. Therefore, we proposed an innovative approach to protect agricultural products in this review. Biocontrol bacteria are safe alternatives with low stability and low efficiency in the free-form formulation. The encapsulation technique for covering active compounds (e.g., antimicrobials) represents a more efficient protection technology because encapsulation causes the controlled release of bioactive materials and reduces the application doses. Of the biopolymers able to form a capsule, starch exhibits several advantages, such as its ready availability, cost-effectively, edible, colorless, and tasteless. Nevertheless, the poor mechanical properties of starch can be improved with other edible biopolymers. In addition, applying formulations incorporated with more than one antimicrobial material offers synergistic effects. This review presented the starch-based capsules used to enclose antimicrobial agents as effective tools against phytopathogens.

An investigation on pickering nano-emulsions stabilized by dihydromyricetin/high-amylose corn starch composite particles: Preparation conditions and carrier properties

With dihydromyricetin (DMY)/high-amylose corn starch (HCS) composite particles as the emulsifier, Pickering nano-emulsions were fabricated by combining high-speed shearing and high-pressure homogenization. The effect of particle properties and processing conditions on the formation and physicochemical properties of the Pickering nano-emulsions was then investigated systematically. The results showed that the DMY content of the composite particles, the oil phase volume fraction of the emulsion, and the homogenization conditions had obvious effects on the droplet size of the emulsion, where appropriate DMY content in the composite particles (5-20%) contributed to the formation of stable Pickering nano-emulsions. The oil phase of the obtained emulsions exhibited good stability during high-temperature storage, and their β-carotene protecting performance against UV irradiation was superior to the emulsion stabilized by Tween 20. The in vitro simulated digestion analysis indicated that the nano-emulsions developed by the composite particles could enhance the bioaccessibility of β-carotene and inhibit starch hydrolysis.

Strategic developments in the drug delivery of natural product dihydromyricetin: applications, prospects, and challenges

Dihydromyricetin (DHM) is an important natural flavonoid that has attracted much attention because of its various functions such as protecting the cardiovascular system and liver, treating cancer and neurodegenerative diseases, and anti-inflammation effect, etc. Despite its great development potential in pharmacy, DHM has some problems in pharmaceutical applications such as low solubility, permeability, and stability. To settle these issues, extensive research has been carried out on its physicochemical properties and dosage forms to produce all kinds of DHM preparations in the past ten years. In addition, the combined use of DHM with other drugs is a promising strategy to expand the application of DHM. However, although invention patents for DHM preparations have been issued in several countries, the current transformation of DHM research results into market products is insufficient. To date, there is still a lack of deep research into the pharmacokinetics, pharmacodynamics, toxicology, and action mechanism of DHM preparations. Besides, preparations for combined therapy of DHM with other drugs are scarcely reported, which necessitates the development of dosage forms for this application. Apart from medicine, the development of DHM in the food industry is also of great potential. Due to its multiple effects and excellent safety, DHM preparations can be developed for functional drinks and foods. Through this review, we hope to draw more attention to the development potential of DHM and the above challenges and provide valuable references for the research and development of other natural products with a similar structure-activity relationship to this drug.

Preparation of Oxidized Starch/β-Lactoglobulin Complex Particles Using Microfluidic Chip for the Stabilization of Astaxanthin Emulsion

Here, we designed an oxidized starch/β-lactoglobulin (OS/β-lg) complex colloidal particle using a dual-channel microfluidic chip for the stabilization of astaxanthin emulsion. The effect of the mixing ratio, pH, and the degree of substitution (DS) of the oxidized starch on the formation of OS/β-lg complex particles was investigated in detail. The optimal complexation occurred at a pH of 3.6, a mixing ratio of 2:10, and a DS of 0.72%, giving an ideal colloidal particle with near-neutral wettability. With this optimum agent, the astaxanthin-loaded oil-in-water emulsions were successfully prepared. The obtained emulsions showed the typical non-Newton fluid behavior, and the rheological data met the Herschel–Bulkley model. The microscopic images confirmed the dense adsorption of the particle on the oil/water interface. In vitro release and stability studies demonstrated this compact layer contributed to the controlled-release and excellent stability of astaxanthin emulsions facing heat, ultraviolet, and oxidative intervention. This work suggests the potential of microfluidics for the production of food-grade solid emulsifiers.

Fabrication of chitosan-protocatechuic acid conjugates to inhibit lipid oxidation and improve the stability of β-carotene in Pickering emulsions: Effect of molecular weight of chitosan

In this study, chitosan (CS) with different molecular weights was functionalized with protocatechuic acid (PA) by free-radical grafting reaction, and used for the inhibition of lipid oxidation and the enhancement of stability of β-carotene in Pickering emulsions. The order of grafting ratio of PA in CS-PA conjugates was CS400 (400 kDa CS) > CS200 (200 kDa CS) > CS100 (100 kDa CS). UV-vis, FT-IR and ¹H NMR spectra proved that PA was covalently bonded to CS through amino and ester linkages. Compared with native CS, three CS-PA conjugates exhibited reduced crystallinity and thermal stability and improved antioxidant activity, with a molecular weight-dependent relationship. Besides, CS-PA-conjugate particles formed by ionic gelling procedure were spherically shaped and homogeneously dispersed, which substantially improved the stability of β-carotene in Pickering emulsions than CS particles under ultraviolet irradiation, natural light exposure and heat treatment, and the retention rates of β-carotene were in the following order: CS200-PA- > CS400-PA- > CS100-PA-conjugate particles. Furthermore, the oxidation stability of Pickering emulsions fabricated by CS-PA-conjugate particles was also higher than that of CS particles. These results will provide valuable information for the application of CS-PA conjugates to protect bioactive components and inhibit lipid oxidation in emulsion systems.

Recent progresses in the delivery of β-carotene: From nano/microencapsulation to bioaccessibility

Beta-carotene (BC) as an efficient pro-vitamin is effective in improving vision, immune system and cognitive function as well as preventing coronary diseases and cancer. However, besides its poor chemical stability, the high lipophilic nature of BC reduces its dispersibility and consequently bioavailability which limits its application into food, pharmaceutical and nutraceuticals. Different carriers with vesicular or particulate structures have been studied and utilized for promoting BC solubility, dispersibility, and protection against diverse operational or environmental stresses and also controlling BC release and subsequent bioaccessibility. The current study, therefore reviews different micro/nanocarriers reported on BC encapsulation with special focusing on its bioavailability. Liposomal structures have been successfully used for enhancing BC stability and bioavailability. Besides, emulsion-based carriers including Pickering emulsions, nanoemulsions and microemulsions have been widely evaluated for BC encapsulation and protection. In addition, lipid-based nanoparticles and nanostructural carriers have also been applied successfully for this context. Moreover, gel structures including emulgels, hydrogels and oleogels are studied in some researches. Most of these delivery systems led to higher hydro-solubility and dispersibility of BC which consequently increased its bioavailability; thereupon could promote its application into food, cosmetic and nutraceutical products. However, for remarkable incorporation of BC and other bioactive compounds into edible products, the safety and toxicological aspects of these delivery system especially those designed in nano scale should be addressed in the further researches.

Zein/pullulan complex colloidal particle-stabilized Pickering emulsions for oral delivery of polymethoxylated flavones: protection effect and in vitro digestion

BACKGROUND

Polymethoxylated flavones (PMFs) show multiple biological functions, while their high hydrophobicity leads to a low bioaccessibility and limits their wide applications. The design of a reasonable food-grade drug delivery system is an effective strategy to improve the low bioaccessibility of PMFs. In this study, sinensetin, tangeretin and nobiletin were encapsulated in Pickering emulsions stabilized by zein/pullulan complex colloidal particles (ZPPs), and the protection effect and in vitro digestion were characterized.

RESULTS

Rheological analysis revealed that ZPP-Pickering emulsion loading with PMFs maintained a strong gel-like network structure. Moreover, the ability to scavenge free radicals of PMFs was improved by the emulsion delivery system. The antioxidant activity of PMFs encapsulated in Pickering emulsion was positively correlated with the oil volume fraction (φ). ZPP-Pickering emulsion loading with PMFs can effectively delay lipid oxidation, and the φ (70%) of Pickering emulsion showed the most pronounced effects, in which the lipid hydroperoxide content and malondialdehyde content decreased by 64.3% and 38.3% after 15 days of storage, compared with the bulk oil group, respectively. The bioaccessibility of the three PMFs has been increased by ZPP-Pickering emulsion simultaneously and it presented the highest values as its φ was 50%, in which the bioaccessibility of sinensetin, tangeretin and nobiletin increased by 2.5, 3.2 and 3.9 times, compared with the bulk oil group, respectively.

CONCLUSION

Pickering emulsion stabilized by ZPPs is an excellent nutrient delivery system for delivering three PMFs simultaneously and imparting functional properties to bioactive delivery systems. © 2022 Society of Chemical Industry.

In Vitro Digestion and Storage Stability of β-Carotene-Loaded Nanoemulsion Stabilized by Soy Protein Isolate (SPI)-Citrus Pectin (CP) Complex/Conjugate Prepared with Ultrasound

In this study, we employed the ultrasound-prepared electrostatic complex and covalent conjugate of soy protein isolate (SPI) and citrus pectin (CP) to prepare β-carotene-loaded nanoemulsions. The in vitro digestion and storage stability of nanoemulsions stabilized by different types of emulsifiers were investigated and compared. Nanoemulsions stabilized by ultrasound-treated complex/conjugate showed the highest encapsulation efficiency; during gastric digestion, these nanoemulsions also demonstrated the smallest droplet sizes and the highest absolute values of zeta potential, indicating that both electrostatic complexation/covalent conjugation and ultrasound treatment could significantly improve the stability of the resulting nanoemulsions. In comparison, complexes were more beneficial for the controlled release of β-carotene; however, the conjugate-stabilized nanoemulsion showed an overall higher bioaccessibility. The results were also confirmed by optical micrographs. Furthermore, nanoemulsions stabilized by ultrasound-prepared complexes/conjugates exhibited the highest stability during 14-day storage at 25 °C. The results suggested that ultrasound-prepared SPI–CP complexes and conjugates had great application potential for the delivery of hydrophobic nutrients.

Development of Millettia speciosa champ polysaccharide conjugate stabilized oil-in-water emulsion for oral delivery of β-carotene: Protection effect and in vitro digestion fate

In this study, a natural antioxidant emulsifier, Millettia speciosa Champ polysaccharide conjugates (MSC-PC), was used for fabricating oil-in-water emulsion, and the influences of MSC-PC on β-carotene stability and bioaccessibility were studied. Results suggested that MSC-PC stabilized emulsion exhibited excellent resistance to a wide range of salt levels (0-500 mM of Na⁺), thermal treatments (50-90 °C) and pH values (3.0-11.0). MSC-PC also exhibited an outstanding inhibition capacity on lipid oxidation. Besides, MSC-PC stabilized emulsion had a better protective effect on β-carotene than other systems. Interestingly, in spite of similar lipolysis extent, β-carotene bioaccessibility in MSC-PC fabricated emulsion (14.75 %) was markedly higher than that in commercial Tween 80 fabricated emulsion (10.08 %), likely due to the steric-hindrance effect and antioxidant ability of MSC-PC, building interfacial layers that prevented β-carotene from degradation. This work supplied a deep insight into elucidating the mechanisms of emulsifying performance and β-carotene protection effect of MSC-PC fabricated emulsion.