Fabrication and characterization of soybean oil bodies encapsulated in maltodextrin and chitosan-EGCG conjugates: An in vitro digestibility study

Chitosan-Based Oleogels: Emulsion Drying Kinetics and Physical, Rheological, and Textural Characteristics of Olive Oil Oleogels

Oleogels are of high interest as promising substitutes for trans fats in foods. An emulsion-templated method was used to trap olive oil in the chitosan crosslinked with vanillin matrix. Oil in water emulsions (50:50 w/w) with different chitosan content (0.7 and 0.8% w/w) with a constant vanillin/chitosan ratio (1.3) were air-dried at different temperatures (50, 60, 70, and 80 °C) and freeze-dried (-26 °C and 0.1 mbar) to produce oleogels. Only falling rate periods were determined during air-drying kinetics and were successfully modeled with empirical and diffusional models. At a drying temperature of 70 °C, the drying kinetics were the fastest. The viscoelasticity of oleogels showed that the elastic modulus significantly increased after drying at 60 and 70 °C, and those dried at 50 °C and freeze-dried were weaker. All oleogels showed high oil binding capacity (>91%), but the highest values (>97%) were obtained in oleogels with a threshold elastic modulus (50,000 Pa). The oleogels' color depended on the drying temperature and chitosan content (independent of the drying method). Significant differences were observed between air-dried and freeze-dried oleogels with respect to oxidative stability. Oxidation increased with the air-drying time regardless of chitosan content. The found results indicated that drying conditions must be carefully selected to produce oleogels with specific features.

Chitosan derivatives act as a bio-stimulants in plants: A review

Chitosan has been considered an eco-friendly biopolymer. Chitosan is a natural polycationic linear polysaccharide composed of D-glucosamine and N-acetyl-D-glucosamine linked by β-1,4-glycosidic bonds. Chitosan has been used as an eco-friendly biopolymer for so many agricultural applications. Unfortunately, the relatively poor solubility and poor antimicrobial properties limit its widespread applications in agriculture sciences. Hence, chitosan derivatives are produced via various chemical approaches such as cross-linking, carboxylation, ionic binding, and so on. As an alternative to chemical fertilizers, chitosan derivatives, chitosan conjugates, nanostructures, semisynthetic derivatives, oligo mixes, chitosan nanoparticles, and chitosan nano-carriers are synthesized for various agricultural applications. Its several chemical and physical properties such as biocompatibility, biodegradability, permeability, cost-effectiveness, low toxicity, and environmental friendliness make it useful for many agricultural applications. Hence, popularizing its use as an elicitor molecule for different host-pathogen interaction studies. Thus, the versatile and plethora of chitosan derivatives are gaining momentum in agricultural sciences. Bio-stimulant properties and multifunctional benefits are associated with further prospective research. Therefore, in the present review, we decipher the potential pros and cons of chitosan derivatives in plants.

Construction of protein-, polysaccharide- and polyphenol-based conjugates as delivery systems

Natural polymers, such as polysaccharides and proteins, have been used to prepare several delivery systems owing to their abundance, bioactivity, and biodegradability. They are usually modified or combined with small molecules to form the delivery systems needed to meet different needs in food systems. This paper reviews the interactions of proteins, polysaccharides, and polyphenols in the bulk phase and discusses the design strategies, coupling techniques, and their applications as conjugates in emulsion delivery systems, including traditional, Pickering, multilayer, and high internal-phase emulsions. Furthermore, it explores the prospects of the application of conjugates in food preservation, food development, and nanocarrier development. Currently, there are seven methods for composite delivery systems including the Maillard reaction, carbodiimide cross-linking, alkali treatment, enzymatic cross-linking, free radical induction, genipin cross-linking, and Schiff base chemical cross-linking to prepare binary and ternary conjugates of proteins, polysaccharides, and polyphenols. To design an effective target complex and its delivery system, it is helpful to understand the physicochemical properties of these biomolecules and their interactions in the bulk phase. This review summarizes the knowledge on the interaction of biological complexes in the bulk phase, preparation methods, and the preparation of stable emulsion delivery system.

Effect of Heat Treatment on the Digestive Characteristics of Different Soybean Oil Body Emulsions

Soybean oil body (SOB) emulsions were prepared using OBs extracted at pH 11.0 and pH 7.0. The pH 11.0-SOB comprised oleosins, whereas pH 7.0-SOB comprised extrinsic proteins and oleosins. All SOB emulsions were heated at 60-100 °C for 15 min. Heating may lead to the release of extrinsic proteins from the surface of pH 7.0-SOB due to heat-induced denaturation. The total proportion of α-helix and β-sheets gradually decreased from 77 (unheated) to 36.2% (100 °C). During stomach digestion, the extrinsic protein hydrolysis of heated pH 7.0-SOB emulsions was fast between 60 and 80 °C, and it then slowed between 90 and 100 °C; heating inhibited the oleosin hydrolysis of pH 7.0- and 11.0-SOBs. Heat treatment promoted aggregation and coalescence, and it resulted in increased particle sizes for all emulsions. Larger aggregates were found in heated pH 7.0-SOB emulsions, and larger oil droplets were found in heated pH 11.0-SOB emulsions. After intestinal digestion, the droplets of all SOB emulsions gradually dispersed, and particle sizes decreased. Different heating temperatures had lesser effects on particle sizes and microstructures. Lipolysis was affected by the extraction pH and heating. For pH 11.0-SOB emulsions, the FFA release tendency was greatly affected by the heating temperature, and heating to 80 °C resulted in the highest FFA release (74%). However, all pH 7.0-SOB emulsions had similar total FFA releases. In addition, the droplet charges of heated pH 7.0-SOB emulsions were lower than those of unheated pH 7.0-SOB emulsions in both the intestine and stomach phases; however, the charge changes in different pH 11.0-SOB emulsions showed the opposite tendency. This study will offer guidance regarding the application of SOB emulsions in food.

Stability of glycosylated complexes loaded with Epigallocatechin 3-gallate (EGCG)

The application of Epigallocatechin-3-gallate (EGCG) in food industry was limited by its low stability in aqueous solutions and poor bioavailability in vivo. The novel EGCG glycosylated arachin nanoparticles (Ara-CMCS-EGCG) and EGCG glycosylated casein nanoparticles (Cas-CMCS-EGCG) were prepared to improve the stability and bioavailability of EGCG. The effect of different variables on the storage stability and the slow-release behavior of novel glycosylation complexes in nanoparticle background solution and artificial gastrointestinal fluid were investigated. The results showed that the DPPH scavenging activity of Ara-CMCS-EGCG and Cas-CMCS-EGCG were stable in temperature (25 ∼ 70 °C). EGCG could enhance the crosslinking effect of molecular particles in glycosylation complexes solution. The glycosylated protein nanoparticles were stable to acid-base and enzymolysis in simulated gastrointestinal fluid. The release rate of EGCG in simulated intestinal fluid was higher than that in simulated gastric fluid. The glycosylated protein carrier can not only release EGCG slowly, but also significantly improve the stability and bioavailability of EGCG in simulated gastrointestinal fluid.

Enhancing the Stability and Bioaccessibility of Tree Peony Seed Oil Using Layer-by-Layer Self-Assembling Bilayer Emulsions

Tree peony seed oil (TPSO) is an important plant source of n-3 polyunsaturated fatty acid (α-linolenic acid, ALA > 40%) that is receiving increasing attention for its excellent antioxidant and other activities. However, it has poor stability and bioavailability. In this study, a bilayer emulsion of TPSO was successfully prepared using a layer-by-layer self-assembly technique. Among the proteins and polysaccharides examined, whey protein isolate (WPI) and sodium alginate (SA) were found to be the most suitable wall materials. The prepared bilayer emulsion contained 5% TPSO, 0.45% whey protein isolate (WPI) and 0.5% sodium alginate (SA) under selected conditions and its zeta potential, droplet size, and polydispersity index were -31 mV, 1291 nm, and 27%, respectively. The loading capacity and encapsulation efficiency for TPSO were up to 84% and 90.2%, respectively. It was noteworthy that the bilayer emulsion showed significantly enhanced oxidative stability (peroxide value, thiobarbituric acid reactive substances content) compared to the monolayer emulsion, which was accompanied by a more ordered spatial structure caused by the electrostatic interaction of the WPI with the SA. This bilayer emulsion also exhibited markedly improved environmental stability (pH, metal ion), rheological properties, and physical stability during storage. Furthermore, the bilayer emulsion was more easily digested and absorbed, and had higher fatty acid release rate and ALA bioaccessibility than TPSO alone and the physical mixtures. These results suggest that bilayer emulsion containing WPI and SA is an effective TPSO encapsulation system and has significant potential for future functional food development.

Oil body extraction from high-fat and high-protein soybeans by laccase cross-linked beet pectin: physicochemical and oxidation properties

BACKGROUND

Soybean oil bodies (SOB) are droplets of natural emulsified oil. Soybean oil emulsifies well but it is easily oxidized during storage. Beet pectin is a complex anionic polysaccharide, which can be adsorbed on the surface of liposomes to improve their resistance to flocculation. Laccase can covalently cross-link ferulic acid in beet pectin, and its structure is irreversible, which can improve the stability of polysaccharides.

RESULTS

At pH 2.5, laccase cross-linked beet pectin high-oil soybean oil body (HOSOB) and high-protein soybean oil body (HPSOB) emulsions showed obvious aggregation and severe stratification, and the oxidation of the emulsions was also high. The flocculation of emulsions decreased with an increase in the pH. The effect of pH on the flocculation of emulsion was confirmed by confocal laser electron microscopy. The ζ potential, emulsification, and rheological shear force increased with increasing pH whereas the particle size and surface hydrophobicity decreased with increasing pH.

CONCLUSION

This experiment indicates that the physicochemical stability of the two composite emulsions was strongly affected under acidic conditions but stable under neutral and weakly alkaline conditions. Under the same acid-base conditions, the degree of oxidation of HPSOB composite emulsion changes substantially. The results of this study can provide a basis for the design of very stable emulsions to meet the demand for natural products. © 2023 Society of Chemical Industry.

Effect of maltodextrin on the oxidative stability of ultrasonically induced soybean oil bodies microcapsules

Introduction

Encapsulation of soybean oil bodies (OBs) using maltodextrin (MD) can improve their stability in different environmental stresses and enhance the transport and storage performance of OBs.

Methods

In this study, the effects of different MD addition ratios [OBs: MD = 1:0, 1:0.5, 1:1, 1:1.5, and 1:2 (v/v)] on the physicochemical properties and oxidative stability of freeze-dried soybean OBs microcapsules were investigated. The effect of ultrasonic power (150–250 W) on the encapsulation effect and structural properties of oil body-maltodextrin (OB-MD) microcapsules were studied.

Results

The addition of MD to OBs decreased the surface oil content and improved the encapsulation efficiency and oxidative stability of OBs. Scanning electron microscopy images revealed that the sonication promoted the adsorption of MD on the surface of OBs, forming a rugged spherical structure. The oil-body-maltodextrin (OB-MD) microcapsules showed a narrower particle size distribution and a lower-potential absolute value at an MD addition ratio of 1:1.5 and ultrasonic power of 250 W (32.1 mV). At this time, MD-encapsulated OBs particles had the highest encapsulation efficiency of 85.3%. Ultrasonic treatment improved encapsulation efficiency of OBs and increased wettability and emulsifying properties of MD. The encapsulation of OBs by MD was improved, and its oxidative stability was enhanced by ultrasound treatment, showing a lower hydrogen peroxide value (3.35 meq peroxide/kg) and thiobarbituric acid value (1.65 μmol/kg).

Discussion

This study showed that the encapsulation of soybean OBs by MD improved the stability of OBs microcapsules and decreased the degree of lipid oxidation during storage. Ultrasonic pretreatment further improved the encapsulation efficiency of MD on soybean OBs, and significantly enhanced its physicochemical properties and oxidative stability.

Storage stability and in vitro digestion of apigenin encapsulated in Pickering emulsions stabilized by whey protein isolate–chitosan complexes

Few studies have investigated the encapsulation of apigenin in solid particle-stabilized emulsions. In this work, Pickering emulsions containing apigenin and stabilized by whey protein isolate-chitosan (WPI-CS) complexes were created to enhance the bioavailability of apigenin. Different lipids including medium-chain triglycerides (MCTs), ethyl oleate (EO), and corn oil (CO) were selected to fabricate lipid-based delivery systems. The microstructure of the Pickering emulsions, as revealed by optical and cryo-scanning electron microscopies, showed that the oil droplets were dispersed evenly and trapped by a three-dimensional network formed by the WPI-CS complexes, which was further confirmed by rheology properties. After 30 days of storage, Pickering emulsions with MCTs achieved the highest apigenin retention rate, exhibiting 95.05 ± 1.45% retention when stored under 4°C. In vitro gastrointestinal tract experiments indicated that the lipid types of the emulsions also affected the lipid digestion and release rate of apigenin. Pickering emulsions with MCTs achieved a higher bioaccessibility compared to that of the other two emulsions (p < 0.01). These results indicate that the delivery system of Pickering emulsions with MCTs stabilized by WPI-CS complexes offers good storage stability and improved bioaccessibility of apigenin.

Soy oil and SPI based-oleogels structuring with glycerol monolaurate by emulsion-templated approach: Preparation, characterization and potential application

In this study, soybean oil-based oleogels were prepared using soy-protein isolate (SPI) and glycerol monolaurate (GML) in an emulsion-template approach. The rheological, texture, microstructure, and oil-retention properties of the obtained oleogels were analyzed. Results showed that the soy oil-based oleogel prepared with 6 wt% GML exhibited high oil loss, low-hardness, and needle-like morphology compared to the soy-oil/SPI-based oleogel. On the other hand, soy oil-based /SPI-based oleogels structured by 3 or 6 wt% GML presented moderate thermal-stability and lowest oil loss than those prepared without GML. Furthermore, SPI-based oleogel containing 6 wt% GML showed highest free fatty acids release (62.07%) with significantly improved elastic modulus and apparent viscosity. Additionally, the obtained oleogels displayed the occurrence of van der Waals interactions and intermolecular hydrogen bonds, presenting enhanced thermal stability. These results contribute to a better understanding of oleogelation-based emulsions for formulating trans-free and low-saturated foodstuffs with desired physical and functional properties.

Food-Grade Microencapsulation Systems to Improve Protection of the Epigallocatechin Gallate

Epigallocatechin gallate (EGCG) is a catechin and one of the most abundant polyphenols in green tea, and it is under research for its potential benefit to human health and for its potential to be used in disease treatments, such as for cancer. However, the effectiveness of polyphenols depends on preserving their bioactivity, stability, and bioavailability. The EGCG was microencapsulated by a spray-drying process, using different biopolymers as encapsulating agents (gum arabic, modified chitosan and sodium alginate), in order to overcome some of the limitations of this compound. The microparticles showed a diameter around 4.22 to 41.55 µm (distribution in volume) and different morphologies and surfaces, depending on the encapsulating agent used. The EGCG release was total, and it was achieved in less than 21 min for all the formulations tested. The EGCG encapsulation efficiency ranged between 78.5 and 100.0%. The release profiles were simulated and evaluated using three kinetic models: Korsmeyer-Peppas (R²: 0.739-0.990), Weibull (R²: 0.963-0.994) and Baker-Lonsdale (R²: 0.746-0.993). The Weibull model was the model that better adjusted to the experimental EGCG release values. This study proves the success of the EGCG microencapsulation, using the spray-drying technique, opening the possibility to insert dried EGCG microparticles in different food and nutraceutical products.

Recent advances on formation mechanism and functionality of chitosan-based conjugates and their application in o/w emulsion systems: A review

Chitosan is very attractive in the food industry due to its good biocompatibility and high biodegradability. In particular, it can be used as a preferred material for the fabrication of stabilizers in emulsion-based foods. However, poor solubility and antioxidant activity limit its wide application. The functionality of chitosan can be extended by forming chitosan-based conjugates, which can be used to modulate the characteristics of the oil-water interface, thereby improving the stability and performance of the o/w emulsions. This review highlights the recent progress of chitosan-based conjugates, focusing on the classification, formation mechanism and functional properties, and the applications of these conjugates in o/w emulsions are summarized. Lastly, the promising research trends and challenges of chitosan-based conjugates and their emulsion systems in this field are also discussed. This review will provide a theoretical basis for the wide application of chitosan-based conjugates in emulsion systems.

Polysaccharides as wall materials in spray-dried microencapsulation of bioactive compounds: Physicochemical properties and characterization

Natural bioactive compounds (BCs) are types of chemicals found in plants and certain foods that promote good health, however they are sensitive to processing and environmental conditions. Microencapsulation by spray drying is a widely used and cost-effective approach to create a coating layer to surround and protect BCs and control their release, enabling the production of high functional products/ingredients with extended shelf life. In this process, wall materials determine protection efficiency, and physical properties, bioavailability, and storage stability of microencapsulated products. Therefore, an understanding of physicochemical properties of wall materials is essential for the successful and effective spray-dried microencapsulation process. Typically, polysaccharide-based wall materials are generated from more sustainable sources and have a wider range of physicochemical properties and applications compared to their protein-based counterparts. In this review, we highlight the essential physicochemical properties of polysaccharide-based wall materials for spray-dried microencapsulation of BCs including solubility, thermal stability, and emulsifying properties, rheological and film forming properties. We provide further insight into possibilities for the chemical structure modification of native wall materials and their controlled release behaviors. Finally, we summarize the most recent studies involving polysaccharide biopolymers as wall materials and/or emulsifiers in spray-dried microencapsulation of BCs.

Sodium Dodecyl Sulfate-Dependent Disassembly and Reassembly of Soybean Lipophilic Protein Nanoparticles: An Environmentally Friendly Nanocarrier for Resveratrol

The development of protein-based nanocarriers to improve the water solubility, stability, and bioavailability of hydrophobic or poorly soluble bioactive molecules has attracted increasing interest in the food and pharmaceutical industries. In this study, a network-like nanostructure of soybean lipophilic protein (LP) was obtained through sodium dodecyl sulfate (SDS)-dependent decomposition and recombination. This nanostructure served as an excellent nanocarrier for resveratrol (Res), a poorly soluble biologically active molecule. The structure of LP gradually decomposed into its independent subunits at SDS concentrations ≤5% (w/v). After the removal of SDS, the dissociated subunits partially reassembled into a fibrous network-like nanostructure in which the Res molecules were encapsulated, and they preferentially interacted with the hydrophobic subunits (α and α' subunits and the 24 kDa subunit) of the protein. This system exhibited a high encapsulation efficiency (95.93%), high water solubility (85.29%), extraordinary oxidation resistance (DPPH radical scavenging activity of 67.1%), and improved Res digestibility (78.7%).

Effects of different surfactants on the conjugates of soybean protein-polyphenols for the preparation of β-carotene microcapsules

In this study, we investigated the spray-drying microencapsulation of β-carotene in oil co-stabilized by soy protein isolate-epigallocatechin-3-gallate conjugate (SPE) and small molecule surfactants [sodium dodecyl sulfate (SDS), hexadecyl trimethyl ammonium bromide (CTAB), and tea saponin (TS)] of different concentrations [0.1, 0.5, and 1.0% (w/v)], as a prospective approach to stabilize β-carotene. The results show that different surfactant types and concentrations significantly affect the encapsulation efficiency, water dispersibility, microstructure, and digestion of the microcapsules. Interactions between the surfactants and the SPE at the interface were found to include both synergistic and competitive effects, and they depended on the surfactant type and concentration. Moreover, the addition of SDS and TS before spray drying significantly improved the microencapsulation performance of the microcapsules and the water dispersion behavior of the corresponding spray-dried powders. The highest encapsulation efficiency was achieved for the SPE-0.1TS-encapsulated β-carotene microcapsules. In contrast, the addition of CTAB was not conducive to microcapsule formation, resulting in poor encapsulation efficiency, water dispersibility, thermal stability, β-carotene retention rate, and oxidation stability. In vitro gastrointestinal digestion results revealed that the addition of CTAB promotes the release of β-carotene and improves the bioaccessibility of β-carotene. In contrast, except for SPE-1.0SDS, the addition of SDS and TS inhibited β-carotene release and reduced β-carotene bioaccessibility. This study demonstrated that this novel β-carotene encapsulation formulation can overcome stability limitations for the development of β-carotene supplements with a high bioaccessibility.

Establishment and Characterization of Stable Zein/Glycosylated Lactoferrin Nanoparticles to Enhance the Storage Stability and in vitro Bioaccessibility of 7,8-Dihydroxyflavone

In this work, the lactoferrin (LF) was glycosylated by dextran (molecular weight 10, 40, and 70 kDa, LF 10K, LF 40K, and LF 70K) via Maillard reaction as a stabilizer to establish zein/glycosylated LF nanoparticles and encapsulate 7,8-dihydroxyflavone (7,8-DHF). Three zein/glycosylated LF nanoparticles (79.27–87.24 nm) with low turbidity (<0.220) and polydispersity index (PDI) (<0.230) were successfully established by hydrophobic interactions and hydrogen bonding. Compared with zein/LF nanoparticles, zein/glycosylated LF nanoparticles further increased stability to ionic strength (0–500 mM NaCl) at low pH conditions. Zein/glycosylated LF nanoparticles had nanoscale spherical shape and glycosylated LF changed surface morphology of zein nanoparticles. Besides, encapsulated 7,8-DHF exhibited an amorphous state inside zein/glycosylated LF nanoparticles. Most importantly, zein/glycosylated LF nanoparticles had good water redispersibility, high encapsulation efficiency (above 98.50%), favorable storage stability, and bioaccessibility for 7,8-DHF, particularly LF 40K. Collectively, the above research provides a theoretical reference for the application of zein-based delivery systems.

Soybean Oil Enriched with Antioxidants Extracted from Watermelon (Citrullus colocynthis) Skin Sap and Coated in Hydrogel Beads via Ionotropic Gelation

Many plants and fruits are rich in antioxidant and antimicrobial compounds, such as phenolic compounds. Watermelon is one example, as various parts of the fruit present interesting phytochemical profiles. This study demonstrates that a natural C. colocynthis (watermelon) (W) skin sap (SS) extract can effectively improve the oxidative stability of microencapsulated soybean (SB) oil. By employing a combination of alginate–xanthan gums (AXG) in a matrix hydrogel bead model with WSS extract, high encapsulation efficiency can be obtained (86%). The effects of process variables on the ultrasound-assisted extraction (UAE) of phenolic compounds from watermelon (W) skin sap (SS) using the response surface methodology (RSM), as an optimized and efficient extraction process, are compared with the effects of a conventional extraction method, namely the percolation method. The WSS extracts are obtained via UAE and RSM or the conventional percolation extraction method. The two obtained extracts and synthetic antioxidant butylated hydroxytolune (BHT) are added to SB oil separately and their antioxidant effects are tested and compared. The results show the improved oxidative stability of SB oil containing the extract obtained via the optimized method (20–30%) compared to the SB oil samples containing extract obtained via the percolation extraction method, synthetic antioxidant (BHT), and SB oil only as the control (no antioxidant added). According to existing studies, we assume that the use of WSS as an effective antioxidant will ensure the prolonged stability of encapsulated SB oil in hydrogel beads, as it is well known that extended storage under different conditions may lead to severe lipid oxidation.

Preparation of β-lactoglobulin/gum arabic complex nanoparticles for encapsulation and controlled release of EGCG in simulated gastrointestinal digestion model

In this work, the β-lactoglobulin/gum arabic (β-Lg-GA) complexes were prepared to encapsulate epigallocatechin gallate (EGCG), forming β-Lg-GA-EGCG complex nanoparticles with an average particle size of 133 nm. The β-Lg-GA complexes exhibited excellent encapsulation efficiency (84.5%), and the antioxidant performance of EGCG in vitro was improved after encapsulation. It was recorded that 86% of EGCG could be released in simulated intestinal fluid after 3 h of digestion, much faster than that in simulated gastric fluid, indicating that the β-Lg-GA complexes were effective in enhancing EGCG stability, which was confirmed using SDS-PAGE and SEM. Further spectrum results demonstrated that various intramolecular interactions including electrostatic, hydrophobic and hydrogen bonding interactions contribute to the formation of β-Lg-GA-EGCG complex nanoparticles. Also, XRDexperiments indicated that EGCG was successfully encapsulated by β-Lg-GA complexes. Therefore, the β-Lg-GA complexes hold great potentials in the protective delivery of sensitive bioactives.

Establishment of a stable complex formed from whey protein isolate and chitosan and its stability under environmental stresses

This study aimed to investigate the stability of a complex formed with whey protein isolate (WPI) and chitosan under environmental stress. The optical density, particle size, zeta potential, chemical characteristics, electrostatic interactions, and surface morphology were evaluated for the stable complexes; the optimum conditions for the generation of the stable complex were 0.2% (wt/wt) whey protein with 0.05% (wt/wt) chitosan at pH 5.7. Under these conditions, the complex particle size was 217.8 ± 11.3 nm and the zeta potential was 16.7 ± 0.92 mV. The complex was formed through electrostatic interactions between the amine groups of chitosan (-NH₃⁺) and carboxyl groups of whey protein (-COO^-), and contained a porous network interspaced by heterogeneously sized vacuoles. The complex displayed stable physiochemical characteristics under environmental stresses including NaCl (0-75 mM) or sugar (0-5%) at ambient temperature and upon heating for 15 min at 25-65 °C, up to 65 °C for 30 min. Moreover, the complex could be stably stored for 30 d at 4 °C and for 20 d at 25 °C. The present results provide theoretical insights into the industrial production of chitosan-protein complexes and for microencapsulation of sensitive food or medicinal ingredients to increase their intestinal absorption.

Pacific white shrimp (Litopenaeus vannamei) shell chitosan and the conjugate with epigallocatechin gallate: Antioxidative and antimicrobial activities

Chitin was isolated from Pacific white shrimp (Litopenaeus vannamei) shell by demineralization and deproteinization using 1 M HCl (1:20, w/v) for 2 hr and 1 M NaOH (1:30 w/v) for 80 min at 70ºC, respectively, with 29.96% optimum yield. Thereafter, the chitin was deacetylated at various temperatures for different times, in which the chitosan prepared at 130ºC for 4 hr (CS-130-4) showed higher yield (73.11%), crystallinity index (19.75%), and 85.28% degree of deacetylation (DDA) as measured by ¹ H-NMR. CS-130-4 was then conjugated to epigallocatechin gallate (EGCG) at various concentrations (2-8%, w/w of chitosan). CS-130-4 was grafted with 8% EGCG (CE-8) had the higher conjugation efficiency (92.63%) and antimicrobial/antioxidant activities as compared to other conjugates (p < .05). ¹ H-NMR analysis also confirmed the successful conjugation of CE-8. All the conjugates were completely water soluble. Therefore, CE-8 may be used as the natural antimicrobial and antioxidant agents in various food products. PRACTICAL APPLICATIONS: Shrimp shells are generally considered as processing by-products of the shellfish industries and can cause environmental pollution when improperly disposed. Chitosan from shrimp shells has been widely produced but it is soluble mainly in acidic solutions, which limits its applications. However, grafting of epigallocatechin gallate (EGCG) onto chitosan yielded water-soluble conjugates with enhanced antioxidant and antimicrobial properties. Although several preservatives have been applied in foods, their health hazards have been a major concern. To mitigate this limitation, chitosan-EGCG conjugates could be employed as alternative natural preservatives or additives for shelf-life extension of various foods.

Nature-Assembled Structures for Delivery of Bioactive Compounds and Their Potential in Functional Foods

Consumers are demanding more natural, healthy, and high-quality products. The addition of health-promoting substances, such as bioactive compounds, to foods can boost their therapeutic effect. However, the incorporation of bioactive substances into food products involves several technological challenges. They may have low solubility in water or poor stability in the food environment and/or during digestion, resulting in a loss of their therapeutic properties. Over recent years, the encapsulation of bioactive compounds into laboratory-engineered colloidal structures has been successful in overcoming some of these hurdles. However, several nature-assembled colloidal structures could be employed for this purpose and may offer many advantages over laboratory-engineered colloidal structures. For example, the casein micelles and milk fat globules from milk and the oil bodies from seeds were designed by nature to deliver biological material or for storage purposes. These biological functional properties make them good candidates for the encapsulation of bioactive compounds to aid in their addition into foods. This review discusses the structure and biological function of different nature-assembled carriers, preparation/isolation methods, some of the advantages and challenges in their use as bioactive compound delivery systems, and their behavior during digestion.

Antimicrobial Chitosan Conjugates: Current Synthetic Strategies and Potential Applications

As a natural polysaccharide, chitosan possesses good biocompatibility, biodegradability and biosafety. Its hydroxyl and amino groups make it an ideal carrier material in the construction of polymer-drug conjugates. In recent years, various synthetic strategies have been used to couple chitosan with active substances to obtain conjugates with diverse structures and unique functions. In particular, chitosan conjugates with antimicrobial activity have shown great application prospects in the fields of medicine, food, and agriculture in recent years. Hence, we will place substantial emphasis on the synthetic approaches for preparing chitosan conjugates and their antimicrobial applications, which are not well summarized. Meanwhile, the challenges, limitations, and prospects of antimicrobial chitosan conjugates are described and discussed.

Plant-based Milks: A Review of the Science Underpinning Their Design, Fabrication, and Performance

Many consumers are interested in decreasing their consumption of animal products, such as bovine milk, because of health, environmental, and ethical reasons. The food industry is therefore developing a range of plant-based milk alternatives. These milk substitutes should be affordable, convenient, desirable, nutritional, and sustainable. This article reviews our current understanding of the development of plant-based milks. Initially, an overview of the composition, structure, properties, and nutritional profile of conventional bovine milk is given, because the development of successful alternatives depends on understanding the characteristics of real milk. The two main production routes for fabricating plant-based milks are then highlighted: (i) disruption of plant materials (such as nuts, seeds, or legumes) to form aqueous suspensions of oil bodies; (ii) formation of oil-in-water emulsions by homogenization of oil, water, and emulsifiers. The roles of the different functional ingredients in plant-based milks are highlighted, including oils, emulsifiers, thickeners, antioxidants, minerals, and other additives. The physicochemical basis of the appearance, texture, and stability of plant-based milks is covered. The importance of the sensory attributes and gastrointestinal fate of bovine milk and plant-based alternatives is also highlighted. Finally, potential areas for future work are discussed.