Formation of a novel coating material containing lutein and zeaxanthin via a Maillard reaction between bovine serum albumin and fucoidan

Fucoidan and chitosan electrostatically coated nanoliposomes enhance physicochemical stability and bioavailability of rutin

Rutin, a promising bioactive hydrophobic compound, suffers from poor physicochemical stability, resulting in low bioavailability. Herein, we used positively charged chitosan and negatively charged fucoidan as biopolymers coating rutin-nanoliposome (RNL) via electrostatic layer-by-layer self-assembly approach to prepare fucoidan/chitosan-coated rutin-nanoliposome (FC-RNL). The FC-RNL exhibited the encapsulation efficiency of 77.01% for rutin, with the particle size of 346 nm and a zeta potential of -33.5 mV under the optimized conditions (lecithin to rutin ratio of 10, 0.05 wt% fucoidan and 0.20 wt% chitosan). The results of Fourier transform infrared, X-ray diffraction, and transmission electron microscopy suggested that fucoidan/chitosan-coated nanoliposome could effectively load rutin. The coating of fucoidan and chitosan not only improved the retention rate of rutin (> 85 %) under thermal, oxidative and UV-light conditions, but also showed excellent stability over a wide pH range (pH 3.0-11.0) and high ionic strength (400 mM NaCl). In addition, FC-RNL was more stable than C-RNL and RNL at 4 °C for 5-week storage. In vitro simulated digestion indicated that FC-RNL significantly controlled the rutin release, and preserved 6.86 % and 50.47 % of rutin at the end of simulated gastric and intestinal digestion, respectively. Furthermore, FC-RNL exhibited satisfactory biocompatibility, and cellular uptake studies demonstrated that FC-RNL displayed the highest Rh123 uptake efficiency reaching approximately 189 %. This study provides an effective fucoidan/chitosan-coated nanoliposome carrier for the delivery of hydrophobic bioactive compounds within the functional food industry.

Pickering Emulsions Stabilized by Pea Protein Isolate-Cellulose Conjugates Prepared via the Maillard Reaction and Their Application in Active Substance Protection

The development of innovative solid particles from renewable resources possessing high biocompatibility and exceptional emulsification capabilities is crucial for stabilizing Pickering emulsions and advancing carrier systems. In this study, a pea protein isolate (PPI)-cellulose conjugate particle was prepared by the Maillard reaction. Compared to the isoelectric point of pH 4.6 of pure PPI, the isoelectric point of these conjugate particles decreased to pH ∼1. The prepared conjugates could stabilize Pickering emulsions with a high oil phase content (65%), and the prepared emulsion demonstrates long-term storage stability (more than 5 weeks), pH stability (stable from pH 5 to 9 for at least 14 days), and thermal stability (maintained at 80 °C for 48 h). Furthermore, the emulsion demonstrates good protective capabilities for curcumin, with its activity decreasing by only 10% after storage for 10 days. Therefore, the prepared emulsions can be widely used in various fields, such as the food, cosmetic, and pharmaceutical industries.

The relationship between the secondary structure and the emulsifying ability of protein-based particles and the Pickering emulsions stabilized by the zein-lysine complex

Due to the sustainability and widespread use of proteins, protein-based materials are extensively utilized in the preparation of Pickering emulsions. However, the relationship between the secondary structure of proteins and their emulsifying ability has not been further investigated. This study used the addition of three different amino acids to influence the interaction between zein chains, which may induce changes in the secondary structure of the prepared zein complex particles. This study demonstrates that the emulsifying properties of proteins, such as dispersibility, zeta potential, three-phase contact angles, interfacial affinity, adsorption rates, and the volume of the stabilized oil phase, are closely related to the β-sheet content of the complex particles, providing a theoretical reference for protein-based stabilizers. Additionally, amino acids, as the blocks of proteins, have high compatibility with proteins, and using amino acids as modifiers aligns with the safety requirements for food processing. In this study, the prepared zein-lysine complex particles have good emulsifying ability, capable of stabilizing a 50 (v/v)% emulsion at a lower concentration (10 mg mL-1), and the prepared emulsion exhibits high-temperature stability and ionic resistance. This characteristic makes the emulsion potentially valuable for application in systems with high salt concentrations and those that may undergo heat treatment.

Conjugation prepared by wet-Maillard reactions improves the stability and properties of lutein and lycopene loaded nanoparticles

In this study, lutein and lycopene were encapsulated in plant protein (faba bean protein concentrate, (FPC))-carrageenan (Car) conjugates prepared by Maillard reaction in an aqueous media. The conjugation improved encapsulation yield that reached to 82.69% and 93.07%, for lycopene and lutein, respectively. The mean particle diameters for lutein loaded nanoparticles observed smaller in FPC-Car conjugates (66.60 nm) than FPC (71.49 nm). Scanning electron microscopy images showed that FPC-Car conjugates were more spherical and no fractures or fissures on the surface, revealing that wall materials provided better protection and retention for core materials. The diameter of lycopene nanoparticles coated with FPC remained constant between pH 3-4 and 7-9 but increased to 220 nm at pH 4-6. Even though the diameter of lutein nanoparticles coated with FPC remains steady between pH 5 and 9, increased to 953 nm at pH 3. The bioaccessibility of the lutein or lycopene samples encapsulated by FPC were found as higher than FPC-Car conjugates. These findings suggest that protein-polysaccharide conjugates could be used as a wall material to encapsulate lipophilic lutein and lycopene in order to improve their stability, property and bioaccessibility. As a result, FPC-Car conjugates may be an alternative for the formation of functional beverages as well as other nutraceutical products.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05976-4.

Protection effect of lutein-loaded Pickering emulsion prepared via ultrasound-assisted Maillard reaction conjugates on dry age-related macular degeneration

Age-related macular degeneration (AMD) is a prominent cause of vision loss among the elderly, and the treatment options for dry AMD (dAMD) are severely limited. Lutein has a favorable effect on the treatment of dAMD. Algae oil, rich in docosahexaenoic acid (DHA), is considered an effective intervention for eye diseases. In this study, casein-mannose conjugates were prepared to form algal oil-in-water Pickering emulsions by ultrasound-assisted Maillard reaction. As the ultrasound time increased from 0 to 25 min, the droplet size decreased to 648.2 ± 21.18 nm, which substantially improved the stability of the Pickering emulsions. The retention of lutein in the Pickering emulsions under ultrasonic treatment for 20 min was significantly improved under different conditions. The simulated gastrointestinal digestion revealed that ultrasound-assisted Pickering emulsions are an effective method for improving the bioaccessibility of lutein (19.76%-53.34%). In vivo studies elucidated that the lutein-loaded Pickering emulsions could effectively alleviate retinal thinning induced by sodium iodate (NaIO3) in mice with dAMD. Mechanistically, lutein-loaded Pickering emulsions significantly reduced oxidative stress by decreasing the MDA level, increasing the SOD production, and reducing the retinal ROS production. These findings explored the protective effects of lutein-loaded Pickering emulsions on dAMD and offered promising prospects for the nutritional intervention of dAMD.

Apricot polysaccharides as new carriers to make curcumin nanoparticles and improve its stability and antibacterial activity

Apricot polysaccharides (APs) as new types of natural carriers for encapsulating and delivering active pharmaceutical ingredients can achieve high-value utilization of apricot pulp and improve the solubility, the stability, and the antibacterial activity of insoluble compounds simultaneously. In this research, the purified APs reacted with bovine serum albumin (BSA) by the Maillard reaction, and with d-α-tocopheryl succinate (TOS) and pheophorbide A (PheoA) by grafting to fabricate two materials for the preparation of curcumin (Cur)-encapsulated AP-BSA nanoparticles (CABNs) and Cur-embedded TOS-AP-PheoA micelles (CTAPMs), respectively. The biological activities of two Cur nano-delivery systems were evaluated. APs consisted of arabinose (22.36%), galactose (7.88%), glucose (34.46%), and galacturonic acid (31.32%) after the optimized extraction. Transmission electron microscopy characterization of CABNs and CTAPMs displayed a discrete and non-aggregated morphology with a spherical shape. Compared to the unencapsulated Cur, the release rates of CABNs and CTAPMs decreased from 87% to 70% at 3 h and from 92% to 25% at 48 h, respectively. The antioxidant capacities of CABNs and CTAPMs were significantly improved. The CTAPMs exhibited a better antibacterial effect against Escherichia coli than CABNs due to the synergistic photosensitive effect between Cur and PheoA.

Targeted treatment of atherosclerosis with protein-polysaccharide nanoemulsion co-loaded with photosensitiser and upconversion nanoparticles

Macrophages are the most abundant cell group in atherosclerosis (AS) lesions and play a vital role in all stages of AS progression. Recent research has shown that reactive oxygen species (ROS) generation from photodynamic therapy (PDT) induces macrophage autophagy to improve abnormal lipid metabolism and inflammatory environment. Especially in macrophage-derived foam cells, which has become a potential strategy for the treatment of AS. In this study, we prepared the conjugate (DB) of dextran (DEX) and bovine serum albumin (BSA). The DB was used as the emulsifier to prepare nanoemulsion loaded with upconversion nanoparticles (UCNPs) and chlorin e6 (Ce6) (UCNPs-Ce6@DB). The DEX modified on the surface of the nanoemulsion can recognise and bind to the scavenger receptor class A (SR-A) highly expressed on macrophages and promote the uptake of macrophage-derived foam cells in AS plates through SR-A-mediated endocytosis. In addition, UCNPs-Ce6@DB-mediated PDT enhanced ROS generation and induced autophagy in macrophage-derived foam cells, enhanced the expression of ABCA1, a protein closely related to cholesterol efflux, and inhibited the secretion of pro-inflammatory cytokines. Ultimately, UCNPs-Ce6@DB was shown to inhibit plaque formation in mouse models of AS. In conclusion, UCNPs-Ce6@DB offers a promising treatment for AS.

Behavior of protein-polysaccharide conjugate-stabilized food emulsions under various destabilization conditions

The sensitivity of protein-stabilized emulsions to flocculation, coalescence, and phase separation under destabilization conditions (i.e., heating, aging, pH, ionic strength, and freeze-thawing) may limit the widespread use of proteins as effective emulsifiers. Therefore, there is a great interest in modulating and improving the technological functionality of food proteins by conjugating them with polysaccharides, through the Maillard reaction. The present review article highlights the current approaches of protein-polysaccharide conjugate formation, their interfacial properties, and the behavior of protein-polysaccharide conjugate stabilized emulsions under various destabilization conditions, including long-term storage, heating and freeze-thawing treatments, acidic conditions, high ionic strength, and oxidation. Protein-polysaccharide conjugates are capable of forming a thick and cohesive macromolecular layer around oil droplets in food emulsions and stabilizing them against flocculation and coalescence under unfavorable conditions, through steric and electrostatic repulsion. The protein-polysaccharide conjugates could be therefore industrially used to design emulsion-based functional foods with high physicochemical stability.

Synthesis and characterization of fucoidan/chitosan-coated nanoliposomes for enhanced stability and oral bioavailability of hydrophilic catechin and hydrophobic juglone

This study aimed to improve the thermodynamic performance of nanoliposomes (NLs) using fucoidan (F) as the second-layer coating biopolymer along with chitosan (CS), to control the delivery and bioavailability of catechin (C) and juglone (J). The stabilized liposomal carrier of F/CS-conjugated JC-NL (F-CS-JC-NL) was developed with optimum concentrations of CS (0.09 wt%) and F (0.10 wt%), with the highest encapsulation efficiency of juglone (95.47%) and catechin (90.88%). Physicochemical characterization revealed that F-CS-JC-NL disclosed improved stability under different pH and ionic strengths, with the maximum juglone/catechin retention under thermal, oxidative and storage conditions. In vitro digestion revealed that NL double-coating (F-CS-JC-NL) significantly reduced compound leakage in the gastrointestinal tract, providing a controlled release and better bioavailability of juglone/catechin compared to CS-JC-NL and JC-NL. Conclusively, this study provides a novel NL-based delivery carrier with enhanced physicochemical stability and controlled release that might have promising use in delivering functional ingredients.

Sulfated polysaccharides act as baits to interfere with the binding of the spike protein (SARS-CoV-2) to the ACE2 receptor and can be administered through food

Human civilization is experiencing a global crisis involving an unprecedented viral pandemic, with a high mortality rate, uncontrolled spread, and few effective drugs for treatment. Here, we critically evaluate how sulfated polysaccharides can be applied via foods to reduce the infectious process and increase the chances of an adequate immune response. The approach is directed to the infectious process by SARS-CoV-2 and protein S as a therapeutic focus. We discuss the antiviral activities of certain natural and specific sulfated polysaccharides that bind tightly to protein S. Finally, we identified that sulfated polysaccharides act as baits to interfere with the binding of the spike protein (SARS-CoV-2) to the ACE2 receptor and can be administered through food.

Food protein glycation: A review focusing on stability and in vitro digestive characteristics of oil/water emulsions

Recently, increasing studies have shown that the functional properties of proteins, including emulsifying properties, antioxidant properties, solubility, and thermal stability, can be improved through glycation reaction under controlled reaction conditions. The use of glycated proteins to stabilize hydrophobic active substances and to explore the gastrointestinal fate of the stabilized hydrophobic substances has also become the hot spot. Therefore, in this review, the effects of glycation on the structure and function of food proteins and the physical stability and oxidative stability of protein-stabilized oil/water emulsions were comprehensively summarized and discussed. Also, this review sheds lights on the in vitro digestion characteristics and edible safety of emulsion stabilized by glycated protein. It can further serve as a research basis for understanding the role of structural features in the emulsification and stabilization of glycated proteins, as well as their utilization as emulsifiers in the food industry.

Structural and functional modification of proteins from black soybean Aquasoya via ultrasonication

Plant-based proteins obtained from agricultural by-products have garnered growing interest in response to consumer awareness of health and environmental issues. This study aimed to improve the functionalities of the proteins recovered from black soybean Aquasoya (PBSA) by modifying their structure via ultrasonication. PBSA was ultrasonicated with a frequency of 40 kHz at 350 W for different time periods (0, 20, 40, and 60 min), and its structural characteristics, physicochemical properties, and functional properties were investigated. Ultrasonication left the primary structure intact but altered the secondary and tertiary structures of the PBSA; α-helix and β-sheet contents decreased, random coil contents increased, and buried non-polar amino acid residues were exposed. Moreover, ultrasound promoted an increase in free sulfhydryl content and a reduction in particle size. Consequently, functional properties, such as solubility, emulsion stability, and foaming performance were improved by modifying the structure and physicochemical properties of PBSA. This work demonstrates the potential of ultrasound, which is favorable for modifying the spatial conformation and related functionalities of proteins, thus meeting the needs of manufacturers to use function-enhanced proteins as food additives.

Recent advances in biological properties of brown algae-derived compounds for nutraceutical applications

The increasing demand for nutraceuticals in the circular economy era has driven the research toward studying bioactive compounds from renewable underexploited resources. In this regard, the exploration of brown algae has shown significant growth and maintains a great promise for the future. One possible explanation could be that brown algae are rich sources of nutritional compounds (polyunsaturated fatty acids, fiber, proteins, minerals, and vitamins) and unique metabolic compounds (phlorotannins, fucoxanthin, fucoidan) with promising biological activities that make them good candidates for nutraceutical applications with increased value-added. In this review, a deep description of bioactive compounds from brown algae is presented. In addition, recent advances in biological activities ascribed to these compounds through in vitro and in vivo assays are pointed out. Delivery strategies to overcome some drawbacks related to the direct application of algae-derived compounds (low solubility, thermal instability, bioavailability, unpleasant organoleptic properties) are also reviewed. Finally, current commercial and legal statuses of ingredients from brown algae are presented, considering future therapeutical and market perspectives as nutraceuticals.

Fucoidan-based nanomaterial and its multifunctional role for pharmaceutical and biomedical applications

Fucoidans are promising sulfated polysaccharides isolated from marine sources that have piqued the interest of scientists in recent years due to their widespread use as a bioactive substance. Bioactive coatings and films, unsurprisingly, have seized these substances to create novel, culinary, therapeutic, and diagnostic bioactive nanomaterials. The applications of fucoidan and its composite nanomaterials have a wide variety of food as well as pharmacological properties, including anti-oxidative, anti-inflammatory, anti-cancer, anti-thrombic, anti-coagulant, immunoregulatory, and anti-viral properties. Blends of fucoidan with other biopolymers such as chitosan, alginate, curdlan, starch, etc., have shown promising coating and film-forming capabilities. A blending of biopolymers is a recommended approach to improve their anticipated properties. This review focuses on the fundamental knowledge and current development of fucoidan, fucoidan-based composite material for bioactive coatings and films, and their biological properties. In this article, fucoidan-based edible bioactive coatings and films expressed excellent mechanical strength that can prolong the shelf-life of food products and maintain their biodegradability. Additionally, these coatings and films showed numerous applications in the biomedical field and contribute to the economy. We hope this review can deliver the theoretical basis for the development of fucoidan-based bioactive material and films.

Hyaluronic acid and human/bovine serum albumin shelled nanocapsules: Interaction with mucins and in vitro digestibility of interfacial films

Liquid lipid nanocapsules are oil droplets surrounded by a protective shell, which enable high load and allow controlled delivery of lipophilic compounds. However, their use in food formulations requires analysing their digestibility and interaction with mucin. Here, serum albumins and hyaluronic acid shelled olive oil nanocapsules are analysed to discern differences between human and bovine variants, the latter usually used as model system. Interfacial interaction of albumins and hyaluronic acid reveals that human albumin presents limited conformational changes upon adsorption, which increase by complexation with the polysaccharide present at the interface. The latter also promotes hydrophobic interactions with mucin, especially at pH 3 and protects albumin interfacial layer under in vitro gastric digestion. The interfacial unfolding induced in human albumin by hyaluronic acid facilitates in vitro lipolysis while its limited conformational changes provide the largest protection against in vitro lipolysis.

Glycated α-lactalbumin based micelles for quercetin delivery: Physicochemical stability and fate of simulated digestion

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ALA-dextran conjugates were fabricated by Maillard reaction.

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The conjugates had the high encapsulation efficiency on loading quercetin.

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The micelles showed excellent pH, ionic strength and photothermal stability.

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The micelles exhibited sustained release of quercetin by the resistance to enzymes.

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The excellent stability made the conjugates promising materials for oral delivery.

Glycated protein is a kind of promising material that can improve the bioavailability of bioactive compounds and achieve sustained release under digestion. In this study, the α-lactalbumin (ALA)-dextran conjugates synthesized by Maillard reaction were fabricated to load and protect quercetin. Quercetin-loaded micelles stabilized by the ALA-dextran conjugates 1:4 showed the smallest size (428.57 ± 5.64 nm) with highest encapsulation efficiency (94.38% ± 0.50%) of quercetin. Compared to ALA/dextran mixture complex, the conjugates-based micelles had better pH, ionic strength and photothermal stability. Furthermore, the micelles composed of the conjugates 1:2 and 1:4 showed the best controlled release effect during the simulated digestion, releasing 62.41% and 66.15% of quercetin from the total encapsulated contents, respectively, which was mainly related to the resistance of glycated ALA to the enzymes. The findings indicated that ALA-dextran conjugates could be effectively designed for the ideal delivery system of hydrophobic bioactive compounds in food industry.

Interaction of ovalbumin with lutein dipalmitate and their effects on the color stability of marigold lutein esters extracts

In this study, the interaction of ovalbumin with lutein dipalmitate and the effect of ovalbumin on marigold lutein esters extracts were investigated. Lutein dipalmitate quenched the fluorescence of ovalbumin by static quenching. Binding and thermodynamic parameters proved that lutein dipalmitate bound to ovalbumin spontaneously by van der Waals force and hydrogen bond, and the complex stoichiometry was 1:1. Through three-dimensional fluorescence spectroscopy, Fourier transform infrared spectroscopy and circular dichroism experiments, the conformation of ovalbumin was unfolded, and alteration in the ovalbumin secondary structure induced by lutein dipalmitate was observed. The results of transmission electron microscopy and particle size revealed that there were spherical and nano-sized aggregates in the ovalbumin-lutein dipalmitate system, indicating the lutein dipalmitate not only could bind to ovalbumin at molecular level, but also promote the aggregation of ovalbumin. Additionally, the addition of ovalbumin had a positive effect on the stability of marigold lutein esters extracts.

Effect of the emulsifier type on the physicochemical stability and in vitro digestibility of a lutein/zeaxanthin-enriched emulsion

Lutein (L) and zeaxanthin (Z), as macular pigments, are water-insoluble, chemically unstable, and have low bioaccessibilities; they are often emulsified to overcome these limitations. This study investigated the impact of various emulsifiers (ethyl lauroyl arginate (LAE); Tween 80; and sodium dodecyl sulfate (SDS)) on the physicochemical properties and in vitro digestibilities of L/Z-fortified oil-in-water emulsions. Droplet aggregation and creaming extents were dependent on the emulsifier type. The ζ-potentials of emulsions stabilized by LAE, Tween 80, and SDS were + 87, - 26, and - 95 mV, respectively. SDS-stabilized emulsion had the smallest particles, while the particle sizes for the LAE- and Tween 80-stabilized emulsions were larger and not significantly different. The rates of L/Z degradation were sensitive to the emulsifier type and to heat, not to light. The L/Z bioaccessibility was the highest for the Tween 80 emulsion. Surfactants should therefore be carefully selected to optimize L/Z physicochemical stability and bioaccessibility in emulsions.

Enhancing bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems

The consumption of foods rich in antioxidants, vitamins, minerals including carotenoids etc. can boost the immune system to help fight off various infections including SARS- CoV 2 and other viruses. Carotenoids have been gaining attention particularly in food and pharmaceutical industries owing to their diverse functions including their role as pro-vitamin A activity, potent antioxidant properties, and quenching of reactive oxygen (ROS), such as singlet oxygen and lipid peroxides within the lipid bilayer of the cell membrane. Nevertheless, carotenoids being lipophilic, have poor solubility in aqueous medium and are also chemically instable. They are susceptible to degrade under stimuli environmental conditions during food processing, storage and gastrointestinal passage. They also exhibit poor oral bioavailability, thus, their applications in aqueous-based foods are limited. As a consequent, suitable delivery systems including colloids-based are needed to enhance the solubility, stability and bioavailability of carotenoids. This review presents challenges of incorporation and delivery of carotenoids focusing on stability and factors affecting bioavailability. Furthermore, designed factors impacting bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems are explicitly explained. Each delivery system exhibits its own advantages and disadvantages; thus, the delivery systems should be designed based on their targets and their further applications.