Effect of enzymolysis and glycosylation on the curcumin nanoemulsions stabilized by β-conglycinin: Formation, stability and in vitro digestion

Curcumin and omega-3 polyunsaturated fatty acids as bioactive food components with synergistic effects on Alzheimer's disease

Curcumin and omega-3 polyunsaturated fatty acids (ω-3 PUFA) are multifunctional compounds which play an important role in Alzheimer's disease (AD) and little has been addressed about the role of these two compounds together in the progression of the disease. There is evidence of the beneficial effect of combined administration of ω-3 PUFA and other dietary supplements such as vitamins and polyphenols in the prevention of AD, although much remains to be understood about their possible complementary or synergistic activity. Therefore, the objective of this work is to review the research focused on studying the effect and mechanisms of action of curcumin, ω-3 PUFA, and the combination of these nutraceutical compounds, particularly on AD, and to integrate the possible ways in which these compounds can potentiate their effect. The most important pathophysiologies that manifest in AD will be addressed, in order to have a better understanding of the mechanisms of action through which these bioactive compounds exert a neuroprotective effect.

Molecular modification of low-dissolution soy protein isolates by anionic xanthan gum, neutral guar gum, or neutral konjac glucomannan to improve the protein dissolution and stabilize fish oil emulsion

Herein, the effects of anionic xanthan gum (XG), neutral guar gum (GG), and neutral konjac glucomannan (KGM) on the dissolution, physicochemical properties, and emulsion stabilization ability of soy protein isolate (SPI)-polysaccharide conjugates were studied. The SPI-polysaccharide conjugates had better water dissolution than the insoluble SPI. Compared with SPI, SPI-polysaccharide conjugates had lower β-sheet (39.6 %-56.4 % vs. 47.3 %) and α-helix (13.0 %-13.2 % vs. 22.6 %) percentages, and higher β-turn (23.8 %-26.5 % vs. 11.0 %) percentages. The creaming stability of SPI-polysaccharide conjugate-stabilized fish oil-loaded emulsions mainly depended on polysaccharide type: SPI-XG (Creaming index: 0) > SPI-GG (Creaming index: 8.1 %-21.2 %) > SPI-KGM (18.1 %-40.4 %). In addition, it also depended on the SPI preparation concentrations, glycation times, and glycation pH. The modification by anionic XG induced no obvious emulsion creaming even after 14-day storage, which suggested that anionic polysaccharide might be the best polysaccharide to modify SPI for emulsion stabilization. This work provided useful information to modify insoluble proteins by polysaccharides for potential application.

Improved bioavailability and antioxidation of β-carotene-loaded biopolymeric nanoparticles stabilized by glycosylated oat protein isolate

The limited bioavailability of β-carotene hinders its potential application in functional foods, despite its excellent antioxidant properties. Protein-based nanoparticles have been widely used for the delivery of β-carotene to overcome this limitation. However, these nanoparticles are susceptible to environmental stress. In this study, we utilized glycosylated oat protein isolate to prepare nanoparticles loaded with β-carotene through the emulsification-evaporation method, aiming to address this challenge. The results showed that β-carotene was embedded into the spherical nanoparticles, exhibiting relatively high encapsulation efficiency (86.21 %) and loading capacity (5.43 %). The stability of the nanoparticles loaded with β-carotene was enhanced in acidic environments and under high ionic strength. The nanoparticles offered protection to β-carotene against gastric digestion and facilitated its controlled release (95.76 % within 6 h) in the small intestine, thereby leading to an improved in vitro bioavailability (65.06 %) of β-carotene. This improvement conferred the benefits on β-carotene nanoparticles to alleviate tert-butyl hydroperoxide-induced oxidative stress through the upregulation of heme oxygenase-1 and NAD(P)H quinone dehydrogenase 1 expression, as well as the promotion of nuclear translocation of nuclear factor-erythroid 2-related factor 2. Our study suggests the potential for the industry application of nanoparticles based on glycosylated proteins to effectively deliver hydrophobic nutrients and enhance their application.

Development and evaluation of anti-reflux functional-oral suspension raft composed of sodium alginate-mung bean protein complex

This study aimed to develop a sodium alginate (Na alginate) and mung bean protein (MBP) raft complex to improve gastric reflux symptoms. Na alginate and MBP complexes with different ratios (1:1, 2:1, and 3:1, respectively) were used for raft formulations through a wet Maillard reaction. Structural properties of raft strength, reflux resistance, intrinsic fluorescence emission spectroscopy, and Fourier transform infrared spectroscopy (FTIR) were investigated for rafts. The suspension 1:1 Na alginate/MBP with 0 h Maillard reaction time exhibited the lowest sedimentation volume among the suspensions. In contrast, 3:1 Na alginate/MBP with 6 h Maillard reaction time showed the highest sedimentation volume. Based on the results, the 3:1 Na alginate/MBP rafts had the best results, and the results were within acceptable limits. Functional properties, including antioxidant properties, the Helicobacter pylori inhibition assay, the pancreatic lipase inhibition assay, and angiotensin-converting enzyme (ACE) inhibition, were investigated for rafts. The Na alginate/MBP raft has similar characteristics to Gaviscon syrup and can be used for obesity, Helicobacter pylori infection, high blood pressure, and gastric reflux.

Construction of astaxanthin loaded Pickering emulsions gel stabilized by xanthan gum/lysozyme nanoparticles with konjac glucomannan from structure, protection and gastrointestinal digestion perspective

Pickering emulsion gels have demonstrated their efficacy in delivering bioactive compounds by effectively preventing droplet aggregation, Ostwald maturation, and phase separation through gel network. Astaxanthin (AST) Pickering emulsion gels stabilized by xanthan gum/lysozyme nanoparticles (XG/Ly NPs) and konjac glucomannan (KGM) were studied from rheological tests and textural analysis. The Pickering emulsion gel demonstrated the highest water holding capacity (WHC) at concentration of 2 % XG/Ly NPs, 60 % oil phase fraction, and 0.5 % KGM concentration. The presence of KGM was observed to enhance the plasticity of Pickering emulsion gels, as evidenced by the dense gel network structure formed on the surface of the droplets. Furthermore, the utilization of Pickering emulsion gels containing AST has demonstrated enhanced photostability and a protective effect on AST, as evidenced by antioxidant experiments. Moreover, the incorporation of KGM in Pickering emulsion gels has been found to reduce the release of free fatty acids (FFA) and the bioaccessibility of AST, as indicated in vitro digestion results. Overall, these findings indicate the potential of KGM-based Pickering emulsion gels as effective vehicles for the delivery of hydrophobic bioactive compounds within the food industry.

Effects of soy protein and its hydrolysates on the formation of heterocyclic aromatic amines in roasted pork

This study investigated the influence mechanism of soy protein and its hydrolysates (under three different degree of hydrolysis) on formation of heterocyclic aromatic amines (HAAs) formation in roasted pork. The results showed that 7S and its hydrolysates significantly inhibited the formation of quinoxaline HAAs, and the maximum inhibitory rate of MeIQx, 4,8-MeIQx, and IQx was 69%, 79%, and 100%, respectively. However, soy protein and its hydrolysates could promote the formation of pyridine HAAs (PhIP, and DMIP), its content increased significantly with the increase in the degree of hydrolysis of the protein. The content of PhIP increased 41, 54, and 165 times with the addition of SPI, 7S, and 11S at 11% degree of hydrolysis, respectively. In addition, they promoted the formation of β-carboline HAAs (Norharman and Harman), in a manner similar with that of PhIP, especially the 11S group. The inhibitory effect on quinoxaline HAAs was probably correlated with DPPH radical scavenging capacity. Nevertheless, the promotive effect on other HAAs might be related to the high levels of free amino acids and reactive carbonyls. This research may provide recommendation for the application of soy protein in high-temperature meat products.

Esterified Soy Proteins with Enhanced Antibacterial Properties for the Stabilization of Nano-Emulsions under Acidic Conditions

Soy protein isolate (SPI), including β-conglycinin (7S) and glycinin (11S), generally have low solubility under weakly acidic conditions due to the pH closed to their isoelectric points (pIs), which has limited their application in acidic emulsions. Changing protein pI through modification by esterification could be a feasible way to solve this problem. This study aimed to obtain stable nano-emulsion with antibacterial properties under weakly acidic conditions by changing the pI of soy protein emulsifiers. Herein, the esterified soy protein isolate (MSPI), esterified β-conglycinin (M7S), and esterified glycinin (M11S) proteins were prepared. Then, pI, turbidimetric titration, Fourier transform infrared (FTIR) spectra, intrinsic fluorescence spectra, and emulsifying capacity of esterified protein were discussed. The droplet size, the ζ-potential, the stability, and the antibacterial properties of the esterified protein nano-emulsion were analyzed. The results revealed that the esterified proteins MSPI, M7S, and M11S had pIs, which were measured by ζ-potentials, as pH 10.4, 10.3, and 9.0, respectively, as compared to native proteins. All esterified-protein nano-emulsion samples showed a small mean particle size and good stability under weakly acidic conditions (pH 5.0), which was near the original pI of the soy protein. Moreover, the antibacterial experiments showed that the esterified protein-based nano-emulsion had an inhibitory effect on bacteria at pH 5.0.

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.

Glycated Soy β-Conglycinin Nanoparticle for Efficient Nanocarrier of Curcumin: Formation Mechanism, Thermal Stability, and Storage Stability

In this study, soy β-conglycinin (7S) was glycated with dextran of different molecular masses (40, 70, 150, 500 kDa) by the dry-heating method to synthesize soy β-conglycinin-dextran (7S-DEX) conjugates. The curcumin (Cur) loaded nanocomplexes were prepared based on 7S-DEX conjugates by a pH-driven self-assemble strategy to enhance the solubility and thermal stability of curcumin. Results showed that the 7S-150 conjugates (glycated from 7S with dextran (150 kDa)) could remain stable in the pH 3.0-pH 8.0 range and during the heat treatment. The results of fluorescence quenching and FT-IR indicated that glycated 7S were combined with curcumin mainly by hydrogen bonding and hydrophobic interaction, and 7S-150 conjugates had higher binding affinity than natural 7S for curcumin. The loading capacity (μg/mg) and encapsulation efficiency (EE%) of 7S-150-Cur were 16.06 μg/mg and 87.51%, respectively, significantly higher than that of 7S-Cur (12.41 μg/mg, 51.15%). The XRD spectrum showed that curcumin was exhibited in an amorphous state within the 7S-150-Cur nanocomplexes. After heating at 65 °C for 30 min, the curcumin retention of the 7S-150-Cur nanocomplexes was about 1.4 times higher than that of free curcumin. The particle size of 7S-150-Cur nanocomplexes was stable (in the range of 10-100 nm) during the long storage time (21 days).

Physicochemical Antioxidative and Emulsifying Properties of Soybean Protein Hydrolysates Obtained with Dissimilar Hybrid Nanoflowers

This study investigated the changes in the structure and properties of soybean protein after hydrolysis using two types of hybrid nanoflowers (alcalase@Cu3(PO4)2•3H2O (ACHNs) and dispase@Cu3(PO4)2•3H2O (DCHNs)) and examined the basic properties and oxidative stability of hydrolyzed soybean protein emulsions. The formations of the two hybrid nanoflowers were first determined using a scanning electron microscope, transmission electron microscope, and Fourier infrared spectroscopy. The structure and functional properties of soybean protein treated with hybrid nanoflowers were then characterized. The results indicated that the degree of hydrolysis (DH) of the ACHNs hydrolysates was higher than that of the DCHNs for an identical reaction time. Soybean protein hydrolysates treated with two hybrid nanoflowers showed different fluorescence and circular dichroism spectra. The solubility of the hydrolysates was significantly higher (p < 0.05) than that of the soybean protein (SPI) at all pH values tested (2.0−10.0)*: at the same pH value, the maximum solubility of ACHNs hydrolysates and DCHNs hydrolysates was increased by 46.2% and 42.2%, respectively. In addition, the ACHNs hydrolysates showed the highest antioxidant activity (DPPH IC50 = 0.553 ± 0.009 mg/mL, ABTS IC50 = 0.219 ± 0.019 mg/mL, and Fe2+ chelating activity IC50 = 40.947 ± 3.685 μg/mL). The emulsifying activity index of ACHNs and DCHNs hydrolysates reached its maximum after hydrolysis for 120 min at 61.38 ± 0.025 m2/g and 54.73 ± 0.75 m2/g, respectively. It was concluded that the two hydrolysates have better solubility and antioxidant properties, which provides a theoretical basis for SPI product development. More importantly, the basic properties and oxidative stability of the soybean-protein-hydrolysates oil-in-water emulsions were improved. These results show the importance of proteins hydrolyzed by hybrid nanoflowers as emulsifiers and antioxidants in the food and pharmaceutical industry.

Gel Property of Soy Protein Emulsion Gel: Impact of Combined Microwave Pretreatment and Covalent Binding of Polyphenols by Alkaline Method

This study investigated the effects of microwave modification, alkali polyphenol (ferulic acid) covalently combined modification, and microwave-alkali polyphenol covalently combined modification on the gel properties of soy protein emulsions. The results showed that the properties of soy protein emulsions were improved significantly by the three modification methods. After three kinds of modification, the viscoelasticity of soy protein emulsion gel increased, and a gel system with stronger elasticity was formed. The texture, water-holding, and hydration properties of the emulsion gel increased significantly. The SEM and ClSM results showed that the modified soy protein emulsion gel had a more compact and uniform porous structure, and the oil droplets could be better embedded in the network structure of the gel. Among the three modification methods, the microwave-alkali method polyphenol covalently combining the compound modification effect was best, and the microwave modification effect was least effective compared to the other two methods. Our obtained results suggested that for gel property modification of soy protein emulsion gels, microwave pretreatment combined with the covalent binding of polyphenols by an alkaline method is an effective method.

Effect of carbon numbers and structures of monosaccharides on the glycosylation and emulsion stabilization ability of gelatin

Herein, the effect of saccharide glycosylation by nine monosaccharides on bovine bone gelatin for the stabilization of fish oil-loaded emulsions was explored. The gelatin modification was analyzed and then the emulsifying properties of monosaccharide-modified gelatins were analyzed at pH 9.0 and 3.0. The results demonstrated that glycosylated gelatin structure, droplet stability, creaming stability, and liquid-gel transition time were dependent on monosaccharide carbon numbers, monosaccharide structures, and solution pH. Glycosylation modification of gelatins did not obviously change the emulsion droplet stability at pH 9.0, whereas it increased the emulsion droplet stability at pH 3.0. Glycosylation modification of gelatins did not obviously change the emulsion creaming index values (5.1%-8.4% at pH 9.0 and 25.8%-33.1% at pH 3.0). Three-carbon and four-carbon monosaccharides glycosylation significantly increased emulsion liquid-gel transition times. This work provided useful information to understand the effects of carbon numbers and structures of monosaccharides on the protein modification.

Anti-aging properties of phytoconstituents and phyto-nanoemulsions and their application in managing aging-related diseases

Aging is spontaneous and inevitable process in all living beings. It is a complex natural phenomenon that manifests as a gradual decline of physiological functions and homeostasis. Aging inevitably leads to age-associated injuries, diseases, and eventually death. The research on aging-associated diseases aimed at delaying, preventing or even reversing the aging process are of great significance for healthy aging and also for scientific progress. Numerous plant-derived compounds have anti-aging effects, but their therapeutic potential is limited due to their short shelf-life and low bioavailability. As the novel delivery system, nanoemulsion can effectively improve this defect. Nanoemulsions enhance the delivery of drugs to the target site, maintain the plasma concentration for a longer period, and minimize adverse reaction and side effects. This review describes the importance of nanoemulsions for the delivery of phyto-derived compounds and highlights the importance of nanoemulsions in the treatment of aging-related diseases. It also covers the methods of preparation, fate and safety of nanoemulsions, which will provide valuable information for the development of new strategies in treatment of aging-related diseases.

Emulsion, hydrogel and emulgel systems and novel applications in cannabinoid delivery: a review

Emulsions, hydrogels and emulgels have attracted a high interest as tools for the delivery of poorly soluble hydrophobic nutraceuticals by enhancing their stability and bioavailability. This review provides an overview of these delivery systems, their unique qualities and their interactions with the human gastrointestinal system. The modulation of the various delivery systems to enhance the bioavailability and modify the release profile of bioactive encapsulates is highlighted. The application of the delivery systems in the delivery of cannabinoids is also discussed. With the recent increase of cannabis legalization across North America, there is much interest in developing cannabis edibles which can provide a consistent dose of cannabinoids per portion with a rapid time of onset. Indeed, the long time of onset of psychoactive effects and varied metabolic responses to these products result in a high risk of severe intoxication due to overconsumption. Sophisticated emulsion or hydrogel-based delivery systems are one potential tool to achieve this goal. To date, there is a lack of evidence linking specific classes of delivery systems with their pharmacokinetic profiles in humans. More research is needed to directly compare different classes of delivery systems for the gastrointestinal delivery of cannabinoids.

Preparation and characterization of soybean protein isolate/pectin-based phytosterol nanodispersions and their stability in simulated digestion

In this study, stigmasterol was nanoencapsulated in soy protein isolate -pectin-based nanodispersions. Based on the particle size and zeta-potential, the optimal pectin/SPI ratio of stigmasterol nanodispersion was determined to be 1:10. At this ratio, nanodispersions was manufactured with an average particle size of 477 ± 33 nm, an encapsulation efficiency of 89.37%, and a loading amount of 17.87%. The physical properties and morphology of the nanodispersion were investigated. Fourier transform infrared spectroscopy and differential scanning calorimetry analysis revealed that stigmasterol was loaded in nanodispersions successfully. The pectin, which was used to stable nanodispersion, could restrict the release of stigmasterol in the simulated gastric fluid. This experiment indicated that the presence of pectin can improve the stability of the nanodispersion and can be used to achieve controlled release of bioactive compounds.

Comparison of Different Protein Emulsifiers on Physicochemical Properties of β-Carotene-Loaded Nanoemulsion: Effect on Formation, Stability, and In Vitro Digestion

In this study, β-carotene-loaded nanoemulsions are emulsified using four biomacromolecular proteins-peanut protein isolate (PPI), soy protein isolate (SPI), rice bran protein isolate (RBPI), and whey protein isolate (WPI)-in order to explore their emulsion stability and in vitro digestion characteristics. All four nanoemulsions attained high encapsulation levels (over 90%). During the three-stage in vitro digestion model (including oral, gastric, and small intestine digestion phases), the PPI-emulsified nanoemulsion showed the highest lipolysis rates (117.39%) and bioaccessibility (37.39%) among the four nanoemulsions. Moreover, the PPI-emulsified nanoemulsion (with the smallest droplet size) also demonstrated the highest stability during storage and centrifugation, while those for the RBPI-emulsified nanoemulsion (with the largest droplet size) were the lowest. In addition, all four nanoemulsions showed superior oxidation stability when compared with the blank control of corn oil. The oxidation rates of the PPI- and WPI-stabilized groups were slower than the other two groups.

Improvement of protein emulsion stability through glycosylated black bean protein covalent interaction with (-)-epigallocatechin-3-gallate

This study investigated the effects of covalent conjugates combined by glycosylated black bean protein isolate (BBPI-G) and (−)-epigallocatechin-3-gallate (EGCG) on the emulsion stability. Fourier transform infrared (FTIR) spectroscopy showed that covalent binding of EGCG with BBPI-G made the protein molecule unfolded. Besides, the emulsifying properties of BBPI-G were increased after combined with EGCG. BBPI-G–EGCG emulsion had lower mean particle size and higher content of interfacial protein adsorption (AP), which resulted in thicker and more impact oil–water interface. Therefore, the stability of emulsions was significantly improved. Furthermore, the emulsions prepared by BBPI-G–EGCG compounds exhibited considerable stability in storage, oxidation, thermal treatments, freeze–thaw and freeze-dried powders resolubility. This study demonstrated that the covalent bond of glycosylated protein and polyphenols could advance the emulsifying performance of protein, and BBPI-G–EGCG covalent complex was an effective emulsifier for preparing high stability emulsions.

Stability improvement of emulsions stabilized by covalent conjugation with glycosylated black bean protein and EGCG (BBPI-G–EGCG) was studied through structure changes of proteins and emulsion properties.

The Improvement of Nanoemulsion Stability and Antioxidation via Protein-Chlorogenic Acid-Dextran Conjugates as Emulsifiers

In this experiment, the peanut protein isolate (PPI), soybean protein isolate (SPI), rice bran protein isolate (RBPI), and whey protein isolate (WPI) were modified by linking chlorogenic acid covalently and linking dextran by Maillard reaction to prepare protein-chlorogenic acid-dextran (PCD) conjugates. As for structures, conformational changes of conjugates were determined by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE), Fourier transform infrared (FT-IR), and fluorescence measurements. The molecular weights of PCD conjugates became larger, the structure became disorder, and the amino acid residues inside the protein were exposed to the polar environment when compared to protein-chlorogenic acid (PC) and native proteins (NPs). As for properties, the interfacial tension reduced and antioxidant activity of PCD conjugates enhanced in varying degrees. Based on this, PCD conjugates were used as emulsifiers in order to investigate the properties of nanoemulsions and compared with PC conjugates and NPs. The mean droplet diameters (MDD) results showed that the nanoemulsions that were stabilized by PCD conjugates had the smallest particle sizes and exhibited uniformly dispersed spherical shapes. The storage and oxidative stabilities of PCD conjugates were also significantly improved. In comparison, nanoemulsion that was stabilized by PPI-chlorogenic acid-dextran conjugate had the smallest particle size and optimal stability among four protein stabilized nanoemulsions.

Cellulose nanocrystals/nanofibrils loaded astaxanthin nanoemulsion for the induction of apoptosis via ROS-dependent mitochondrial dysfunction in cancer cells under photobiomodulation

The present study investigated effects of low-level laser therapy with cellulose nanocrystals/cellulose nanofibrils loaded in nanoemulsion (NE) against skin cancer cells on apoptosis. The nanoemulsion was fabricated and characterized by the standard methods. The toxicity level by cytotoxicity assays, generation of reactive singlet oxygen (ROS) and antioxidant potential, cell proliferation and migration were confirmed by using standard assays. The cellular uptake efficacy was evaluated by differential staining. The protein levels of EGFR, PI3K, AKT, ERK, GAPDH, and β-actin were detected by western blot. The samples showed a spherical shaped structure with the average size confirmed strong and stable hydrogen bonding forces with high degradation temperature and endothermic transition peaks. The fabricated samples showed no toxicity and high cell proliferation by generating more singlet oxygen levels and antioxidants. The intracellular signaling pathways was regulated with high protein expression levels, which was stimulated by specific molecules for cell proliferation, migration, and differentiation in cancer cells. The results proved that combined treatment regulated the intracellular signaling pathways in cancer cells. The current study showed a novel strategy for improving therapeutic efficacy of nanoemulsion by using low-level laser therapy. Further, the current favorable outcomes will be evaluated in in vivo animal models.

Comparison of protein hydrolysates against their native counterparts in terms of structural and antioxidant properties, and when used as emulsifiers for curcumin nanoemulsions

The stability and in vitro digestion of nanoemulsions stabilized by natural protein hydrolysates (PPI, SPI and WPI) are discussed.