In vitro digestion and cellular antioxidant activity of β-carotene-loaded emulsion stabilized by soy protein isolate-Pleurotus eryngii polysaccharide conjugates

Physicochemical properties and in vitro digestion behavior of emulsion micro-gels stabilized by κ-carrageenan and whey protein: Effects of sodium alginate addition

Emulsion micro-gels exhibit significant potential as functional ingredients for modifying food texture, replacing saturated fats, or serving as templates for the controlled release of bioactive compounds. Structural design principles are being applied more frequently to develop innovative emulsion micro-gels. In this paper, whey protein concentrate (WPC), κ-carrageenan and sodium alginate (SA) were utilized for preparing emulsion micro-gels. To reveal the regulation mechanism of the structural and physicochemical properties of emulsion micro-gels on lipid digestion, the influence of SA additions on the structural, physicochemical properties and in vitro digestion behavior of κ-carrageenan/WPC-based emulsion micro-gel were explored. The FTIR results suggest that the emulsion micro-gels are formed through non-covalent interactions. With the increase of SA addition (from 0.7 g/100 mL to 1.0 g/100 mL), the decreased mean droplet size, the increased hardness, elasticity indexes, and water holding capacity, the reduced the related peak times all indicated that the emulsion micro-gels exhibit enhanced rheological, stability, and mechanical properties. It can be concluded from the microstructure, particle size distribution of the emulsion micro-gels during simulated digestion and free fatty acid release that both κ-carrageenan/WPC-based emulsion micro-gel and κ-carrageenan/WPC/SA-based emulsion micro-gel can inhibit lipid digestion due to the ability to maintain structural stability and hindering the penetration of bile salts and lipase through the hydrogel networks. And the ability is regulated by the binding properties the gel matrix and oil droplets, which determine the structure and physicochemical properties of emulsion micro-gels. The research suggested that the structure of emulsion micro-gels can be modified to produce various lipid digestion profiles. It may be significant for certain practical application in the design of low-fat food and controlled release of bioactive agents.

Enhanced functional properties of pea protein isolate microgel particles modified with sodium alginate: Mixtures and conjugates

Protein microgels are emerging as versatile soft particles due to their desirable interfacial activities and functional properties. In this study, pea protein isolate microgel particles (PPIMP) were prepared by heat treatment and transglutaminase crosslinking, and PPIMP were non-covalently and covalently modified with sodium alginate (SA). The effects of polymer ratio and pH on the formation of PPIMP-SA mixtures and conjugates were investigated. The optimal ratio of PPIMP and SA was found to be 20:1, with the optimal pH being 7 and 10, respectively. PPIMP-SA conjugates were prepared by Maillard reaction. It was found that ultrasound (195 W, 40 min) enhanced the degree of glycation of PPIMP, with a highest value of 37.21 ± 0.71 %. SDS-PAGE, browning intensity and FTIR data also confirmed the formation of PPIMP-SA conjugates. Compared with PPIMP and PPIMP-SA mixtures, PPIMP-SA conjugates exhibited better thermal stability, antioxidant, emulsifying and foaming properties, which opens up opportunities for protein microgel in various food applications.

Digestive characteristics of astaxanthin oil in water emulsion stabilized by a casein-caffeic acid-glucose ternary conjugate

To overcome the barrier of poor oral bioavailability of astaxanthin, a stable oil-in-water emulsion was constructed using casein-caffeic acid-glucose ternary conjugates (CSC) to deliver astaxanthin, and its gastrointestinal behavior was evaluated in vitro with sodium caseinate (CSN) as a control. Results showed that, CSC-stabilized emulsion shower better resistance to the adverse conditions of the gastric environment than CSN-stabilized emulsion, and exhibited lower average particle size and aggregation (4972.33 nm, -5.93 mv) after simulated gastric digestion. Besides, after simulated intestinal digestion, the reducing capacity and astaxanthin transfer efficiency of CSC emulsion into the micellar phase were 686.74 μmol Trolox/100 mL and 26.2 %, which were 2.6 and 4.05-fold higher than that of CSN emulsion. The above results suggest that CSC can be used for better delivery of astaxanthin, which could be useful in designing foods such as functional beverages, pharmaceuticals and nutritional supplements for delivery of lipophilic bioactives.

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.

Structural and interfacial properties of acetylated Millettia speciosa Champ polysaccharide and stability evaluation of the resultant O/W emulsion containing β-carotene

The aim of this study was to investigate the effects of acetylation modification on the structural, interfacial and emulsifying properties of Millettia speciosa Champ polysaccharide (MSCP). Besides, the influence of acetylation modification on the encapsulation properties of polysaccharide-based emulsion was also explored. Results indicated that modification resulted in a prominent reduction in molecular weight of MSCP and the interfacial layer thickness formed by acetylated MSCP (AC-MSCP) was also decreased, but the adsorption rate and ability of AC-MSCP to reduce interfacial tension were improved. AC-MSCP formulated emulsion possessed smaller droplet size (6.8 μm) and exhibited better physical stability under stressful conditions. The chemical stability of β-carotene was also profoundly enhanced by AC-MSCP fabricated emulsion. Moreover, AC-MSCP improved lipids digestion extent, thus facilitating the formation of micelle and increasing bioaccessibility of β-carotene. This study provided insights for rational modification of polysaccharide-based emulsifier and designing delivery system for chemically labile hydrophobic bioactive components.

Delivery systems designed to enhance stability and suitability of lipophilic bioactive compounds in food processing: A review

Lipophilic compounds, such as flavors, fat-soluble vitamins, and hydrophobic nutrients possess vital properties including antioxidant effects, functional attributes, and nutritional value that can improve human health. However, their susceptibility to environmental factors including heat, pH changes, and ionic strength encountered during food processing poses significant challenges. To address these issues, diverse bioactive delivery systems have been developed. This review explores delivery systems designed to optimize the stability and suitability of lipophilic bioactive compounds in food processing. Extensive literature analysis reveals that tailoring delivery systems with various biopolymers can protect bioactives through steric hindrance and formation of thick interfacial layers on the emulsion surfaces. Thus, the access of oxygen, prooxidants, and free radicals at the emulsion interface could be inhibited, resulting in enhanced processing suitability of bioactives as well as chemical stability under diverse environmental conditions. The insights presented in this review hold immense value for the food and beverage industries.

Co-delivery of vitamin C and β-carotene in W/O/W emulsions stabilized by modified aggregated insoluble soybean protein hydrolysate-xanthan gum complexes

Environmentally friendly emulsifiers safe for human consumption are urgently needed to stabilize emulsions for applications in the food industry. In this study, we prepared complexes combining modified aggregated insoluble soybean protein hydrolysate (AISPH) mixed with xanthan gum (XG) (0.05-0.3 %, w/v), and further to construct water-in-oil-in-water (W/O/W) emulsions to deliver vitamin C and β-carotene. We observed a decrease in the AISPH α-helix and β-sheet content, surface hydrophobicity, and fluorescence intensity all decreased after binding. In contrast, the particle size and absolute ξ-potential significantly increased, indicating that molecular non-covalent interactions occurred in the solution. The emulsification property of AISPH was also improved by adding XG, and the AISPH-XG-stabilized emulsion showed improved stability, encapsulation efficiency, and rheological properties. Among them, AISPH-XG-0.25-stabilized emulsion exhibited a smaller particle size (8.41 ± 0.49 μm) and the highest encapsulation efficiency for vitamin C (90.03 ± 0.23 %) and β-carotene (70.56 ± 0.06 %). Additionally, simulated gastric digestion indicated that vitamin C and β-carotene bioavailability increased by 3.6 and 5.8 times, respectively. Finally, the emulsion exhibited good pH, ionic, and thermal stability. In general, AISPH-XG-stabilized W/O/W emulsions showed good stability and carrying capacity, providing a theoretical basis for improving their application.

Emulsion for stabilizing β-carotene and curcumin prepared directly using a continuous phase of polysaccharide-rich Schizophyllum commune fermentation broth

In this study, we examined the effect of Schizophyllum commune fermentation broth (SCFB) rich in polysaccharides (SCFP) on the stability and bioaccessibility of β-carotene and curcumin. An SCFB-stabilized oil-in-water (o/w) emulsion (SCFBe) was prepared using SCFB as the continuous phase, and then evaluated for storage stability using an SCFP-based emulsion (SCFPe) as the control. The findings revealed that SCFBe is more stable at 60 °C than SCFPe, and stratification or droplet size varied at differing pH levels (3-9) and concentrations of Na+ (0.1-0.5 M) and Ca2+ (0.01-0.05 M). Since the absolute value of the zeta potential of SCFBe is much lower at 60 °C than that at 4 °C and 25 °C, a higher temperature (60 °C) may enhance the reactivity of polysaccharides and proteins in SCFB to improve the stability of SCFBe. Both the protective impact of SCFB on functional food molecules and their capacity to block lipid oxidation increased as polysaccharide content improved. The bioaccessibility of β-carotene after in vitro simulated gastrointestinal digestion is 11.18 %-12.28 %, whereas that of curcumin is 31.64 %-33.00 %. By fermenting edible and medicinal fungi in liquid, we created a unique and environmentally friendly approach for getting food-grade emulsifiers without extraction.

Properties of Heat-Assisted pH Shifting and Compounded Chitosan from Insoluble Rice Peptide Precipitate and Its Application in the Curcumin-Loaded Pickering Emulsions

Curcumin exhibits antioxidant and antitumor properties, but its poor chemical stability limits its application. Insoluble peptide precipitates formed by proteolysis of rice glutelin are usually discarded, resulting in resource waste. The coupled treatment of heat-assisted pH shifting and compounded chitosan (CS) was used to fabricate rice peptide aggregate-chitosan complexes (RPA-CS). The structure, interfacial behavior, emulsion properties, and digestibility of curcumin-loaded RPA-CS Pickering emulsions were investigated. Increasing the CS concentration led to lower interfacial tension but larger particle size, and the three-phase contact angle of the RPA-CS complexes approached 90°. Quartz crystal microbalance with dissipation (QCM-D) indicated that RPA-CS complexes with 6 g·kg-1 of CS (RPA-CS6) had the highest K1 (0.592 × 106 Hz-1) and K4 (0.487 × 106 Hz-1), suggesting that the softest interfacial layers were formed. The solid-liquid balance of RPA-RPA-CS emulsions was lower than 0.5, declaring that they had more elastic behavior than that of RPA emulsions. RPA-RPA-CS4-and RPA-CS6 emulsions had better storage stability, lower FFA release (79.8% and 76.3%, respectively), and higher curcumin bioaccessibility (65.2% and 68.2%, respectively) than RPA emulsions. This study showed that a low-value insoluble rice peptide precipitate could be used as a valuable emulsifier in foods, which may increase the economics and sustainability of the food supply.

Physicochemical and functional property of the Maillard reaction products of soy protein isolate with L-arabinose/D-galactose

BACKGROUND

Soy protein isolate (SPI) is widely used in the food industry because of its nutritional and functional properties. During food processing and storage, the interaction with co-existing sugars can cause changes in the structural and functional properties of SPI. In this study, SPI-l-arabinose conjugate (SPI:Ara) and SPI-d-galactose conjugate (SPI:Gal) were prepared using Maillard reaction (MR), and the effects of five-carbon/six-carbon sugars on the structural information and function of SPI were compared.

RESULTS

MR unfolded and stretched the SPI, changing its ordered conformation into disorder. Lysine and arginine of SPI were bonded with the carbonyl group of sugar. The MR between SPI and l-arabinose has a higher degree of glycosylation compared to d-galactose. MR of SPI enhanced its solubility, emulsifying property and foaming property. Compared with SPI:Ara, SPI:Gal exhibited better aforementioned properties. The functionalities of amphiphilic SPI were enhanced by MR, SPI:Gal possessed better hypoglycemic effect, fat binding capacity and bile acid binding ability than SPI:Ara. MR endowed SPI with enhanced biological activities, SPI:Ara showed higher antioxidant activities, and SPI:Gal exhibited stronger antibacterial activities.

CONCLUSION

Our work revealed that l-arabinose/d-galactose exhibited different effects on the structural information of SPI, and further affected its physicochemical and functional property. © 2023 Society of Chemical Industry.

Effect of protein oxidation on the emulsion carrier prepared by rice bran protein for improving stability and bioavailability of β-carotene

The emulsion carriers which prepared by rice bran protein (RBP) with different oxidation extents were utilized to deliver β-carotene (BC). The effects of RBP oxidation extent on stability and bioaccessibility of BC in rice bran protein emulsion (RBPE) were investigated by measuring the droplet size, microstructure, digestive stability, cellular antioxidant, and delivery property of BC-RBPE. The results showed that BC-RBPE prepared by moderately oxidized RBP (extracted from rice bran with a storage time of 5 d) presented excellent digestive stability and delivery property during gastrointestinal digestion. The particle size of initial BC-RBPE, BC-RBPE after gastric digestion, and BC-RBPE after intestinal digestion were 509.73, 2149.33, and 997.82 nm, respectively. Compared with free BC suspension, the BC retention after gastric digestion and the BC bioavailability of BC-RBPE prepared by moderately oxidized RBP increased by 23.50% and 27.54%, respectively. In addition, the BC cellular antioxidant activity and BC cellular uptake of BC-RBPE prepared by moderately oxidized RBP were significantly higher than that of free BC-suspension, which increased by 29.63% and 13.84%, respectively. In summary, the study showed that oil-in-water emulsion prepared by moderately oxidized protein is a potential delivery system of BC, which can provide a theoretical basis for improving the utilization of protein by adjusting the extent of protein oxidation.

Fabrication, in-vitro digestion and pH-responsive release behavior of soy protein isolate glycation conjugates-based hydrogels

Hydrogel made by glycated soy protein isolate (SPI) conjugates is a promising gastrointestinal targeted delivery system for bioactives. In this study, SPI conjugates were prepared with dextran molecules at various molecular weights by Maillard reaction -based heating, and then used to fabricate hydrogel aided by transglutaminase. The modification on the structure, interfacial and rheological properties of SPI by dextran was studied. The physicochemical properties, digestion behavior and curcumin-encapsulation capacity of resultant SPI-dextran hydrogels were comprehensively studied. As compared to SPI and SPI-glucose conjugates-based hydrogels, SPI-dextran hydrogels showed lower mechanical properties but more homogeneous gel network. Dextran with higher molecular weight showed lower grafting degree on SPI, but was more effective on improving the thermos-set gel performance, and resistance to in vitro gastrointestinal digestion. The contribution of glycinin and β-conglycinin, two major individual proteins of SPI, in the dextran conjugates formation were predicated by molecular docking for the first time. The impact of molecular weight of dextran on glycated SPI hydrogel-based delivery systems was comprehensively investigated, which is promising for development of functional food applications.

Effects of glycation methods on the interfacial behavior and emulsifying performance of soy protein isolate-gum Arabic conjugates

Glycated conjugation of plant protein such as soy protein isolate (SPI) with saccharides is one popular strategy to modify the physicochemical characteristics of these plant protein resources, which may be affected by the glycation methods including dry-heating and wet-heating. In this study, the impact of these two glycation methods on the rheological and emulsifying properties of a binary system made by SPI-gum Arabic (GA) was studied. The results indicated that dry-heating conjugates had higher viscosity and more elastic characteristics than those wet-heating conjugates. The emulsifying properties of SPI-GA conjugates by different preparation routes were evaluated by various oil phases including eugenol, cinnamaldehyde and soybean oil. Overall, emulsions stabilized by dry-heating conjugates showed lower zeta-potential value than those with wet heating conjugates. The interfacial properties of these conjugates were compared using soybean oil emulsion as a model. Higher emulsifying ability and stability were obtained by emulsions with dry-heating conjugates, which was attributed to their more compact structures, higher protein adsorption capacity and thicker viscoelastic films formed at the interface, and therefore enhanced electrostatic repulsion between droplets. The findings in this study are useful for fabrication and utilization of protein-polysaccharide glycation conjugates as emulsifiers in functional foods.

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.

Encapsulation of lycopene into electrospun nanofibers from whey protein isolate-Tricholoma lobayense polysaccharide complex stabilized emulsions: Structural characterization, storage stability, in vitro release, and cellular evaluation

In this study, lycopene-loaded nanofibers were successfully fabricated by electrospinning of oil-in-water (O/W) emulsions stabilized by whey protein isolate-polysaccharide TLH-3 (WPI-TLH-3) complexes. The lycopene encapsulated in the emulsion-based nanofibers exhibited enhanced photostability and thermostability, and achieved improved targeted small intestine-specific release. The release of lycopene from the nanofibers followed Fickian diffusion mechanism in simulated gastric fluid (SGF) and first-order model in simulated intestinal fluid (SIF) with the enhanced release rates. The bioaccessibility and cellular uptake efficiency of lycopene in micelles by Caco-2 cells after in vitro digestion were significantly improved. The intestinal membrane permeability and transmembrane transport efficiency of lycopene in micelles across Caco-2 cells monolayer were greatly elevated, thus promoting the effective absorption and intracellular antioxidant activity of lycopene. This work opens a potential approach for electrospinning of emulsions stabilized by protein-polysaccharide complexes as a novel delivery system for liposoluble nutrients with enhanced bioavailability in functional food industries.

Whey Protein Isolate-Mesona chinensis Polysaccharide Conjugate: Characterization and Its Applications in O/W Emulsions

Mesona chinensis polysaccharide (MCP), a common thickener, stabilizer and gelling agent in food and pharmaceuticals, also has antioxidant, immunomodulatory and hypoglycemic properties. Whey protein isolate (WPI)-MCP conjugate was prepared and used as a stabilizer for O/W emulsion in this study. FT-IR and surface hydrophobicity results showed there could exist interactions between -COO- in MCP and -NH³⁺ in WPI, and hydrogen bonding may be involved in the covalent binding process. The red-shifted peaks in the FT-IR spectra suggested the formation of WPI-MCP conjugate, and MCP may be bound to the hydrophobic area of WPI with decreasing surface hydrophobicity. According to chemical bond measurement, hydrophobic interaction, hydrogen bond and disulfide bond played the main role in the formation process of WPI-MCP conjugate. According to morphological analysis, the O/W emulsion formed by WPI-MCP had a larger size than the emulsion formed by WPI. The conjugation of MCP with WPI improved the apparent viscosity and gel structure of emulsions, which was concentration-dependent. The oxidative stability of the WPI-MCP emulsion was higher than that of the WPI emulsion. However, the protection effect of WPI-MCP emulsion on β-carotene still needs to be further improved.

The effect of lactose and its isomerization product lactulose on functional and structural properties of glycated casein

Lactulose is an isomer of lactose, formed under thermal processing of milk. Alkaline conditions favor the isomerization of lactose. As reducing sugar, lactose and lactulose could participate in the Maillard reaction and cause protein glycation in milk products. In this study, the influence of lactose and lactulose on the functional and structural properties of glycated casein was investigated. The results demonstrated that compared with lactose, lactulose led to severer changes in molecular weight, more disordered spatial structure and decrease of tryptophan fluorescence intensity of casein. Besides, the glycation degree and advanced glycation end products (AGEs) results suggested that lactulose exhibited stronger glycation ability than lactose due to the higher proportion of open chain in solution. Furthermore, higher glycation degree induced by lactulose resulted in lower solubility, surface hydrophobicity, digestibility and emulsifying capacity of casein-glycoconjugates compared with lactose. The results of this study are essential for tracking the effects of harmful Maillard reaction products on the quality of milk and dairy products.

Effects of Sequential Enzymolysis and Glycosylation on the Structural Properties and Antioxidant Activity of Soybean Protein Isolate

The effects of limited hydrolysis following glycosylation with dextran on the structural properties and antioxidant activity of the soybean protein isolate (SPI) were investigated. Three SPI hydrolysate (SPIH) fractions, F30 (>30 kDa), F30-10 (10-30 kDa), and F10 (<10 kDa), were confirmed using gel permeation chromatography. The results demonstrated that the glycosylation of F30 was faster than that of F30-10 or F10. The enzymolysis caused the unfolding of the SPI to expose the internal hydrophobic cores, which was further promoted by the grafting of dextran, making the obtained conjugates have a loose spatial structure, strong molecular flexibility, and enhanced thermal stability. The grafting of dextran significantly enhanced the DPPH radical or •OH scavenging activity and the ferrous reducing power of the SPI or SPIH fractions with different change profiles due to their different molecular structures. The limited enzymolysis following glycosylation was proven to be a promising way to obtain SPI-based food ingredients with enhanced functionalities.

Disposable face masks release micro particles to the aqueous environment after simulating sunlight aging: Microplastics or non-microplastics?

This study focuses on characterizing microplastics and non-microplastics released from surgical masks (SMs), N95 masks (N95), KN95 masks (KN95), and children's masks (CMs) after simulating sunlight aging. Based on micro-Raman spectrum analysis, it was found that the dominant particles released from masks were non-microplastics (66.76-98.85%). Unfortunately, CMs released the most microplastics, which is 8.92 times more than SMs. The predominant size range of microplastics was 30-500 µm, and the main polymer types were PP and PET. Compared with the whole SMs, the microplastic particles released from the cutting-SMs increased conspicuously, which is 12.15 times that of the whole SMs. The main components of non-microplastics include β-carotene, microcrystalline cellulose 102, and eight types of minerals. Furthermore, non-microplastics were mainly fibrous and fragmented in appearance, similar to the morphology of microplastics. After 15 days of UVA-aging, the fibers of the face layers had cracks to varying degrees. It was estimated that these four types of masks can release at least 31.5 trillion microplastics annually in China. Overall, this study demonstrated that the masks could release a large quantity of microplastics and non-microplastics to the environment after sunlight aging, deserving urgent attention in the future study.

Antioxidant Activities of Natural Polysaccharides and Their Derivatives for Biomedical and Medicinal Applications

Many chronic diseases such as Alzheimer's disease, diabetes, and cardiovascular diseases are closely related to in vivo oxidative stress caused by excessive reactive oxygen species (ROS). Natural polysaccharides, as a kind of biomacromolecule with good biocompatibility, have been widely used in biomedical and medicinal applications due to their superior antioxidant properties. In this review, scientometric analysis of the highly cited papers in the Web of Science (WOS) database finds that antioxidant activity is the most widely studied and popular among pharmacological effects of natural polysaccharides. The antioxidant mechanisms of natural polysaccharides mainly contain the regulation of signal transduction pathways, the activation of enzymes, and the scavenging of free radicals. We continuously discuss the antioxidant activities of natural polysaccharides and their derivatives. At the same time, we summarize their applications in the field of pharmaceutics/drug delivery, tissue engineering, and antimicrobial food additives/packaging materials. Overall, this review provides up-to-date information for the further development and application of natural polysaccharides with antioxidant activities.

Impact of Guar Gum and Locust Bean Gum Addition on the Pasting, Rheological Properties, and Freeze-Thaw Stability of Rice Starch Gel

Improving the gel texture and stability of rice starch (RS) by natural hydrocolloids is important for the development of gluten-free starch-based products. In this paper, the effects of guar gum and locust bean gum on the pasting, rheological properties, and freeze−thaw stability of rice starch were investigated by using a rapid visco analyzer, rheometer, and texture analyzer. Both gums can modify the pasting properties, revealed by an increment in the peak, trough, and final viscosities, and prevent the short-term retrogradation tendency of RS. Dynamic viscoelasticity measurements also indicated that the starch−gum system exhibits superior viscoelastic properties compared with starch alone, as revealed by its higher storage modulus (G′). Compared with the control, the hysteresis loop area of the guar gum-containing system and locust bean gum-containing system was reduced by 37.7% and 24.2%, respectively, indicating that the addition of gums could enhance shear resistance and structure recovery properties. The thermodynamic properties indicated that both gums retard short-term retrogradation as well as long-term retrogradation of the RS gels. Interestingly, the textural properties and freeze−thaw stability of the RS gel were significantly improved by the addition of galactomannans (p < 0.05), and guar gum was more effective than locust bean gum, which may be due to the different mannose to galactose ratio. The results provide alternatives for gluten-free recipes with improved texture properties and freeze−thaw stability.

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.

Effects of Different Amounts of Corn Silk Polysaccharide on the Structure and Function of Peanut Protein Isolate Glycosylation Products

Covalent complexes of peanut protein isolate (PPI) and corn silk polysaccharide (CSP) (PPI-CSP) were prepared using an ultrasonic-assisted moist heat method to improve the functional properties of peanut protein isolate. The properties of the complexes were affected by the level of corn silk polysaccharide. By increasing the polysaccharide addition, the grafting degree first increased, and then tended to be flat (the highest was 38.85%); the foaming, foam stability, and solubility were also significantly improved. In a neutral buffer, the solubility of the sample with a protein/polysaccharide ratio of 2:1 was 73.69%, which was 1.61 times higher than that of PPI. As compared with PPI, the complexes had higher thermal stability and lower surface hydrophobicity. High addition of CSP could made the secondary structure of PPI change from ordered α-helix to disordered β-sheet, β-turn, and random coil structure, and the complex conformation become more flexible and loose. The results of multiple light scattering showed that the composite solution exhibited high stability, which could be beneficial to industrial processing, storage, and transportation. Therefore, the functional properties of peanut protein isolate glycosylation products could be regulated by controlling the amount of polysaccharide added.

Fabrication of High-Acyl Gellan-Gum-Stabilized β-Carotene Emulsion: Physicochemical Properties and In Vitro Digestion Simulation

The β-carotene emulsion system using high-acyl gellan gum (HA) as an emulsifier was fabricated and systematically studied. The stability and stabilizing mechanism of the emulsion using medium-chain triglyceride as oil phase with a water-oil mass ratio of 9:1 under different physicochemical conditions of heat, pH, and ions were investigated by analyzing mean particle size (MPS), emulsion yield (EY), and dynamic stability. The effects of the HA-β-carotene emulsion system on the bioaccessibility of β-carotene in vitro were conducted. During the simulated oral digestion stage (SODP) and simulated gastric digestion stage (SGDP), the emulsion systems stabilized with different HA contents showed good stability, and the changes of MPS and zeta potential (ZP) were within 2.5 μm and 3.0 mV, respectively. After entering the simulated intestinal digestion phase (SIDP), β-carotene was released from oil droplets and formed micelles with bile salts, phospholipids, etc. HA-β-carotene emulsion can enhance the release rate of free fatty acid (FFA), which ultimately affects the β-carotene bioaccessibility. These results indicate that HA can be used to prepare carotene emulsion and improve its bioavailability. The study provides a reference for the application of HA as a natural emulsifier and the delivery of β-carotene.

The Effect of Glycosylated Soy Protein Isolate on the Stability of Lutein and Their Interaction Characteristics

Lutein is a natural fat-soluble carotenoid with various physiological functions. However, its poor water solubility and stability restrict its application in functional foods. The present study sought to analyze the stability and interaction mechanism of the complex glycosylated soy protein isolate (SPI) prepared using SPI and inulin-type fructans and lutein. The results showed that glycosylation reduced the fluorescence intensity and surface hydrophobicity of SPI but improved the emulsification process and solubility. Fluorescence intensity and ultraviolet–visible (UV–Vis) absorption spectroscopy results showed that the fluorescence quenching of the glycosylated soybean protein isolate by lutein was static. Through thermodynamic parameter analysis, it was found that lutein and glycosylated SPI were bound spontaneously through hydrophobic interaction, and the binding stoichiometry was 1:1. The X-ray diffraction analysis results showed that lutein existed in the glycosylated soybean protein isolate in an amorphous form. The Fourier transform infrared spectroscopy analysis results revealed that lutein had no effect on the secondary structure of glycosylated soy protein isolate. Meanwhile, the combination of lutein and glycosylated SPI improved the water solubility of lutein and the stability of light and heat.

Preparation, Characteristics, and Advantages of Plant Protein-Based Bioactive Molecule Delivery Systems

As a renewable resource, the market trend of plant protein has increased significantly in recent years. Compared with animal protein, plant protein production has strong sustainability factors and a lower environmental impact. Many bioactive substances have poor stability, and poor absorption effects limit their application in food. Plant protein-based carriers could improve the water solubility, stability, and bioavailability of bioactive substances by different types of delivery systems. In this review, we present a detailed and concise summary of the effects and advantages of various plant protein-based carriers in the encapsulation, protection, and delivery of bioactive substances. Furthermore, the research progress of food-grade bioactive ingredient delivery systems based on plant protein preparation in recent years is summarized, and some current challenges and future research priorities are highlighted. There are some key findings and conclusions: (i) plant proteins have numerous functions: as carriers for transportation systems, a shell or core of a system, or food ingredients; (ii) plant protein-based carriers could improve the water solubility, stability, and bioavailability of bioactive substances by different types of delivery systems; and (iii) plant protein-based carriers stabilize bioactive substances with potential applications in the food and nutrition fields.

Influence of Proteins on the Absorption of Lipophilic Vitamins, Carotenoids and Curcumin - A Review

While proteins have been widely used to encapsulate, protect, and regulate the release of bioactive food compounds, little is known about the influence of co-consumed proteins on the absorption of lipophilic constituents following digestion, such as vitamins (A, D, E, K), carotenoids, and curcumin. Their bioavailability is often low and very variable, depending on the food matrix and host factors. Some proteins can act as emulsifiers during digestion. Their liberated peptides have amphiphilic properties that can facilitate the absorption of microconstituents, by improving their transition from lipid droplets into mixed micelles. Contrarily, the less well digested proteins could negatively impinge on enzymatic accessibility to the lipid droplets, slowing down their processing into mixed micelles and entrapping apolar food compounds. Interactions with mixed micelles and proteins are also plausible, as shown earlier for drugs. This review focuses on the ability of proteins to act as effective emulsifiers of lipophilic vitamins, carotenoids, and curcumin during digestion. The functional properties of proteins, their chemical interactions with enzymes and food constituents during gastro-intestinal digestion, potentials and limitations for their use as emulsifiers are emphasized and data from human, animal, and in vitro trials are summarized.

Spectrum-effect relationship between ultra-high-performance liquid chromatography fingerprints and antioxidant activities of Lophatherum gracile Brongn

Lophatherum gracile Brongn. is a medicinal and edible plant resource as well as a natural additive in the functional food market. To better understand its characteristics and efficacy, a method combining chromatographic fingerprints and antioxidant activity was proposed. A total of 21 common peaks were confirmed from liquid chromatography fingerprints and were identified as 14 flavonoids and 7 phenolic acids by ultra-high-performance liquid chromatography (UHPLC) coupled with quadrupole Orbitrap mass spectrometry (Q-Orbitrap/MS). Their antioxidant activities were evaluated by 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH), 2,2'-diazide-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and ferric reducing antioxidant power (FRAP) assay. The results showed that all of the test samples had moderate to high antioxidant effects, with IC50 values ranging from 5.2 to 16.1 mg/ml and 1.2 to 2.8 mg/ml for DPPH and ABTS assays, and the FeSO4 concentrations of 1.84-4.20 mmol/L for the FRAP assay. The spectrum-effect relationship between UHPLC fingerprints and antioxidant activity was investigated through Pearson correlation analysis and Grey relational analysis (GRA) to identify the antioxidant constitutes in Lophatherum gracile Brongn. The results showed that 11 compounds were greatly associated with the antioxidant activity with a correlation degree >0.80, which can be used as the quality marker of Lophatherum gracile Brongn.

Protein-polysaccharide interactions for the fabrication of bioactive-loaded nanocarriers: Chemical conjugates and physical complexes

As unique biopolymeric architectures, covalently and electrostatically protein-polysaccharide (PRO-POL) systems can be utilized for bioactive delivery by virtue of their featured structures and unique physicochemical attributes. PRO-POL systems (i. e, microscopic /nano-dimensional multipolymer particles, molecularly conjugated vehicles, hydrogels/nanogels/oleogels/emulgels, biofunctional films, multilayer emulsion-based delivery systems, particles for Pickering emulsions, and multilayer coated liposomal nanocarriers) possess a number of outstanding attributes, like biocompatibility, biodegradability, and bioavailability with low toxicity that qualify them as powerful agents for the delivery of different bioactive ingredients. To take benefits from these systems, an in-depth understanding of the chemical conjugates and physical complexes of the PRO-POL systems is crucial. In this review, we offer a comprehensive study concerning the unique properties of covalently/electrostatically PRO-POL systems and introduce emerging platforms to fabricate relevant nanocarriers for encapsulation of bioactive components along with a subsequent sustained/controlled release.

Development of dendrimer-like glucan-stabilized Pickering emulsions incorporated with β-carotene

The impact of sugary maize dendrimer-like glucan octenyl succinate (OSA-SMDG) on the storage stability and antioxidant activity of β-carotene (BC)-loaded emulsions as well as bioaccessibility were investigated. The encapsulation efficiency of β-carotene in emulsions containing 3% OSA-SMDG (3OSA-SMDG-BC) or 5% OSA-SMDG (5OSA-SMDG-BC) was 89.6% and 94.9%, respectively. The antioxidant activity of both emulsions was higher than that of pure β-carotene. During simulated digestion, the particle size of emulsions was immediately reduced, whereas zeta-potential was continuously increased in intestinal digestion. After 2 h digestion, the free fatty acids (FFA) release rate of 3OSA-SMDG-BC and 5OSA-SMDG-BC was significantly higher than that of blank emulsion. Bioaccessibility of β-carotene encapsulated in 3OSA-SMDG-BC and 5OSA-SMDG-BC was also significantly higher than that of blank emulsion. FFA release rate and β-carotene bioaccessibility of 5OSA-SMDG-BC were higher than that of 3OSA-SMDG-BC. These results demonstrated that OSA-SMDG could be used to fabricate food-grade O/W Pickering emulsion as a delivery system for bioactive compounds.

Maillard-Type Protein-Polysaccharide Conjugates and Electrostatic Protein-Polysaccharide Complexes as Delivery Vehicles for Food Bioactive Ingredients: Formation, Types, and Applications

Due to their combination of featured properties, protein and polysaccharide-based carriers show promising potential in food bioactive ingredient encapsulation, protection, and delivery. The formation of protein–polysaccharide complexes and conjugates involves non-covalent interactions and covalent interaction, respectively. The common types of protein–polysaccharide complex/conjugate-based bioactive ingredient delivery systems include emulsion (conventional emulsion, nanoemulsion, multiple emulsion, multilayered emulsion, and Pickering emulsion), microcapsule, hydrogel, and nanoparticle-based delivery systems. This review highlights the applications of protein–polysaccharide-based delivery vehicles in common bioactive ingredients including polyphenols, food proteins, bioactive peptides, carotenoids, vitamins, and minerals. The loaded food bioactive ingredients exhibited enhanced physicochemical stability, bioaccessibility, and sustained release in simulated gastrointestinal digestion. However, limited research has been conducted in determining the in vivo oral bioavailability of encapsulated bioactive compounds. An in vitro simulated gastrointestinal digestion model incorporating gut microbiota and a mucus layer is suggested for future studies.

Plant Protein-Based Delivery Systems: An Emerging Approach for Increasing the Efficacy of Lipophilic Bioactive Compounds

The development of plant protein-based delivery systems to protect and control lipophilic bioactive compound delivery (such as vitamins, polyphenols, carotenoids, polyunsaturated fatty acids) has increased interest in food, nutraceutical, and pharmaceutical fields. The quite significant ascension of plant proteins from legumes, oil/edible seeds, nuts, tuber, and cereals is motivated by their eco-friendly, sustainable, and healthy profile compared with other sources. However, many challenges need to be overcome before their widespread use as raw material for carriers. Thus, modification approaches have been used to improve their techno-functionality and address their limitations, aiming to produce a new generation of plant-based carriers (hydrogels, emulsions, self-assembled structures, films). This paper addresses the advantages and challenges of using plant proteins and the effects of modification methods on their nutritional quality, bioactivity, and techno-functionalities. Furthermore, we review the recent progress in designing plant protein-based delivery systems, their main applications as carriers for lipophilic bioactive compounds, and the contribution of protein-bioactive compound interactions to the dynamics and structure of delivery systems. Expressive advances have been made in the plant protein area; however, new extraction/purification technologies and protein sources need to be found Their functional properties must also be deeply studied for the rational development of effective delivery platforms.

Recent progress in Pickering emulsions stabilised by bioderived particles

In recent years, the demand for non-surfactant based Pickering emulsions in many industrial applications has grown significantly because of the option to select biodegradable and sustainable materials with low toxicity as emulsion stabilisers. Usually, emulsions are a dispersion system, where synthetic surfactants or macromolecules stabilise two immiscible phases (typically water and oil phases) to prevent coalescence. However, synthetic surfactants are not always a suitable choice in some applications, especially in pharmaceuticals, food and cosmetics, due to toxicity and lack of compatibility and biodegradability. Therefore, this review reports recent literature (2018-2021) on the use of comparatively safer biodegradable polysaccharide particles, proteins, lipids and combinations of these species in various Pickering emulsion formulations. Also, an overview of the various tuneable factors associated with the functionalisation or surface modification of these solid particles, that govern the stability of the Pickering emulsions is provided.

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.

Ultrasonic-assisted extraction of polysaccharides from coix seeds: Optimization, purification, and in vitro digestibility

To optimize the extraction of polysaccharides from coix seeds (CSP), an auxiliary method of ultrasound was developed by response surface methodology (RSM). The maximum extraction yield (8.340%) was obtained under 480 W power, 16 min ultrasound extraction (UE) time and 21.00 mL/g water to raw material ratio. Compared to hot water extraction (HE), UE-treated CSP led to a higher extraction efficiency and decreased average CSP molecular weight. FT-IR indicated that CSP extracted by UE and HE were neutral polysaccharides, and linkages between sugar units were mainly in the α-conformation. Furthermore, NMR spectra indicated that UE-treated CSP was a neutral polysaccharide with (1 → 6)-linked α-d-glucopyranose in the main chain. Two polysaccharide components (CSP-A and CSP-B) were purified by anion exchange chromatography, therein, CSP-A was more resistant to the digestion in stomach and intestine. These results suggest that CSP-A has the potential to be a functional agent utilized by gut microbes.

Role of Food Antioxidants in Modulating Gut Microbial Communities: Novel Understandings in Intestinal Oxidative Stress Damage and Their Impact on Host Health

Dietary components have an important role on the structure and function of host gut microbial communities. Even though, various dietary components, such as carbohydrates, fats, proteins, fibers, and vitamins, have been studied in depth for their effect on gut microbiomes, little attention has been paid regarding the impact of several food antioxidants on the gut microbiome. The long-term exposure to reactive oxygen species (ROS) can cause microbial dysbiosis which leads to numerous intestinal diseases such as microbiota dysbiosis, intestinal injury, colorectal cancers, enteric infections, and inflammatory bowel diseases. Recently, it has been shown that the food derived antioxidant compounds might protect the host from intestinal oxidative stress via modulating the composition of beneficial microbial species in the gut. The present review summarizes the impact of food antioxidants including antioxidant vitamins, dietary polyphenols, carotenoids, and bioactive peptides on the structure as well as function of host gut microbial communities. Several in vitro, animal model, and clinical studies indicates that food antioxidants might modify the host gut microbial communities and their health status. However, still further clarification is needed as to whether changes in certain microbial species caused by food additives may lead to changes in metabolism and immune function.

Effect of the silkworm pupa protein-glucose conjugate on the thermal stability and antioxidant activity of anthocyanins

Anthocyanin (cyanidin-3-O-glucose) is a natural water-soluble pigment with a robust antioxidant capacity. However, its poor stability and bioavailability limits its application as a functional food ingredient. This study explored the ability of the silkworm pupa protein-glucose (Spp-Glu) conjugate, developed under wet-heating conditions, to improve the thermal stability and antioxidant activity of cyanidin-3-O-glucose (C3G) at pH 3.0 and 6.8. The characterization experiments suggested that C3G complexed with the Spp-Glu conjugate could modify the protein's microenvironment and cause unfolding of the protein's secondary structures under varied pH conditions. Spectroscopic techniques further revealed the formation of complexes via hydrophobic interactions and static quenching processes when C3G was bound to Spp or Spp-Glu. The formation of these complexes effectively attenuated C3G degradation, thereby enhancing its stability under heat treatment over a range of pH values, and the experiments measuring antioxidant activity suggested that the Spp-Glu conjugate formed does not affect the efficacy of C3G after complexation. Therefore, our study suggests that Spp-Glu has the potential to effectively protect and deliver anthocyanins during industrial application for functional food formulation.