Development of double network gels based on soy protein isolate and sugar beet pectin induced by thermal treatment and laccase catalysis

Phased characterization of soy protein gel modified by lactobacillus plantarum JYLP-326 in cooperation with acidic tremella fuciformis fruiting body polysaccharide: Focus on structural network, interaction and gel properties

Soybean protein isolate (SPI) and acidic tremella fuciformis fruiting body polysaccharide (AP) were used to prepare phased products "sterilized soft gel (SPI-AP)" and "fermented strong gel (FSPI-AP)" to study the structural network, interaction and gel characteristics. The contents of α-helix (20.43 % to 25.36 %) and β-sheet (31.24 % to 35.12 %) of FSPI-AP increased compared with that of SPI. The introduction of AP and microorganisms improved the orderliness of peptide chain through non-covalent and covalent interactions, with hydrophobic (33.33 %), electrostatic (26.77 %), and disulfide bonds (24.45 %) being the dominant forces in the formation of gels. Furthermore, AP could decrease the crystallinity and disrupt the regular rigid structure of protein molecules, so FSPI-AP had stronger cohesion to resist external force. FSPI-AP had the highest proportion of interaction (12.57 %) in the interaction network, while SPI-AP was 9.07 %. This study will provide a new idea for innovating the application of protein-polysaccharide gel systems.

Enhanced physicochemical properties and riboflavin delivery ability of soy isolate protein/sugar beet pectin composite freeze-dried gels prepared by double crosslinking strategy

Improving the mechanical strength of protein freeze-dried gels materials has become a research priority in the field of nutrient delivery system development in recent years. In this study, double crosslinking freeze-dried gels were prepared by integrating laccase catalyzed sugar beet pectin (SBP) as a highly active filler molecule into the soybean isolate protein (SPI) thermally induced gel network, followed by freeze-drying. The double crosslinking freeze-dried gels were a porous material and the addition of SBP resulted in the formation of amorphous forms of freeze-dried gels with lower binding energy. The freeze-dried gels with 2.0 % SBP addition had the densest microstructure with the highest density (19.00 mg/cm3) and mechanical strength (180.43 ± 15.27 KPa), and hydrogen bonding, NH, CN, and CO bands were the most important factors to maintain the freeze-dried gels structure. As the concentration of sugar beet pectin increased, the release mechanism of riboflavin underwent a shift from a Fickian to a non-Fickian diffusion mechanism. In addition, the highest bioavailability of riboflavin was found in the freeze-dried gels spiked with 2.0 % SBP. These results will contribute to the development of double crosslinking freeze-dried gels carriers for targeted slow release of hydrophilic bioactive.

Gellan Gum Enhances the Quality of Egg-Based Yoghurt by Changing the Water Phase Distribution and Improving the Gel Texture

Egg-based yoghurt (EBY) is a novel yoghurt fermented by lactic acid bacteria with high nutritional and health values, serving as a potential alternative to milk-based yoghurt. However, the hardness, adhesiveness, and water-holding capacity of egg-based yoghurt need to be further improved. In this study, the improvement in EBY quality by gellan gum and its underlying mechanism were investigated. The results showed that gellan gum significantly improved the quality of EBY (p < 0.05). Among the five concentration gradients tested, the EBY supplemented with 0.045% gellan gum exhibited the best quality with the highest sensory score of 83.57. With the increasing amount of gellan gum, hydrogen bonding interactions in the yoghurt significantly increased, while ionic bonding remained unchanged, but hydrophobic interactions and disulphide bonding gradually decreased. Low-field NMR assay results demonstrated that gellan gum significantly raised the amount of strongly bonded water while decreasing the amount of immobile water in the yoghurt. Confocal laser scanning microscopy revealed that EBY with 0.045% gellan gum had a better texture, whereas too much or too little gellan gum led to a coarser structure. In summary, gellan gum altered the water phase state and enhanced the water holding capacity through increased hydrogen bonding interactions, which consequently improved the yoghurt's texture and sensory qualities. This study provides a reference for the development and application of EBY.

Structure-functionality relationship and modification strategies of oat protein: Challenges and opportunities

The increasing preference for plant-based proteins over animal-derived equivalents has intensified research into alternative protein sources, with oats emerging as a noteworthy specialty crop due to their rich array of functional and bioactive components. Despite the growing interest, research into oat proteins remains in its early stages, particularly in understanding the structure-function relationship and modification strategies within food systems. Designing novel food products using oat protein presents both opportunities and challenges; the compact quaternary structure and high thermal stability of oat globulin limit its functionality in diverse applications. This review aims to detail the composition and structural characteristics of oat protein, highlighting the complex relationship between these structural traits and their functional properties. A significant focus is placed on innovative structural modification techniques that enable the cost-effective transformation of oat protein into a functional ingredient or base for new food product development.

Structure formation mechanism of pectin-soy protein isolate gels: Unraveling the role of peach pectin fractions

This study investigated the macro & micro properties of the composite gels formed by soy protein isolate (SPI) and peach pectin fractions: water-soluble pectin (WSP), chelator-soluble pectin (CSP), and sodium carbonate soluble pectin (NSP). Specially, the interaction between pectin fractions and SPI was studied to explain the formation mechanism of the composite gels. WSP, as a high methoxyl pectin, exhibited rich branching (sugar ratio B = 3.10). CSP, as a low methoxyl pectin, depicted a high linearity. NSP, with low linearity (sugar ratio A = 6.14), contained numerous side chains. Due to the strong interaction between pectin fractions and SPI, the new composites with excellent dense network microstructures were formed, accompanied by increased apparent viscosity, higher G' and G'', and reduced particle size. XRD and FT-IR analysis highlighted the modifications in gel structures. SEM-dispersive X-ray spectroscopy observed elemental distribution and framework composition in pectin-SPI gels. Hydrophobic interaction was the most important chemical force in pectin-SPI binding. Molecular docking results indicated that galacturonic acid in pectin bound more strongly to 7S than to 11S, with tighter hydrogen bonds. Notably, WSP-SPI showed the lowest turbidity, indicating enhanced solubility and particle dispersion, which helped prevent aggregation. CSP-SPI demonstrated the highest G' and G'', ascribing to the high linearity and abundant carboxyl groups in CSP. NSP-SPI showed the highest apparent viscosity and irregular structure. Overall, the texture properties of pectin-SPI gels were driven by pectin's structure properties, which would provide new and valuable information for texture control in gel formulation.

Covalent Pectin/Arabinoxylan Hydrogels: Rheological and Microstructural Characterization

This research aimed to evaluate the gelation process of ferulated pectin (FP) and ferulated arabinoxylan (AXF) in a new mixed hydrogel and determine its microstructural characteristics. FP from sugar beet (Beta vulgaris) and arabinoxylan from maize (Zea mays) bran were gelled via oxidative coupling using laccase as a crosslinking agent. The dynamic oscillatory rheology of the mixed hydrogel revealed a maximum storage modulus of 768 Pa after 60 min. The scanning electron microscopy images showed that mixed hydrogels possess a microstructure of imperfect honeycomb. The ferulic acid content of the mixed hydrogel was 3.73 mg/g, and ferulic acid dimer 8-5' was the most abundant. The presence of a trimer was also detected. This study reports the distribution and concentration of ferulic acid dimers, and the rheological and microstructural properties of a mixed hydrogel based on FP and AXF, which has promising features as a new covalent biopolymeric material.

Mechanism on microbial transglutaminase and Tremella fuciformis polysaccharide-mediated modification of lactoferrin: Development of functional food

Lactoferrin (LF) with various biological functions demonstrates great application potential. However, its application was restricted by its poor gelation and instability. The aim of this work was to explore the effect of microbial transglutaminase (MTGase) and Tremella fuciformis polysaccharide (TP) on the functional properties of LF. The formation of a self-supporting LF gel could be induced by MTGase through generating covalent crosslinks between the LF protein molecules. Meanwhile, TP was introduced into the gel system to improve the strength of LF-TP composite gels by enhancing non-covalent interactions such as hydrogen bond and electrostatic interactions during gel formation. Additionally, the LF-TP composite gel exhibited outstanding functional characteristics such as gastrointestinal digestive stability and antioxidant property. This work clarified the mechanism on MTGase and TP-mediated modification of lactoferrin, offered a novel strategy to increase the functional characteristics of LF, and enlarged the application range of LF and TP.

Laccase: Sustainable production strategies, heterologous expression and potential biotechnological applications

Laccase is a multicopper oxidase enzyme that target different types of phenols and aromatic amines. The enzyme can be isolated and characterized from microbes, plants and insects. Its ubiquitous nature and delignification ability makes it a valuable tool for research and development. Sustainable production methods are being employed to develop low cost biomanufacturing of the enzyme while achieving high titers. Laccase have significant industrial application ranging from food industry where it can be used for wine stabilization, texture improvement and detection of phenolic compounds in food products, to cosmetics offering benefits such as skin brightening and hair colouring. Dye decolourization/degradation, removal of pharmaceutical products/emerging pollutants and hydrocarbons from wastewater, biobleaching of textile fabrics, biofuel production and delignification of biomass making laccase a promising green biocatalyst. Innovative methods such as using inducers, microbial co-culturing, recombinant DNA technology, protein engineering have pivotal role in developing laccase with tailored properties. Enzyme immobilization using new age compounds including nanoparticles, carbonaceous components, agro-industrial residues enhance activity, stability and reusability. Commercial formulations of laccase have been prepared and readily available for a variety of applications. Certain challenges including production cost, metabolic stress in response to heterologous expression, difficulty in purification needs to be addressed.

Stability mechanism of Monascus pigment-soy protein isolate-maltodextrin complex

BACKGROUND

Monascus pigment (MP) is a natural food coloring with vital physiological functions but prone to degradation and color fading under light conditions.

RESULTS

This study investigated the effect of complex formation of soybean protein isolate (SPI), maltodextrin (MD), and MP on the photostability of MP. Light stability was assessed through retention rate and color difference. Fluorescence spectroscopy (FS), circular dichroism (CD), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) explored MP, SPI, and MD interactions, clarifying the MP-SPI-MD complex mechanism on the light stability of MP. Microstructure and differential scanning calorimetry (DSC) analyzed the morphology and thermal properties. The retention rate of MP increased to approximately 80%, and minimal color difference was observed when adding SPI and MD simultaneously. FS revealed hydrophobic interaction between MP and SPI. FTIR analysis showed intensity changes and peak shifts in amide I band and amide II band, which proved the hydrophobic interaction. CD showed a decrease in α-helix content and an increase in β-sheet content after complex formation, indicating strengthened hydrogen bonding interactions. Scanning electron microscopy (SEM) analysis demonstrated that MP was attached to the surface and interior of complexes. XRD showed MP as crystalline, while SPI and MD were amorphous, complexes exhibited weakened or absent peaks, suggesting MP encapsulation. The results of DSC were consistent with XRD.

CONCLUSION

SPI and MD enveloped MP through hydrogen bonding and hydrophobic interaction, ultimately enhancing its light stability and providing insights for pigment-protein-polysaccharide interactions and improving pigment stability in the food industry. © 2024 Society of Chemical Industry.

The Effect of High Hydrostatic Pressure (HHP) Induction Parameters on the Formation and Properties of Inulin-Soy Protein Hydrogels

The aim of this study was to determine the effect of high hydrostatic pressure (HHP) induction parameters on the formation and properties of inulin-soy protein hydrogels. Solutions containing 20 g/100 g of inulin and 3 or 6 g/100 g of soy protein isolate (3 SPI; 6 SPI) were subjected to HHPs of 150, 300, or 500 MPa for 5, 10, or 20 min. The HHP parameters had no significant impact on the effectiveness of hydrogel formation. In most cases, the time of solution pressurization had no significant effect on the characteristics of hydrogels. However, increasing the induction pressure from 150 to 300 MPa resulted in hydrogels with different characteristics being obtained, e.g., more flattened microstructure; higher stability (only 3 SPI); higher yield stress, firmness, and adhesiveness; and lower spreadability. These changes were more noticeable in the hydrogels with lower protein content. An increase in the induction pressure (to 500 MPa) did not result in a significant strengthening of the hydrogel structure. However, in the case of 6 SPI hydrogels, induction with a pressure of 500 MPa had an unfavorable effect on their stability. The results indicate that HHP (300 MPa) can be used as an effective method for strengthening the structure of inulin-protein hydrogels.

Effect of sanxan as novel natural gel modifier on the physicochemical and structural properties of microbial transglutaminase-induced mung bean protein isolate gels

Mung bean protein isolate (MBPI) has attracted much attention as an emerging plant protein. However, its application was limited by the poor gelling characteristics. Thus, the effect of sanxan (SAN) on the gelling behavior of MBPI under microbial transglutaminase (MTG)-induced condition were explored in this study. The results demonstrated that SAN remarkably enhanced the storage modulus, water-holding capacity and mechanical strength. Furthermore, SAN changed the microstructure of MBPI gels to become more dense and ordered. The results of zeta potential indicated the electrostatic interactions existed between SAN and MBPI. The incorporation of SAN altered the secondary structure and molecular conformation of MBPI, and hydrophobic interactions and hydrogen bonding were necessary to maintain the network structure. Additionally, in vitro digestion simulation results exhibited that SAN remarkably improved the capability of MBPI gels to deliver bioactive substances. These findings provided a practical strategy to use natural SAN to improve legume protein gels.

Soybean protein isolate-sodium alginate double network emulsion gels: Mechanism of formation and improved freeze-thaw stability

Soybean protein isolate (SPI) is widely used in the food industry. However, SPI-based emulsion gels tend to aggregate and undergo oiling-off during freeze-thawing. In this study, emulsion gels were prepared by a combination of heat treatment and ionic cross-linking using SPI and sodium alginate (SA) as raw materials. The focus was on exploring the mechanistic effects of the SPI-SA double network structure on the freeze-thaw stability of emulsion gels. The results showed that the addition of SA could form different types of network structures with SPI, due to different degrees of phase separation. In addition, SA appearing on the SPI network indicated that the addition of Ca2+ shielded the electrostatic repulsion between SPI and SA to form SPI-SA complexes. The disappearance of the characteristic peaks of SA and SPI in Fourier transform infrared spectroscopy analysis also confirmed this view. Low-field nuclear magnetic resonance data revealed that SA played a role in restricting water migration within the emulsion gels, increasing bound water content, and thereby improving the water-holding capacity of the emulsion gels. Therefore, the incorporation of SA improved the freeze-thaw stability of SPI emulsion gels. These findings offer a theoretical basis and technical support for SPI application in frozen products.

Emerging Chemical, Biochemical, and Non-Thermal Physical Treatments in the Production of Hypoallergenic Plant Protein Ingredients

Allergies towards gluten and legumes (such as, soybean, peanut, and faba bean) are a global issue and, occasionally, can be fatal. At the same time, an increasing number of households are shifting to plant protein ingredients from these sources, which application and consumption are limited by said food allergies. Children, the elderly, and people with immune diseases are particularly at risk when consuming these plant proteins. Finding ways to reduce or eliminate the allergenicity of gluten, soybean, peanut, and faba bean is becoming crucial. While thermal and pH treatments are often not sufficient, chemical processes such as glycation, polyphenol conjugation, and polysaccharide complexation, as well as controlled biochemical approaches, such as fermentation and enzyme catalysis, are more successful. Non-thermal treatments such as microwave, high pressure, and ultrasonication can be used prior to further chemical and/or biochemical processing. This paper presents an up-to-date review of promising chemical, biochemical, and non-thermal physical treatments that can be used in the food industry to reduce or eliminate food allergenicity.

Lactoferrin-Chitosan Composite Hydrogels Induced by Microbial Transglutaminase: Potential Delivery Systems for Thermosensitive Bioactive Substances

In this work, lactoferrin (LF)-chitosan (CS) composite hydrogels with good loading capacity of thermosensitive bioactive substances were successfully obtained by microbial transglutaminase (MTG)-induced cross-linking. We evaluated the rheological, textural, and microstructural characteristics of the composite hydrogels under different conditions. The results demonstrated that the concentrations of LF and CS as well as the amount of MTG could regulate the textural properties, rheological properties, and water holding capability. The results of FTIR and fluorescence spectroscopy indicated that the main interactions within the composite gel were hydrogen and isopeptide bonds. Additionally, in vitro digestion simulation results verified that riboflavin kept stable in stomach due to the protection of LF-CS composite hydrogels and was released in small intestine. These results suggested that thermosensitive bioactive substance could be encapsulated and delivered by the LF-CS composite hydrogel, which could be applied in lots of potential applications in functional food as a new material.

Sucrose and Ca2+ synergistically regulate the rheological properties of apple high-methoxyl pectin

The thickening and gelling mechanism of high-methoxyl pectins (HMPs) with different degree of esterification (DE) values (60.6 %, 66.1 %, and 72.4 %) synergistically affected by calcium ion (Ca2+) and sucrose was investigated using several technical methods. Rheological measurements, including steady-shear flow, thixotropy and dynamic viscoelasticity tests, texture analysis, water-holding capacity (WHC), thermal analyses (TG), and microstructure observation (TEM), were all systemically conducted. The results showed that the main thickening and gelling mechanism of Ca2+ on different HMPs was complex and the presence of sucrose had a synergistic effect on structure formation in HMP systems. Ca2+ was not always conducive to structure formation, and excessive Ca2+ addition may hinder structure formation. HMP systems with lower DE values had higher gel strengths due to the presence of more binding domains. The results of the texture properties, WHC, and thermal characteristics coincided with those obtained from the rheological measurements, which reflect the variations in HMPs affected by Ca2+ and DE. All of these results showed that Ca2+ addition at an appropriate concentration in the presence of sucrose favors HMP gelation even in the absence of acid. The results obtained here are expected to broaden the application of HMPs in acid-free gel food products.

Effect of apple high-methoxyl pectin on heat-induced gelation of silver carp myofibrillar protein

The effect of adding apple high-methoxy pectin (HMP) (0-3 mg∙mL-1) on heat-induced gel characteristics of low concentration silver carp myofibrillar protein (MP) (15 mg∙mL-1) was studied. It was found that the hardness of gel increased by 20.6 times with adding 2 mg∙mL-1 HMP. Besides, HMP aided in the development of disulfide bonds and the aggregation of hydrophobic groups. During gel formation, the maximal storage modulus (G') of samples supplemented with 2 mg·mL-1 HMP was raised by a factor of 2.7. Of note, the images of SEM showed that protein and water were tightly combined with a proper amount of HMP and made its pores more uniform and dense. Meantime, the addition of moderate amounts of HMP enabled the formation of gels with favorable texture and performance at low concentration of MP was identified, which could provide a theoretical reference for the design and production of flesh low-calorie food gel.

Hawthorn pectin/soybean isolate protein hydrogel bead as a promising ferrous ion-embedded delivery system

In this study, hydrogel beads [SPI/HP-Fe (II)] were prepared by cross-linking soybean isolate protein (SPI) and hawthorn pectin (HP) with ferrous ions as a backbone, and the effects of ultrasound and Fe2+ concentration on the mechanical properties and the degree of cross-linking of internal molecules were investigated. The results of textural properties and water-holding capacity showed that moderate ultrasonic power and Fe2+ concentration significantly improved the stability and water-holding capacity of the hydrogel beads and enhanced the intermolecular interactions in the system. Scanning electron microscopy (SEM) confirmed that the hydrogel beads with 60% ultrasonic power and 8% Fe2+ concentration had a denser network. X-ray photoelectron spectroscopy (XPS) and atomic absorption experiments demonstrated that ferrous ions were successfully loaded into the hydrogel beads with an encapsulation efficiency of 82.5%. In addition, in vitro, simulated digestion experiments were performed to understand how the encapsulated Fe2+ is released from the hydrogel beads, absorbed, and utilized in the gastrointestinal environment. The success of the experiments demonstrated that the hydrogel beads were able to withstand harsh environments, ensuring the bioactivity of Fe2+ and improving its bioavailability. In conclusion, a novel and efficient ferrous ion delivery system was developed using SPI and HP, demonstrating the potential application of SPI/HP-Fe (II) hydrogel beads as an iron supplement to overcome the inefficiency of intake of conventional iron supplements.

Lysozyme amyloid fibril-chitosan double network hydrogel: Preparation, characterization, and application on inhibition of Nε-(carboxyethyl)lysine

Nε-(carboxyethyl)lysine (CML), a typical advanced glycosylation end product produced during the processing of meat under high temperature, poses health risks. Active substances like polyphenols are known to inhibit the formation of harmful products during the processing of food. In this study, our objective was to prepare a double network hydrogel (DN) loaded with gallic acid using amyloid fibers and chitosan as a rigid and flexible network, respectively. The network as well as the interactions between the two networks were observed and analyzed. Chitosan concentration was the key factor regulating the structure and properties of the DN. At a chitosan concentration of 0.7%wt, the structure of DN became dense and its mechanical properties were improved, with the loading capacity and loading efficiency being increased by 143.79 % and 128.21 %, compared with those of amyloid fibril alone. Furthermore, the digestibility of gallic acid in simulated intestinal fluid was increased by 215.10 %. Moreover, adding DN to the beef patties effectively inhibited the formation of CML in a dose-response dependent manner. Addition of 3 wt% DN resulted in the inhibitory rate of CML in roast beef patties reaching a high 73.09 %. The quality and palatability of beef patties were improved. These findings suggest that DN shows great potential as an application that may be utilized to deliver active substances aimed at inhibiting CML in the meat processing industry.

Insights into the impact of modification methods on the structural characteristics and health functions of pectin: A comprehensive review

Pectin is a complex polysaccharide that is widely present in plant cells and has multiple physiological functions. However, most pectin exists in the form of protopectin, which has a large molecular weight and cannot be fully absorbed and utilized in the human gut to exert its effects. The significant differences in the structure of different sources of pectin also limited their application in the food and medical fields. In order to achieve greater development and utilization of pectin functions, this paper reviewed several commonly used methods for pectin modification from physical, chemical, and biological perspectives, and elaborated on the relationship between these modification methods and the structure and functional properties of pectin. At the same time, the functional characteristics of modified pectin and its application in medical health, such as regulating intestinal health, anticancer, anti-inflammatory, and drug transport, were reviewed, so as to provide a theoretical basis for targeted modification of pectin and the development of new modified pectin products.

Effect of soluble dietary fiber on soy protein isolate emulsion gel properties, stability and delivery of vitamin D3

Emulsion gels with denser network microstructure and stronger mechanical properties have attracted increasing attentions for delivering lipophilic compounds. In this study, the effect of three distinct soluble dietary fiber (inulin (IN), resistant dextrin (RD) and stachyose (ST)) on the rheological, mechanical and microstructural properties of soy protein isolate (SPI) emulsion gel were firstly investigated. Compared with RD and IN, ST significantly accelerated water holding capacity and thermal stability, which exhibited more compact microstructure and more uniform emulsified oil droplets. Subsequently, the stability and bioavailability of vitamin D3 (VD3) in different delivery systems (medium chain triglycerides (MCT) embedding, SPI-ST emulsion embedding, SPI emulsion gel embedding and SPI-ST emulsion gel embedding) were continue evaluated. In vitro simulated digestion experiment demonstrated that the bioaccessibility of encapsulated VD3 in SPI-ST emulsion gel (69.95 %) was much higher than that of free embedding (48.99 %). In vivo pharmacokinetic experiment revealed that the bioavailability of VD3 was significantly enhanced in SPI-ST gel (p < 0.05), with the AUC0-24h value of 25-OH VD3 (the main circulating form of VD3) were 1.34-fold, 1.23-fold higher than that of free embedding, MCT embedding, respectively. These findings provide a possible approach for the development of high protein/fiber functional foods containing enhanced hydrophobic bioactives.

Towards superior biopolymer gels by enabling interpenetrating network structures: A review on types, applications, and gelation strategies

Gels derived from single networks of natural polymers (biopolymers) typically exhibit limited physical properties and thus have seen constrained applications in areas like food and medicine. In contrast, gels founded on a synergy of multiple biopolymers, specifically polysaccharides and proteins, with intricate interpenetrating polymer network (IPN) structures, represent a promising avenue for the creation of novel gel materials with significantly enhanced properties and combined advantages. This review begins with the scrutiny of newly devised IPN gels formed through a medley of polysaccharides and/or proteins, alongside an introduction of their practical applications in the realm of food, medicine, and environmentally friendly solutions. Finally, based on the fact that the IPN gelation process and mechanism are driven by different inducing factors entwined with a diverse amalgamation of polysaccharides and proteins, our survey underscores the potency of physical, chemical, and enzymatic triggers in orchestrating the construction of crosslinked networks within these biomacromolecules. In these mixed systems, each specific inducer aligns with distinct polysaccharides and proteins, culminating in the generation of semi-IPN or fully-IPN gels through the intricate interpenetration between single networks and polymer chains or between two networks, respectively. The resultant IPN gels stand as paragons of excellence, characterized by their homogeneity, dense network structures, superior textural properties (e.g., hardness, elasticity, adhesion, cohesion, and chewability), outstanding water-holding capacity, and heightened thermal stability, along with guaranteed biosafety (e.g., nontoxicity and biocompatibility) and biodegradability. Therefore, a judicious selection of polymer combinations allows for the development of IPN gels with customized functional properties, adept at meeting precise application requirements.

The three-dimensional culture of L929 and C2C12 cells based on SPI-SA interpenetrating network hydrogel scaffold with excellent mechanical properties

Cell-cultured meat, which is obtained by adsorbing cells on the three-dimensional scaffold, is considered a potential solution to animal welfare issues. Edible and safe cell-cultured meat scaffolds are a key part of its research. Soy protein isolate (SPI) hydrogel has a three-dimensional network structure and has been studied for L929 cell culture because of its non-toxicity and biocompatibility. However, the toughness and mechanical properties of SPI hydrogel are not enough to bear the requirements of cell cultivation. In this paper, sodium alginate (SA) was added to SPI hydrogel, and the interpenetrating network (IPN) technology was used to construct SPI-SA IPN hydrogel by transglutaminase and Ca2+ double crosslinking method. SPI-SA IPN hydrogel has excellent mechanical properties, structural stability and biodegradable performance than SPI hydrogel. The bio-compatibility and degradability of L929 and C2C12 cells on SPI-SA IPN hydrogel were studied by cytotoxicity, trypan blue and living/dead cell staining, and the growth law of the hydrogel as a scaffold for cell culture was analyzed. The results showed that L929/C2C12 cells can proliferate normally and adhere in hydrogel and have good bio-compatibility. L929 cells with size about 20-50 µm have better adhesion and growth abilities on SPI-SA IPN hydrogel than C2C12 cells with 100-300 µm. Therefore, the SPI-SA IPN hydrogel is non-toxic and supports the growth of cells in the pores of the material. This study provides a reference for the application of SPI-SA IPN hydrogels in vitro cell growth.

Construction of Manganese-Based Oyster (Crassostrea gigas) Ferritin Nanozyme with Catalase-like Enzyme Activity

MnO2 is a nanozyme that inhibits the decomposition of hydrogen peroxide (H2O2) into a hydroxyl radical (OH•), thus preventing its conversion into reactive oxygen species (ROS). Oyster ferritin (GF1) is a macromolecular protein that provides uniform size and high stability and serves as an excellent template for the biomineralization of nanozyme. This study presents a unique method in which MnO2 is grown in situ in the GF1 cavity, yielding a structurally stable ferritin-based nanozyme (GF1@Mn). GF1@Mn is demonstrated to be stable at 80 °C and pH 4-8, exhibiting a higher affinity with H2O2 than many other catalases (CAT) with a Michaelis constant (Km) of 25.45 mmol/L. In vitro experiments have demonstrated the potential of GF1@Mn to enhance cell survival by reducing nitric oxide (NO) production while mitigating macrophage damage from ROS. The findings are essential to developing ferritin-based nanozymes and hold great potential for applications in functional food development.

Conjugation of soymilk protein and arabinoxylan induced by peroxidase to improve the gel properties of tofu

Arabinoxylan (AX) can form stable covalent bonds with protein to improve gel properties. We aimed to prepare a conjugate between soymilk protein (SMP) and AX by peroxidase, followed by the addition of transglutaminase (TG) to prepare tofu gels. The conjugate's properties and their effects on the mechanical properties, rheological properties, and microstructure of tofu gels were evaluated. Results revealed that the α-helix content decreased, the β-sheet content increased, and the surface hydrophobicity reduced from 1.60 × 105 to 1.27 × 105. The optimal amount of AX required to improve the properties of tofu gel was 1.0%. The tofu gel showed better hardness (118.44 g), water holding capacity (WHC) (86.17%), and higher storage modulus (G') and loss modulus (G″). Low-Field NMR (LF-NMR) showed that the water was evenly distributed. Scanning electron microscopy (SEM) revealed a denser and more regular three-dimensional gel network.

Wheat bran arabinoxylan-soybean protein isolate emulsion-filled gels as a β-carotene delivery carrier: Effect of polysaccharide content on textural and rheological properties

This study aimed to investigate the effects of different wheat bran arabinoxylan (WBAX) concentrations (1, 2, 3, and 4 wt%) on the structural and physicochemical properties of WBAX-soybean protein isolate (SPI) emulsion-filled gels (EFGs) prepared using laccase and heat treatment. The properties of the various gels as well as their microstructure, rheology, and in vitro digestion behaviors were investigated. Results showed that WBAX-SPI EFGs with a 3 wt% WBAX concentration had a smooth and uniform appearance, high water holding capacity (98.5 ± 0.2 %), and enhanced mechanical properties. Rheological experiments suggested that a stronger and closer gel network was formed at 3 wt% WBAX concentration. Fourier transform infrared spectroscopy showed that laccase and heat treatment not only catalyzed the intramolecular crosslinking of WBAX and SPI, respectively, but also promoted the interaction between WBAX and SPI. Confocal laser scanning microscopy revealed that the WBAX gel network was interspersed within the SPI network. The interactions contributing to the gelation analysis revealed that chemical (disulfide bond) and physical (hydrogen bond and hydrophobic) interactions promoted the formation of denser EFGs. Furthermore, the WBAX-SPI EFGs provided a β-carotene bioaccessibility of 21.8 ± 0.6 %. Therefore, our study suggests that WBAX-SPI EFGs hold promising potential for industrial applications in the delivery of β-carotene.

Effects of direct addition of curdlan on the gelling characteristics of thermally induced soy protein isolate gels

In this study, the effects of the direct addition of curdlan on the physicochemical, structural, and functional properties of heat-induced soy protein isolate (SPI) gels were evaluated. Results demonstrated that the direct incorporation of curdlan enhanced the gel-forming performance, water-holding capacity, and gel strength of heat-induced SPI gels. The presence of curdlan reduced the free water molecules and α-helix content in the SPI structure and contributed to the construction of stable SPI gels with uniform and compact network structures, as visually proven by microstructure observations. Moreover, compared with the SPI gel alone, the curdlan-SPI composite gels presented a more pronounced viscoelastic property and thermal stability mainly due to the intermolecular hydrogen bonding interaction between curdlan and the SPI molecules. Our findings suggest that the direct incorporation of curdlan can effectively ameliorate the gelling characteristics of heat-induced SPI gels, indicating its potential application as a promising gel improver in the food industry.

Fabrication and rheological properties of a novel interpenetrating network hydrogel based on sage seed hydrocolloid and globulin from the hydrocolloid extraction by-product

In this study, interpenetrating polymer network hydrogels were developed based on sage seed gum (SSG) and globulin protein (Glo) extracted from the mucilage-free seeds. By combining Glo hydrogel with the SSG network the inherent weak gelation of the single SSG system was compensated. As the fraction of Glo increased, various properties of the interpenetrating polymer network (IPN) hydrogels improved substantially. Electrophoretic analysis under reducing conditions showed that Glo dissociated into subunits of approximately 30 kDa and 20 kDa, suggesting it comprises 11S globulin. FTIR spectrum revealed new peaks at 1645 cm-1 and 1537 cm-1 in the amide I and II regions, respectively, for the IPN hydrogels, indicating interactions between two hydrogel networks. Based on the weight loss measurements, the IPN hydrogels exhibited lower mass loss, particularly at higher Glo fractions up to 6 %. The IPN hydrogels also displayed enhanced elasticity, pseudoelasticity, thixotropy, and creep resistance compared to SSG hydrogel, indicating suitability for food, pharmaceutical, and biomedical applications. More broadly, this research provides a sustainable strategy toward innovative material development while advancing bio-based hydrogels.

Effects of Transglutaminase Concentration and Drying Method on Encapsulation of Lactobacillus plantarum in Gelatin-Based Hydrogel

Lactobacillus plantarum is a kind of probiotic that benefits the host by regulating the gut microbiota, but it is easily damaged when passing through the gastrointestinal tract, hindering its ability to reach the destination and reducing its utilization value. Encapsulation is a promising strategy for solving this problem. In this study, transglutaminase (TGase)-crosslinked gelatin (GE)/sodium hexametaphosphate (SHMP) hydrogels were used to encapsulate L. plantarum. The effects of TGase concentration and drying method on the physiochemical properties of the hydrogels were determined. The results showed that at a TGase concentration of 9 U/gGE, the hardness, chewiness, energy storage modulus, and apparent viscosity of the hydrogel encapsulation system were maximized. This concentration produced more high-energy isopeptide bonds, strengthening the interactions between molecules, forming a more stable three-dimensional network structure. The survival rate under the simulated gastrointestinal conditions and storage stability of L. plantarum were improved at this concentration. The thermal stability of the encapsulation system dried via microwave vacuum freeze drying (MFD) was slightly higher than that when dried via freeze drying (FD). The gel structure was more stable, and the activity of L. plantarum decreased more slowly during the storage period when dried using MFD. This research provides a theoretical basis for the development of encapsulation technology of probiotics.

A comparative study of the impacts of preparation techniques on the rheological and textural characteristics of emulsion gels (emulgels)

A subtype of soft solid-like substances are emulsion gels (emulgels; EGs). These composite material's structures either consist of a network of aggregated emulsion droplets or a polymeric gel matrix that contains emulsion droplets. The product's rheological signature can be used to determine how effective it is for a specific application. The interactions between these structured system's separate components and production process, however, have a substantial impact on their rheological imprint. Therefore, rational comprehension of interdependent elements, their structural configurations, and the resulting characteristics of a system are essential for accelerating our progress techniques as well as for fine-tuning the technological and functional characteristics of the finished product. This article presents a comprehensive overview of the mechanisms and procedures of producing EGs (i.e., cold-set and heat-set) in order to determine the ensuing rheological features for various commercial applications, such as food systems. It also describes the influence of these methods on the rheological and textural characteristics of the EGs. Diverse preparation methods are the cause of the rheological-property correlations between different EGs. In many ways, EGs can be produced using various matrix polymers, processing techniques, and purposes. This may lead to various EG matrix structures and interactions between them, which in turn may affect the composition of EGs and ultimately their textural and rheological characteristics.

Ultrasonic and homogenization: An overview of the preparation of an edible protein-polysaccharide complex emulsion

Emulsion systems are extensively utilized in the food industry, including dairy products, such as ice cream and salad dressing, as well as meat products, beverages, sauces, and mayonnaise. Meanwhile, diverse advanced technologies have been developed for emulsion preparation. Compared with other techniques, high-intensity ultrasound (HIUS) and high-pressure homogenization (HPH) are two emerging emulsification methods that are cost-effective, green, and environmentally friendly and have gained significant attention. HIUS-induced acoustic cavitation helps in efficiently disrupting the oil droplets, which effectively produces a stable emulsion. HPH-induced shear stress, turbulence, and cavitation lead to droplet disruption, altering protein structure and functional aspects of food. The key distinctions among emulsification devices are covered in this review, as are the mechanisms of the HIUS and HPH emulsification processes. Furthermore, the preparation of emulsions including natural polymers (e.g., proteins-polysaccharides, and their complexes), has also been discussed in this review. Moreover, the review put forward to the future HIUS and HPH emulsification trends and challenges. HIUS and HPH can prepare much emulsifier-stable food emulsions, (e.g., proteins, polysaccharides, and protein-polysaccharide complexes). Appropriate HIUS and HPH treatment can improve emulsions' rheological and emulsifying properties and reduce the emulsions droplets' size. HIUS and HPH are suitable methods for developing protein-polysaccharide forming stable emulsions. Despite the numerous studies conducted on ultrasonic and homogenization-induced emulsifying properties available in recent literature, this review specifically focuses on summarizing the significant progress made in utilizing biopolymer-based protein-polysaccharide complex particles, which can provide valuable insights for designing new, sustainable, clean-label, and improved eco-friendly colloidal systems for food emulsion. PRACTICAL APPLICATION: Utilizing complex particle-stabilized emulsions is a promising approach towards developing safer, healthier, and more sustainable food products that meet legal requirements and industrial standards. Moreover, the is an increasing need of concentrated emulsions stabilized by biopolymer complex particles, which have been increasingly recognized for their potential health benefits in protecting against lifestyle-related diseases by the scientific community, industries, and consumers.

Characterization of structural and functional properties of soy protein isolate and sodium alginate interpenetrating polymer network hydrogels

BACKGROUND

This study used enzymatic and Ca2+ cross-linking methods to prepare edible soy protein isolate (SPI) and sodium alginate (SA) interpenetrating polymer network hydrogels to overcome the disadvantages of traditional interpenetrating polymer network (IPN) hydrogels, such as poor performance, high toxicity, and inedibility. The influence of changes in SPI and SA mass ratio on the performance of SPI-SA IPN hydrogels was investigated.

RESULTS

Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure of the hydrogels. Texture profile analysis (TPA), rheological properties, swelling rate, and Cell Counting Kit-8 (CCK-8) were used to evaluate physical and chemical properties and safety. The results showed that, compared with SPI hydrogel, IPN hydrogels had better gel properties and structural stability. As the mass ratio of SPI-SA IPN changed from 1:0.2 to 1:1, the gel network structure of hydrogels also tended to be dense and uniform. The water retention and mechanical properties of these hydrogels, such as storage modulus (G'), loss modulus (G"), and gel hardness increased significantly and were greater than those of the SPI hydrogel. Cytotoxicity tests were also performed. The biocompatibility of these hydrogels was good.

CONCLUSIONS

This study proposes a new method to prepare food-grade IPN hydrogels with mechanical properties of SPI and SA, which may have strong potential for the development of new foods. © 2023 Society of Chemical Industry.

Food gel-based systems for efficient delivery of bioactive ingredients: design to application

Food gels derived from natural biopolymers are valuable materials with significant scientific merit in the food industry because of their biocompatibility, safety, and environmental friendliness compared to synthetic gels. These gels serve as crucial delivery systems for bioactive ingredients. This review focuses on the selection, formulation, characterization, and behavior in gastrointestinal of hydrogels, oleogels, and bigels as delivery systems for bioactive ingredients. These three gel delivery systems exhibit certain differences in composition and can achieve the delivery of different bioactive ingredients. Hydrogels are suitable for delivering hydrophilic ingredients. Oleogels are an excellent choice for delivering lipophilic ingredients. Bigels contain both aqueous and oil phases, whose gelation makes their structure more stable, demonstrating the advantages of the above two types of gels. Besides, the formation and properties of the gel system are confirmed using different characterization methods. Furthermore, the changing behavior (e.g., swelling, disintegration, collapse, erosion) of the gel structure in the gastrointestinal is also analyzed, providing an opportunity to formulate soft substances that offer better protection or controlled release of bioactive components. This can further improve the transmissibility and utilization of bioactive substances, which is of great significance.

Effect of Flaxseed Gum on the Textural, Rheological, and Tribological Properties of Acid-Induced Soy Protein Isolate Gels

This study aimed to investigate the effects of incorporating different concentrations of flaxseed gum (FG) into acid-induced soy protein isolate (SPI) gels. The investigation focused on assessing the effects of FG on the textural, rheological, and tribological properties of the resultant SPI gels. The results showed that adding a small amount of FG (0.05%) to the SPI gel system increased the storage modulus (G') and enhanced gelation while improving textural properties including hardness, viscosity, elasticity, and adhesion. Moreover, these gels exhibited strong water-holding capacity, a desirable property in various food products. However, when the concentration was increased to 0.3%, the WHC of the gel decreased, as did the hardness and cohesiveness. The particle size of the gel also increased with increasing concentration. Tribological investigations revealed that at 0.05-0.2% FG addition, the coefficient of friction (μ) of the composite gel was decreased compared to the pure SPI gel. In the sliding speed range of 1-100 mm/s, the coefficient of friction gradually increased with increasing concentration. When the FG concentration was 0.05%, the μ of the gel system was the lowest. In summary, low concentration of FG (0.05%) was found to play an important role in improving the properties of SPI gel, including enhancing textural, rheological, and lubricating properties.

Legume protein/polysaccharide food hydrogels: Preparation methods, improvement strategies and applications

For the development of innovative foods and nutritional fortification, research into food gel is essential. As two types of rich natural gel material, both legume proteins and polysaccharides have high nutritional value and excellent application potential, attracting wide attention worldwide. Research has focused on combining legume proteins with polysaccharides to form hybrid hydrogels as their combinations show improved texture and water retention compared to single legume protein or single polysaccharide gels, and these properties can be tailored for specific applications. This article reviews hydrogels of common legume proteins and discusses heat induction, pH induction, salt ion induction, and enzyme-induced assembly of legume protein/polysaccharide mixtures. The applications of these hydrogels in fat replacement, satiety enhancement, and delivery of bioactive ingredients are discussed. Challenges for future work are also highlighted.

Solidification of concentrated pea protein-pectin mixtures as potential binder

BACKGROUND

Binders in plant-based meat analogues allow different components, such as extrudate and fat particles, to stick together. Typically, binders then are solidified to transform the mass into a non-sticky, solid product. As an option for a clean-label binder possessing such properties, the solidification behavior of pea protein-pectin mixtures (250 g kg^-1 , r = 2:1, pH 6) was investigated upon heating, and upon addition of calcium, transglutaminase, and laccase, or by combinations thereof.

RESULTS

Mixtures of (homogenized) pea protein and apple pectin had higher elastic moduli and consistency coefficients and lower frequency dependencies upon calcium addition. This indicated that calcium physically cross-linked pectin chains that formed the continuous phase in the biopolymer matrix. The highest degree of solidification was obtained with a mixture of pea protein and sugar beet pectin upon addition of laccase that covalently cross-linked both biopolymers involved. All solidified mixtures lost their stickiness. A mixture of soluble pea protein and apple pectin solidified only slightly through calcium and transglutaminase, probably due to differences in the microstructural arrangement of the biopolymers.

CONCLUSION

The chemical makeup of the biopolymers and their spatial distribution determines solidification behavior in concentrated biopolymer mixtures. In general, pea protein-pectin mixtures can solidify and therefore have the potential to act as binders in meat analogues. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Impacts of Industrial Modification on the Structure and Gel Features of Soy Protein Isolate and its Composite Gel with Myofibrillar Protein

Native soy protein isolate (N-SPI) has a low denaturation point and low solubility, limiting its industrial application. The influence of different industrial modification methods (heat (H), alkaline (A), glycosylation (G), and oxidation (O)) on the structure of SPI, the properties of the gel, and the gel properties of soy protein isolate (SPI) in myofibril protein (MP) was evaluated. The study found that four industrial modifications did not influence the subunit composition of SPI. However, the four industrial modifications altered SPI's secondary structure and disulfide bond conformation content. A-SPI exhibits the highest surface hydrophobicity and I_850/830 ratio but the lowest thermal stability. G-SPI exhibits the highest disulfide bond content and the best gel properties. Compared with MP gel, the addition of H-SPI, A-SPI, G-SPI, and O-SPI components significantly improved the properties of the gel. Additionally, MP-ASPI gel exhibits the best properties and microstructure. Overall, the four industrial modification effects may impact SPI's structure and gel properties in different ways. A-SPI could be a potential functionality-enhanced soy protein ingredient in comminuted meat products. The present study results will provide a theoretical basis for the industrialized production of SPI.

Gelation behaviors and mechanism of a new pectic polysaccharide from apple pomace as a potential gelatin substitute

In this study, we reported a pectic polysaccharide industrially obtained from apple pomace by metal ion precipitation technique showing an unexpected gelation behavior. Structurally, this apple pectin (AP) is a macromolecular polymer with a weight-average molecular weight (Mw) of 361.7 kDa, and DM (degree of methoxylation) of 12.5 %, comprising 60.38 % glucose, 19.41 % mannose, 17.60 % galactose and 1.00 % rhamnose and 1.61 % glucuronic acid. The low acidic sugar percentage relative to the total monosaccharide amount indicated a high branching structure of AP. On addition of Ca²⁺ ions, AP exhibited a remarkable gelling ability upon cooling its heat solution to low temperature (e.g., 4 °C). However, at room temperature (e.g., 25 °C) or in the absence of Ca²⁺, no gel was formed. At a fixed pectin concentration (0.5 %, w/v), AP showed increasing gel hardness and gelation temperature (T_gel) with CaCl₂ concentration increasing to 0.05 % (w/v); however, further addition of CaCl₂ weakened AP gels and even abolished the gelation. On reheating, all gels melted below 35 °C, which suggests the potential use of AP as a gelatin substitute. The gelation mechanism was explained as an intricate balance of the synchronous formation of hydrogen bond and Ca²⁺ crosslinks between AP molecules during cooling.

A review of oil and water retention in emulsified meat products: The mechanisms of gelation and emulsification, the application of multi-layer hydrogels

Emulsified meat products are key deep-processing products due to unique flavor and high nutritional value. Myosin dissolves, and protein aggregation and heat-induced gelation occur after myosin unfolds and hydrophobic groups are exposed. Myosin could form interfacial protein membranes and wrap fat globules. Emulsified fat globules may be filled in heat-induced gel networks. Therefore, this review intends to discuss the influences of heat-induced gelation and interfacial adsorption behavior on oil and water retention. Firstly, the mechanism of heat-induced gelation was clarified from the perspective of protein conformation and micro-structure. Secondly, the mechanism of emulsification stability and its factors affecting interfacial adsorption were demonstrated as well as limitations and challenges. Finally, the structure characteristics and application of multi-layer hydrogels in the gelation and emulsification were clarified. It could conclude that the characteristic morphology, spatial conformation and structure adjustment affected heat-induced gelation and interfacial adsorption behavior. Spatial conformation and microstructure were adjusted to improve the oil and water retention by pH, ionic strength, amino acid, oil phase characteristic and protein interaction. Multi-layer hydrogels facilitated oil and water retention. The comprehensive review of gelation and emulsification mechanisms could promote the development of meat products and improvement of meat processing technology.

Fabrication of high strength cold-set sodium alginate/whey protein nanofiber double network hydrogels and their interaction with curcumin

Enhancing the bio-based hydrogels strength is fundamental to extend their engineering applications. In this study, high strength cold-set sodium alginate/whey protein nanofiber (SA/WPN) double network hydrogels were prepared and their interaction with curcumin (Cur) was studied. Our results indicated that the rheological and textural properties of SA/WPN double network hydrogels were enhanced with increasing WPN by forming SA-COO^--Ca²⁺-^-OOC-WPN bridge through electrostatic interactions. The storage modulus (768.2 Pa), hardness (273.3 g), adhesiveness (318.7 g·sec) and cohesiveness (0.464) of SA/WPN50 (WPN concentration of 50 mg/mL) double network hydrogels were 3.75, 2.26, 3.76 and 2.19 times higher than those of SA hydrogels, respectively. Cur was combined with SA/WPN hydrogels through hydrogen bonding, van der Waals forces and hydrophobic interactions with an encapsulation efficiency of 91.6 ± 0.8 %, and the crystalline state was changed after binding. In conclusion, SA/WPN double network hydrogels can be enhanced by the addition of WPN and have potential as carriers for hydrophobic bioactive substances.

Elastic and transparent ovalbumin hydrogels formed via succinylation combined with pH-shifting treatment

Ovalbumin (OVA) is a model protein with extensive research on structure and function, however, the application of OVA in food processing is limited due to its low gelation properties. In this study, thermally-induced highly transparent and elastic hydrogels from OVA pretreated by succinylation combined with pH-shifting method were reported. Transmission electron microscope (TEM) and free sulfhydryl groups determination revealed that the pretreatment induced the stretching of the protein structure and promoted the formation of preliminary aggregates. Further heating the pretreated OVA suspension resulted in a homogeneous and macroporous gel network with thin connecting walls. Such homogeneous gel network structures may be related to the effective modulation of the thermal aggregation efficiency of proteins by succinylation and the high level of protein unfolding by pH-shifting treatments, which synergistically allowed for more active sites to be created during heating to facilitate intermolecular interactions, including hydrogen bonding and hydrophobic interactions. Notably, the method resulted in a 507.14% increase in elasticity, a 60.74% increase in water holding capacity of the OVA hydrogels compared to the native OVA hydrogels without pretreatment. Also, the hydrogels were transparent with 73.11% light transmittance. In conclusion, succinylation and pH-shifting combined treatment could be an effective method for the preparation of OVA hydrogels with superior gelation properties.

Extraction of structurally intact and well-stabilized rice bran oil bodies as natural pre-emulsified O/W emulsions and investigation of their rheological properties and components interaction

The isolated plant oil bodies (OBs) have shown promising applications as natural pre-emulsified O/W emulsions. Rice bran OBs can be used as a new type plant-based resource with superior fatty acids composition and abundant γ-oryzanol. This paper investigated the method of extracting structurally intact and stable rice bran OBs. Due to the adequate steric hindrance and electrostatic repulsion effects, rice bran OBs extracted by NaHCO₃ medium had smaller particle size, better physical stability, and natural structure. The protein profile of NaHCO₃-extracted rice bran OBs showed oleosin-L and oleosin-H, while exogenous proteins in PBS and enzyme-assisted- extracted rice bran OBs could interact with interfacial proteins through hydrophobic forces to aggregate adjacent OBs, further remodeling the OBs interface. It was also found that the small-sized rice bran OBs could adsorb on the interface of the larger-sized rice bran OBs like Pickering stabilizers. Rice bran OBs exhibited pseudoplastic fluids characteristic, but underwent a transition from solid-like to liquid-like behavior depending on the extraction method. The disorder of NaHCO₃-extracted rice bran OBs protein molecules increased their surface hydrophobicity. The random coil structure favored more proteins adsorption at the interface of rice bran OBs extracted by PBS. Enzyme-assisted extraction of rice bran OBs had the highest content of β-sheet structure, which facilitated the stretching and aggregation of protein spatial structure. It was also confirmed the hydrogen bonding and hydrophobic interaction between the triacylglycerol or phospholipid and proteins molecules, and the membrane compositions of rice bran OBs differed between extraction methods.

The interaction of trehalose and molten globule state soybean 11S globulin and its impact on foaming capacities

BACKGROUND

Soybean 11S globulin has good functional properties, which are widely used in the field of food. However, natural soybean 11S globulin (N-11S) has low flexibility and is easy to aggregate, impacting its foaming process. Studies have shown that soybean 11S globulin in molten globule state (MG-11S) has better molecular flexibility than N-11S, and trehalose has been shown to improve the properties of proteins. Therefore, this study investigated the interaction mechanism between trehalose and MG-11S, and its impact on rheological and foaming properties of MG-11S.

RESULTS

The molecular docking and intrinsic fluorescence results showed that hydrogen bonding was the main interaction force at lower than 0.5 mol L^-1 trehalose added. Meanwhile, rheology and foaming showed that the MG-11S-trehalose complexes had better viscoelasticity, foaming ability (66.67-86.67%) and foaming stability (75.00-89.29%) than N-11S (16.67% foaming ability and 40.00% foaming stability); however, when the trehalose was higher than 0.5 mol L^-1 , molecular crowding occurred and H-bonds were weakened, resulting in reduction of foaming capacities. Microstructure determination showed that trehalose attached to the surface of foam membrane; meanwhile, the foaming structure of the complex with 0.5 mol L^-1 trehalose had a thicker liquid film with decreased drainage rate, less agglomeration and disproportionation of foam, illustrating the best foaming ability and foaming stability.

CONCLUSION

The results suggested that trehalose at different concentrations can interact with MG-11S through different mechanisms, and improve the foaming capacity of MS-11S. This provided a reference for the application of MS-11S in foaming food. © 2022 Society of Chemical Industry.

Binary Hydrogels: Induction Methods and Recent Application Progress as Food Matrices for Bioactive Compounds Delivery-A Bibliometric Review

Food hydrogels are biopolymeric materials made from food-grade biopolymers with gelling properties (proteins and polysaccharides) and a 3D network capable of incorporating large amounts of water. They have sparked considerable interest because of their potential and broad application range in the biomedical and pharmaceutical sectors. However, hydrogel research in the field of food science is still limited. This knowledge gap provides numerous opportunities for implementing their unique properties, such as high water-holding capacity, moderated texture, compatibility with other substances, cell biocompatibility, biodegradability, and high resemblance to living tissues, for the development of novel, functional food matrices. For that reason, this article includes a bibliometric analysis characterizing research trends in food protein-polysaccharide hydrogels (over the last ten years). Additionally, it characterizes the most recent developments in hydrogel induction methods and the most recent application progress of hydrogels as food matrices as carriers for the targeted delivery of bioactive compounds. Finally, this article provides a future perspective on the need to evaluate the feasibility of using plant-based proteins and polysaccharides to develop food matrices that protect nutrients, including bioactive substances, throughout processing, storage, and digestion until they reach the specific targeted area of the digestive system.

Pea protein–sugar beet pectin binders can provide cohesiveness in burger type meat analogues

Methylcellulose is commonly used in meat analogues for binding ingredients. In this study, we compared the binding properties of a methylcellulose hydrogel (5% w/w) to a novel, clean-label binder based on a mixture of pea protein and sugar beet pectin (r = 2:1, 22.5% w/w, pH 6.0) with and without laccase addition in a burger type meat analogue. It was shown that the pea protein–pectin binder glued vegetable protein particles and fat mimic particles together prior to cooking and frying, thereby improving forming of the mass into burger patties. Furthermore, sensory analysis revealed that the cohesiveness of the fried burger patties was better when the protein–pectin binder was used. However, the used binder system did not affect the hardness of the burger patties indicating that the binders rather affected the coherence of the structural elements. Burgers with solid fat particles were rated better in terms of appearance as compared to emulsified fat particles, since the former were not visible. This study is useful to better understand meat analogue product design for a higher acceptance among consumers.

Comparison of Binding Properties of a Laccase-Treated Pea Protein-Sugar Beet Pectin Mixture with Methylcellulose in a Bacon-Type Meat Analogue

A bacon-type meat analogue consists of different structural layers, such as textured protein and a fat mimetic. To obtain a coherent and appealing product, a suitable binder must glue those elements together. A mixture based on pea protein and sugar beet pectin (r = 2:1, 25% w/w solids, pH 6) with and without laccase addition and a methylcellulose hydrogel (6% w/w) serving as benchmark were applied as binder between textured protein and a fat mimetic. A tensile strength test, during which the layers were torn apart, was performed to measure the binding ability. The pea protein-sugar beet pectin mixture without laccase was viscoelastic and had medium and low binding strength at 25 °C (F ≤ 3.5 N) and 70 °C (F ≈ 1.0 N), respectively. The addition of laccase solidified the mixture and increased binding strength at 25 °C (F ≥ 4.0 N) and 70 °C (F ≈ 2.0 N), due to covalent bonds within the binder and between the binder and the textured protein or the fat mimetic layers. Generally, the binding strength was higher when two textured protein layers were glued together. The binding properties of methylcellulose hydrogel was low (F ≤ 2.0 N), except when two fat mimetic layers were bound due to hydrophobic interactions becoming dominant. The investigated mixed pectin-pea protein system is able serve as a clean-label binder in bacon-type meat analogues, and the application in other products seems promising.