Physicochemical, rheological and digestive characteristics of soy protein isolate gel induced by lactic acid bacteria

Impact of Lactobacillus plantarum fermentation on the structural, physicochemical, emulsification, and digestibility properties of foxtail millet protein

The digestibility of foxtail millet protein is greatly limited by its intrinsic structure. This study was aimed to assess the effect of fermentation on the structural, physicochemical, and digestibility properties of foxtail millet protein. Results showed that fermentation increased the porosity and roughness of protein particles, while producing small-molecule proteins and peptides. Compared with original protein, the α-helix of protein decreased by 17.34 %-36.07 % after fermentation, while the content of β-sheet increased by 28.95 %-67.94 %, indicating changes in the secondary structure of proteins. Additionally, fermentation enhanced the hydrogen bonding interactions, increased air-water and oil-water interfacial tensions, and weakened disulfide bonds and electrostatic interactions. These changes reduced the surface hydrophobicity and emulsification capacity of proteins by 1.19 %-56.32 % and 13.31 %-49.26 %, respectively. Notably, fermentation increased protein digestibility from 68.63 % to 78.55 %. Thus, fermentation has great potential as a processing technology to improve the digestive properties of foxtail millet protein.

Improvement of compositional, textural, and rheological characteristics in plant-based cheese analogs fermented by kefir grain

Although plant-based cheese has been developed as a healthful food, it has limitations in terms of texture and flavor. In this study, novel soybean-based cheese analogs were prepared using soy protein isolate and kefir grains for improved properties. The analogs containing 3 % (w/v) soy protein isolate exhibited high water-holding capacity (90.80 %), and the sample prepared with 0.3 % (w/v) CaCl2 showed the high hardness (0.52 N). Additionally, hydrophobic interactions mainly contributed to structure formation and a significant proportion (> 90 %) of immobilized water was determined using low-field nuclear magnetic resonance analysis. Furthermore, the enhanced thermal stability and secondary structures of the analogs were demonstrated using thermogravimetric analysis, Fourier-transform infrared spectroscopy, and X-ray diffraction. The porous and compact microstructures of the analogs were observed using scanning electron microscopy. Our results provide an innovative approach for the preparation and application of plant-based cheese analogs using kefir grains.

The influence of γ-aminobutyric acid production and fat content on the gel properties, protein conformation, and nutritional characteristics of fermented milk: Achieved through interactions with milk proteins

The quality characteristics of fermented milk are closely related to the production of γ-aminobutyric acid in lactic acid bacteria and the fat content in milk. However, the mechanism of the effect of γ-aminobutyric acid (GABA) production and fat content on the gel properties and nutritional properties of fermented milk is still unclear. Therefore, this study used scanning electron microscopy, fourier transform infrared spectroscopy, circular dichroism spectroscopy and other technical means to clarify that GABA and fat can interact with milk protein, thereby promoting the formation of a more dense and stable gel network structure in fermented milk. This interaction has a significant impact on the texture, particle size, zeta potential, water holding capacity and rheological properties of fermented milk, revealing that the change of protein conformation is the internal factor to improve the performance of gel. In addition, by analyzing the free amino acids, short-chain fatty acids, and untargeted metabolomics of fermented milk, the significant regulatory effects of GABA and fat on its amino acid and fatty acid metabolism pathways were clarified, which influenced the nutritional composition of fermented milk. These findings elucidate the key roles and underlying mechanisms of GABA and fat in enhancing the quality of fermented milk, providing a theoretical basis and technical support for further optimizing the production process of fermented milk and improving product quality.

Thiol-modified hyaluronic acid and hydroxyl radical-induced oxidation synergistically enhance the gelling capacity of ginkgo seed proteins

The objective of this work was to investigate the effect of synthetic thiol-modified hyaluronic acid (HASH) on the gelation properties of ginkgo seed protein isolate (GSPI) under non-oxidizing (NOX) or oxidizing (OX) conditions. Under NOX conditions, HASH mediated the disruption of disulfide bonds, leading to a dose-dependent dissociation of GSPI. Conversely, in OX conditions, hydroxyl radical-induced oxidation facilitated the formation of interprotein disulfide bonds. Incremental increases in HASH concentration were found to significantly enhance the textural characteristics of the GSPI gel, achieving optimal elasticity. Moreover, HASH incorporation conferred increased rigidity and porosity to the gel matrix, markedly improving the water holding capacity and reducing the protein leachability. Additionally, OX conditions amplified the beneficial effect of HASH on gel strength and hydration properties. This study elucidates a novel approach for enhancing the gel properties of GSPI and modulating protein-polysaccharide interaction through the chemical modification of natural polysaccharides.

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.

Comparative Study on the Physical and Chemical Properties Influenced by Variations in Fermentation Bacteria Groups: Inoculating Different Fermented Mare's Milk into Cow's Milk

Fermented strains play a crucial role in shaping the physicochemical properties and functionality of fermented cow's milk. The natural fermentation system demonstrates a certain degree of stability and safety after undergoing continuous domestication. Fermented mare's milk has been consumed for its intestinal health benefits in regions such as Xinjiang and Inner Mongolia in China. This consumption is closely related to the fermented strains present. Consequently, from the perspective of fermented strains, this study aimed to compare the microbiota diversity of naturally fermented mare's milk with that of inoculated fermented cow's milk, using it as a fermentation system to develop new functional fermented cow's milk products. Water retention, rheology, texture, pH, and titration acidity were analyzed to evaluate the quality of fermented cow's milk with the obtained transmission strain system. Importantly, the correlation between the property of fermented cow's milk and the diversity of fermentation system has been thoroughly analyzed. The findings indicate that the gel property of fermented cow's milk is not directly linked to the strain diversity or the core strain of fermentation. Instead, the abundance of Lactobacillus, Lactococcus, Hafnia-Obesumbacterium, Leuconostoc, Acetobacter, and Acinetobacter bacteria significantly influences the quality of fermented cow's milk. Consequently, this study has successfully developed a new type of fermented cow's milk and provided a reliable theoretical foundation for the functional enhancement of specialized fermented cow's milk products.

Metal ions binding and colloidal destabilization in the model systems: Implication on the magnesium chloride coagulation mechanism in tofu making

MgCl2-induced soymilk coagulation mechanism in tofu making was explored from perspectives of Mg2+ binding and colloidal properties in model systems. Isothermal titration calorimetry of bovine serum albumin (BSA)-small molecule mixtures revealed proteins contributed negligibly to Mg2+ binding sites, instead, substantial Mg2+ were bound by soymilk-borne small molecules. The results thus suggested the "protein-Mg2+-protein bridge" was hardly formed in tofu making. Zeta potentials for both BSA-small molecule system and defatted soymilk changed in a similar pattern relative to the unbound Mg2+ concentration, indicating only those small molecules-unbound Mg2+ effectively neutralized the electronegative charges on protein colloidal particles. Turbidity and particle size results revealed a critical zeta potential (-11 mV) was required to induce marked Mg2+-defatted soymilk coagulation. For heated defatted soymilks, a critical minimum protein concentration (8 mg/mL) was needed to observe the significant Mg2+-induced coagulation. This study is expected to deepen our understanding of Mg2+ coagulation mechanism in tofu making.

Enhancement of gluconolactone-induced soybean protein isolate gels by low concentrations of oxidized konjac glucomannan: Gel properties and microstructure

Gluconolactone (GDL) induces soybean protein isolate (SPI) gelation by gradually releasing H+, lowering the pH to promote protein aggregation. However, excessive GDL often lead to an undesirable acidic taste in food gels. This study evaluated the effects of oxidized konjac glucomannan (OKGM) and varying H+ release levels on SPI gel properties, aiming to enhance gel quality while reducing GDL dependency. Results demonstrated that OKGM significantly improved gel texture and viscoelasticity, with low concentrations (0.5-1.5%, w/v) promoting SPI aggregation and forming a denser, more elastic gel network. Notably, OKGM accelerated the gelation process, reducing the gelation time from 12.88 ± 0.14 to 11.26 ± 0.00 min, while also increasing gel strength and stability. Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) revealed that OKGM interacted with SPI through Schiff-base reactions, enhancing thermal stability. However, at high OKGM concentrations (2.0-2.5%, w/v), thermodynamic incompatibility led to phase separation, increasing surface hydrophobicity and free sulfhydryl content, which disrupted gel uniformity. Overall, OKGM synergized with GDL to induce gelation, enabling a reduction in acid coagulant usage while enhancing gel quality. This study provides a novel approach to designing low-calorie, fiber-rich SPI gels, offering a promising alternative to traditional soy gels in the food industry.

Enhanced dextran production by Weissella confusa in co-culture with Candida shehatae and its quorum sensing regulation mechanism

Lactic acid bacteria (LAB) are well-known for its expertise in synthesizing exopolysaccharides (EPS), which are linked to significant health benefits, such as its prebiotic effects and ability to modulate the immune system. However, the synthesis of EPS is hindered by low yields. The objective of this study was to investigate the impact of co-cultivation on EPS output by Weissella confusa XG-3 when paired with Candida shehatae. The structure and characteristics of the purified EPS were analyzed. Gel permeation chromatography (GPC) revealed a molecular weight of 3.45 × 106 Da. High-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) spectroscopy and fourier transform infrared (FT-IR) spectroscopy showed that the EPS was a linear homopolysaccharide, mainly composed of glucose units, with a proposed structure of dextran featuring α-(1, 6) glycosidic linkages and occasional α-(1,3) branching. Fermentation processes were conducted in both mono-culture and co-culture settings, with tracking of pivotal gene expression. The result showed that the expression of luxS, ackA and wzb was significantly up-regulated in the co-culture system, which was positively correlated with dextransucrase activity and dextran production. C. shehatae promoted the growth of W. confusa XG-3 by consuming organic acids in the culture system through direct contact, initiating quorum sensing (QS), inducing dsr expression, increasing dextransucrase activity, and ultimately promoting dextran synthesis.

Effects of Tweens on the Structure, interfacial Characteristics, and emulsifying and foaming properties of Ovalbumin

Parameters such as interfacial tension, dynamics, and rheology are intricately linked to the emulsifying and foaming properties of proteins. In this study, the effects of different Tween types and concentrations on the structure and interfacial characteristics of ovalbumin (OVA) were examined, and their relationships with emulsifying and foaming properties were explored. The results showed that the addition of Tween caused the structure of OVA to become looser and more disordered (β-sheets gradually transformed into β-turns) and exposed more hydrophobic groups. In addition, with the increase in Tween concentration, OVA-Tween systems exhibited lower interfacial tension and could adsorb more rapidly at both the air-water and oil-water interfaces. Additionally, the interfacial elastic modulus of these systems also increased. Compared with natural OVA (EAI = 4.023 m2/g, FA = 60.00 %), OVA-Tween showed significantly enhanced emulsifying and foaming abilities. However, higher Tween concentrations (0.1 %) led to competitive adsorption between OVA and Tween, inducing a reduction in the interfacial modulus and a slight decrease in the emulsifying and foaming stability. The emulsifying and foaming performance of the four composite systems were as follows: OVA-Tween 20 > OVA-Tween 40 > OVA-Tween 80 > OVA-Tween 60. Correlation analysis revealed a significant association between the structure and interfacial properties and the emulsifying and foaming performance of OVA-Tween (p < 0.05). These results demonstrated that Tween can significantly enhance the emulsifying and foaming properties of OVA. The findings provide a theoretical basis for the application of the novel OVA-Tween emulsifier in regulating OVA-based dairy products and baked foods.

Investigating the effects of citric acid concentrations on acidification, rheological, and microbial properties of fermented soy protein isolate yogurts

As consumer awareness grows regarding the environmental and health impacts of animal-based products, plant-based alternatives are gaining popularity in developed countries. Plant-based proteins, like soy protein isolate (SPI), are valued for their sustainability and ability to complement animal proteins. SPI is commonly used in plant-based yogurts due to its high-quality protein, strong gelling capacity, and support for lactic acid bacteria (LAB) growth. Typically, plant-based yogurts use citric acid (CA) as a preservative, but its effect on LAB quality and effects is not fully understood. This study examines how different CA concentrations (0%, 1%, 1.5%, 2%, and 3%) influence the physicochemical, rheological, and microbial properties of fermented SPI yogurts under various temperature conditions over time (0, 15, and 24 h at 45°C and 48 h readings at 4°C). Higher CA concentrations led to lower pH, higher total titratable acidity, a loss modulus (G″) exceeding the storage modulus (G'), and increased viscosity. LAB growth was significant at refrigeration temperatures across all samples, indicating LAB adaptation to produce more lactic acid during storage. The study highlights that fermentation duration, temperature, storage conditions, and CA concentration significantly affect the properties of plant-based yogurts. Yogurts with 1% CA exhibited the best quality attributes while maintaining a pH below 4.6 as a food safety process control. This research provides insights into the preservation, safety, and quality of plant-based yogurts. PRACTICAL APPLICATION: This research aims to help food manufacturers improve the quality and safety of plant-based yogurts by optimizing citric acid levels. By balancing acidity and probiotic content, producers can create healthier, more sustainable yogurt alternatives that appeal to environmentally conscious consumers.

Highly ordered aggregation of soy protein isolate particles for enhanced gel-related properties through konjac glucomannan addition

This study assessed the effect of konjac glucomannan (KGM) on the aggregation of soy protein isolate (SPI) and its gel-related structure and properties. Raman results showed that KGM promoted the rearrangement of SPI to form more β-sheets, contributing to the formation of an ordered structure. Atomic force microscopy, confocal laser scanning microscopy, and small-angle X-ray scattering results indicated that KGM reduced the size of SPI particles, narrowed their size distribution, and loosened the large aggregates formed by the stacking of SPI particles, improving the uniformity of gel system. As the hydrogen bonding between the KGM and SPI molecules enhanced, a well-developed network structure was obtained, further reducing the immobilized water's content (T22) and increasing the water-holding capacity (WHC) of SPI gel. Furthermore, this gel structure showed improved gel hardness and resistance to both small and large deformations. These findings facilitate the design and production of SPI-based gels with desired performance.

Exploring gelation properties and structural features on 3D printability of compound proteins emulsion gels: Emphasizing pH-regulated non-covalent interactions with xanthan gum

Rational regulation of pH and xanthan gum (XG) concentration has the potential to modulate interactions among macromolecules and enhance 3D printability. This study investigated non-covalent interactions between XG and other components within compound proteins emulsion gel systems across varying pH values (4.0-8.0) and XG concentrations (0-1 wt%) and systematically explored impacts of gelation properties and structural features on 3D printability. The results of rheological and structural features indicated that pH-regulated non-covalent interactions were crucial for maintaining structural stability of emulsion gels with the addition of XG. The 3D printability of emulsion gels would be significantly improved through moderate depletion flocculation produced when XG concentration was 0.75 wt% at the pH 6.0. Mechanical properties like viscosity exhibited a strongly negative correlation with 3D printability, whereas structural stability showed a significantly positive correlation. Overall, this study provided theoretical insights for the development of emulsion gels for 3D printing by regulating non-covalent interactions.

Enhancing salt-induced gelation of egg yolk granules through pH-ultrasound combined treatment: A physicochemical and microstructural analysis

Salted duck eggs are a popular food product, but their high salt content and uneven salt distribution can reduce acceptability. This study investigated the effects of pH-high-intensity ultrasound combined treatment on the salt-induced gelation properties of egg yolk granules. The results showed that the pH5 + 150 W treatment group exhibited the best physical and gelation properties, with the smallest particle size (1597.33 nm), optimal dispersibility (PDI 0.29), and good stability. The gelation properties of this group also demonstrated excellent springiness (0.30 mm), cohesiveness (0.56), and gumminess (0.05 N). Furthermore, the pH5 + 150 W group had the highest water holding capacity of 97.42 % and relatively high hydrophobicity (173.39 μg). Notably, it also showed high oil exudation (2.83 %) and good sandiness (62.07 %). The pH5 + 150 W led to a significant redshift of the fluorescence peak at 335 nm and an enhancement of the peak intensity at 562 nm compared to the control group. Structural characterization revealed a more ordered protein structure and a uniform gel structure with enhanced electrostatic repulsion between oil droplets. Secondary structure analysis of the proteins showed a significant reduction in α-helix and β-sheet, while β-turn and random coil increased. In summary, the pH5 + 150 W treatment displayed the best gelation properties, providing theoretical guidance for enhancing the processing performance of yolk and expanding their application in the food industry.

Ultrasonic Treatment of Soybean Protein Isolate: Unveiling the Mechanisms for Gel Functional Improvement and Application in Chiba Tofu

Soybean protein isolate (SPI) cannot meet the needs of modern food production due to various shortcomings. By change of its structural characteristics, its application in the food field may be increased. This study explored the impact of ultrasonic treatment on the structural and gelation properties of the SPI dispersions. By subjecting SPI to ultrasonic treatment at 0-800 W for 10 min, it was found that this treatment significantly reduced the particle size of SPI to 196 nm and caused an increase in its solubility, surface hydrophobicity, and sulfhydryl content as well as significant changes in the protein structure. At an optimal ultrasonic power of 200 W, SPI gels demonstrated an enhanced gelling ability, strength, and water-holding capacity, forming a more uniform and compact structure. Application in Chiba tofu showed that water retention, elasticity, and sensory quality were optimized at 200 W. The findings highlight that a sonication power of 200 W significantly improves the physicochemical and structural properties of SPI, resulting in a denser and more functional gel suitable for Chiba tofu production.

Physicochemical and Functional Properties of DND358 (A Hypocholesterolemic Soybean) Protein Isolate

The properties and applications of soybean protein isolates (SPIs) have been extensively investigated. In this study, we determined the optimal conditions for the preparation of the DND358 soybean protein isolate (DND358-SPI), assessed its physicochemical and functional properties, and investigated its potential applications in the food industry. According to the results, the highest extraction rate of DND358-SPI was observed when the pH was 9.5, the temperature was 55 °C, the duration was 80 min, and the material-to-liquid ratio was 1:20 (w/v). With regard to the functional properties, the water-holding capacity (WHC) and oil-binding capacity (OBC) of DND358-SPI were higher than those of other varieties, reaching 4.73% and 11.04%, respectively. In addition, the hardness, adhesiveness, chewiness, and resilience of DND358-SPI were higher than those of other varieties, reaching 159.27 g, 186.07 g, 6.78 mj, and 1.88, respectively. These findings indicate that DND358-SPI can reduce cholesterol levels and may be used to produce cholesterol-lowering food products.

Effect of transglutaminase crosslinking combined with lactic fermentation on the potential allergenicity and conformational structure of soy protein

BACKGROUND

Food allergies are a growing concern worldwide, with soy proteins being important allergens that are widely used in various food products. This study investigated the potential of transglutaminase (TGase) and lactic acid bacteria (LAB) treatments to modify the allergenicity and structural properties of soy protein isolate (SPI), aiming to develop safer soy-based food products.

RESULTS

Treatment with TGase, LAB or their combination significantly reduced the antibody reactivity of β-conglycinin and the immunoglobulin E (IgE) binding capacity of soy protein, indicating a decrease in allergenicity. TGase treatment led to the formation of high-molecular-weight aggregates, suggesting protein crosslinking, while LAB treatment resulted in partial protein hydrolysis. These structural changes were confirmed by Fourier transform infrared spectroscopy, which showed a decrease in β-sheet content and an increase in random coil and β-turn contents. In addition, changes in intrinsic fluorescence and ultraviolet spectroscopy were also observed. The alterations in protein interaction and the reduction in free sulfhydryl groups highlighted the extensive structural modifications induced by these treatments.

CONCLUSION

The synergistic application of TGase and LAB treatments effectively reduced the allergenicity of SPI through significant structural modifications. This approach not only diminished antibody reactivity of β-conglycinin and IgE binding capacity of soy protein but also altered the protein's primary, secondary and tertiary structures, suggesting a comprehensive alteration of SPI's allergenic potential. These findings provide a promising strategy for mitigating food allergy concerns and lay the foundation for future research on food-processing techniques aimed at allergen reduction. © 2024 Society of Chemical Industry.

Advances in the formation mechanism of set-type plant-based yogurt gel: a review

Plant-based yogurt has several advantages over traditional yogurt, such as being lactose and cholesterol-free, making it more suitable for individuals with cardiovascular and gastrointestinal diseases. The formation mechanism of the gel in plant-based yogurt needs more attention because it is associated with the gel properties of yogurt. Most plant proteins, except for soybean protein, have poor functional abilities, such as solubility and gelling properties, which limits their application in most food items. This often results in undesirable mechanical quality of plant-based products, particularly plant-based yogurt gels, including grainy texture, high syneresis, and poor consistency. In this review, we summarize the common formation mechanism of plant-based yogurt gel. The main ingredients, including protein and non-protein components, as well as their interactions involved in the gel are discussed to understand their effects on gel formation and properties. The main interventions and their effects on gel properties are highlighted, which have been shown to improve the properties of plant-based yogurt gels effectively. Each type of intervention method may exhibit desirable advantages in different processes. This review provides new opportunities and theoretical guidance for efficiently improving the gel properties of plant-based yogurt for future consumption.

Improvement of physicochemical properties and quercetin delivery ability of fermentation-induced soy protein isolate emulsion gel processed by ultrasound

This study aimed to investigate the effects of ultrasonic treatment at different powers on the physicochemical properties, microstructure and quercetin delivery capacity of fermentation-induced soy protein isolate emulsion gel (FSEG). The FSEG was prepared by subjecting soy protein isolate (SPI) emulsion to ultrasonic treatment at various powers (0, 100, 200, 300, and 400 W), followed by lactic acid bacteria fermentation. Compared with the control group (0 W), the FSEG treated with ultrasound had higher hardness, water holding capacity (WHC) and rheological parameters. Particularly, at an ultrasonic power of 300 W, the FSEG had the highest hardness (101.69 ± 4.67 g) and WHC (75.20 ± 1.07%) (p < 0.05). Analysis of frequency sweep and strain scanning revealed that the storage modulus (G') and yield strains of FSEG increased after 300 W ultrasonic treatment. Additionally, the recovery rate after creep recovery test significantly increased from 18.70 ± 0.49% (0 W) to 58.05 ± 0.54% (300 W) (p < 0.05). Ultrasound treatment also resulted in an increased β-sheet content and the formation of a more compact micro-network structure. This led to a more uniform distribution of oil droplets and reduced mobility of water within the gel. Moreover, ultrasonic treatment significantly enhanced the encapsulation efficiency of quercetin in FSEG from 81.25 ± 0.62 % (0 W) to 90.04 ± 1.54% (300 W). The bioaccessibility of quercetin also increased significantly from 28.90 ± 0.40% (0 W) to 42.58 ± 1.60% (300 W) (p < 0.05). This study enriches the induction method of soy protein emulsion gels and provides some references for the preparation of fermented emulsion gels loaded with active substances.

A novel approach has been developed to produce pure plant-based gel soy yogurt by combining soy proteins (7S/11S), high pressure homogenization, and glycation reaction

This research sought to examine how the physicochemical characteristics of soy globulins and different processing techniques influence the gel properties of soy yogurt. The goal was to improve these gel properties and rectify any texture issues in soy yogurt, ultimately aiming to produce premium-quality plant-based soy yogurt. In this research study, the investigation focused on examining the impact of 7S/11S, homogenization pressure, and glycation modified with glucose on the gel properties of soy yogurt. A plant-based soy yogurt with superior gel and texture properties was successfully developed using a 7S/11S globulin-glucose conjugate at a 1:3 ratio and a homogenization pressure of 110 MPa. Compared to soy yogurt supplemented with pectin or gelatin, this yogurt demonstrated enhanced characteristics. These findings provide valuable insights into advancing plant protein gels and serve as a reference for cultivating new soybean varieties by soybean breeding experts.

Understanding the nutritional benefits through plant proteins-probiotics interactions: mechanisms, challenges, and perspectives

The nutritional benefits of combining probiotics with plant proteins have sparked increasing research interest and drawn significant attention. The interactions between plant proteins and probiotics demonstrate substantial potential for enhancing the functionality of plant proteins. Fermented plant protein foods offer a unique blend of bioactive components and beneficial microorganisms that can enhance gut health and combat chronic diseases. Utilizing various probiotic strains and plant protein sources opens doors to develop innovative probiotic products with enhanced functionalities. Nonetheless, the mechanisms and synergistic effects of these interactions remain not fully understood. This review aims to delve into the roles of promoting health through the intricate interplay of plant proteins and probiotics. The regulatory mechanisms have been elucidated to showcase the synergistic effects, accompanied by a discussion on the challenges and future research prospects. It is essential to recognize that the interactions between plant proteins and probiotics encompass multiple mechanisms, highlighting the need for further research to address challenges in achieving a comprehensive understanding of these mechanisms and their associated health benefits.

Legume protein fermented by lactic acid bacteria: Specific enzymatic hydrolysis, protein composition, structure, and functional properties

In recent years, with increasing emphasis on healthy, green, and sustainable consumption concepts, plant-based foods have gained popularity among consumers. As widely sourced plant-based raw materials, legume proteins are considered sustainable and renewable alternatives to animal proteins. However, legume proteins have limited functional properties, which hinder their application in food products. LAB fermentation is a relatively natural processing method that is safer than chemical/physical modification methods and can enrich the functional properties of legume proteins through biodegradation and modification. Therefore, changes in legume protein composition, structure, and functional properties and their related mechanisms during LAB fermentation are described. In addition, the specific enzymatic hydrolysis mechanisms of different LAB proteolytic systems on legume proteins are also focused in this review. The unique proteolytic systems of different LAB induce specific enzymatic hydrolysis of legume proteins, resulting in the production of hydrolysates with diverse functional properties, including solubility, emulsibility, gelability, and foamability, which are determined by the composition (peptide/amino acid) and structure (secondary/tertiary) of legume proteins after LAB fermentation. The correlation between LAB-specific enzymatic hydrolysis, protein composition and structure, and protein functional properties will assist in selecting legume protein raw materials and LAB strains for legume plant-based food products and expand the application of legume proteins in the food industry.

Impact of Oil Bodies on Structure, Rheology and Function of Acid-Mediated Soy Protein Isolate Gels

Oil bodies (OBs) are naturally occurring pre-emulsified oil droplets that have broad application prospects in emulsions and gels. The main purpose of this research was to examine the impact of the OB content on the structure and functional aspects of acid-mediated soy protein isolate (SPI) gel filled with OBs. The results indicated that the peanut oil body (POBs) content significantly affected the water holding capacity of the gel. The rheological and textural analyses showed that POBs reduced the gel strength and hardness. The scanning electron and confocal laser scanning microscopy analyses revealed that POBs aggregated during gel formation and reduced the gel network density. The Fourier transform infrared spectrum (FTIR) analysis demonstrated that POBs participated in protein gels through hydrogen bonds, steric hindrance and hydrophobic interactions. Therefore, OBs served as inactive filler in the acid-mediated protein gel, replaced traditional oils and provided alternative ingredients for the development of new emulsion-filled gels.

Effect of exopolysaccharides yield and addition concentration of Lactobacillus helveticus on the processing characteristics of fermented milk and its mechanism

Exopolysaccharides (EPS) yield and added concentration of lactic acid bacteria can greatly affect the processing characteristics of fermented milk. In order to investigate the effects and mechanisms of EPS yield and added concentration on fermented milk, researchers extracted EPS from 50 strains of Lactobacillus helvedicus (L. helvedicus) and selected the two strains with the largest difference in EPS yield (L. helvedicus LH18 and L. helvetigus LH33) for subsequent experiments. The physicochemical properties of EPS-LH18 and EPS-LH33 were analyzed. The gel characteristics and protein conformation of fermented milk were studied by means of texture analyzer, rheometer, scanning electron microscopy, nuclear magnetic resonance machine, fluorescence spectrophotometer and circular dichroism. The results indicate that the monosaccharide compositions of EPS-LH18 and EPS-LH33 are the same and have good thermal stability. The texture and rheological properties of L. helveticus LH18 fermented milk are significantly superior to other fermented milk. The reason is that L. helveticus LH18 EPS has the highest yield, which leads to a denser gel structure, lower surface hydrophobicity and free sulfhydryl content of its fermented milk. According to circular dichroism analysis, β- sheet and random coil are the internal factors leading to the difference in fermented milk gel. In addition, the fermented milk improved even more favorably as the concentration of the two EPS additions increased. As described above, L. helveticus LH18 has the potential to be an excellent yogurt starter, and both of the above EPS can be used as probiotic stabilizer alternatives for fermented dairy products.

Exopolysaccharides of lactic acid bacteria: Structure, biological activity, structure-activity relationship, and application in the food industry: A review

Over the past few decades, researchers have discovered that probiotics play an important role in our daily lives. With the further deepening of research, more and more evidence show that bacterial metabolites have an important role in food and human health, which opens up a new direction for the research of lactic acid bacteria (LAB) in the food and pharmaceutical industry. Many LAB have been widely studied because of the ability of exopolysaccharides (EPS). Lactic acid bacteria exopolysaccharides (LAB EPS) not only have great potential in the treatment of human diseases but also can become natural ingredients in the food industry to provide special qualitative structure and flavor. This paper has organized and summarized the biosynthesis, strain selection, production process parameters, structure, and biological activity of LAB EPS, filling in the monotony and incompleteness of previous articles' descriptions of LAB EPS. Therefore, this paper focuses on the general biosynthetic pathway, structural characterization, structure-activity relationship, biological activity of LAB EPS, and their application in the food industry, which will help to deepen people's understanding of LAB EPS and develop new active drugs from LAB EPS. Although the research results are relatively affluent, the low yield, complex structure, and few clinical trials of EPS are still the reasons that hinder its development. Therefore, future knowledge expansion should focus on the regulation of structure, physicochemical properties, function, higher production of EPS, and clinical trial applications, which can further increase the commercial significance and value of EPS. Furthermore, better understanding the structure-function relationship of EPS in food remains a challenge to date.

Lactobacillus paracasei JY062 Alleviates Glucolipid Metabolism Disorders via the Adipoinsular Axis and Gut Microbiota

Glycolipid metabolic disorders (GLMD) refer to a series of metabolic disorders caused by abnormal processes of glucose and lipid synthesis, decomposition, and absorption in the body, leading to glucose and lipid excess, insulin resistance, and obesity. Probiotic intervention is a new strategy to alleviate metabolic syndrome. Lactobacillus paracasei JY062 (L. paracasei JY062) was separated from the Tibet-fermented dairy products. The results demonstrated a strong ability to relieve blood glucose disorders, blood lipid disorders, and tissue damage. The LPH group had the best effect, significantly decreasing the total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), leptin, insulin, and free fatty acid (FFA) concentrations and increasing the high-density lipoprotein cholesterol, adiponectin, and GLP-1 level compared to HFD-group mice. L. paracasei JY062 could activate the APN-AMPK pathway, increased AdipoQ, AMPK GLUT-4, and PGC-1α mRNA expression and decreased SREBP-1c, ACC, and FAS mRNA expression. L. paracasei JY062 intervention decreased the relative abundance of harmful bacteria, increased the relative abundance of beneficial bacteria, and restored the imbalance of gut microbiota homeostasis caused by a high-glucose-fat diet. L. paracasei JY062 alleviated glucolipid metabolism disorders via the adipoinsular axis and gut microbiota. This study provided a theoretical basis for probiotics to ameliorate glucolipid metabolism disorders by regulating the adipoinsular axis.

Identification, characterization and optimization of culture medium conditions for organic acid-producing lactic acid bacteria strains from Chinese fermented vegetables

Lactic acid bacteria (LAB) are widely exploited in fermented foods and are gaining attention for novel uses due to their safety as biopreservatives. In this study, several organic acid-producing LAB strains were isolated from fermented vegetables for their potential application in fermentation. We identified nine novel strains belonging to four genera and five species, Lactobacillus plantarum PC1-1, YCI-2 (8), YC1-1-4B, YC1-4 (4), and YC2-9, Lactobacillus buchneri PC-C1, Pediococcus pentosaceus PC2-1 (F2), Weissella hellenica PC1A, and Enterococcus sp. YC2-6. Based on the results of organic acids, acidification, growth rate, antibiotic activity and antimicrobial inhibition, PC1-1, YC1-1-4B, PC2-1(F2), and PC-C1 showed exceptional biopreservative potential. Additionally, PC-C1, YC1-1-4B, and PC2-1(F2) recorded higher (p < 0.05) growth by utilizing lower concentrations of glucose (20 g/L) and soy peptone (10 g/L) as carbon and nitrogen sources in optimized culture conditions (pH 6, temperature 32 °C, and agitation speed 180 rpm) at 24hr and acidification until 72hr in batch fermentation, which suggests their application as starter cultures in industrial fermentation.

Replacing animal proteins with plant proteins: Is this a way to improve quality and functional properties of hybrid cheeses and cheese analogs?

The growing emphasis on dietary health has facilitated the development of plant-based foods. Plant proteins have excellent functional attributes and health-enhancing effects and are also environmentally conscientious and animal-friendly protein sources on a global scale. The addition of plant proteins (including soy protein, pea protein, zein, nut protein, and gluten protein) to diverse cheese varieties and cheese analogs holds the promise of manufacturing symbiotic products that not only have reduced fat content but also exhibit improved protein diversity and overall quality. In this review, we summarized the utilization and importance of various plant proteins in the production of hybrid cheeses and cheese analogs. Meanwhile, classification and processing methods related to these cheese products were reviewed. Furthermore, the impact of different plant proteins on the microstructure, textural properties, physicochemical attributes, rheological behavior, functional aspects, microbiological aspects, and sensory characteristics of both hybrid cheeses and cheese analogs were discussed and compared. Our study explores the potential for the development of cheeses made from full/semi-plant protein ingredients with greater sustainability and health benefits. Additionally, it further emphasizes the substantial chances for scholars and developers to investigate the optimal processing methods and applications of plant proteins in cheeses, thereby improving the market penetration of plant protein hybrid cheeses and cheese analogs.

Chitin nanocrystals as natural gel modifier for yielding stronger acid-induced soy protein isolate gel

This study aimed to enhance the rheological properties and thermal stability of acid-induced soy protein isolate (SPI) gels by incorporating chitin nanocrystals (ChNCs) and proposing a gelation mechanism. SPI gels exhibited pseudo-plastic behavior. Increasing ChNCs concentration from 0.00 % to 1.00 % improved G' values, recovery rate, and initial degradation temperature: from 75.6 Pa to 1024.3 Pa, 80.27 % to 85.47 %, and 261.5 °C to 275.8 °C, respectively. FTIR analysis confirmed electrostatic and hydrogen bonding interactions between SPI and ChNCs. Adding 1.00 % ChNCs reduced α-helix content from 19.7 % to 12.1 % while increasing β-sheet content from 46.5 % to 52.6 %. This led to protein unfolding, exposure of Trp residues, and orderly aggregation, forming a dense cross-linked gel network. Gel particle size increased from 185.5 nm (no ChNCs) to 504.4 nm (1.00 % ChNCs), with reduced surface charges. Hydrophobic and electrostatic interactions were key forces stabilizing SPI-ChNCs gels. These findings offer a practical approach to enhancing traditional acid-induced protein gel-based functional foods using naturally sourced chitin nanocrystals.

Recent advance in modification strategies and applications of soy protein gel properties

Soy protein gel can be developed into a variety of products, ranging from traditional food (e.g., tofu) to newly developed food (e.g., soy yogurt and meat analog). So far, efforts are still needed to be made on modifying the gel properties of soy protein for improving its sensory properties as animal protein-based food substitutes. Furthermore, there is always a need to regulate its gel properties for designing novel and tailored products of soy protein gels due to the fast-growing plant protein-based product market. This review gave an emphasis on the latest modification strategies and applications of gel properties of soy protein. The modifying methods of soy protein gel properties were reviewed from an aspect of composition or processing. Compositional modification included changing protein composition and gelling conditions and using additives, whereas processing strategies can be achieved through physical, chemical, and enzymatic treatments. Several compositional modification and processing strategies have been both proven to alter the gel properties of soy protein effectively. So far, soy protein gel has been applied in the field of food and biomedicine. In the future, more mechanistic studies on the modification methods are still needed to facilitate the full application of soy protein gel.

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.

Construction of hypoallergenic microgel by soy major allergen β-conglycinin through enzymatic hydrolysis and lactic acid bacteria fermentation

Soy allergenicity is a public concern, and the combination of multiple processing methods may be a promising strategy for reducing soy allergenicity. In this study, a novel two-step enzymatic hydrolysis followed by lactic acid bacteria fermentation was proposed for the construction of hypoallergenic soybean protein microgel. β-Conglycinin was used as the main soy allergen. The effects of different enzymatic hydrolysis (Alcalase, Neutrase, and Protamex) and LAB fermentation on β-conglycinin microgel formation and its immunoreactivity were investigated. Results showed that the use of different enzymes and the attainment of different degrees of hydrolysis affected the particle distribution and zeta potential in the microgels and leads to differences in microstructure and immunoreactivity. All hydrolysates compared with intact protein accelerated the formation of gel during LAB fermentation. Among the three assayed enzymes, fermented Protamex hydrolysates at 60 min (PF-60) demonstrated a microgel with an overall reduced average particle size (741.20±7.18 nm), lower absolute values of zeta potential (10.43±0.65 mV), and regular gel network. The antigenicity and IgE-binding capacity decreased to the lowest value of 0.30 % and 6.93 %, respectively. Peptidomics and immunoinformatic analysis suggested that PF-60 disrupted 17/30, 16/44, and 23/75 epitopes in the α, α', and β subunits, respectively. Unlike the LAB-fermented unhydrolyzed β-conglycinin disrupted epitopes mostly located at the loop domain, PF-60 primarily promoted the exposure and disruption of allergen epitopes with β-sheet structure located at the core barrel domain. These findings can provide new perspectives on the preparation of hypoallergenic soybean-gel products on edible particulate systems.

FolE gene expression for folic acid productivity from optimized and characterized probiotic Lactobacillus delbrueckii

BACKGROUND

Lactobacillus delbrueckii was one of the most common milk lactic acid bacterial strains (LAB) which characterized as probiotic with many health influencing properties.

RESULTS

Among seven isolates, KH1 isolate was the best producer of folic acid with 100 µg/ml after 48 h of incubation; FolE gene expression after 24 h of incubation was in the highest value in case of KH1 with three folds. Lactose was the best carbon source for this KH1, besides the best next isolates KH80 and KH98. The selected three LAB isolates were identified through 16S rDNA as Lactobacillus delbrueckii. These three isolates have high tolerance against acidic pH 2-3; they give 45, 10, and 22 CFUs at pH 3, besides 9, 6, and 4 CFUs at pH2, respectively. They also have resistance against elevated bile salt range 0.1-0.4%. KH1 recorded 99% scavenging against 97.3% 1000 µg/ml ascorbic acid. Docking study exhibits the binding mode of folic acid which exhibited an energy binding of - 8.65 kcal/mol against DHFR. Folic acid formed four Pi-alkyl, Pi-Pi, and Pi-sigma interactions with Ala9, Ile7, Phe34, and Ile60. Additionally, folic acid interacted with Glu30 and Asn64 by three hydrogen bonds with 1.77, 1.76, and 1.96 Å.

CONCLUSION

LAB isolates have probiotic properties, antioxidant activity, and desired organic natural source for folic acid supplementation that improve hemoglobin that indicated by docking study interaction.

Effect of extrusion temperature on the structure and emulsifying properties of soy protein isolate-oat β-glucan conjugates formed during high moisture extrusion

In this study, extrusion was used to induce Maillard reaction between soy protein isolate (SPI) and oat β-glucan (OG) and effect of extrusion temperature (70, 90, 110 and 130 °C) on the structure and emulsifying properties of extruded SPI-OG was investigated. SDS-PAGE and fluorescence spectroscopy provided evidence for the formation of SPI-OG conjugates during extrusion. The results showed that 90 °C and 110 °C extruded SPI-OG had the highest level of degree of glycosylation (were 14.34% and 13.70%, respectively, p > 0.05). Structural analysis found that α-helix content of extruded SPI-OG decreased by 8.93-13.14% compared to mixture of SPI and OG. Meanwhile, extruded SPI-OG had lower protein solubility (29.83-34.38%) and surface hydrophobicity (1549-2027), larger average particle size (2363-4807 nm) and higher emulsion stability (74.33-90.15%). Therefore, these findings may provide a theoretical basis for the development of novel food emulsion stabilizers.

Effects of Dextran on the Gel Properties of Faba Bean Protein Isolates Prepared Using Different Processes

The properties of faba bean (Vicia faba L.) protein isolate (FPI) gels depend on their starting protein material and can be modulated by the addition of polysaccharides. In order to investigate the interplay between these two factors, commercial FPI (FPI1) and FPI prepared in-house (FPI2) were used to fabricate glucono-delta-lactone-induced gels, with or without dextran (DX) addition. FPI1 exhibited lower solubility in water and a larger mean particle size, likely because it experienced extensive degradation due to the intense conditions involved in its preparation. The FPI1 gel showed a similar water-holding capacity as the FPI2 gel; however, its hardness was lower and viscoelasticity was higher. After DX addition, the hardness of both FPI gels decreased, while their water-holding capacity increased. Interestingly, DX addition decreased the viscoelasticity of the FPI1 gel but enhanced the viscoelasticity of the FPI2 gel. The microstructural analysis demonstrated that the density of the aggregation network decreased in the FPI1 gel after DX addition but increased in the FPI2 gel. This was consistent with the changes observed in the dominant protein interaction forces in these gels after DX addition. Overall, these findings have the potential to guide ingredient selection for the tailored preparation of FPI gels.

Improvement of kefir fermentation on rheological and microstructural properties of soy protein isolate gels

Soy protein isolate (SPI) has become a promising plant-based material as an animal protein products alternative. However, its application was limited due to the weak gelling properties. To investigate the effect of kefir fermentation on SPI gels properties, SPI-polysaccharide gels was produced by unfermented and kefir-fermented SPI using different concentration of KGM, chitosan, and calcium chloride in this study. Characterization of fermented SPI gels showed that fermentation by kefir grains can be applied to improve the textural strength, mechanical structure, and thermal characteristics of SPI gels. Compared to unfermented SPI gels, the water-holding capacity was remarkably enhanced to 63.11% and 65.71% in fermented SPI-chitosan gels. Moreover, the hardness of fermented SPI-KGM gels were significantly increased to 13.43 g and 27.11 g. And the cohesiveness and resilience of fermented-KGM gels were also improved than unfermented samples. Results of rheological characterization and thermogravimetric analysis revealed the strengthened mechanical features and higher thermal stability of fermented SPI gels. Additionally, the main role of hydrophobic interactions and secondary structure variations of SPI gels were demonstrated by intermolecular force measurements, Fourier-transform infrared spectroscopy, and X-ray diffraction. Moreover, the network structure was observed more compact and homogeneous performed by microstructural images in fermented SPI gels. Therefore, this research provided a novel approach combining multi-species fermentation with protein gelation to prepare SPI gel materials with improved nutrition and structural properties.

Research Advances in Plant Protein-Based Products: Protein Sources, Processing Technology, and Food Applications

Plant proteins are high-quality dietary components of food products. With the growing interest in sustainable and healthy food alternatives, plant proteins have gained significant attention as viable substitutes for animal-based proteins. Understanding the diversity of protein sources derived from plants, novel processing technology, and multiple applications is crucial for developing nutritious and sustainable plant protein-based products. This Review summarizes the natural sources of traditional and emerging plant proteins. The classifications, processing technologies, and applications of plant protein-based products in the food industry are explicitly elucidated. Moreover, the advantages and disadvantages of plant protein-based food products are revealed. Strategies such as protein fortification and complementation to overcome these shortcomings are critically discussed. We also demonstrate several issues that need to be addressed in future development.

Phenotypic and genomic analyses of bacteriocin-producing probiotic Enterococcus faecium EFEL8600 isolated from Korean soy-meju

Enterococcus faecium is a prevalent species found in fermented soybean products, known for its contributions to flavor development and inhibition of pathogenic microorganisms during fermentation. This study aims to provide comprehensive phenotypic and genomic evidence supporting the probiotic characteristics of E. faecium EFEL8600, a bacteriocin-producing strain isolated from Korean soy-meju. Phenotypic analysis revealed that EFEL8600 produced a peptide with inhibitory activity against Listeria monocytogenes, estimated to be 4.6 kDa, corresponding to the size of enterocins P or Q. Furthermore, EFEL8600 exhibited probiotic traits, such as resilience in gastrointestinal conditions, antioxidant and anti-inflammatory activities, and protection of the intestinal barrier. Safety assessments demonstrated no hemolytic and bile salt deconjugation activities. Genomic analysis revealed the presence of several genes associated with probiotic characteristics and bacteriocin production, while few deleterious genes with a low likelihood of expression or transferring were detected. Overall, this study highlights E. faecium EFEL8600 as a potent anti-listeria probiotic strain suitable for use as a starter culture in soymilk fermentation, providing potential health benefits to consumers.

Updates on Plant-Based Protein Products as an Alternative to Animal Protein: Technology, Properties, and Their Health Benefits

Plant-based protein products, represented by "plant meat", are gaining more and more popularity as an alternative to animal proteins. In the present review, we aimed to update the current status of research and industrial growth of plant-based protein products, including plant-based meat, plant-based eggs, plant-based dairy products, and plant-based protein emulsion foods. Moreover, the common processing technology of plant-based protein products and its principles, as well as the emerging strategies, are given equal importance. The knowledge gap between the use of plant proteins and animal proteins is also described, such as poor functional properties, insufficient texture, low protein biomass, allergens, and off-flavors, etc. Furthermore, the nutritional and health benefits of plant-based protein products are highlighted. Lately, researchers are committed to exploring novel plant protein resources and high-quality proteins with enhanced properties through the latest scientific and technological interventions, including physical, chemical, enzyme, fermentation, germination, and protein interaction technology.

Comparative analysis of exopolysaccharide-producing Lactiplantibacillus plantarum with ropy and non-ropy phenotypes on the gel properties and protein conformation of fermented milk

In this study, we evaluated the impact of Lactiplantibacillus plantarum (L. plantarum) with ropy and non-ropy phenotypes on gel structure and protein conformation of fermented milk. Ropy L. plantarum (T1 & CL80) secreted EPS with high molecular weight (1.41 × 10⁶, 1.19 × 10⁶ Da) and intrinsic viscosity (486.46, 316.32 mL/g), effectively enhances fermented milk viscosity and water holding capacity (WHC) (65.4%, 84.6%) by forming a dense gel structure. Non-ropy L. plantarum (CSK & S-1A) fermented milk gel's high surface hydrophobicity and free sulfhydryl content caused high hardness and low WHC. Raman spectroscopy combined with circular dichroism analysis showed that high levels of α-helix (29.32-30.31%) and random roil (23.06-25.36%) protein structures are the intrinsic factors that contribute to the difference among fermented milk gels of ropy and non-ropy strains. This study provides a basis for understanding the structural variability of fermented milk gels using ropy or non-ropy lactic acid bacteria.

A comparison of study on intestinal barrier protection of polysaccharides from Hericium erinaceus before and after fermentation

The intestinal barrier protects the host from harmful substances. This paper investigated two polysaccharides extracted from the Hericium erinaceus before and after fermentation (HEP and FHEP). The effects of two polysaccharides on the intestinal barrier were investigated in cell and mice models. The results showed that polysaccharides had a protective effect against acrylamide-induced injury in IEC-6 cell. Compared with HEP, FHEP significantly increased TEER and paracellular permeability (P < 0.05). Both polysaccharides the expression of alter tight junction (TJ) and mucin (MUC) as observed in cell Western Bolt (WB). Polysaccharides also enhance the intestinal barrier function in mice by improving cyclophosphamide induced cytokines level, TJ and MUC expression, and gut microbiota. The results showed that FHEP significantly increased IgA, IgG, and IgM levels while decreasing TNF-, IL-1, and IL-6 levels (P < 0.05). The immunohistochemical results showed that both polysaccharides significantly increased the expression of occludin, ZO-1, ZO-2, claudin-3, claudin-4, MUC2 and decreased claudin-2. In parallel, polysaccharides could alter the composition of the gut microbiota, indicating that increased in Bacteriodetes, Firmicutes and decreased in Klebsiella and Shigella. This work provides important views on the protective effect of fermented polysaccharides on the intestinal barrier, and provides a potential mechanism for the beneficial health properties of these biomacromolecules.

Influence of anaerobic biotransformation process of agro-industrial waste with Lactobacillus acidophilus on the rheological parameters: case of study of pig manure

This study evaluated the rheological behavior of the pig waste biotransformation process to produce lactic acid (LA) and biomass with Lactobacillus acidophilus in a stirred reactor. In addition, cell growth, carbohydrate consumption, and LA production were measured at three different agitation speeds, 100, 150, and 200 rpm at 37 °C, with a reaction time of 52 h. During the development of the process, the kinetic and rheological parameters were obtained using the logistic, Gompertz, generalized Gompertz, Ostwald de Waele, and Herschel-Bulkley mathematical models, respectively. The substrate used was pig manure, to which molasses was added at 12% v/v to increase the concentration of carbohydrates. The results suggest that mass exchange is favorable at low agitation speeds. Nevertheless, the presence of molasses rich in carbohydrates as a carbon source modifies the characteristics of the fluid, dilatant (n > 1) at the beginning of the process to end up as pseudoplastic (n < 1) due to the addition of exopolysaccharides and the modification of the physical structure of the substrate. This effect was confirmed by the Herschel-Bulkley model, which presented a better fit to the data obtained, in addition to finding a direct relationship between viscosity and pH that can be used as variables for the control of bioconversion processes of pig manure into biomass rich in Lactobacillus acidophilus.

Non-beany flavor soymilk fermented by lactic acid bacteria: Characterization, stability, antioxidant capacity and in vitro digestion

LAB fermentation could reduce the beany flavor, the sensitization of soymilk and improve the digestibility of soymilk, easy to be accepted by consumers. This study evaluated the characterization, stability, in vitro digestion and antioxidant capacity of soymilk fermented by different Lactic acid bacteria (LAB). The results showed that fat content of L.plantarum-S (0.77 g/100 mL) was the lowest, which proved that L.plantarum had a significant effect on lipid degradation, the protein content of L.delbrueckii-S (23.01 mg/mL) was higher. L.delbrueckii-S and L.paracasei-S were more acceptable to people, as well as high overall ratings. L.paracasei fermented soymilk has better suspension stability and smaller particle size. The fermented soymilk showed higher free amino acids (FAA) content, peptide content and stronger antioxidant activity than soymilk after digestion. The soymilk fermented by L. plantarum contained higher FAA content and L.delbrueckii contained the highest peptide content compared with other strains. L.acidophilus-S and L.rhamnosus-S showed stronger DPPH scavenging rate and FARP, which were 57.03 % and 52.78 % stronger than unfermented soymilk, respectively. These results may be provided a theoretical basis for the strain screening of fermented soymilk.

Emulsion Properties during Microencapsulation of Cannabis Oil Based on Protein and Sucrose Esters as Emulsifiers: Stability and Rheological Behavior

The effects of different emulsifiers, such as soy protein isolate-sucrose ester (SPI-SE) and whey protein isolate-sucrose ester (WPI-SE), on the properties of the emulsion during the microencapsulation of cannabis oil were studied. The influence of SE concentration on the emulsion properties of the two emulsifying systems was analyzed. The results of the adsorption kinetics show that SE can decrease the interfacial tension, particle size and zeta potential of the emulsions. The results of the interfacial protein concentration show that SE could competitively replace the protein at the oil-water interface and change the strength of the interfacial film. The results of the viscoelastic properties show that the emulsion structure of the two emulsion systems results in the maximum value when the concentration of SE is 0.75% (w/v), and the elastic modulus (G') of the emulsion prepared with SPI-SE is high. The viscosity results show that all emulsions show shear-thinning behavior and the curve fits well with the Ostwald-Dewaele model. The addition of SE in the emulsions of the two emulsion systems can effectively stabilize the emulsion and change the composition and strength of the oil-water interface of the emulsion. The cannabis oil microcapsules prepared with protein-SE as an emulsion system exhibit high quality.

Assessment of In Vitro Digestive Behavior of Lactic-Acid-Bacteria Fermented Soy Proteins: A Study Comparing Colloidal Solutions and Curds

This study investigated the effect of lactic-acid-bacteria fermentation on the microstructure and gastrointestinal digestibility of soy proteins using a digestomics approach. Fermented soy protein isolates (FSPIs) under varied fermentation-terminal pH demonstrated a colloidal solution (FSPI-7.0/6.0) or yogurt-like curd (FSPI-5.0/4.0) state. Cryo-electron microscopy figures demonstrated the loosely stacked layer of FSPI-7.0/6.0 samples, whereas a denser gel network was observed for FSPI-5.0/4.0 samples. Molecular interactions shifted from dominant ionic bonds to hydrophobic forces and disulfide bonds. The gastric/intestinal digestion demonstrated that the curd samples afforded a significantly low particle size and high-soluble protein and peptide contents in the medium and late digestive phases. A peptidomics study showed that the FSPI-6.0 digestate at early intestinal digestion had a high peptidome abundance, whereas FSPI curd digestates (FSPI-5.0/4.0) elicited a postponed but more extensive promotion during medium and late digestion. Glycinin G2/G4 and β-conglycinin α/α' subunits were the major subunits promoted by FSPI-curds. The spatial structures of glycinin G2 and β-conglycinin α subunits demonstrated variations located in seven regions. Glycinin G2 region 6 (A349-K356) and β-conglycinin α subunit region 7 (E556-E575), which were located at the interior of the 3D structure, were the key regions contributing to discrepancies at the late stage.