Soy Β-conglycinin Research Articles

Effect of Thermal Treatment on Gelling and Emulsifying Properties of Soy β-Conglycinin and Glycinin.

This study investigated the impact of different preheat treatments on the emulsifying and gel textural properties of soy protein with varying 11S/7S ratios. A mixture of 7S and 11S globulins, obtained from defatted soybean meal, was prepared at different ratios. The mixed proteins were subjected to preheating (75 °C, 85 °C, and 95 °C for 5 min) or non-preheating, followed by spray drying or non-spray drying. The solubility of protein mixtures rich in the 7S fraction tended to decrease significantly after heating at 85 °C, while protein mixtures rich in the 11S fraction showed a significant decrease after heating at 95 °C. Surprisingly, the emulsion stability index (ESI) of protein mixtures rich in the 7S fraction significantly improved twofold during processing at 75 °C. This study revealed a negative correlation between the emulsifying ability of soy protein and the 11S/7S ratio. For protein mixtures rich in either the 7S or the 11S fractions, gelling proprieties as well as emulsion activity index (EAI) and ESI showed no significant changes after spray drying; however, surface hydrophobicity was significantly enhanced following heating at 85 °C post-spray drying treatment. These findings provide insights into the alterations in gelling and emulsifying properties during various heating processes, offering great potential for producing soy protein ingredients with enhanced emulsifying ability and gelling property. They also contribute to establishing a theoretical basis for the standardized production of soy protein isolate with specific functional characteristics.

Comparison and inhibition mechanism study on the in vitro digestibility of rice starch complex with soy β-conglycinin and soy glycinin

To inhibit the digestion of indica rice starch (IRS), an excellent strategy was to add exogenous proteins that interact with IRS, which was closely associated with the protein components. Herein, this study compared the effects of soy protein subfractions, soy β-conglycinin (7S) and soy glycinin (11S), on IRS digestion and explored its inhibition mechanisms. This study used hydrothermal processing to prepare IRS complexes with soy protein subfractions (7S and 11S) at different starch-protein ratios. The results found that adding 7S and 11S exhibited different inhibitory patterns on starch digestion. Compared to IRS, a higher slowly digestible starch (SDS) content (40.91%, p < 0.05) was observed at the IRS-7S ratios of 20:8, while the 20:6 IRS-11S complex showed a higher resistant starch (RS) content (15.76%, p < 0.05). Subsequently, the interactions between IRS and soy protein subfractions and their multi-scale structural changes were explored. The rheological results revealed that hydrophobic interaction and hydrogen bonding were the main driving forces. Various structural changes were closely associated with inhibitory modes of soy protein subfractions on IRS digestion. In detail, the increased SDS content in IRS-7S complexes was attributed to the formation of compact protein physical barriers, aggregated structures with more ordered regions, and flexible secondary conformations of 7S. However, the high-density structures and the stable secondary conformations of 11S were responsible for the increased RS content in IRS-11S complexes. Thus, this study could provide directions for developing SDS-enriched or RS-enriched starch-based products.

Development of controlled-release soy β-conglycinin nanoparticles containing curcumin using genipin as crosslinker

Recent advances in nanocarriers for bioactives have focused on finding more sustained-release, natural materials. In this study, genipin-crosslinked soy β-conglycinin (β-CG)-curcumin nanoparticles (G-SCP) significantly enhanced the stability of curcumin and released curcumin controllably in the gastric environment. The optimal intra-particle crosslinkage for G-SCP was obtained under the genipin concentration less than 0.2 mg/mL and stirring at 37 °C for 24 h, which was confirmed by ninhydrin assay, amino acid analysis, dynamic light scattering (DLS) and flourier transform infrared spectroscopy (FT-IR) analysis. Transmission electron microscopy (TEM), DLS and release of trichloroacetic acid (TCA)-soluble nitrogen were used to systematically evaluate the sustained-release behavior and mechanism of curcumin from the G-SCP. The anti-cancer activity of oral-intake curcumin was investigated by collecting the G-SCP digestion supernatant and analyzing its cellular uptake and proliferation in HepG2 cells. The results revealed that the bioaccessible curcumin released from G-SCP had stronger anti-proliferation for HepG2 cells than free curcumin. On normal liver cells L02, interestingly, bioaccessible curcumin had considerably lower cytotoxicity than it did on HepG2 cells. These findings suggested that the G-SCP was a protein-based carrier that could effectively transfer insoluble bioactives in the gastric environment.

Controlling the assembly of soy β-conglycinin to fabricate heat-stable particles for high protein liquid systems.

Recently, there is a growing interest in developing protein-fortified liquid systems, which are formulated to provide special nutrient combinations to those with special dietary needs. The fabrication of heat-stable protein for protein-fortified liquid systems relies heavily on precise control of the edible protein-building process. Results suggested that heat-stable 7S protein particles (7SPPs) could be obtained by preheating at 100 °C for an extended time, whereas 7S proteins with better gelling properties were discovered after preheating at lower temperatures. According to the findings of the protein conformational and morphological characterization, the 7SPPs showed rather stable tertiary and secondary structures as well as size distributions, which might be responsible for their heat stability. Additionally, during the reheating test, suspensions of 7SPPs showed no signs of gelation and had a low viscosity even though the protein content was as high as 120 mg mL-1 . However, 7S proteins with improved gelling properties were found to show rising aggregate size, higher susceptibility and larger conformational structure changing rates upon reheating treatment. Soy β-conglycinin (7S) proteins with tunable heat stability were successfully prepared by preheating 10 mg mL-1 protein dispersions at various temperatures (80-120 °C) and durations (15-120 min). These findings provide fundamental insights for developing 7S-based protein-fortified systems. © 2023 Society of Chemical Industry.

Use of oligomeric globulins to efficiently fabricate nanoemulsions: Importance of enhanced structural stability by introducing trehalose

Food-grade nanoemulsions using plant proteins as the sole emulsifier has attracted increasing interest in the food field. However, plant proteins present limitations in emulsification performance owing to their extensive aggregation and unfavorable adsorption behavior, when applied to stabilize emulsions. In the current work, a novel strategy to efficiently form nanoemulsions using plant oligomeric globulins (soy β-conglycinin and glycinin) as the sole emulsifier was proposed through the introduction of trehalose prior to emulsification, in order to overcome the above-mentioned limitations. The formed nanoemulsions were small-sized and well-dispersed, and displayed high stability against flocculation and coalescence. The underlying mechanism for this was largely associated with the enhanced structural stability of protein which contributes to improved interfacial adsorption behavior. Results indicated that the proteins were highly stable during microfluidization and adsorption at the interface in the presence of trehalose. Further research on protein adsorption behavior revealed more rapid diffusion rate, as well as less structural unfolding and rearrangement at oil-water interface of protein particles in trehalose-rich system, than in the trehalose-poor system. Through trehalose coating, oligomeric globulins could perform as outstanding Pickering particles with a strong structural integrity at oil-water interface.

Soy-fortelin: A ghrelin sensitivity-enhancing peptide that stimulates food intake in aged mice.

Ghrelin sensitivity is known to decrease with aging in mice and humans, and the decrease contributes to anorexia with aging. In this study, we discovered novel ghrelin sensitivity-enhancing peptides. Ghrelin sensitivity was evaluated by examining whether dipeptide samples enhanced the calcium response to ghrelin in the growth hormone secretagogue receptor-transfected cell line. First, dipeptides were screened using a 336-dipeptide library and we revealed that Ser-Tyr (SY) potentiated ghrelin sensitivity in particular. Based on the structure-activity relationship determined using the dipeptide library and comprehensive analysis of peptides in the chymotrypsin digest of soy β-conglycinin (β-CG), which enhanced ghrelin sensitivity, candidate peptides were narrowed down. Among the chemosynthesized peptides, we discovered that an undecapeptide, SLVNNDDRDSY, corresponding to β-CGα(267-277), stimulated ghrelin sensitivity in vitro. This peptide enhanced the orexigenic activity of ghrelin in C57BL/6 mice and stimulated food intake. Thus, we demonstrated that SLVNNDDRDSY stimulated ghrelin sensitivity in vitro and in vivo and named it "soy-fortelin". Moreover, orally administered soy-fortelin had a similar but smaller effect in the young C57BL/6 mice, whereas it strongly stimulated food intake in 2-year-old aged mice that exhibited high blood ghrelin levels and low ghrelin sensitivity. In conclusion, we discovered soy-fortelin as a novel peptide that enhances ghrelin sensitivity in vivo and in vitro and increases food intake in young and aged ghrelin-resistant mice. Soy-fortelin is the first food-derived peptide reported to enhance ghrelin sensitivity.

Preparation, characterization, and foaming properties of soy protein nanoparticles by the cross-linking reaction induced by microbial transglutaminase

Native soy proteins have limited surface properties, but fortunately, it is expected that their foaming behaviors can be improved through the enzymatic cross-linking method. In this paper, by using the cross-linking method with microbial transglutaminase (mTG) as the catalyst, soy protein isolate (SPI), soy β-conglycinin (7S), and soy glycinin (11S) nanoparticles (NPs) were prepared in the molten state of the protein induced by dithiothreitol (DTT). We compared the structural characteristics of these nanoparticles, including particle sizes, morphologies, zeta potentials, surface hydrophobicities, changes of spatial structure, and cross-linking degrees. In addition, their foaming properties, including foamabilities, foam stabilities, and bubble diameters, were also tested. The results show that there are no significant differences in the foamabilities between the native soy proteins and their nanoparticles with similar initial foam heights. However, it is found that 11S NPs have enhanced foam stabilities with longer half-lives and smaller changes in bubble size, which is closely related to their high wettability and cross-linking degree. This study may provide references for the application of soy protein nanoparticles as new foam stabilizers to replace the traditional foaming agents in the food industry.

Dietary Combination of Fish Oil and Soy β-Conglycinin Inhibits Fat Accumulation and Reduces Blood Glucose Levels by Altering Gut Microbiome Composition in Diabetic/Obese KK-A y Mice.

Dietary fish oil containing n-3 polyunsaturated fatty acids provides health benefits by lowering lipid levels in the liver and serum. β-Conglycinin (βCG) is a major constituent protein in soybean with many physiological effects, such as lowering blood triglyceride levels, preventing obesity and diabetes, and improving hepatic lipid metabolism. However, the combined effects of fish oil and βCG remain unclear. Here, we investigated the effects of a dietary combination of fish oil and βCG on lipid and glucose parameters in diabetic/obese KK-A y mice. KK-A y mice were divided into three groups: control, fish oil, and fish oil + βCG; these groups were fed a casein-based diet containing 7% (w/w) soybean oil, a casein-based diet containing 2% (w/w) soybean oil and 5% (w/w) fish oil, and a βCG-based diet containing 2% (w/w) soybean oil and 5% (w/w) fish oil, respectively. The effects of the dietary combination of fish oil and βCG on blood biochemical parameters, adipose tissue weight, expression levels of fat- and glucose metabolism-related genes, and cecal microbiome composition were evaluated. The total white adipose tissue weight (p < 0.05), levels of total serum cholesterol (p < 0.01), triglyceride (p < 0.01), and blood glucose (p < 0.05), and expression levels of fatty acid synthesis-related genes (including Fasn (p < 0.05) and Acc (p < 0.05)), and glucose metabolism-related genes (such as Pepck (p < 0.05)) were lower in the fish oil and fish oil + βCG groups than in the control group. Furthermore, the relative abundance of Bacteroidaceae and Coriobacteriaceae differed significantly between the fish oil + βCG and control groups. These findings suggest that dietary intake of fish oil + βCG may prevent obesity and diabetes, alleviate lipid abnormalities, and alter the gut microbiome composition in diabetic/obese KK-A y mice. Further research is needed to build on this study to evaluate the health benefits of major components of Japanese food.

Lactic acid bacteria fermented soy β-conglycinin: Assessment of structural conformational feature and immunoglobulin E reactivity

Lactic acid bacterial fermentation applies as an emerging strategy for alleviating soy antigenicity. However, the knowledge regarding the underlying relationship between protein structure and immunoreactivity is insufficient. In the present study, β-conglycinin, a major soy allergen, was isolated, and the effect of Lactiplantibacillus plantarum B1-6 fermentation on its structure and immunoreactivity was investigated. The results demonstrated that the immunoreactivity and conformational structures of β-conglycinin were regulated by varied fermentation terminal pH (FT-pH) levels (6.0, 4.5, 4.0, and 3.5) and different β-conglycinin concentrations (0.1%, 0.5%, 1%, and 2%, w/v). The most significant reduction in soy immunoreactivity, which was assayed using a sandwich enzyme-linked immunosorbent assay kit test and the serum of soybean allergy patients, was observed at FT-pH 4.5 regardless of β-conglycinin concentration. The conformational study demonstrated that the loss of the α-helix structure, opening of the tertiary structure, and the formation of aggregates (0.1%–1%, w/v) or gel network (2%, w/v) contributed to the loss of immunoreactivity. Among the four selected concentrations, 2% β-conglycinin (w/v) demonstrated the lowest band intensity in β-subunit, the highest surface hydrophobicity, and the lowest immunoreactivity. Principal component analysis confirmed that fermentation induced changes in protein particle size, intrinsic fluorescence intensity, and hydrogen bond, which were closely related to the immunoreactivity reduction of β-conglycinin.

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

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

Protective effect of isoflavone enriched soy β-conglycinin on osteoporosis in ovariectomized rats.

Research shows that the consumption of soybean foods can reduce the incidence rate of bone fractures in women after menopause. The aim of this study was to investigate the effects of different complex of soy β-conglycinin (7S) and isoflavones (7S-ISO) on osteoporosis in ovariectomized rats. All treatments were administrated intragastrically to the groups every afternoon for 3 months. The treatments were administrated at 1mL·(100 g)-1 , the animals were given 50 mg·kg-1 ·d-1 ISO, and the concentration of protein was about 2wt. %. The bone mineral density (BMD) and the bone biomechanics results of left tibia' maximum load in the 7S-ISO group is significantly higher than in the ovariectomized group and the 7S group (p < .05). Otherwise, the serum tartrate-resistant acid phosphatase (s-TRACP), serum osteocalcin (s-BGP), and serum estradiol (s-E2 ) levels in 7S-ISO were all significantly different from the OVX, OVX + casein, and the OVX + 7S group (p < .05). The serum calcium (s-Ca) level was not significantly different among all the groups. 7S-ISO may exhibit moderate estrogenic activities and as compared to 7S and ISO in osteoporosis (OP) of ovariectomized rats. PRACTICAL APPLICATIONS: The effects of soy proteins on the health of females have always been a concern. It has been extensively reported soy 7S globulin (7S) as a type of trimer glycoprotein can depress blood fats. The aim of this study was to investigate the effects of different complex of soy β-conglycinin and isoflavones (ISO), the main storage proteins and polyphenols in soy, on osteoporosis in ovariectomized rats.

Fabrication and characterization of soy β-conglycinin-dextran-polyphenol nanocomplexes: Improvement on the antioxidant activity and sustained-release property of curcumin

In this study, glycated soy β-conglycinin (β-CG) stabilized curcumin (Cur) composites were fabricated by a unique reversible self-assembly character of β-conglycinin-dextran conjugates (β-CG-DEX). Intrinsic fluorescence and far-UV CD spectra revealed that glycation did not affect the self-assembly property of β-CG in the pH-shifting treatment. The structure of β-CG-DEX could be unfolded at pH 12.0 and reassembled during acidification (from pH 12.0 to 7.0). Meanwhile, β-CG-DEX-3d, which was incubated at 60 °C for 3 days, exhibited a high loading capacity (123.4 mg/g) for curcumin, which far exceeds that (74.90 mg/g) of β-CG-Cur. Moreover, the reassembled β-CG-DEX-3d-Cur showed eminent antioxidant activity of approximately 1.5 times higher than that of free curcumin. During the simulated gastrointestinal condition, compared with β-CG-Cur, β-CG-DEX-3d-Cur nanoparticles showed a more stable and sustained release of curcumin. Thus, β-CG-DEX has immense potential to become a new delivery carrier for hydrophobic food components by means of a self-assembly strategy.

An insight into the changes in conformation and emulsifying properties of soy β-conglycinin and glycinin as affected by EGCG: Multi-spectral analysis

The binding mechanisms between soy β-conglycinin/glycinin and (−)-epigallocatechin-3-gallate (EGCG) were evaluated using multi-spectral techniques and molecular modeling. Additionally, the emulsifying properties of β-conglycinin/glycinin were investigated in their interactions with EGCG. Fluorescence analysis revealed that the quenching of β-conglycinin/glycinin by EGCG was static quenching. Specifically, EGCG to β-conglycinin/glycinin resulted in the conformation changes of the Trp and Tyr residues, around which the polarity toward more hydrophilic. The dominated binding between β-conglycinin and EGCG was hydrogen bonding, whereas was mainly hydrophobic force between glycinin and EGCG. Such affinity induced a more organized protein confirmation with decreased random coil and increased α-helix and β-structures. The docking data indicated the better affinity between glycinin and EGCG, compared to β-conglycinin. The emulsifying ability and capacity of β-conglycinin were enhanced with involvement EGCG, however no effect was found for glycinin. Our findings deliver insights in understanding of the interaction mechanisms between β-conglycinin/glycinin and EGCG.

Impact of Soy β-Conglycinin Peptides on PCSK9 Protein Expression in HepG2 Cells.

Background: Dyslipidaemias, particularly elevated plasma low-density lipoprotein cholesterol (LDL-C) levels, are major risk factors for cardiovascular disease (CVD). Besides pharmacological approaches, a nutritional strategy for CVD prevention has gained increasing attention. Among functional foods, the hypocholesterolemic properties of soy are driven by a stimulation of LDL-receptor (LDL-R) activity. Aim: To characterize the effect of two soy peptides, namely, β-conglycinin-derived YVVNPDNDEN and YVVNPDNNEN on the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), one of the key-regulators of the LDL-R. Methods: PCSK9 promoter activity (luciferase assay), PCSK9 protein expression (WB) and secretion (ELISA), PCSK9 interaction with LDL-R (binding assay) and human HepG2 cells were the objects of this investigation. Results: Treatment with YVVNPDNNEN peptide has led to a rise in PCSK9 gene expression (90.8%) and transcriptional activity (86.4%), and to a decrement in PCSK9 intracellular and secreted protein (−42.9%) levels. YVVNPDNNEN peptide reduced the protein expression of transcriptional factor HNF1α. Most changes driven by YVVNPDNDEN peptide were not statistically significant. Neither peptide inhibited the PCSK9–LDLR interaction. Conclusions: Although sharing a common effect on LDL-R levels through the inhibition of 3-hydroxy-3-methylglutaryl CoA reductase activity, only the YVVNPDNNEN peptide has an additional mechanism via the downregulation of PCSK9 protein levels.

New insights into the NaCl impact on emulsifying properties of globular proteins

In the work, the emulsifying properties of three representative globular proteins (soy β-conglycinin, glycinin and bovine serum albumin; designated as SC, SG and BSA, respectively) with different structural characteristics, as affected by the addition of NaCl (0–1000 mM), were investigated and compared, using two emulsion systems at oil fractions (ø) of 0.2 and 0.8, respectively. The modulation of physicochemical properties and conformations of these three proteins by NaCl was first evaluated in terms of solubility, ζ-potential, surface hydrophobicity, particle size and intrinsic fluorescence profile. The electrostatic screening by the presence of appropriate concentrations (50–100 mM) of NaCl resulted in progressive increases in extent of protein aggregation and surface hydrophobicity of both SC and SG, but the addition of high concentrations (>300 mM) of NaCl was favorable for the ‘salting-in’ effects. At ø = 0.2, the presence of NaCl impaired the emulsification performance of SC, while in the SG case, the emulsification performance was slightly affected. At ø = 0.8, the presence of NaCl remarkably improved the emulsification performance of SC, and facilitated the droplet flocculation and gel network formation in the HIPEs, while in the SG case, the gel stiffness of the HIPEs was also improved. All the evidences indicated that at low ø values, the influence of NaCl on the emulsifying properties of oligomeric globulins was dominated by the electrostatic screening effect, while at high ø values (e.g., 0.8), the hydration repulsion between bound hydrated Na+ played a crucial role in the performance of these globulins as Pickering stabilizers. The findings are of importance for the understanding of the salt impact on the properties and stability of food protein emulsion formulations.

Characterization of iron reducibility of soy protein amyloid fibrils and their applications in iron fortification

Iron deficiency is a common nutritional disorder worldwide. Iron fortification of food is an effective strategy to control iron deficiency anemia (IDA), however, traditional iron fortificants usually provoke undesirable organoleptic changes or have limited colloid stability. In this research, we investigated iron reducibility of soy protein amyloid fibrils made from soy protein isolates (SPI), soy β-conglycinin (7S) and soy glycinin (11S), and explored their applications in iron fortification. All three protein fibrils showed iron reducibility. The reducibility was utilized to generate fibril-iron nanoparticle composites. The iron reducibility was affected by fibril concentration, degree of fibrillation and reducing amino acid composition. We identified 11S had the most significant effect on reducing Fe (III) to more bioavailable Fe (II) state, whereas 7S showed the optimal result for generation of iron nanoparticle on fibrils in situ. The resulted fibril-iron nanoparticle hybrids showed high dispersibility in various liquid foods, without distinct color change.

Interaction between pH-shifted β-conglycinin and flavonoids hesperetin/hesperidin: Characterization of nanocomplexes and binding mechanism

This study characterized the nanoparticles and the binding mechanism between pH-shifted soy β-conglycinin (β-CG) and hesperetin (Ht)/hesperidin (Hd). Different structural characteristics and concentrations of Ht/Hd were found to affect the encapsulation efficiency, loading amount, and particle size of pH-shifted β-CG‒Ht/Hd nanoparticles. This was the result of two glycosyl substituents (7-position of the C-ring) in the presence of Hd containing six hydroxyl groups interacting with the polar groups of proteins to form hydrogen bonds, which facilitated the formation of nanocomplexes. Besides, the exposed hydrophobic groups in the β-CG proteins resulting from pH shift treatment developed hydrophobic interactions with the benzene ring or glucoside in the flavonoids. Moreover, Ht/Hd strongly quenched the fluorescence of pH-shifted β-CG in static mode. After binding with flavonoids, the tertiary and secondary structures of pH-shifted β-CG were significantly changed. The finding presented in this study provided evidence of the binding mechanism of soy proteins and different structural flavonoids and will aid in the design of soy protein/flavonoid enriched-food.

Outstanding antioxidant pickering high internal phase emulsions by co-assembled polyphenol-soy β-conglycinin nanoparticles

This work reports a kind of novel antioxidant Pickering high internal phase emulsions (HIPEs; with an oil fraction, ϕ > 0.74) stabilized by soy β-conglycinin (β-CG) and polyphenol complex nanoparticles, as outstanding protective containers for lipophilic nutraceuticals. The nanoparticles with a representative polyphenol ((-)-epigallocatechin-3-gallate; EGCG) encapsulated were fabricated through an ethanol-mediated dissociation and re-assembly process of β-CG, with greater particle size and higher surface hydrophilicity observed at higher initial EGCG concentrations. Using these co-assembled nanoparticles as sole stabilizers, a kind of HIPE gels with similar gel stiffness and microstructure, could be easily fabricated at ϕ = 0.8 and a protein concentration in the aqueous phase of 1.0 wt% using polyunsatuated fatty acid-rich flaxseed oil as the dispersed phase. These HIPE gels were extraordinarily stable against heating or long-term storage, but susceptible to freeze-thawing. The as-fabricated HIPEs showed an excellent protection to β-carotene (encapsulated in oil phase) against heating, as well as an inhibition of lipid oxidation. The oxidation protection was in an EGCG concentration dependent manner. The results would be of interest for providing a novel strategy to fabricate functionalized Pickering HIPEs as potential containers or delivery systems for lipophilic nutraceuticals.

Soy β-Conglycinin Peptide Attenuates Obesity and Lipid Abnormalities in Obese Model OLETF Rats.

We previously reported that soy β-conglycinin (βCG) improves obesity-induced metabolic abnormalities, but not obesity, in obese model Otsuka Long-Evans Tokushima fatty (OLETF) rats. In the present study, we aimed to investigate the effects of βCG-derived peptide consumption on obesity and lipid abnormality in OLETF rats. To this end, wild-type Long-Evans Tokushima Otsuka and OLETF rats were provided a normal diet containing 20% casein for four weeks as a control. In addition, we prepared βCG peptide by enzymatic hydrolysis, and OLETF rats were fed a diet in which half of the casein was replaced by βCG peptide (βCG peptide group). Consequently, rats in the βCG peptide group showed decreased abdominal white adipose tissue weight and lipid content (serum and liver triglycerides, and serum and liver cholesterol) compared to control OLETF rats. Further analysis demonstrated that βCG peptide consumption decreased lipogenic enzyme activity and increased lipolytic enzyme activity in the liver of OLETF rats. In addition, suppressive effects on both synthesis and absorption of cholesterol were observed in βCG peptide-fed OLETF rats. These findings suggest that peptidization of βCG enhanced the anti-obese and hypolipidemic effects of βCG.

Interaction between soyasaponin and soy β-conglycinin or glycinin: Air-water interfacial behavior and foaming property of their mixtures

The interaction between soyasaponin and soy β-conglycinin (7S) or glycinin (11S), adsorption of their mixtures at air-water interface, and foaming properties of the mixed system were investigated in this study. Fluorescence spectroscopy results showed that there was a weak binding of soyasaponin with 7S or 11S in bulk solutions, leading to the conformational changes of protein by nonspecific hydrophobic interactions. Dynamic surface properties of soyasaponin-7S/11S mixtures indicated that the composite layers formed via their weak interactions due to the synergy of reducing surface tension and the plateau of elasticity at the interface. Most mixtures represented high foam forming ability and stability except 0.2 % soyasaponin mixture, which could be a consequence that the surface behavior was dominated by soyasaponin under this concentration, and low surface elasticity lead to a less stable interfacial film. Overall, foamability of soyasaponin-7S mixtures were better than 11S ones. All data of this work was helpful to understand air-water behaviors of soyasaponin-7S/11S mixtures. This mixed system has shown good potential for further foam related industrial applications.