Effects of galactooligosaccharide glycation on the functional properties of soy protein isolate and its application in noodles

Soybean protein has high nutritional value, but its functional properties are easily affected by external factors,which limits its application in food industry. In the study, soybean protein isolate(SPI) was modified by dry heat glycation of galactooligosaccharides(GOS). The gel properties, antioxidant properties and structural changes of SPI-GOS conjugates were investigated. The application of SPI-GOS conjugates in noodles was also explored. The results observed that the glycation degree of SPI increased with the increasing reaction time. SDS-PAGE and spectral analysis showed the changes of spatial conformation of SPI after glycation. The antioxidant activity of SPI increased after glycation and DPPH radical scavenging activity of SPI-GOS peaked at 48 h of reaction. The hardness, elasticity and resilience of soybean protein gel reached their relative maximum at 48 h, 48 h and 12 h of glycation reaction, respectively. Moreover, the appropriate addition of glycated SPI improved the quality of noodles. The noodles with 4% addition of SPI-GOS had higher hardness, elasticity and tensile properties. This study will provide an effective method to modify soybean protein and expand the use of soybean protein in food industry.

Effect of ionic strength and mixing ratio on complex coacervation of soy protein isolate/Flammulina velutipes polysaccharide

Soy protein isolate(SPI)is a commercial protein with balanced amino acids,while the poor solubility impedes its use in traditional foods.To overcome the problem,the complex coacervation of SPI/Flammulina velutipes polysaccharide(FVP)were investigated.Initial results revealed that the suitable amounts of FVP contributed to reducing the turbidity of SPI solution.Under electrostatic interaction,the formation of SPI/FVP coacervates were spontaneous and went through a nucleation and growth process.Low salt concentration(C_(NaCl)=10,50 mmol/L)led to an increase in the critical pH values(pHc,pHφ1)while the critical pH values decreased when C_(NaCl)≥100 mmol/L.The concentration of NaCl ions increased the content ofα-helix.With the increase of FVP,the critical pH values decreased and the content ofβ-sheet increased through electrostatic interaction.At SPI/FVP ratio of 10:1 and 15:1,the complex coacervation of SPI/FVP were saturated,and the coacervates had the same storage modulus value.SPI/FVP coacervates exhibited solid-like properties and presented the strongest storage modulus at C_(NaCl)=50 mmol/L.The optimal pH,SPI/FVP ratio and NaCl concentration of complex coacervation were collected,and the coacervates demonstrated a valuable application potential to protect and deliver bioactives and food ingredients.

Comparative effects of soy protein concentrate,enzyme‑treated soybean meal,and fermented soybean meal replacing animal protein supplements in feeds on growth performance and intestinal health of nursery pigs

Background Soy protein supplements,with high crude protein and less antinutritional factors,are produced from soybean meal by different processes.This study evaluated the comparative effects of various soy protein supplements replacing animal protein supplements in feeds on the intestinal immune status,intestinal oxidative stress,mucosaassociated microbiota,and growth performance of nursery pigs.Methods Sixty nursery pigs(6.6±0.5 kg BW)were allotted to five treatments in a randomized complete block design with initial BW and sex as blocks.Pigs were fed for 39 d in 3 phases(P1,P2,and P3).Treatments were:Control(CON),basal diet with fish meal 4%,2%,and 1%,poultry meal 10%,8%,and 4%,and blood plasma 4%,2%,and 1%for P1,P2,and P3,respectively;basal diet with soy protein concentrate(SPC),enzyme-treated soybean meal(ESB),fermented soybean meal with Lactobacillus(FSBL),and fermented soybean meal with Bacillus(FSBB),replacing 1/3,2/3,and 3/3 of animal protein supplements for P1,P2,and P3,respectively.Data were analyzed using the MIXED procedure in SAS 9.4.Results The SPC did not affect the BW,ADG,and G:F,whereas it tended to reduce(P=0.094)the ADFI and tended to increase(P=0.091)crypt cell proliferation.The ESM did not affect BW,ADG,ADFI,and G:F,whereas tended to decrease(P=0.098)protein carbonyl in jejunal mucosa.The FSBL decreased(P<0.05)BW and ADG,increased(P<0.05)TNF-α,and Klebsiella and tended to increase MDA(P=0.065)and IgG(P=0.089)in jejunal mucosa.The FSBB tended to increase(P=0.073)TNF-α,increased(P<0.05)Clostridium and decreased(P<0.05)Achromobacter and alpha diversity of microbiota in jejunal mucosa.Conclusions Soy protein concentrate,enzyme-treated soybean meal,and fermented soybean meal with Bacillus could reduce the use of animal protein supplements up to 33%until 7 kg body weight,up to 67%from 7 to 11 kg body weight,and entirely from 11 kg body weight without affecting the intestinal health and the growth performance of nursery pigs.Fermented soybean meal with Lactobacillus,however,increased the immune reaction and oxidative stress in the intestine consequently reducing the growth performance.

Supplementing the early diet of broilers with soy protein concentrate can improve intestinal development and enhance short-chain fatty acid-producing microbes and short-chain fatty acids,especially butyric acid

Background:Research on nutrition in early-life commonly focuses on the maturation of the intestine because the intestinal system is crucial for ensuring continued growth.To explore the importance of early nutrition regulation in animals,soy protein concentrate(SPC)was added to the early diet of broilers to investigate its effects on amino acid digestibility,intestinal development,especially intestinal microorganisms,and broiler metabolites.A total of 192 oneday-old Arbor Acres(AA)male broilers were randomly assigned to two experimental treatments with 8 replicates of 12 birds.The control group was fed a basal diet(control),and the treatment group was fed a basal diet supplemented with 12%SPC(SPC12)during the first 10 d(starter phase).From d 11 to 21(grower phase)and d 22 to 42(finisher phase),a basal diet was fed to both treatment groups.Results:SPC reduced the pH value and acid-binding capacity of the starter diet(P<0.05,d 10);SPC in the early diet enhanced the gizzard weight(P<0.05,d 10 and d 42)and the ileum weight(P<0.05,d 10)and decreased the weight and length of the jejunum(P<0.05,d 10)and the relative length of the duodenum and jejunum(P<0.05,d 10).At the same time,SPC enhanced villus height(P<0.05,d 10)and muscle thickness in the jejunum and ileum(P<0.05,d 10)and increased the number of goblet cells in the duodenum(P<0.05,d 10).Meanwhile,SPC increased the Chao1 index and the ACE index(P<0.05,d 10)and altered the composition of caecal microflora at d 10.SPC also increased the relative abundance of Alistipes,Anaerotruncus,Erysipelatoclostridium,Intestinimonas and Flavonifractor bacteria(P<0.05,d 10).At the same time,the concentrations of caecal butyric acid and total short-chain fatty acids(SCFAs)were also increased in the SPC12 group(P<0.05,d 10).Conclusions:In summary,the results showed that supplementing the starter diet of broilers with SPC has a significant effect on the early development of the intestine and the microflora.

Drying kinetics of soy protein isolate-corn starch film during preparation and its moisture adsorption characteristics during storage

To better understand the mass transfer process of moisture in the soy protein isolate-corn starch(SPI-CS)films during preparation and storage process,the drying kinetics model of SPI-CS films with different formation conditions during the drying process and the moisture adsorption characteristics of the SPI-CS films under different humidity conditions were investigated.Within the range of experimental conditions,the moisture migration rule in the SPI-CS films during the drying preparation was combined with the Page model which was expressed as MR=exp(-kt^(n)).It was found that the adsorption equilibrium needed shorter time(about 3 h)when the SPI-CS films existed in the environment with lower humidity(RH<54%).Additionally,the secondorder adsorption kinetic equation was successful to describe the moisture adsorption characteristic of the SPICS films during storage under different humidity conditions.

Crosslinking Mechanism of Soy Protein-based Adhesives based on Glyoxal and a Compound of Protein Model

The crosslinking mechanism of glyoxal and asparagine was analyzed,and the relationship between the mechanism and practical performances of soy protein-based adhesives was also discussed.It is shown that when pH=1 and 3,glyoxal reacted with asparagine in the form of major cyclic ether compounds.When pH=5,glyoxal reacted with asparagine in two structural forms of sodium glycollate and cyclic ether compounds.However,amidogens of asparagine were easy to develop protonation under acid conditions.Supplemented by the instability of cyclic ether compounds,the reaction activity and reaction degree between glyoxal and asparagine were relatively small.Under alkaline conditions,glyoxal mainly reacted with asparagine in the form of sodium glycollate.With the increase of pH,the polycondensation was more sufficient and the produced polycondensation products were more stable.The reaction mechanism between glyoxal and asparagine had strong correspondence to the practical performances of the adhesives.Glyoxal solution could develop crosslinking reactions with soy protein under both acid and alkaline conditions.Bonding strength and water resistance of the prepared soy protein-based adhesives were increased significantly.When pH>7,glyoxal had relatively high reaction activity and reaction intensity with soy protein,and the prepared adhesives had high crosslinking density and cohesion strength,showing relatively high bonding strength,water resistance and thermal stability.

MALDI ToF Investigation of the Reaction of Soy Protein Isolate with Glutaraldehyde for Wood Adhesives

Soy protein adhesives are currently a hot research topic in the wood panels industry for the abundant raw material reserves,reasonable price and outstanding environmental features.But their poor water resistance,low bonding strength and intolerance to mold are major drawbacks,so that proper modification before use is essential.Glutaraldehyde is one of the more apt cross-linking agents for soybean protein adhesives,which can effectively improve the bonding strength and water resistance of the adhesive.Equally,glutaraldehyde is also an efficient and broad-spectrum fungicide that can significantly improve the anti-fungal properties of a soy protein adhesive.In the work presented here,matrix assisted laser desorption ionization(MALDI-ToF)mass spectrometry and Fourier transform infrared spectroscopy techniques were used to analyze the reaction mechanism of glutaraldehyde cross-linking soybean protein.The results confirmed the reaction of the aldehyde group with amino groups of the side chains and the amide groups of the peptide linkages constituting the skeletal chain of the protein.The laboratory plywood and particleboard bonded with glutaraldehyde-soy bean protein adhesives were prepared to determine the adhesive bonding properties,the dry strength,24 h cold water soaking wet strength and 3 h hot water(63°C)wet strength of plywood were 2.03,1.13 and 0.75 MPa,respectively,which satisfied the requirements of industrial production.

Soy Protein Isolate Non-Isocyanates Polyurethanes(NIPU)Wood Adhesives

Soy-protein isolate(SPI)was used to prepare non-isocyanate polyurethane(NIPU)thermosetting adhesives for wood panels by reacting it with dimethyl carbonate(DMC)and hexamethylene diamine.Both linear as well as branched oligomers were obtained and identified,indicating how such oligomer structures could further cross-link to form a hardened network.Unusual structures were observed,namely carbamic acid-derived urethane linkages coupled with lactam structures.The curing of the adhesive was followed by thermomechanical analysis(TMA).It appeared to follow a two stages process:First,at a lower temperature(maximum 130℃),the growth of linear oligomers occurred,finally forming a physically entangled network.This appeared to collapse and disentangle,causing a decrease of MOE,as the temperature increases.This appears to be due to the ever more marked Brownian movements of the linear oligomer chains with the increase of the temperature.Second,chemical cross-linking of the chains appeared to ensue,forming a hardened network.This was shown by the thermomechanical analysis(TMA)showing two distinct MOE maxima peaks,one around 130℃ and the other around 220℃,with a very marked MOE decrease between the two.Plywood panels were prepared and bonded with the SPI-NIPU wood adhesive and the results obtained are presented.The adhesive appeared to pass comfortably the requirements for dry strength of relevant standards,showing to be suitable for interior grade plywood panels.It did not pass the requirements for wet tests.However,addition of 15%of glycerol diglycidyl ether improved the wet tests results but still not enough to satisfy the standards requirements.

Comprehensive lifestyle intervention vs soy protein-based meal regimen in non-alcoholic steatohepatitis

BACKGROUND Non-alcoholic steatohepatitis(NASH) has become one of the leading causes of liver disease in the western world. In obese patients weight reduction is recommended. Up to now there are no specific guidelines for weight loss in order to reduce hepatic fat content.AIM To investigate the effects of a 24-wk guided lifestyle intervention program compared to a meal replacement regimen based on soy protein.METHODS Twenty-six subjects with NASH participated in a randomized single-center study. They were randomly assigned to either meal replacement group(MR-G)with soy-yogurt-honey preparation or to guided lifestyle change group(LC-G)with endurance activity and nutrition counselling. Serum alanine transaminase(ALT), aspartate transaminase(AST), lipid parameters, and adipokines were measured. Liver fat content and lipid composition were determined by magnetic resonance imaging and magnetic resonance spectroscopy. Body fat mass and lean body mass were assessed using Bod Pod? device. Pre-and post-intervention monitoring of parameters was performed. Statistical analyses were conducted with SPSS software, results were expressed as median(interquartile range).RESULTS Twenty-two subjects(MR-G, n = 11 and LC-G, n = 11) completed the study(9 women, 13 men; age 52.1(15.0) years, body mass index(BMI) 32.3(3.3) kg/m^2).In both groups a significant weight loss was achieved(MR-G:-6.4(3.6) kg, P <0.01; LC-G:-9.1(10.4) kg, P < 0.01). BMI dropped in both groups(MR-G:-2.3(1.5)kg/m^2, P = 0.003; LC-G:-3.0(3.4) kg/m^2, P = 0.006). Internal fat and hepatic lipid content were markedly reduced in both groups in comparable amount. There was a strong correlation between reduction in liver fat and decrease in ALT.Likewise, both groups showed an improvement in glycemic control and lipid profile. Changes in adipokines, particularly in adiponectin and leptin were closely related to intrahepatic lipid changes.CONCLUSION Comprehensive lifestyle intervention and meal replacement regimen have comparable effects on body and liver fat, as well as decrease in markers of hepatic inflammation among NASH patients.

Soy Protein Isolate Film by Incorporating Mandelic Acid as Well as Through Fermentation Mediated by Bacillus Subtilis

Soy protein isolate(SPI)biopolymeric films were prepared by adding different contents of mandelic acid(1 to 5%wrt SPI)to glycerol plasticized SPI by solution casting method.Also,SPI was fermented by Bacillus subtilis to get fermented SPI films by solution casting.Molecular mass determination of mandelic acid incorporated and fermented SPI films was carried out by sodium dodecyl sulphate-polyacrylamide gel electrophoresis(SDS-PAGE).Mandelic acid incorporated and fermented SPI films were characterized by Fourier-transform infrared spectroscopy(FT-IR),dynamic mechanical analysis(DMA),tensile strength,water uptake and optical transmittance studies.Results indicated that incorporation of mandelic acid in SPI resulted in high tensile strength(8.03 MPa)and highα-relaxation(Tα)as well as low water uptake.On the other hand,films cannot be prepared from fermented SPI with SPI contents of 8%and 12%.However,film from fermented SPI with 16%SPI content could be prepared but it exhibited low tensile strength(3.18 MPa)and low Tαas well as high water uptake.The resulting mandelic acid incorporated SPI films were also subjected to antimicrobial studies.At all the concentration of mandelic acid,we can easily observe the antimicrobial effect in mandelic acid incorporated SPI films unlike fermented SPI films.This work will be helpful in fabricating antimicrobial SPI film from renewable resources.

PREPARATION AND CHARACTERIZATION OF SOY PROTEIN ISOLATE(SPI)/MONTMORILLONITE(MMT) BIONANOCOMPOSITES

The bionanocomposites of soy protein isolate(SPI)/montmorillonite(MMT) have been prepared successfully via simple melt mixing,in which MMT was used as nanofiller and glycerol was used as plasticizer.Their structures and properties were characterized with X-ray diffraction(XRD),differential scanning calorimetry(DSC),scanning electron microscopy(SEM),thermogravimetric analysis and tensile testing.XRD、TEM and SEM results indicated that the MMT layers could be easily intercalated by the SPI matrix even by simpl...

ZnSe Nanoparticles Reinforced Biopolymeric Soy Protein Isolate Film

ZnSe nanoparticles have been synthesized by microwave assisted method by using zinc chloride,selenium powder and ethylene diamine.The synthesized nanoparticles have been characterized structurally by FT-IR and XRD as well as morphological characterization was done by scanning electron microscope(SEM).The crystallite size after synthesis was obtained around 30 nm for pure ZnSe nanocrystallites.However,from SEM micrograph,agglomerated ZnSe nanoparticles of irregular shapes were observed.The as-synthesized ZnSe nanoparticles at different contents(1 to 5%w/w w.r.t SPI)were incorporated into soy protein isolate(SPI)to produce reinforced SPI films by solution casting method.The ZnSe nanoparticles incorporated SPI suspensions were subjected to molecular mass and specific conductivity studies.Neat and ZnSe nanoparticles incorporated SPI films were structurally and mechanically characterized by FT-IR and tensile properties,respectively.Transmittance and water uptake studies were also carried out for ZnSe nanoparticles incorporated SPI films.The tensile strength and modulus increased from 5.80 MPa to 10.06 MPa and 18.84 MPa to 94.70 MPa with the increase in the contents of ZnSe nanoparticles from 0 to 5%.Moreover,the results also revealed a good antibacterial effect in ZnSe nanoparticles incorporated SPI film.The main application of nanoparticles incorporated SPI film will be in the area of biodegradable packaging.

Rheological Properties of Soy Protein Isolate and Polyurethane in the PAN/DMSO Solution

The rheological properties of soy protein isolate （SPI） and polyurethane （PU） in the PAN/DMSO solution were investigated in this study. The results showed that all these solutions possessed pseudo-plastic solution properties. There are opposite effects of SPI and PU in the PAN/DMSO solution. Their apparent viscosity, degree of non-Newtonian fluid, and extent of structuralization of blend system increase with the addition of SPI, whereas, all of these decrease with the addition of PU. Moreover, the theological properties of PAN/DMSO solution were affected when SPI and PU were added equally, and SPI presented more effect when the proportion of ingredient was less, and PU presented more effect when the proportion of ingredient was more.

Completely Green Synthesis of Ag Nanoparticles Stabilized by Soy Protein Isolate under UV Irradiation

A completely green pathway for the preparation of Ag nanoparticles was proposed, by using soy protein isolate （SPI） as stabilizer under UV irradiation and H2O as the environmentally benign solvent throughout the preparation. Transmission electronic microscopy （TEM） and zeta potential characterization results indicated that the Ag nanoparticles were stable and well dispersed with an average diameter about 13 nm, and X-ray diffraction （XRD） analysis of SPI/Ag composite nanoparticles confirmed the formation of metallic silver. UV-Vis spectrum showed that the Ag nanoparticles dispersion solution had the maximum absorbance at about 430 nm due to surface plasmon resonance of the Ag nanoparticles. Infrared spectroscopy confirmed that the polypeptide backbone of SPI was not cleaved during the conjugation process and that some active amino groups were oxidized. The SPI/Ag composite nanoparticles have excellent antibacterial activity against two representative bacteria, staphylococcus aureus （Gram positive） and escherichia coli （Gram negative） in the presence of SPI.

Study on the Hydrogen Bond Interaction Between Soy Protein Isolate and Glycerol Using Two-Dimensional Correlation Fourier-Transform Infrared Spectroscopy

A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.

Study on Application of Ultrafiltration in Reclamation of Soy Protein Wastewater

This pilot study involved the application of a crossflow ultrafiltration （UF） membrane module employing hollow fiber polysulphone membranes in the reclamation of protein and oligosaccharides from soy protein wastewater. The optimal membrane molecular weight cut-off （MWCO） was selected as 10 ku upon retaining ratios of protein and oligosaccharides as well as the variation of permeate flux. The effects of pretreatment strategy and operating conditions, such as transmembrane pressure （TMP）, feed pH and velocity on flux were studied. According to the experimental result, the optimal operating conditions were determined as temperature 45 ℃, pH 4.5, TMP 0.2 MPa and feed velocity 10 L·s^-1. In addition, the permeate flux recovery by pure water backflushing and chemical cleaning was investigated. The experimental result showed that backflushing with pure water could only recover the lost permeate flux by 30%, and the decrease of backflushing interval was helpful in improving UF permeate productivity. Chemical cleaning test revealed that the combination of sodium hydroxide and EDTA was an ideal agent for cleaning the fouled membranes.

Solution Properties of Soy Protein in DMSO/Urea Solvent System

Solution properties of 7S globulins (7S), 11S globulins (11S) and soy protein isolates (SPI) in dimethylsulfoxide (DMSO)/urea solvent system were studied by intrinsic viscosity and particle size distributions. The results showed that the existence of urea was the main reason for the denaturation and solubility of soy protein in the system, and the effects were more obvious with increasing of urea concentration in solutions. Suitably dissolution temperature and time contributed to the solubility of soy proteins.

Moisture Sorption Isotherms of Soy Protein IsolatelCarboxymethyl Chitosan Blend Films

Soy protein isolate/carboxymethyl chitosan （SPI/CMCH） blended films incorporated with glycerol were prepared using solution casting to investigate the effects of the SPI and CMCH ratios （100：0, 88：12, 67：33, 50：50, 33：67, 12：88, 0：100） on the water sorption isotherm. The moisture sorption isotherm of the SPI/CMCH blended films was determined using various relative humidity＇s （16%, 35%, 55% and 76% RH） at 25 ± 1℃. The isotherms showed that the equilibrium moisture content （EMC） of the films increased with increasing CMCH content and the EMC value sharply increased above aw = 0.55. Understanding of sorption isotherms is important for prediction of moisture sorption properties of films via moisture sorption empirical models. The Guggenheim-Oswin, Brunauer-Emmett-Teller （BET）, and Anderson-de Boer （GAB） sorption model predictions were tested against the experimental data. The root mean square （RMS） values from the Oswin, BET, and GAB models respectively ranged from 698.54 to 1,557.54, 38.85 to 58.30, and 52.52 to 95.95. Therefore, the BET model was found to be the best-fit model for SPI/CMCH blended films at 25 ± 1 ℃.

Effect of Acid Treatment on Interfacial and Foam Properties of Soy Proteins

The goal of the present work was to study the effects of acid treatment on the foaming properties of a soybean protein isolate （SPI） and its fractions, glycinin （11S） and β-conglycinin （7S）. The structural characteristics, interfacial properties, foaming capacity and stability of the treated proteins were studied. Results from surface hydrophobicity and differential scanning calorimetry （DSC） showed that the acid treatment caused the complete denaturation of 11S and a partial denaturation of 7S. This protein unfolding affected their interracial properties, which led to an improvement in the foaming properties of both protein fractions and isolate. Treated 7S showed the best behavior in the rearrangement process, probably due to its smaller size and its modified structural characteristics. All treated proteins showed stronger interracial films. The foams of treated proteins were destabilized mostly due to gravitational drainage rather than Ostwald ripening.

Influence of soy protein isolate on the gel properties of walnut protein isolate-κ-carrageenan treated with NaCl

The demand for plant protein is increasing significantly due to the shortage of protein resources.Walnut protein,the main by-product of preparing walnut oil,has limited application in the food industry due to its poor solubility.It was found that the soy protein isolate(SPI)concentration had significant effects on the gel properties of the walnut protein isolate(WNPI)-κ-Carrageenan(KC)composite system treated with 15 mmol/L NaCl.The results showed that the gel strength of the composite system increased first and then decreased with the increased concentration of SPI from 0 to 2.5%.The best rheological properties,texture properties,water holding capacity((92.03±1.05)%),swelling ratio((2.04±0.19)%),freeze-thaw stability and thermal stability(85.53°C)of the composite gel were found at an SPI concentration of 1%.In the meantime,the secondary structure of protein had the least α-helix content of 10.17% and the highest β-sheet content of 39.64%,the fluorescence intensity and free sulfhydryl content reached the highest value.1% SPI could also act as a filler for WNPI to enhance the intermolecular forces such as hydrophobic interaction between the two substances,thus forming a stable gel network structure.This study can provide technical support for improving the gel properties of walnut protein and producing new plant protein gel products.