Emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate obtained by Corolase PP under high hydrostatic pressure

Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydrostatic pressure(HHP)treatment has attracted much interest and has been used in several studies on protein modification.Hence,the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments(0.1,100,200,and 300 MPa for 1-5 h at 50℃)on the emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate(SPIH).As observed,the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index(47.49 m^(2)/g)and emulsifying stability index(92.98%),and it had higher antioxidant activities(44.77%DPPH free radical scavenging activity,31.12%superoxide anion radical scavenging activity,and 61.50%copper ion chelating activity).At the same time,the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size.In addition,the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability.This study has a broad application prospect in developing food ingredients and healthy foods.

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.

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.

The Effect of Hydrolysis with Neutrase on Molecular Weight,Functional Properties,and Antioxidant Activities of Alaska Pollock Protein Isolate

In this study, the Alaska pollock protein isolate(APPI) was hydrolyzed by Neutrase for 20, 40, 80, 120, 160, 200, and 240 min. Hydrolysates with different molecular weights were produced and they were named as H1–H7. Furthermore, the effects of hydrolysis on the average molecular weights, functional properties(solubility, oil-holding capacities, foaming activities, and emulsifying properties), and antioxidant activities(1, 1-diphenyl-2-picrylhydrazyl, superoxide, and hydroxyl free radical-scavenging activities) were determined. It was found that when the degree of hydrolysis(DH) increased, the average molecular weights of the hydrolysates decreased significantly. The functional properties of APPI were also significantly improved. The hydrolysates of APPI exhibited better solubility, emulsifying activities, and foaming activities. Hydrolysates with low molecular weights(<1 kDa) had better solubility, oil-holding capacities, and emulsifying activities, while hydrolysates with higher molecular weights(>1 kDa) had better foaming activities. In addition, the hydrolysates exhibited excellent antioxidant properties, while the inhibition values of 1, 1-diphenyl-2-picryl hydroxyl(DPPH), superoxide, and hydroxyl free radical-scavenging activities, were 85.22%, 53.56%, and 75.00% respectively, when the concentration of the hydrolysates was 5.0 mg mL^(-1). The lower the average molecular weight was, the higher was the antioxidant activity. These results indicated that hydrolysis with Neutrase is an effective method for improving the functional and antioxidant properties of APPI. The hydrolysates of APPI displayed great potentials to be used as natural antioxidants in protein-rich aqueous foods such as nutrient supplements and sports beverages.

Succinylated whey protein isolate as a sustained-release excipient of puerarin derivative oral tablets:Preparation,optimization and pharmacokinetics

This work was done to investigate succinylated commercial whey protein isolate(S-WPI)as an oral sustained-release delivery carrier for puerarin 5(PR-5). The succinylation condi-tions were established for S-WPIs by optimization of single factor study and Box–Beehnkendesign. The effect of succinylation degree on S-WPIs solubility was evaluated. Physicochem-ical properties of S-WPIs dried by different three methods on their flow ability, particle size,morphology and in vitro release behavior were studied. After preparing PR-5 sustained re-lease protein tablets with S-WPIs as the carrier by direct powder compression method, thedrug release were studied in vitro and the oral pharmacokinetics and bioavailability wasevaluated using in vivo dog model. It was observed that concentration of substrate has asignificant effect on succinylation. Release behavior in vitro showed spry dried S-WPIs with100% succinylation rate and 30% drug loading would be applied to the preparation of PR-5 sustained-release protein tablets based on the swelling mechanism(protein loss). Comparedwith PR-5 conventional tablet with oral administration, T max value of PR-5 sustained-releaseprotein tablets was approximately 1.58 fold greater than those of the conventional tablets asfurther evidenced by the significantly prolonged MRT and T 1/2. The findings demonstratedthat spray-dried S-WPIs has potential as a promising functional excipient for the design of PR-5 oral sustained-release tablets which can fully improve sustained-release effect and oral bioavailability.

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.

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...

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.

Influence of particle size and ionic strength on the freeze-thaw stability of emulsions stabilized by whey protein isolate

The influence of particle size and ionic strength on the freeze-thaw(FT) stability of emulsions stabilized by whey protein isolate(WPI) was investigated in this study. The destabilization of emulsions during the FT process could be suppressed in a way by decreasing the particle size of the initial emulsions, which was the result of retarding the coalescence between oil droplets. To further improve the FT stability of emulsions, different amounts of Na Cl were added before emulsification. The emulsions with the ionic strength at 30–50 mmol/L exhibited good FT stability. Notably, the ionic strength in this range would not lower the freezing point of emulsions below the freezing temperature used in this study. Salt addition could improve the structural properties of proteins, which was available to strengthen the rigidity and thickness of interfacial layers, sequentially building up the resistance that the destruction of ice crystals to emulsions. Moreover, stronger flocculation between emulsion droplets could promote the formation of a gel-like network structure dominated by elasticity in the emulsion system, which might effectively inhibit the movement of droplets, and improve the FT stability of emulsions eventually. The result was of great significance for the preparation of emulsion-based foods with improved FT stability.

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.

Serum-Derived Bovine Immunoglobulin/Protein Isolate Therapy for Patients with Refractory Irritable Bowel Syndrome

Background: A small double-blind study showed benefits of serum-derived bovine immunoglobulin/protein isolate (SBI), for diarrhea-predominant irritable bowel syndrome (IBS-D) [1]. The purpose of this chart review was to assess safety and clinical outcomes of SBI in refractory irritable bowel syndrome (IBS) patients. Methods: A retrospective review of 35 IBS patients with diarrhea or mixed diarrhea/constipation pattern (IBS-M) who were administered SBI 5 grams twice daily was performed. Clinical response (“good response” or “no response”) and adverse events were determined by follow-up after four weeks of therapy. Patients were included for evaluation if a lactulose breath test (LBT) had been performed prior to SBI. All patients were refractory to common IBS therapies. The response rate to the inclusion of SBI was calculated in three separate groups: dividing patients based on their LBT results (positive or negative), dividing patients by their IBS diagnosis (IBS-D or IBS-M) and grouping all patients together. Results: Analysis was carried out on 26 IBS-D/-M patients with LBT results. Two patients were lost to follow-up and were excluded from data analysis. The positive LBT group (N = 11) had a 73% (p = 0.117) positive response rate to SBI. The negative LBT group (N = 13) had a significant response rate of 77% (p = 0.040). If patients were divided by IBS diagnosis or grouped together, the response rate to SBI was similarly ranging from 69% - 88%. Adverse events leading to cessation of SBI occurred in 3 of 24 patients. Conclusion: SBI appeared to be a safe and effective nutritional moiety in refractory IBS-D and IBS-M patients. Larger, double-blind studies are needed.

Establishment of two-dimensional gel electrophoresis for soybean protein isolate and its application

To optimize the conditions for the establishment of two-dimensional gel electrophoresis(2-DE)of soybean protein isolate(SPI),we investigated Ampholine mixture,anodic and cathodic electrolytes,loading amount of sample,acrylamide concentration,p H gradient and gel staining method in twodimensional gel electrophoresis to optimize the protein imaging conditions in two-dimensional gel.The results of mixed-level design experiments showed that Ampholine,loading amount and gel staining method had significant effect(P<0.05)on 2-DE of SPI.The optimal conditions were Ampholine mixture(pH 3–10+pH 5–7 or pH 4–6+pH 5–7),loading amount of 2 mg sample and silver staining.Although the acrylamide concentration of the gel,the p H gradient,the anodic and cathodic electrolyte solutions had significant statistical effects on the protein separation degree,the complexity of the protein composition and the visibility of the gel images were more inclined to the 12%gel,the 3–10 pH gradient and the H3PO4/NaOH electrolyte.According to the established conditions,the hydrolyzed products of SPI emulsion were determined by 2-DE,and the dynamic changes of protein in the process of enzymatic hydrolysis were described.

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.

Efficacy evaluation of the protein isolated from Peganum harmala seeds as an antioxidant in liver of rats

Objective:To evaluate the curative effect of the 132 KD protein isolated from the seeds of Peganum harmala（P.harmala） L against carbon tetrachloride（CCl4） induced oxidative stress in rats.Methods:Animals were post treated intraperitoneally with 132 KO isolated protein at doses of 4 and 8 mg/kg body weight and bovine serum albumin（BSA）（8 mg/kg body weight） as well as vitamin C（250 mg/kg body weight p.o.） for 7 d after they challenged with CCl4 orally（1 ml/Ag body weight） in olive oil（50%） for 2 d.Results:The purified protein from seeds of P.harmala plant showed in vitro antioxidant activity with DPPH assay.Administration of CCl4 induced induction in serum aminotransferases（AST,ALT）,alkaline phosphatase（ALP）,lipid profile parameters and liver malondialdehyde（MDA） and decrease in serum total protein,liver superoxide dismutase （SOD）,catalase（CAT）,and reduced glutathione（GSH） levels.132 KD protein treatment of rats post CCl4 intoxication successfully alleviated the toxic effects of CCl4.Conclusions:The isolated protein possessed strong antioxidant activity comparable to that of BSA（negative control） and vitamin C（positive control）.

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%.

Jackfruit Seeds Protein Isolate by Spray Drying Method: The Functional and Physicochemical Characteristics

With increased demand for plant based proteins by the consumers, the food manufacturers appeal for the new plant proteins with predetermined characteristics. This study aims at isolating the protein fraction from jackfruit seeds and characterizing the protein powder for functional and physicochemical properties. The protein part of the seeds was separated through pH treatments and centrifugation process and finally, the concentrate was converted into powder by spray drying method. The functional properties such as solubility, gelling capacity and emulsion properties and the physicochemical properties such as crystallinity, morphology and particle size distribution of the jackfruit seeds protein isolate (JSPI) were studied. The secondary structural elements of JSPI were also determined by Fourier-transform infrared (FTIR) spectroscopy. About 76.89% protein was estimated in the prepared JSPI with 78.44% solubility in an aquatic solvent. The least gelation concentration of JSPI was 12% in a salt solution. The pH of the solvent significantly affected the emulsifying and foaming properties. The protein isolate possessed amorphous structure, moderate bulk density and almost 75% of the particles fell in a similar size distribution range. The conformational study reported that the β-sheet is the dominant secondary structural element with the highest content of 50.28%. The observed features suggest that the JSPI holds satisfactory functional and physicochemical characteristics for being used in protein-enriched foods.

Effect of Pressurized Soy Protein Isolate upon the Growth and Antioxidants Functions of SD Rat

The objective of this study is to specify the effect of pressurized soy protein isolate (pSPI), upon the physical development, growth hormones and antioxidants functions of SD rats. The methodology depends on the selection of one hundred male SD rats, divided randomly into 5 groups. Each group consists of 20 rats. The groups will be defined as one blank control group, three groups with pSPI at low, medium and high doses and another control group with native soy protein isolates (nSPI). Low, medium and high doses are represented by 0.333 g/kg, 1.667 g/kg and 3.333 g/kg pSPI per weight, respectively. The native soy protein isolate is represented by 3.333 g/kg nSPI per weight. In every group, four animals will be taken out to collect the blood samples and analyze insulin like growth factor-I, growth hormone, thyroid stimulating hormone, thyroxine and triiodothyronin. The other SD rats will be subjected to feeding for 63 consecutive days. The body weight, the body length and food intake of each rat are measured. The total antioxidant capacity, superoxide dismutase (SOD), malondialdehyde and Glutathione Peroxidase in liver and serum of each rat will be analyzed. The results indicated that the groups with medium and high dose of pSPI result in an obvious increase in the body weight, body length and food utilization rate of SD rats. Also, pSPI has a great effect on the growth and antioxidants functions of SD rat.

Isolated Soy Protein-Based Diet Ameliorates Glycemia and Antioxidants Enzyme Activities in Streptozotocin-Induced Diabetes

The objective of this study was to evaluate the changes induced by isolated soy protein (ISP)-based diet on glycemia and oxidative stress biomarkers in diabetic rats. Fifteen male Wistar rats (35 ± 4 g, aged 21 days) were assigned to three groups: Casein (C group), which received casein-based diet during experimental protocol;Diabetic treated with Casein (D + C group) that received casein-based diet before and after diabetes induction;Diabetic treated with ISP (D + S group) that received casein-based diet before diabetes induction and after received ISP-based diet for the experimental protocol. Diabetes was induced by a single dose of streptozotocin (50 mg/kg body weight i.v.). After three weeks of dietary treatment, total nitrates, lipid peroxidation, antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) were measured in heart homogenates. ISP-based diet promoted an improvement in the glycemic levels of diabetic rats compared with casein-based diet (362 ± 25 vs 461 ± 30 mg/dL). CAT activity demonstrated a significant decrease in D + C and D + S groups. D + S group presented a significant increase in SOD and GST activities. Lipid peroxidation was not different among experimental groups. The overall results suggested the potential benefits of ISP-based diet consumption to improve the life quality of diabetic patients.