A comparative study on the foaming properties and behavior at the air-water interface of soy and whey protein isolates were made, Foams were obtained by the method of gas bubbling. The initial rate of passage of liqui...A comparative study on the foaming properties and behavior at the air-water interface of soy and whey protein isolates were made, Foams were obtained by the method of gas bubbling. The initial rate of passage of liquid to the foam （vi） and the maximum volume of liquid incorporated to the foam （VLEmax） were determined. The destabilization process of the formed foams was analyzed by a biphasic second order equation. Measurements of equilibrium surface tension （water/air） and surface rheological properties were carried out in a dynamic drop tensiometer. The foaming capacity （vi and VLEmax） and the stability of foams prepared with the whey protein isolates （WPI） were better than those formulated with the soy protein isolates （SPI）. WPI foams were more stable showing the lower values of rate constants of gravity drainage and disproportion. There were significant differences （P 〈 0.05） in the dilatational modulus in the surface rheology measurements, which were higher at the interface with WPI, implying greater resistance of the film formed to collapse and disproportion. In conclusion, WPI formed better and more stable foams than the SPI.展开更多
The aim of this study was to obtain a protein isolate from Argentine anchovy （Engraulis anchoita） residue produced using the pH shifting process, with acid and alkaline solubilization and isoelectric precipitation o...The aim of this study was to obtain a protein isolate from Argentine anchovy （Engraulis anchoita） residue produced using the pH shifting process, with acid and alkaline solubilization and isoelectric precipitation of the protein, and evaluate their functional properties. The lowest solubility was obtained at pH 5 where 8.32% and 2.96% were found for acid and alkali respectively. The highest solubility was obtained at extreme pH. The maximum water holding capacity was presented by the alkaline protein isolate at pH 11 （9.63 g H20/g protein）. The oil holding capacity was 4.20 mL/g protein, 7.26 mL/g of protein for the acid and alkaline protein isolates, respectively. The strain showed higher oil holding capacity in alkaline pH, lower solubility in pH near the protein isoelectric point and a lower capacity to retain water in extreme pH when compared with the acid isolate.展开更多
Anti-nutritional studies on cowpea (Vigna ungiculata L.) seeds as whole cowpea flour (WCF), dehulled cowpea flour (DCF), dehulled defatted cowpea flour (DDCF) and protein isolates obtained from DDCF by isoelectric (CP...Anti-nutritional studies on cowpea (Vigna ungiculata L.) seeds as whole cowpea flour (WCF), dehulled cowpea flour (DCF), dehulled defatted cowpea flour (DDCF) and protein isolates obtained from DDCF by isoelectric (CPIA) and micellization (CPIB) precipitation. The protein content of WCF and DDCF were 22.3% and 26.75% respectively, while CPIA and CPIB showed 75% and 76% respectively. The abundant minerals in WCF and DCF were calcium (32.38 - 33.61 mg/100 g);potassium (29.25 - 24.99 mg/100 g);and sodium (1.76 - 1.00 mg/100 g). The least abundant minerals were iron (0.004 - 0.013 mg/100 g);copper (0.04 - 0.25 mg/100 g);manganese (0.18 - 0.30 mg/100 g) and zinc (0.26 - 1.22 mg/100 g);respectively. Trypsin inhibitor activity for WCF, CPIA and CPIB was found 16,640 TIU/g, 4293 TIU/g and 4290 TIU/g respectively. Condensed tannins in RCF and DDCF were found 0.003% and 0.004% respectively while phytic acid content 0.8% and 1.17% respectively, no phytic acid and tannins were observed in protein isolates. Cowpea flour was also similar to other edible grain legumes in content of anti-nutritional factors;appropriate processing methods improved cowpea nutritive value and significantly reduced the levels of anti-nutritional factors.展开更多
Sea cucumbers are a good source of proteins and essential amino acids.In this study,protein isolates were recovered from North Atlantic sea cucumber(Cucumaria frondosa)body wall(BWI)and processing by-products,includin...Sea cucumbers are a good source of proteins and essential amino acids.In this study,protein isolates were recovered from North Atlantic sea cucumber(Cucumaria frondosa)body wall(BWI)and processing by-products,including flower(FLI)and internal organs(INI),using the pH-shift method.Functional properties of protein isolates were investigated and compared with those of soy protein isolates(SPI).All protein isolates exhibited a typical U-shaped solubility curve showing a minimum solubility at their isoelectric points.Furthermore,emulsification and foaming properties of the sea cucumber protein isolates were also pH-dependent and corresponded with their solubility.The highest water holding capacity was observed in FLI,whereas SPI showed the lowest oil holding capacity among all tested protein isolates.Sea cucumber protein isolates exhibited significantly higher(p<0.05)surface hydrophobicity and relatively lower sulfhydryl(SH)group and disulfide(SS)bonds compared to SPI.In addition,Fourier transform infrared(FTIR)spectra of sea cucumber protein isolates exhibited unique absorption peaks related to their secondary structures.Amino acid profiles of sea cucumber protein isolates revealed that they could be used as rich and complete sources of essential amino acids.These findings suggest that Atlantic sea cucumber protein isolates could serve as functional food ingredients.展开更多
To further investigate the promoting effect of soybean protein and peptides on Lacticaseibacillus rhamnosus Lra05(L.rhamnosus Lra05),the overall changes of gene expression of it was investigated through transcriptome ...To further investigate the promoting effect of soybean protein and peptides on Lacticaseibacillus rhamnosus Lra05(L.rhamnosus Lra05),the overall changes of gene expression of it was investigated through transcriptome analysis treated with dPEP and dSPI The results showed that there were 890,113,and 1073 differentially expressed genes(DEGs)in dPEP/MRS,dSPI/MRS and dPEP/dSPI comparison,respectively.Besides,we found dPEP could promote the expression of acc and fab family genes related to fatty acid biosynthesis,but dSPI played the opposite role.Moreover,dPEP stimulated genes clustered in pur family and ribosome protein,responsible for purine and protein synthesis.Interestingly,dPEP suppressed genes regulating peptides and amino acids transportation and dSPI specially inhibited the pyr family genes involved in pyrimidine metabolism.These data revealed the knowledge about the metabolic pathways affected by dPEP and dSPI and provide a preliminary understanding of the relationship between soybean proteins and peptides and L.rhamnosus Lra05.展开更多
Camelina and flixweed(sophia)seed protein isolates were prepared using both the conventional extraction and ultrasonic-assisted extraction methods at 40 kHz for 20 min,and their functional properties investigated.SDS-...Camelina and flixweed(sophia)seed protein isolates were prepared using both the conventional extraction and ultrasonic-assisted extraction methods at 40 kHz for 20 min,and their functional properties investigated.SDS-PAGE showed that both ultrasound-assisted and conventional extractions resulted in a similar protein profile of the extract.The application of ultrasound significantly improved protein extraction/content and functional properties(water holding capacity,oil absorption capacity,emulsifying foaming properties,and protein solubility)of camelina protein isolate and sophia protein isolate.The water-holding and oil absorption capacities of sophia protein isolate were markedly higher than those of camelina protein isolate.These results suggest that camelina protein isolate and sophia protein isolate may serve as natural functional ingredients in the food industry.展开更多
Soybean protein is of plant origin and is commonly appropriate for improving the processing characteristics of foods.This study aimed to explore a novel functional ingredient that contained soybean protein isolate(SPI...Soybean protein is of plant origin and is commonly appropriate for improving the processing characteristics of foods.This study aimed to explore a novel functional ingredient that contained soybean protein isolate(SPI)and blueberry anthocyanins(BANs).The spatial conformation and secondary structure of SPI-BANs complexes were analyzed using circular dichroism and fluorescence spectroscopy,the processing properties were investigated as well as the retention of antioxidant activity during thermal treatments.Results showed that the contents of free sulfhydryl and free amino groups in complexes increased to 3.50 and 1.19 folds than those of SPI,respectively,while the surface hydrophobicity decreased by 74.23%.Compared with SPI,the BANs-modified SPI had a smaller particle size of 29.12 nm and a lower zeta-potential of-8.73 mV and on the other hand,the complexes possessed higher solubility(83.08%)and foaming and emulsifying properties(115.08%and 54.03 m^(2)/g).After fortification with SPI-BANs,the baking loss rate and adhe-siveness of chiffon cake were reduced by 10.82%and improved to 0.24 N.mm,respectively.The high antioxidant activities of SPI-BANs under heat led to the cake’s bioactivities largely enhanced by 1.99~12.71 folds,being 345.19µg Trolox/g for the DPPH radical scavenging activity.This study developed the functional food ingredients as antioxidants and a substitute for animal-based proteins in bakery products,which was safe and sustainable by using the dietary components from plant resources.展开更多
The stability of β-carotene microcapsules using Maillard reaction products（MRPs） derived from whey protein isolate（WPI） and galactose as coating materials, was studied under the varying environmental conditions o...The stability of β-carotene microcapsules using Maillard reaction products（MRPs） derived from whey protein isolate（WPI） and galactose as coating materials, was studied under the varying environmental conditions of temperature, pH, air, incandescent light, and ultraviolet（UV） light.Scanning electron microscopy showed that microcapsules prepared by WPI-galactose MRPs displayed a smooth and less concave-convex surface and that the particle size（D_（50）） of the microcapsules made with WPI-galactose MRPs was smaller than those made with WPI-galactose mixture.The storage stability of β-carotene microencapsulated in WPI-galactose MRPs was remarkably better than that of β-carotene microencapsulated in the WPI-galactose mixture and that of β-carotene crystal, in respect of temperature, pH, air, incandescent light, and UV light measurements.When the storage temperature was increased from 5 to 105 ℃, the retention rate of β-carotene microcapsules significantly decreased（P〈0.05）.When p H values were increased from 1 to 12, the β-carotene retention rate of the microcapsules significantly increased and afterward decreased.Compared with the retention rate of β-carotene microencapsulated in a WPI-galactose mixture, the retention rate of β-carotene microencapsulated in WPI-galactose MRPs was at a maximum between pH 8 and 9.Under the actions of air, incandescent light, and UV light, the retention rates of β-carotene microcapsules in WPI-galactose MRPs and WPI-galactose mixture, as well as in β-carotene crystal, decreased significantly as the storage time increased（P〈0.05）.Therefore, the use of WPI-galactose MRPs as coating materials can aid in improving the storage stability of β-carotene microcapsules.展开更多
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 pol...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.展开更多
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...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.展开更多
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 pr...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.展开更多
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 ...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.展开更多
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 hydro...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.展开更多
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 a...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...展开更多
To simplify the assessment method of soy protein isolate （SPI） functionalities, the viscosity and functionalities of commercial SPI products were studied. Viscosity value （y） increases With increasing concentrati...To simplify the assessment method of soy protein isolate （SPI） functionalities, the viscosity and functionalities of commercial SPI products were studied. Viscosity value （y） increases With increasing concentration （x） and exhibits a highly significant correlation with the exponential equation y = a. ebx. The b values of products are gradually enhanced from dispersion, emulsion and injected to gel type. Products with low b values （〈0.2）, and high dispersivity were dispersion-type. Products having high b values （〉0.4） and gel springiness were gel-type. The other products with centered b value （0.2-0.4）, high solubility and emulsifying capacity were emulsion-type.展开更多
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 ...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.展开更多
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 ...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.展开更多
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...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.展开更多
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,...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.展开更多
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 ...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.展开更多
文摘A comparative study on the foaming properties and behavior at the air-water interface of soy and whey protein isolates were made, Foams were obtained by the method of gas bubbling. The initial rate of passage of liquid to the foam （vi） and the maximum volume of liquid incorporated to the foam （VLEmax） were determined. The destabilization process of the formed foams was analyzed by a biphasic second order equation. Measurements of equilibrium surface tension （water/air） and surface rheological properties were carried out in a dynamic drop tensiometer. The foaming capacity （vi and VLEmax） and the stability of foams prepared with the whey protein isolates （WPI） were better than those formulated with the soy protein isolates （SPI）. WPI foams were more stable showing the lower values of rate constants of gravity drainage and disproportion. There were significant differences （P 〈 0.05） in the dilatational modulus in the surface rheology measurements, which were higher at the interface with WPI, implying greater resistance of the film formed to collapse and disproportion. In conclusion, WPI formed better and more stable foams than the SPI.
文摘The aim of this study was to obtain a protein isolate from Argentine anchovy （Engraulis anchoita） residue produced using the pH shifting process, with acid and alkaline solubilization and isoelectric precipitation of the protein, and evaluate their functional properties. The lowest solubility was obtained at pH 5 where 8.32% and 2.96% were found for acid and alkali respectively. The highest solubility was obtained at extreme pH. The maximum water holding capacity was presented by the alkaline protein isolate at pH 11 （9.63 g H20/g protein）. The oil holding capacity was 4.20 mL/g protein, 7.26 mL/g of protein for the acid and alkaline protein isolates, respectively. The strain showed higher oil holding capacity in alkaline pH, lower solubility in pH near the protein isoelectric point and a lower capacity to retain water in extreme pH when compared with the acid isolate.
文摘Anti-nutritional studies on cowpea (Vigna ungiculata L.) seeds as whole cowpea flour (WCF), dehulled cowpea flour (DCF), dehulled defatted cowpea flour (DDCF) and protein isolates obtained from DDCF by isoelectric (CPIA) and micellization (CPIB) precipitation. The protein content of WCF and DDCF were 22.3% and 26.75% respectively, while CPIA and CPIB showed 75% and 76% respectively. The abundant minerals in WCF and DCF were calcium (32.38 - 33.61 mg/100 g);potassium (29.25 - 24.99 mg/100 g);and sodium (1.76 - 1.00 mg/100 g). The least abundant minerals were iron (0.004 - 0.013 mg/100 g);copper (0.04 - 0.25 mg/100 g);manganese (0.18 - 0.30 mg/100 g) and zinc (0.26 - 1.22 mg/100 g);respectively. Trypsin inhibitor activity for WCF, CPIA and CPIB was found 16,640 TIU/g, 4293 TIU/g and 4290 TIU/g respectively. Condensed tannins in RCF and DDCF were found 0.003% and 0.004% respectively while phytic acid content 0.8% and 1.17% respectively, no phytic acid and tannins were observed in protein isolates. Cowpea flour was also similar to other edible grain legumes in content of anti-nutritional factors;appropriate processing methods improved cowpea nutritive value and significantly reduced the levels of anti-nutritional factors.
基金The research was supported by the Natural Sciences and Engineering Research Council(NSERC)of Canada,RGPIN-2015-06121.
文摘Sea cucumbers are a good source of proteins and essential amino acids.In this study,protein isolates were recovered from North Atlantic sea cucumber(Cucumaria frondosa)body wall(BWI)and processing by-products,including flower(FLI)and internal organs(INI),using the pH-shift method.Functional properties of protein isolates were investigated and compared with those of soy protein isolates(SPI).All protein isolates exhibited a typical U-shaped solubility curve showing a minimum solubility at their isoelectric points.Furthermore,emulsification and foaming properties of the sea cucumber protein isolates were also pH-dependent and corresponded with their solubility.The highest water holding capacity was observed in FLI,whereas SPI showed the lowest oil holding capacity among all tested protein isolates.Sea cucumber protein isolates exhibited significantly higher(p<0.05)surface hydrophobicity and relatively lower sulfhydryl(SH)group and disulfide(SS)bonds compared to SPI.In addition,Fourier transform infrared(FTIR)spectra of sea cucumber protein isolates exhibited unique absorption peaks related to their secondary structures.Amino acid profiles of sea cucumber protein isolates revealed that they could be used as rich and complete sources of essential amino acids.These findings suggest that Atlantic sea cucumber protein isolates could serve as functional food ingredients.
基金supported by the National Key Research and Development Program of China(2021YFC2101400)the Graduate Innovation Project of School of Food and Health in 2021 of Beijing Technology and Business University(19008021085)Taif University Researchers Supporting Project(TURSP-2020/09).
文摘To further investigate the promoting effect of soybean protein and peptides on Lacticaseibacillus rhamnosus Lra05(L.rhamnosus Lra05),the overall changes of gene expression of it was investigated through transcriptome analysis treated with dPEP and dSPI The results showed that there were 890,113,and 1073 differentially expressed genes(DEGs)in dPEP/MRS,dSPI/MRS and dPEP/dSPI comparison,respectively.Besides,we found dPEP could promote the expression of acc and fab family genes related to fatty acid biosynthesis,but dSPI played the opposite role.Moreover,dPEP stimulated genes clustered in pur family and ribosome protein,responsible for purine and protein synthesis.Interestingly,dPEP suppressed genes regulating peptides and amino acids transportation and dSPI specially inhibited the pyr family genes involved in pyrimidine metabolism.These data revealed the knowledge about the metabolic pathways affected by dPEP and dSPI and provide a preliminary understanding of the relationship between soybean proteins and peptides and L.rhamnosus Lra05.
文摘Camelina and flixweed(sophia)seed protein isolates were prepared using both the conventional extraction and ultrasonic-assisted extraction methods at 40 kHz for 20 min,and their functional properties investigated.SDS-PAGE showed that both ultrasound-assisted and conventional extractions resulted in a similar protein profile of the extract.The application of ultrasound significantly improved protein extraction/content and functional properties(water holding capacity,oil absorption capacity,emulsifying foaming properties,and protein solubility)of camelina protein isolate and sophia protein isolate.The water-holding and oil absorption capacities of sophia protein isolate were markedly higher than those of camelina protein isolate.These results suggest that camelina protein isolate and sophia protein isolate may serve as natural functional ingredients in the food industry.
基金supported by the Jiangsu Agricultural Science and Technology Innovation Fund[Grant No.CX(22)2026],Chinathe Scholarship Program of China Scholarship Council[Grant No.202108320143],Chinathe Science and Technology Program of Changshu City[Grant No.CN202208],China.
文摘Soybean protein is of plant origin and is commonly appropriate for improving the processing characteristics of foods.This study aimed to explore a novel functional ingredient that contained soybean protein isolate(SPI)and blueberry anthocyanins(BANs).The spatial conformation and secondary structure of SPI-BANs complexes were analyzed using circular dichroism and fluorescence spectroscopy,the processing properties were investigated as well as the retention of antioxidant activity during thermal treatments.Results showed that the contents of free sulfhydryl and free amino groups in complexes increased to 3.50 and 1.19 folds than those of SPI,respectively,while the surface hydrophobicity decreased by 74.23%.Compared with SPI,the BANs-modified SPI had a smaller particle size of 29.12 nm and a lower zeta-potential of-8.73 mV and on the other hand,the complexes possessed higher solubility(83.08%)and foaming and emulsifying properties(115.08%and 54.03 m^(2)/g).After fortification with SPI-BANs,the baking loss rate and adhe-siveness of chiffon cake were reduced by 10.82%and improved to 0.24 N.mm,respectively.The high antioxidant activities of SPI-BANs under heat led to the cake’s bioactivities largely enhanced by 1.99~12.71 folds,being 345.19µg Trolox/g for the DPPH radical scavenging activity.This study developed the functional food ingredients as antioxidants and a substitute for animal-based proteins in bakery products,which was safe and sustainable by using the dietary components from plant resources.
基金Project supported by the Natural Science Foundation of Heilongjiang Province of China(No.C2017029)the Academic Research Program of Northeast Agricultural University(No.16XG21)the National“Twelfth Five-Year”Plan for Science and Technology Support Program of China(No.2013BAD18B06)
文摘The stability of β-carotene microcapsules using Maillard reaction products（MRPs） derived from whey protein isolate（WPI） and galactose as coating materials, was studied under the varying environmental conditions of temperature, pH, air, incandescent light, and ultraviolet（UV） light.Scanning electron microscopy showed that microcapsules prepared by WPI-galactose MRPs displayed a smooth and less concave-convex surface and that the particle size（D_（50）） of the microcapsules made with WPI-galactose MRPs was smaller than those made with WPI-galactose mixture.The storage stability of β-carotene microencapsulated in WPI-galactose MRPs was remarkably better than that of β-carotene microencapsulated in the WPI-galactose mixture and that of β-carotene crystal, in respect of temperature, pH, air, incandescent light, and UV light measurements.When the storage temperature was increased from 5 to 105 ℃, the retention rate of β-carotene microcapsules significantly decreased（P〈0.05）.When p H values were increased from 1 to 12, the β-carotene retention rate of the microcapsules significantly increased and afterward decreased.Compared with the retention rate of β-carotene microencapsulated in a WPI-galactose mixture, the retention rate of β-carotene microencapsulated in WPI-galactose MRPs was at a maximum between pH 8 and 9.Under the actions of air, incandescent light, and UV light, the retention rates of β-carotene microcapsules in WPI-galactose MRPs and WPI-galactose mixture, as well as in β-carotene crystal, decreased significantly as the storage time increased（P〈0.05）.Therefore, the use of WPI-galactose MRPs as coating materials can aid in improving the storage stability of β-carotene microcapsules.
基金supported by the National Key R&D Program of China (2017YFD0400205)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX19_1402)
文摘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.
文摘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.
基金financially supported by National Natural Science Foundation of China (31871844 & 31501530)。
文摘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.
文摘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.
基金supported by the Doctoral Research Foundation of Bohai University (05013/0520bs006)the Science and Technology Project of“Unveiling and Commanding”Liaoning Province (2021JH1/10400033)the Scientific Research Project from Education Department of Liaoning Province (LJ2020010)。
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.50533050 and 20574081)
文摘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...
基金supported by the National Key Technologies Research and Development Program(No. 2012BAD34B04)Ministry of Science and Technology of the People's Republic of China
文摘To simplify the assessment method of soy protein isolate （SPI） functionalities, the viscosity and functionalities of commercial SPI products were studied. Viscosity value （y） increases With increasing concentration （x） and exhibits a highly significant correlation with the exponential equation y = a. ebx. The b values of products are gradually enhanced from dispersion, emulsion and injected to gel type. Products with low b values （〈0.2）, and high dispersivity were dispersion-type. Products having high b values （〉0.4） and gel springiness were gel-type. The other products with centered b value （0.2-0.4）, high solubility and emulsifying capacity were emulsion-type.
文摘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.
基金the National Natural Science Foundation of China (31871748)Natural Science Foundation of Henan Province (242300421317, 242300420462)+2 种基金the Project of Henan University of Technology Excellent Young Teachers (21420064)Zhengzhou Science and Technology Collaborative Innovation Project (21ZZXTCX17)China Postdoctoral Science Fundation (2021M701112) for the financial support。
文摘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.
基金National Natural Science Foundation of China (No.50303003)
文摘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.
基金the National Natural Science Foundation of China(No.31371782)the Key Project of Science and Technology Research of Henan Education Department(No.14A550007)the Basic Research Project of Henan University of Technology(No.171157)。
文摘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.
基金the Grain,Oil and Food Engineering Technology Research Center of the State Grain and Reserves Administration/Key Laboratory of Henan Province,Henan University of Technology(G0202205)the Key Scientific Research Projects of Colleges and Universities of Henan(23A550012)the Science Foundation of Henan University of Technology(2020BS013)。
文摘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.
