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
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
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
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
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
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
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
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
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 pre...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.展开更多
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-dimensi...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%.展开更多
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 sele...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.展开更多
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 d...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.展开更多
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
本实验采用外源蛋白添加和挤压相结合的技术通过增强混合体系内部的凝胶结构来改善大米粉面条弹韧性差、断条严重等问题。向大米粉中添加大豆分离蛋白(Soybean Protein Isolate,SPI)并经过挤压膨化处理制备混合米粉,选择SPI添加量、水...本实验采用外源蛋白添加和挤压相结合的技术通过增强混合体系内部的凝胶结构来改善大米粉面条弹韧性差、断条严重等问题。向大米粉中添加大豆分离蛋白(Soybean Protein Isolate,SPI)并经过挤压膨化处理制备混合米粉,选择SPI添加量、水分含量和挤压温度3个因素,以糊化特性和吸水性指数为指标优化混合米粉的最佳工艺,并对米面条的品质进行评价。各因素对混合米粉制备工艺的影响顺序:SPI添加量>水分含量>挤压温度,最佳工艺条件为SPI添加量10.23%(以400 g大米粉为基准)、水分含量25%和挤压温度133℃。将最优条件下制备的混合米粉与大米粉的吸水性指数、糊化特性和傅里叶红外光谱进行比较,表明混合米粉的吸水性指数远高于大米粉,糊化特性和短程有序程度均低于大米粉。混合米粉面条与大米粉面条相比干物质损失率和断条率有所下降,吸水率、感官评分、硬度、弹性和咀嚼性均升高。添加SPI的大米粉经挤压后制得混合米粉的吸水性和回生特性均有所改善,制作的混合米粉面条的蒸煮特性及感官品质较大米粉面条有显著的提升,不仅提高了大米粉的经济价值又利于促进稻米产业链的延伸,而且拓宽了以大米粉为原料的米制品在主食方面的应用范围。展开更多
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.
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.
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...
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.
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.
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(Nos.50673038 and 20374025)the Fundamental Research Funds for the Central Universities of China(No.JUSRP111A08)
文摘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.
文摘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%.
文摘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.
文摘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.
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.
文摘本实验采用外源蛋白添加和挤压相结合的技术通过增强混合体系内部的凝胶结构来改善大米粉面条弹韧性差、断条严重等问题。向大米粉中添加大豆分离蛋白(Soybean Protein Isolate,SPI)并经过挤压膨化处理制备混合米粉,选择SPI添加量、水分含量和挤压温度3个因素,以糊化特性和吸水性指数为指标优化混合米粉的最佳工艺,并对米面条的品质进行评价。各因素对混合米粉制备工艺的影响顺序:SPI添加量>水分含量>挤压温度,最佳工艺条件为SPI添加量10.23%(以400 g大米粉为基准)、水分含量25%和挤压温度133℃。将最优条件下制备的混合米粉与大米粉的吸水性指数、糊化特性和傅里叶红外光谱进行比较,表明混合米粉的吸水性指数远高于大米粉,糊化特性和短程有序程度均低于大米粉。混合米粉面条与大米粉面条相比干物质损失率和断条率有所下降,吸水率、感官评分、硬度、弹性和咀嚼性均升高。添加SPI的大米粉经挤压后制得混合米粉的吸水性和回生特性均有所改善,制作的混合米粉面条的蒸煮特性及感官品质较大米粉面条有显著的提升,不仅提高了大米粉的经济价值又利于促进稻米产业链的延伸,而且拓宽了以大米粉为原料的米制品在主食方面的应用范围。
