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.

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.

Effects of the addition of edible polysaccharides on the properties of soybean protein isolate gels

The gel properties of soybean isolate protein(SPI)gels are susceptible to the influence of other components in food products,particularly edible polysaccharides.Therefore,six common edible polysaccharides were selected in this study to investigate their effects on the rheological properties,thermal properties,and microstructure of acid-induced soybean isolate protein self-assembled gels(SPIASG).The experimental results showed that the support capacity and creep recovery of SPIASG with added polysaccharides were higher than those of the control group without added polysaccharides,and the gel with Xanthan gum(XG)was the most effective.The hybrid gel,with added Condensed resin(CR),Xanthan gum(XG),Carrageenan(CA),and CMC formed a stronger network structure.Additionally,compared with SPIASG,the hybrid gel with added edible polysaccharides the water-holding capacity of SPI hybrid gels was relatively improved.In this study,a simple and easy method was obtained to significantly improve the gel properties of SPIASG,analyzed and compared the effectiveness of various polysaccharides to enhance its gel properties,and provided some ideas to improve the gel properties of SPI protein gels.

Rheological properties of flaxseed meal and soybean protein isolate blend by extrusion

The rheological properties of flaxseed meal(FM)and Soybean Protein Isolate(SPI)extruded by the two-screw extruder under different processing conditions were investigated.Moisture,temperature,screw speed and SPI concentration were the four major factors for the extrusion process.The rheological properties of extruded products were calculated by steady state flow test,frequency sweep test and creep test.All the samples showed shear-thinning effect that is to say their apparent viscosities decreased with the increases of shear rate.The data fitted well to Power Law model.It was found that both the storage(G′)and loss modulus increased as the rise in the angular frequency(w),which also fitted well to Power Law model.The creep-recovery behavior of the samples fitted well to Burger’s model.In addition,the temperature had no significant effect on the creep recovery rate of the samples.

Transcriptome analysis revealing the mechanism of soybean protein isolates and soybean peptides on Lacticaseibacillus rhamnosus Lra05

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.