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High-speed shearing (HSS) technology was used to mill the okara fibers in raw whole soybean flour (rWSF) suspension for fabrication of whole soybean curd (WSC). By measuring the medium diameter and analyzing the protein subunit composition of rWSF and heated whole soybean flour (hWSF), we found that HSS effectively micronized the insoluble fraction in suspension (especially the component cell layers of seed coat) but destroyed the structure of the native protein and caused the disappearance of specific protein band 7 in sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Further, we made WSC using HSS-treated hWSF suspension and analyzed its characteristics. The relative contents of α-helix, β-sheet, and β-turns all decreased after HSS, but the surface hydrophobicity showed an opposite trend. Additionally, the maximum emission wavelength blue- shifted after HSS. These results indicated that the secondary and tertiary structures of WSC were changed by HSS. Moreover, microstructural analysis based on a field emission scanning electron microscope (FESEM) and texture analyzer suggested that HSS led to the formation of a loose and less connected gel network and weakened the gel strength consequently. In summary, to separate and micronize okara individually and add them back to soymilk for WSC making was a considerable method. [ABSTRACT FROM AUTHOR]

Objectives Amino acid profiles of whole soybean curds (WSCs) and conventional soybean curds (CSCs) were comparatively studied to 1., evaluate their nutritional value and 2., study the suitable soybean material to fabricate WSCs. Materials and Methods Nine types of soybean materials were selected to make WSCs and CSCs. Protein digestibility-corrected amino acid score (PDCAAS) and principal component analysis were selected to perform the comparative analysis of amino acid profiles of the products. Results Total contents of amino acids in WSCs and CSCs were 41.24–54.87 mg/g and 27.77–36.82 mg/g. Content ranges of essential amino acids were 13.59–19.38 mg/g and 8.46–11.76 mg/g for WSCs and CSCs. The essential amino acid pattern of WSCs was basically close to amino acid pattern spectrum requirements except valine and sulfur amino acids. As a limiting amino acid, methionine represented less than 0.4 for PDCAAS in all soybean curds except WSCs made from relay-cropping Nandou12 and Nandou25. Conclusions The overall quality of amino acids in WSCs was higher than that in CSCs, indicating that WSCs indeed exhibited higher nutritional value than CSCs from the viewpoint of amino acid profile. WSCs with the high nutritional value could be made using Nandou25 and relay-cropping Nandou12 as materials. [ABSTRACT FROM AUTHOR]

As a highly hydrated gel-type food, soybean curd is perishable and the development of spoilage bacteria has been described. Whole soybean curd (WSC), an innovative soy product retains the most nutrients in raw ingredients and exhibits more nutritive value compared with conventional soybean curd (CSC). However, the risk assessment of WSC is not well evaluated up to now. In this study, the same species of spoilage microorganism were separated from WSC and CSC. Two main spoilage strains were separated and identified as B. subtilis and B. cereus. The risk ranking scores of WSC was higher than that of CSC but still within medium risk range. In summary, we reported the presence of B. subtilis and B. cereus in WSC for the first time. Further, application of the risk ranger tool confirmed that the risk profile of WSC was medium and acceptable. [ABSTRACT FROM AUTHOR]

The formation and characterization of conjugates of soybean protein isolate (SPI) and dextran with varying molecular weights (4, 10, and 70 kDa) and their effects on quality of glucono-δ-lactone (GDL)-induced tofu were investigated. The extent of glycosylation was negatively related to the molecular weight of dextran. Thus, the SPI-dextran4 conjugate exhibited a darker color and a biggest decrease in whiteness from 70.49 to 45.51. SPI-dextran70 conjugate exhibited an increased surface hydrophobicity and free sulfhydryl content. Volume-average diameter of SPI-dextran70 conjugate-added soymilk and gel strength of the corresponding tofu ranged from 10.34 to 11.24 μm and 0.068 to 0.083 N, respectively, which were lesser than those of the control (11.12 μm and 0.133 N). However, SPI-dextran10 conjugate incubated for 6 days and SPI-dextran4 conjugate incubated for 2 days increased the gel strength of tofu to 0.146 and 0.143 N, respectively. Conjugates-added tofu exhibited an increased water holding capacity and a discontinuous and loose microstructure, but a lowered whiteness and a color change to yellow. Results demonstrated that the selection of dextran with an appropriate molecular weight and controlling the glycosylation degree were capable of improving the quality of SPI-dextran conjugate-added GDL-induced tofu. • Soybean protein isolate (SPI)-dextran (4, 10, 70 kDa) conjugates were prepared. • Molecular weight of dextran affected the physicochemical properties of conjugates. • SPI-dextran70 conjugates reduced particle size of soymilk and gel strength of tofu. • Impact of SPI-dextran4/10 conjugates on gel strength of tofu depended on reaction time. • The addition of conjugates enhanced the water holding capacity of tofu. [ABSTRACT FROM AUTHOR]

Glycinin-carbohydrate conjugate prepared with glucose, fructose, or dextran using a dry-heating method was applied to improve the processing quality and textural properties of whole soybean curd (WSC). The optimal parameters for preparing glycinin-carbohydrate conjugates were obtained using single factor experiment and response surface optimization. Compared to native glycinin, all glycinin-carbohydrate conjugates prepared under the optimized parameters exhibited improved solubility and emulsifying properties, especially the glycinin-dextran conjugate. Yield, hardness, and gel strength of WSC were significantly elevated when glycinin-carbohydrate conjugates were applied as a part of raw material. For instance, when 15% glycinin-dextran conjugate was added, the yield, hardness, and gel strength of WSC were increased by 32.70%, 52.46%, and 32.72% compared to those of the WSC made only from soybean flour, respectively. Meanwhile, glycinin-carbohydrate conjugates modified the microstructure of WSC to be denser and more homogeneous, which was more significant in the glycinin-dextran conjugate-added WSC. In conclusion, glycinin-carbohydrate conjugates exhibited improved functionalities which were beneficial to facilitating the formation of homogenous microstructure and thus, enhancing the processing quality of WSC. Therefore, the addition of glycinin-carbohydrate conjugates could be considered a feasible alternative to elevate the processing quality and textural properties of whole soybean product. Image 1 • Glycosylation of glycinin with glucose, fructose, and dextran are optimized. • Glycinin-carbohydrate conjugates exhibit improved solubility and emulsifying properties. • Processing quality of whole soybean curd (WSC) is enhanced after adding conjugates. • Textural properties and micromorphology of the conjugate-added WSC are also improved. [ABSTRACT FROM AUTHOR]