Preparation and Properties of Fractionated Soybean Protein Isolate Films

Soybean protein isolate (SPI) and its four fractionated products (7S globulin, 11S globulin, upper soybean residue, and lower soybean residue) were compared by fabricating films and film liquids. The separation and grading effects, rheological properties of the film liquids, and difficulty in uncovering the films, in addition to the mechanical properties, water vapor permeability, oil permeability, and surface morphology of the films, were investigated. Results showed that the centrifugal precipitation method could be used to produce fractionated products. The 7S and 11S globulin films exhibited better hydrogels at lower shear rates than the other SPIs; however, they were more difficult to uncover. The tensile strength of the graded films decreased by varying degrees. However, the elongation at the break of the upper soybean residue film considerably increased, reaching 70.47%. Moreover, the permeability and surface morphology of the film were enhanced or weakened. The fractionated products, 7S and 11S globulin films, exhibited better performance. Overall, this study provides a basis for the improved development and use of fractioned SPI products.

Study on the Optimization of the Soluble Dietary Fiber Content of Soybean Residue by Steam Explosion Pretreatment

Because a large amount of soybean residue(SR) what is the byproduct of tofu and soymilk industries is produced annually in the world and is a byproduct with a rich nutritional profile, particularly in proteins, fibers, lipids, and bioactive components, a lot of researchers intensify the study on the SR and the processing and utilization of its have attracted more and more attention due to the increased consumption of SR in recent years. Especially the soluble fiber of SR lowers blood cholesterol and triglyceride levels by binding to cholesterol and helping to pass it out of the body, therefore, the composition proportion of soluble components in dietary fiber is an important factor affecting its physiological function. Steam explosion (SE) is a kind of physical method recently used in food pretreatment. In this study, the insoluble dietary fiber of SR converted to soluble dietary fiber by SE treatment and increased the content of soluble dietary fiber, and optimized the condition of SE treatment processing by response surface methodology(RSM). The results showed that the optimum conditions was: moisture content of 76.3%, steam explosion time of 88S?steam explosion pressure of 1.7MPa; on the conditions?the content of SDF was 36.5%. Through the analysis on the physicochemical properties of SE treated SR in the optimum condition, determined that water solubility of SR increased significantly, while swelling capacity, oil and water holding capacities decreased after SE treatment.

MINERALISASI NITROGEN KOMPOS CAMPURAN RESIDU KEDELAI DAN JERAMI PADI BERBAGAI KOMPOSISI

This study aims to determine the quality of the compost and the amount of nitrogenrelease resulting from mineralization from the compost mixture of soybean residuesand rice straw. The research was conducted in two stages; Stage 1. Making a compostmixture of soybean residue and rice straw with 5 mixed compositions, namely; D1 =100% soybean residue; D2 = 75% soybean residue + 25% rice straw; D3 = 50%soybean residue + 50% rice straw; D4 = 25% soybean residue + 75% rice straw; D5 =100% rice straw. Stage 2.The unwashed incubation experiment aims to determine theamount of nitrogen mineralization from the results of the compost mixture of stage 1 bymeasuring the amount of nitrogen released into the soil, the experiment uses acompletely randomized design (CRD) with the same mixed compost treatment withstage 1 plus 2 comparative treatments, namely control treatment and NPK treatment(D6). The results showed that the mixture of organic matter with different residualqualities of soybean and rice straw gave the same dynamics of N mineralization wherethe cumulative N mineral increased with the increase of soybean residue in the mixtureduring the incubation period (1,2,4 and 8 weeks). Treatment D1 (100% soybeanresidue) showed the highest rate of mineralization and the amount of N released(mineral N) of 0.0602 mg week -1 and 1225.39 mg kg-1, respectively.Keyword : compost, soybean residue, rice straw, mineral N, mineralization