Academic literature on the topic 'Soybean protein isolation (SPI)'

Soy protein isolate (SPI) is the purest form of protein from soybean with minimum protein content of 90%. Due to its high protein content, SPI is commonly used in food processing for improving the quality of food products, including infant formula. The use of SPI in infant formula is mainly designed for infant who cannot tolerate cow’s milk-based formula. This report reviews the benefit of using SPI in soy-based infant formula rather than soymilk from whole soybean itself. It will also review the technology of soy protein isolation which can result SPI for high quality infant formula, including the reducing of unfavourable ingredients which will ensure the safety of soy protein-based infant formula.

The effect of soybean soluble polysaccharide (SSPS) on the formation of glucono-δ-lactone (GDL)-induced soybean protein isolate (SPI) gel was investigated. Electrophoretic analysis showed the SSPS did not change the electrophoretic behavior of SPI during the formation of SPI gel. However, infrared analysis indicated the β-sheet content increased, and the contents of random coil and α-helix decreased in both cooked SPI and SPI gel. The SSPS and SPI might conjugate via the Maillard reaction according to the results of grafting degree, color change, and infrared analyses. The main interactions during the formation of SPI gel changed from non-covalent to electrostatic interaction after adding SSPS. Sulfhydryl group content also increased in both cooked SPI and SPI gel. The water-holding capacity and gel strength of SPI gel decreased as the SSPS concentration increased. Larger aggregate holes were observed in the microstructure of SPI gel at higher SSPS concentration. Thus, SSPS could covalently conjugate with SPI and influence the formation of hydrogen bonds, disulfide bonds, and electrostatic interaction among SPI molecules to eventually form a loose gel network.

New thermoplastic soy protein isolated (SPI) and methyl methacrylate (MMA) copolymers (T-SPI) were prepared using graft copolymerization and initiated with ammonium persulfate (APS). The reaction conditions such as initiator concentration and temperature on the graft percentage (GP) were investigated. The single factor experimental showed that the optimal conditions of the graft reaction. The products were characterized by means of FT-IR and DSC. The results indicated that the monomer was grafted successfully on SPI and the T-SPI had a glass transition at 122°C, and the most important, the water absorption of materials declined obviously.

Textured soybean protein (TSP) is a product made from cooking and extrusion of soybean protein, which has been widely used in food, feed and other industries. This text made soybean protein isolated (SPI) and soybean protein concentrate (SPC) as the raw materials to produce filamentous protein production. By experiment, the influence of puffing temperature, screw speed and feed rate on the quality of the protein products was studied. Finally it was concluded that when the temperature of the barrel was 152 °C, the screw rotation speed was 119 rpm, the feed rate was 0.426 kg/min, the TSP product had the biggest expansion degree.

A soybean protein isolate (SPI) main chain grafted with methyl acrylate (MA) and methyl methacrylate (MMA) as a new thermoplastic copolymer (T-SPI) was prepared. The properties of the material were evaluated with DSC, FT-IR, and rotary rheometry. The results indicated that the monomer was grafted on SPI successfully. The T-SPI had a glass transition at about 66°C. T-SPI was a typical viscoelastic material, and its elastic ratio was 65.27%, the shear viscosity was very sensitive to temperature and the flowability of T-SPI was regulated by temperature.

The soy protein isolates (SPI) extracted from different extruded full-fat soybean flakes (FFSF), and their conformational and functional properties were characterized. Overall, the free thiol (SH) content of SPI increased when the extrusion temperature was below 80 °C and decreased at higher temperatures. Soy glycinin (11S) showed higher stability than β-conglycinin (7S) during extrusion. Results also indicated that the increase in some hydrophobic groups was due to the movement of hydrophobic groups from the interior to the surface of the SPI molecules at extrusion temperatures from 60 to 80 °C. However, the aggregation of SPI molecules occurred at extrusion temperatures of 90 and 100 °C, with decreasing levels of hydrophobic groups. The extrusion temperature negatively affected the emulsifying activity index (EAI); on the other side, it positively affected the emulsifying stability index (ESI), compared to unextruded SPI.

In order to improve the functional properties of soybean protein isolates (SPI), microwave-assisted phosphorylation (MAP) was applied. The result showed that after microwaving at 600 W for 3 min, the phosphorylation level of SPI reached 35.72 mg/g, emulsifying activity and stability were increased 2 times and 1.4 times, respectively, the solubility was increased by 26.0% and the apparent viscosity was decreased by 13.5%. The charge density, content of sulfhydryl groups, and surface hydrophobicity increased significantly. The infra-red spectroscopic analysis indicated PO₄^3–primary and lysine residues for phosphoric acid esterification. The change of amide bond Ι and fluorescence spectrum of variation suggested that the MAP made the secondary and tertiary structures of SPI into a compact conformation. Compared to the regular phosphorylation, the preparation time applied in MAP of SPI was much shorter. These results indicated that MAP can be used as an efficient method to improve the functional properties of SPI.  

Soybean protein isolate (SPI) is a kind of plant derived protein with high nutritional value, but it is underutilized due to its structural limitations and poor functionalities. This study aimed to investigate the effects of high hydrostatic pressure (HHP) treatment on SPI and sodium alginate (SA) conjugates prepared through the Maillard reaction. The physicochemical properties of the conjugate synthesized under 200 MPa at 60 °C for 24 h (SPI–SA–200) were compared with those of the conjugate synthesized under atmospheric pressure (SPI–SA–0.1), SPI-SA mixture, and SPI. The HHP (200 MPa) significantly hindered the Maillard reaction. This effect was confirmed by performing SDS-PAGE. The alterations in the secondary structures, such as α-helices, were analyzed using circular dichroism spectroscopy and the fluorescence intensity was determined. Emulsifying activity and stability indices of SPI-SA-200 increased by 33.56% and 31.96% respectively in comparison with the SPI–SA–0.1 conjugate. Furthermore, reduced particle sizes (356.18 nm), enhanced zeta potential (‒40.95 mV), and homogeneous droplet sizes were observed for the SPI-SA-200 emulsion. The present study details a practical method to prepare desirable emulsifiers for food processing by controlling the Maillard reaction and improving the functionality of SPI.

Food allergy is an immunological response caused by allergens contained in food. Soybean is one of the eight kinds of food products that can cause allergies. Genetically modified food crops that are most widely produced worldwide is soybean (47 % worldwide). Genetically Modified Organisms (GMO) products is concerned may increase the allergenicity of the product. The aims of the research were to study the allergenicity of GMO and non-GMO Soy Protein Isolates (SPI) and the glycation effect to allergenicity of SPI. GMO and non-GMO SPI were glycated with fructooligosaccharides (FOS) through the Maillard reaction in liquid systems. Allergenicity was determined qualitatively using immunoblotting and quantitatively using Enzyme-Linked Immunosorbent Assay (ELISA). The glycation degree of GMO and non-GMO SPI can increase up to 75.03 % and 73.50 % in the liquid system. There were 9 protein allergens in GMO soybean and 8 protein allergens in non-GMO soybean. The glycation reaction could reduce protein allergens in GMO and non-GMO SPI up to 91.69 % and 87.07 %.ABSTRAKAlergi pangan merupakan sebuah respon imunologis yang disebabkan oleh alergen yang terdapat pada pangan. Kacang kedelai merupakan satu dari delapan jenis bahan pangan yang sering menyebabkan alergi. Tanaman pangan hasil rekayasa genetika (GMO) yang banyak diproduksi di dunia adalah kacang kedelai yaitu sekitar 47 %. Produk GMO dikhawatirkan dapat meningkatkan alergenisitasnya. Penelitian ini bertujuan untuk mempelajari tinggat alergenisitas antara Isolat Protein Kedelai (IPK) GMO dan non-GMO serta pengaruh glikasi terhadap alergenisitas IPK. IPK GMO dan non-GMO diglikasi dengan fruktooligosakarida melalui reaksi Maillard dengan sistem cair. Alergenisitas diukur secara kualitatif menggunakan immunobloting dan secara kuantitatif menggunakan Enzyme-Linked Immunosorbent Assay (ELISA). Peningkatan derajat glikasi IPK GMO dan non-GMO pada sistem cair masing-masing memperlihatkan hasil 75,03 % dan 73,50 %. Terdapat 9 protein alergen pada kacang kedelai GMO dan 8 protein alergen pada kacang kedelai non-GMO. Reaksi glikasi dapat mengurangi alergen pada kacang kedelai GMO dan non-GMO hingga 91,69% dan 87,07%.

In order to improve EAI and ESI of Soybean protein isolate (SPI), Glycosylation modification was studied by adding lactose and the operation conditions for modification were established by single factor experiment. On the basis, Box-Behnken model was used to optimize technological conditions, test and analyze the EAI and ESI of modified products under various conditions. The best glycosylation modification was as follows: the augmenter of lactose was 6.9%, reaction temperature was 70.5°C, reaction time was 38.6h, and the EAI and ESI could achieve 0.754 and 24.00 which was 2.32 and 2.67 times of the unmodified SPI. The experiment proved that the modification technology can effectively increase EAI and ESI of SPI.

Cette recherche s'est concentrée sur les bioressources, notamment le tanin, la lignine, les protéines de soja, les humines, pour préparer des adhésifs et des mousses à base de bois bio. Il y a quatre parties principales, dont deux types de préparation de colles à bois en utilisant des bio-ressources, à savoir les colles à bois NIPU biosourcées et les colles à bois biosourcées (tanin, SPI et lignine) sans formaldéhyde toxique ; deux types de produits de mousse de tanin, c'est-à-dire une mousse de tanin-furanique typique et des mousses de polyuréthane sans isocyanate. (1) Les humines commerciales, l'isolement de protéines de soja (SPI) et le tanin de mimosa ont été utilisés pour préparer des adhésifs pour bois, basés sur la formulation de polyuréthanes non-isocyanates (NIPU). Les propriétés de base des adhésifs ont été déterminées. Des techniques telles que MALDI-ToF et FTIR ont été utilisées pour détecter les produits obtenus et pour analyser les mécanismes réactionnels impliqués. Une analyse thermomécanique (TMA) a été utilisée pour étudier le comportement thermique des adhésifs. Enfin, des contreplaqués ou des panneaux de particules de laboratoire ont été préparés pour évaluer les performances de collage des adhésifs. (2) Un nouvel adhésif pour bois à base de biomasse a été préparé avec un extrait de tanin de mimosa commercial et de l'éther diglycidylique de glycérol (GDE) par mélange mécanique pratique. Le GDE a servi d'agent de réticulation du tanin sans aucune addition d'aldéhyde, produisant des réseaux tridimensionnels durcis. Différents rapports pondéraux tanin/GDE ont été étudiés par plusieurs techniques pour déterminer leur influence sur les propriétés finales. Deux types d'adhésifs à base de lignine ont été préparés, c'est-à-dire (ⅰ) la lignine modifiée au glyoxal et l'amidon dialdéhyde réticulé par l'urée; (ⅱ) oxydation du periodate en deux étapes. Les espèces moléculaires formées et le mécanisme réactionnel impliqué ont été déterminés par FT-IR, RMN 13C et spectrométrie de masse MALDI-ToF. Les adhésifs basés sur cette réaction ont été testés par collage de contreplaqué ou de panneaux de particules de laboratoire, par calorimétrie différentielle à balayage (DSC) et analyse thermomécanique (TMA).(3) Une mousse rigide de polyuréthane sans isocyanate (NIPU) à base de tanin a été obtenue. Le mélange d'acide citrique et de glutaraldéhyde a servi d'agent d'expansion et de réticulation utilisé pour fournir de l'énergie moussante et réticuler la résine à base de tanin pour préparer les mousses NIPU. Le mécanisme de réaction des mousses NIPU à base de tanin a été étudié par FT-IR, MALDI-TOF et 13C RMN. De plus, le tanin a également été utilisé comme ignifuge naturel pour améliorer les propriétés finales des mousses NIPU à base de glucose, y compris la résistance au feu et la résistance à la compression. (4) Un déchet de bioraffinerie, des humines et un insolat de protéine de soja (SPI) ont été sélectionnés comme agents de réticulation biosourcés de substitution du formaldéhyde pour deux types de formulations de mousse à base de tanin. Comme attendu, les propriétés ont été améliorées en utilisant ces réticulants biosourcés. Les propriétés de base des mousses de tanin en série ont été étudiées. Les caractéristiques de morphologie et de structure ont été observées par microscopie électronique à balayage (MEB). De plus, les mécanismes de réaction de réticulation entre le tanin avec les deux réticulants bio-sourcés, à savoir les humines et le SPI, ont été déterminés par spectrométrie MALDE-ToF et FTIR. Enfin, la stabilité thermique, les propriétés mécaniques, le caractère ignifuge et l'émission de formaldéhyde ont été évalués par les techniques appropriées
This research was focus on bioresources, including tannin, lignin, soybean protein, humins, to prepare bio-based wood adhesives and foams. There are four main parts, including two kinds of wood adhesives preparation by using bio-resources, i.e., bio-sourced NIPU wood adhesives and bio-based (tannin, SPI, and lignin) wood adhesives without toxic formaldehyde; two kinds of tannin-foam products, i.e., typical tannin-furanic foam and non-isocyanate polyurethane foams. (1) Commercial humins, soybean protein isolation (SPI), and mimosa tannin have been utilized to prepare wood adhesives, based on the formulation of non-isocyanate polyurethanes (NIPU). The basic properties of the adhesives were determined. Techniques such as MALDI-ToF and FTIR were used to detect the products obtained and for analyzing the reaction mechanisms involved. Thermomechanical analysis (TMA) was utilized to investigate the thermal behavior of the adhesives. Finally, the laboratory plywood or particleboard were prepared for evaluating the bonding performances of adhesives. (2) A novel biomass-based wood adhesive was prepared with commercial mimosa tannin extract and glycerol diglycidyl ether (GOE) by convenient mechanical mixing. GOE served as the crosslinker of the tannin without any aldehyde addition yielding hardened three­dimensional networks. Oifferent weight ratios of tannin/GOE were investigated by several techniques to determine their influence on final properties. Two kinds of lignin-based adhesives were prepared, i.e., ( i ) glyoxal modified lignin and dialdehyde starch cross-linked by urea; ( ii ) periodate oxidation by two-steps. The molecular species formed and the reactions mechanism involved were determined by FT-IR, 13C NMR and MALDI-ToF mass spectrometry. The adhesives based on this reaction were tested by bonding laboratory plywood or particleboard, by differential scanning calorimetry (DSC), and thermomechanical analysis (TMA). (3) A tannin-based non-isocyanate polyurethane (NIPU) rigid foam was obtained. Citric acid and glutaraldehyde mixture served as a blowing and crosslinker agent used to provide foaming energy and cross-link the tannin-based resin to prepare the NIPU foams. The reaction mechanism of the tannin-based NIPU foams were investigated by FT-IR, MALDI-TOF, and 13C NMR. Additionally, tannin was also used as a natural tire-retardant to improve the final properties of glucose-­based NIPU foams, including fire retardancy and compression strength. (4) A biorefinery waste, humins, and soybean protein insolate (SPI) were selected as formaldehyde substitute bio-sourced crosslinkers for two kinds of tannin-based foam formulations. As expected, the properties were improved by using these bio-sourced crosslinkers. The basic properties of series tannin foams were investigated. The morphology and structure characteristics were observed by scanning electron microscopy (SEM). Additionally, the crosslinking reaction mechanisms between tannin with the two bio-sourced crosslinkers, i.e., humins and SPI, were determined by MALDE-ToF and FTIR spectrometry. Finally, the thermal stability, mechanical properties, fire retardancy and formaldehyde emission were evaluated by the relevant techniques

Protein co-precipitates were prepared from whey powder and soybean flour using various extraction and co-precipitation techniques. The effect of extraction and co-precipitation on co-precipitate yield was investigated. Native and sodium dodecyl sulfate polyacrylamide gel electrophoresis (Native-PAGE, SDS-PAGE) and light compound microscopy (LCM) were used to study the structure of the co-precipitates. The rheological and gelation properties of the co-precipitates were determined. Highest yield (45%) for NaOH/Isoelectric Point IEP-Heating-Cooling, co-precipitate was obtained using the following conditions of extraction; extraction temperature, 40°C; temperature of precipitation 95°C, and pH of precipitation was 4.5. The yield of co-precipitates was affected by chelating agents and pH of precipitation and temperature of precipitation. Native-PAGE showed that 2 new protein bands result from the interactions between whey and soybean proteins during preparation of the co-precipitate. SDS-PAGE showed that the new proteins dissociated to give the protein subunits of whey and soybean proteins. LCM results showed differences in microscopic structure between the whey and soybean protein precipitates and the protein co-precipitates. Gels were characterized by measurement of water holding capacity (WHC), gelation start temperature (GST) and denaturation start temperature (DST) and gel strength (GS). Gels (16%) from a protein co-precipitate Mixed Powder MP:NaOH/IEP-Cooling had higher WHC and GS than gels from whey protein precipitate, soybean protein precipitate and protein co-precipitates Mixed Extract ME:NaOH/IEP-Cooling and co-precipitates MP: and ME:NaOH/IEP-Heating-Cooling. The DST of protein co-precipitates was dependent on protein concentration and pH, while GST was relatively dependent on protein concentration.

Soybean meal (SBM) is residua product after oil extraction, the SBM with 48% protein is used for poultry, cattle. The SBM contains significant amount of anti-nutritional factors. Degradation of most antigenic proteins and protease inhibitors in SBM fermented by fungal, yeast and bacterial strains. Soybean fermented products are used as feed for livestock or aquaculture. Recently, biofilm forming microorganisms were broadly applied for fermentation process using substrates such as rice bran, corn, soybean meal ... to produce probiotics. In this study, we isolated and selected beneficial microbial strains that are capable of well biofilm forming, produce digestive enzymes and resist pathogenic microorganisms to ferment of soybean meal. The result showed that, four microorganism strains including NA5.3; TB2.1; TB4.3 TB4.4 had ability of forming higher biofilm, producing digestive enzymes such as amylase, protease and cellulose. Among them, NA5.3 and TB 4.4 strains had anti-pathogenic bacteria capacity such as Vibrio parahaemolyticus; Enterococcus faecalis; Bacillus cereus and Escherichia coli. Four selected strains were checked effection of pH, temperature, NaCl and bile salt concentration to their biofilm formation. The result indicated suitable conditions for forming biofilm at pH 6-8 range; temperature range 30-37°C; NaCl concentration of 0-3%, bile salt concentration of 0.5-2%. The selected strains grew well during solid fermentation process, achieved 1011 CFU/gram.
Khô đậu nành là sản phẩm còn lại từ quá trình ép dầu chứa tới 48% protein thô và thường được sử dụng làm thức ăn cho gia cầm, gia súc. Nhưng trong khô đậu nành còn chứa một lượng đáng kể một số chất ức chế dinh dưỡng, các chất ức chế này lại được phân hủy bởi quá trình lên men nhờ một số loài vi khuẩn, nấm mốc hay nấm men. Sản phẩm lên men khô đậu tương được sử dụng làm thức ăn cho gia cầm, gia súc hay nuôi trồng thủy sản. Trong những năm gần đây, các vi sinh vật tạo màng sinh học đã được ứng dụng để lên men các cơ chất như cám gạo, ngô, khô đậu nành… tạo sản phẩm probiotics. Trong nghiên cứu này, chúng tôi đã phân lập và tuyển chọn một số vi sinh vật có lợi tạo màng sinh học cao, sinh các enzyme tiêu hóa và kháng lại một số vi khuẩn gây bệnh cho mục đích lên men khô đậu nành. Kết quả đã lựa chọn được 4 chủng vi khuẩn NA5.3; TB2.1; TB4.3 TB4.4 có khả năng tạo màng sinh học cao, sinh các enzyme như amylase, protease và cellulose.Trong đó,hai chủng NA5.3 và TB4.4 có khả năng kháng lại một số vi khuẩn gây bệnh như Vibrio parahaemolyticus; Enterococcus faecalis; Bacillus cereus và Escherichia coli. Bốn chủng vi khuẩn lựa chọn được nghiên cứu ảnh hưởng của các điều kiện lên khả năng tạo màng sinh học của chúng, chúng thích hợp ở pH 6-8; nhiệt độ 30-37°C; NaCl 0-3%, muối mật 0,5-2%. Sử dụng các chủng vi khuẩn này cho quá trình lên men rắn khô đậu tương, mật độ vi khuẩn sau khi lên men đạt 1011 CFU/gram.

Soy protein isolate (SPI) may serve as a health-enhancing functional ingredient in many food products due to the content of isoflavones. However, the high protein content may also be exploited as a structure modifier in gluten-free noodles. We applied Soy protein isolate to improve rice flour noodles’ structure, textural, and cooking properties by combining cross-linking and cold gelation of soy protein isolate using microbial transglutaminase and glucono-δ-lactone, respectively. The simultaneous cross-linking yielded noodles with improved structure and textural properties, mainly due to a more robust microstructure resulting from an increase in intermolecular protein cross-linking promoted by microbial transglutaminase and glucono-δ-lactone. However, the structurally enhanced noodles showed longer cooking time and reduced cooking yield upon drying. This was solved by employing pre-drying steaming treatments for 5 or 10 min to yield noodles with shorter cooking times, lower cooking losses, and improved cooking yield. We have also developed an alternative process technology using superheated steam (SHS) technology. The superheated steam technology made it possible to open up the structurally enhanced air-dried noodles by promoting faster gelatinization, as evidenced by reduced enthalpy, increased cooking yield, and sustained crystallinity of the starch granules noodle matrix.