Added Soy Protein Isolate Research Articles

The Preparation of W/O/W High-Internal-Phase Emulsions as Coagulants for Tofu: The Effect of the Addition of Soy Protein Isolate in the Internal Water Phase.

Tofu quality is determined by a controlled coagulation process using a W/O/W emulsion coagulant. The impact of adding soy protein isolate (SPI) to the inner water phase on the stability of W/O/W high-internal-phase emulsions (HIPEs) and its application as a coagulant for tofu was assessed. No creaming occurred during 7-day storage with SPI concentrations up to 0.3%, while the emulsion droplets aggregated with 0.5% and 0.7% SPI. Emulsions containing 0.3% SPI maintained a constant mean droplet size after 21 days of storage and exhibited the lowest TURBISCAN stability index value. HIPE stability against freeze-thaw cycles improved after heating. HIPEs with SPI concentrations above 0.3% demonstrated an elastic gel-like behavior. The increased viscosity and aggregation of the protein around droplets indicated that the interaction among emulsion droplets could enhance stability. W/O/W HIPE coagulants significantly increased tofu yield, reduced hardness, and produced a more homogenous tofu gel compared to a MgCl2 solution. The HIPE with 0.3% SPI was found to be optimal for use as a coagulant for tofu.

Pengaruh isolat protein kedelai (IPK) dalam pembuatan kerupuk dari bahan dasar nasi dan tepung tapioka terhadap sifat fisik dan sensoris

Crackers are a popular food consumed by Indonesian people as a side dish or as a snack. The quality of crackers is determined by their swelling power, crunchiness, taste and nutritional value. Crackers are generally made from tapioca flour, so the protein component is low. Therefore, this research utilized soy protein isolate which was added to tapioca and rice dough ingredients to increase the protein content of crackers. The aim of the research is to find the best formula for adding soy protein isolate and thick slices to produce crackers that contain high protein. The research method was experimental, the first treatment factor was the addition of soy protein isolate to the tapioca flour and rice mixture. The second factor is the thickness of the cracker slices. The treatment design was a Completely Randomized Design (CRD) with a 4 X 4 factorial pattern which was repeated 3 times. The research results showed that the interaction effect between the use of soy protein isolate in dough with various slice thicknesses resulted in significant differences in the swellability of crackers, frying time and oil absorption capacity. The average sensory properties of crackers added with soy protein isolate were favorable at a slice thickness of 1mm-1.5mm. The conclusion is that the best formula for making crackers made from tapioca flour and rice is to use 5% to 7.5% soy protein isolate, and the thickness of the cracker slices is 1mm – 1.5mm.

Ultrasound-assisted processing: Changes in gel properties, water-holding capacity, and protein aggregation of low-salt Hypophthalmichthys molitrix surimi by soy protein isolate.

The effects of ultrasound combined (25kHz, 400±20W/L, ultrasonic time of 5, 10 and 15min) with soy protein isolate processing on gelling properties of low-salt silver carp surimi, aggregation and conformation of myofibrillar protein were investigated. The results revealed that, compared with only adding soy protein isolate components, ultrasound-assisted soy protein isolate had a more obvious effect on the protein structure in low-salt surimi, leading to the decrease in α-helix and total sulfhydryl contents, and the increase in β-sheet content and protein solubility. As a result, more proteins participated in the formation of the gel network, and significant improvements in hardness, gel strength and water-holding capacity of the low-salt surimi gel were observed, while the myosin heavy chain in SDS-PAGE was weakened. The low-field NMR results showed that the initial relaxation time of T2 was apparently shorter, the free water content decreased and the bound water content increased under the action of ultrasound. Scanning electron microscope observation found that the surimi gel treated by ultrasound exhibited smaller holes, and had a more stable and denser network structure. In conclusion, the results of our work demonstrated that ultrasound combined with soy protein isolate can significantly improve the gel quality properties of low-salt silver carp.

Pasting Property of Jasmine Rice Flour, Quality and Sensory Evaluation of Gluten-Free Rice Penne as Affected by Protein and Hydrocolloid Addition

Jasmine rice flour (JMRF) is one of the most popularly consumed rice products in Thailand but applications to prepare gluten-free pasta are limited as JMRF amylose content is low. This research was carried out to develop JMRF suitable for gluten-free rice pasta (penne) (GFRP) by adding soy protein isolate (SPI, 5%), egg white protein powder (EW, 5%) and hydrocolloids (guar gum, GG and xanthan gum, XG, 1%). JMRF blended with proteins and hydrocolloids was investigated for pasting properties. JMRF blended with EW and SPI with GG showed the highest peak viscosity, whereas setback values observed in JMRF blended with EW and GG or XG were not significantly different. GFRP was prepared and determined for protein content, color and sensory evaluation. The protein content of GFRP with SPI blended with GG and XG ranged from 10.50 to 10.95% is higher than GFRP with EW and penne without SPI or EW (control). GFRP with SPI had higher yellowness than GFRP with EW. Adding SPI, EW and gums reduced cooking loss, while sensory evaluation showed a higher liking score for GFRP with SPI and GG than GFRP with EW. Results suggested that adding SPI and GG to JMRF improved pasting properties, protein content, color and acceptance. GFRP showed promise as a new alternative sustainable source to replace wheat in pasta products. However, characteristics, such as product chemical composition, texture analysis and nutritional benefits require further evaluation.

Kinetics gelling process of isolated soy protein into a non-dairy beverage

Soy proteins are used for their emulsifying, foaming, gelling properties, among others. These characteristics can be modified depending on the conditions to which the product is located. These modifications can now be risky for companies that evaluate product shelf life. Non-dairy products, such as soy-based beverages are the model for characterizing protein gelling kinetics by subjecting them to four different temperature and concentration changes, checking the viscosity of the product after a while. This work evaluated a soy-based drink by adding soy protein isolate at concentrations of 3% 4%, 5% and 6% and then taking it to pasteurization, which would help us make a safe drink. Once pasteurized, tests were placed at the temperature of 45 ºC, 60 ºC, 65 ºC, and 80 ºC respectively for 48 hours to see a change in the properties in the beverages and calculate the gelling curve of each concentration with each temperature. To see the change generated before and after the temperature, viscosity measures were taken, which will help us to have a clearer change from what happens to the isolated soy protein. Curves and kinetic parameters were obtained by making significant differences mainly at a higher temperature and at high concentration, I have even suspended particles forming a gel type in the drink.

Effect of protein on the thermogenesis performance of natural rubber matrix

Under high-speed strain, the thermogenesis performance of natural rubber products is unstable, leading to aging and early failure of the material. The quality of rubber latex and eventually that of the final products depends among others on the protein content. We found that when the protein is almost removed, the heat generated by the vulcanized rubber increases rapidly. After adding soy protein isolate to the secondary purification rubber, the heat generation of the vulcanized rubber is reduced, and the heat generation is the lowest when the added amount is 2.5–3.0 phr, which on account of protein promotes the construction of a vulcanization network and increases the rigidity of the rubber chain, resulting in a decrease in the potential frictional behavior of the rubber chain during the curl up-extension process.

Resistant starch and soy protein isolate in instant noodles obtained by conventional and vacuum frying

Abstract Health concerns with the consumption of high-fat products and with respect to the intake of fibre are important for consumers. Vacuum frying process is an alternative frying process that increases the quality of foods. The objective was to develop instant noodles aiming to reduce carbohydrate and fat content by adding soy protein isolate (SPI) and resistant starch (RS3), using conventional and vacuum frying processes. A 22 central composite rotational design was used for each type of process, and the formulations were optimized using the Response Surface Methodology. The noodles were characterized with respect to fat absorption, cooking time, final resistant starch content and firmness. The noodles produced at the optimized point were also characterized for their isoflavone content, amino acid profile and by scanning electronic microscopy (SEM). The response surfaces showed that the addition of SPI and RS3 to the formulation resulted in reduced fat absorption and texture. Comparing both frying processes it was found that noodles obtained by vacuum frying absorbed 3% less fat and were less firm than those produced by conventional frying process. The SEM analysis showed that the noodles obtained by conventional frying had a more porous structure, which allowed an easier fat penetration, whereas those produced by vacuum frying showed a more closed structure with fat impregnated on the surface. Regardless of the process used, it was possible to obtain noodles with improved nutritional value, since they showed high fibre (8%) and protein (approximately 11%) contents, considerable isoflavone content (8.20 mg/100 g) and a complete amino acid profile, due to a significant increase in nearly all the amino acids, especially lysine.

Effect of soy protein isolate on the techno‐functional properties and protein conformation of low‐sodium pork meat batters treated by high pressure

AbstractIn this study, the changes of color, emulsion stability, rheological property, and protein secondary structure attributes of pork meat batters (1% sodium chloride) treated by high pressure with different soy protein isolate were investigated. Three batters with 0, 2, and 4% soy protein isolate were prepared under 200 MPa for 10 min, respectively. The pH, emulsion stability, L* and b* values were significantly improved when added soy protein isolate, the a* value was significantly (p < .05) decreased. The pH and color were not significantly different (p > .05) with soy protein isolate increased, but emulsion stability was increased (p < .05). Added soy protein isolate and treated by high pressure delayed the thermal denaturation of meat protein and declined the pre‐gel effects generated by the denaturation of myosin tails from 53°C to 59°C, and induced the α‐helix structure changed into β‐sheet, β‐turn, and random coil structures. Especially, the content of the random coil structure was significantly increased (p < .05) from 11.42 ± 0.26% to 14.22% ± 0.29 with soy protein isolate increased. Overall, the 2% soy protein isolate addition could improve the techno‐functional properties and emulsion stability of pork meat batters treated by high pressure.Practical applicationsThe pork meat batters with soy protein isolate treated by high‐pressure processing should be adopted for lowering sodium content in meat processing industry.

PENGARUH PENAMBAHAN ISOLAT PROTEIN KEDELAI TERHADAP KARAKTERISTIK KAMABOKO IKAN BARRAMUNDI (Lates calcalifer)

The aim of this study was to know the effect of adding soy protein isolate (ISP) to the characteristics of kamaboko barramundi fish (Lates calcalifer) and to know the right addition of ISP that can produce kamaboko with the best characteristics. The study used a completely randomized design with the addition treatment of ISP that consists of 5 levels: 0%, 4%, 8%, 12%, and 16%. The treatment was repeated 3 times to obtain 15 experimental units. The data was analyzed by variance and if it influential to the variable then continued with the Duncan test. The results showed that the addition of ISP on the producing of kamaboko had a highly significant effect to texture (gel strength), moisture content, protein content, ash content, hedonic test (color, texture, taste, overall acceptance) and scoring test (folding test and bite test). The addition of 12% ISP produced kamaboko with the best characteristics with gel strength 1404.76 gf/cm2, water content 74.42%, protein content 15.40%, fat content 3.64%, ash content 3.55%, color, texture, taste, and overall acceptances were liked, aroma rather liked, appearance of meat without fiber and without foreign things, folding test does not crack if folded 4 times, and bite test rather strong specific product elasticity.
 Keywords : soy protein isolate, barramundi fish, kamaboko, characteristics

Mashed potatoes enriched with soy protein isolate and inulin: chemical, rheological and structural basis

Soy protein isolate is typical vegetable protein with health-enhancing activities. Inulin, a prebiotic no digestible carbohydrate, has functional properties. A mashed potato serving of 200 g with added soy protein isolate and/or inulin concentrations of 15-60 g/kg provides from 3 to 12 g of soy protein isolate and/or inulin, respectively. Currently, no information is available about the possible texture-modifying effect of this non-ionizable polar carbohydrate in different soy-based food systems. In this study, the effect of the addition of soy protein isolate and inulin blends at different soy protein isolate: inulin ratios on the degree of inulin polymerization and the rheological and structural properties of fresh mashed and frozen/thawed mashed potatoes were evaluated. The inulin chemical structure remained intact throughout the various treatments, and soy protein isolate did not affect inulin composition being a protein compatible with this fructan. Small-strain rheology showed that both ingredients behaved like soft fillers. In the frozen/thawed mashed potatoes samples, addition of 30 : 30 and 15 : 60 blend ratios significantly increased elasticity (G' value) compared with 0 : 0 control, consequently reducing the freeze/thaw stability conferred by the cryoprotectants. Inulin crystallites caused a significant strengthening effect on soy protein isolate gel. Micrographs revealed that soy protein isolate supports the inulin structure by building up a second fine-stranded network. Thereby, possibility of using soy protein isolate and inulin in combination with mashed potatoes to provide a highly nutritious and healthy product is promising.

TEXTURE PERCEPTION DETERMINED BY SOY PROTEIN ISOLATE AND INULIN ADDITION IN POTATO PUREE: LINKS WITH MECHANICAL AND MICROSTRUCTURAL FEATURES

ABSTRACTThis study evaluated the effect of adding soy protein isolate (SPI) and long‐chain inulin (INL) blends with 10 different SPI : INL ratios on the textural, rheological and microstructural properties of freshly made and frozen/thawed potato puree. All the potato puree samples were subjected to a sensory texture profile analysis and a trained panel rated the intensity of six descriptors, while an untrained panel did the same on six selected frozen/thawed products. The main SPI : INL ratio effect remained significant for all the descriptors evaluated, when the analysis of variance was applied considering the untrained assessors as random effects. However, only trained panel scores for creaminess corresponded well with untrained assessor ratings. Rheological flow index values were linked with variations in perceived consistency, and geometric and surface textural attributes were explained by structural features such as the presence of INL crystallites and SPI coarse strands.PRACTICAL APPLICATIONSA potato puree (PP) serving of 200 g with added soy protein isolate (SPI) and/or inulin (INL) concentrations of 1.5–6% provides from 3 to12 g of SPI and/or INL, respectively. The presence of SPI strands is a dominant factor in texture perception of PP with regard to mouthfeel geometric attributes (visual graininess and fibrousness) and the after‐feel attribute (mouth coating), while INL crystallites are the most important feature influencing creaminess. By adding small amounts of SPI (1.5%) together with INL at >3% increases the intensity of perceived creaminess, which was the most important descriptor in practical terms. In view of the foregoing, PP with ada'ed SPI and INL is a promising foodstuff for incorporating into a diet and in addition, even improves product structure.

Wheat porridge with soy protein isolate and skimmed milk powder: Rheological, pasting and sensory characteristics

Porridges made from raw and roasted wheat grits ( dalia) with added soy protein isolate (SPI) and skimmed milk powder (SMP) were investigated by employing rheological, pasting and sensory tests in order to develop nutritious products. All porridge samples, irrespective of the presence of SPI/SMP and the application of roasting process, exhibited shear-thinning behaviour, fitted well with Cross equation ( r ⩾ 0.972, p ⩽ 0.01) compared to power law and Casson models. The power indices for porridges prepared from raw grits were higher (0.643–0.764) compared to roasted samples (0.582–0.659). Pasting characteristics like peak viscosity, hot paste viscosity, cold paste viscosity, break down viscosity and total set back viscosity decreased due to incorporation of SPI/SMP. Roasted wheat grits exhibited increased pasting temperature but decreased other pasting characteristics. Pasting temperature increased from 64.4 to a maximum of 74.2 °C due to incorporation of SPI/SMP up to 10%. Porridges made from raw grits along with SPI/SMP had excellent sensory characteristics although roasted grit samples were thinner in consistency and had a better flavour.

Interactions and gel strength of mixed myofibrillar with soy protein, 7S globulin and enzyme-hydrolyzed soy proteins

The mixed protein gels were prepared adding soy protein isolate (SPI), 7S globulin, enzyme-hydrolyzed soy proteins, 10- to 100-kDa ultrafiltration fraction and 0.5- to 10-kDa ultrafiltration fraction to myofibril protein isolate (MPI) gels, and five chemical interactions namely nonspecific associations, ionic bonds, hydrogen bonds, hydrophobic interactions and disulfide bonds in these gels were investigated by means of determining gel solubility within 20–75 °C. Furthermore, correlations between gel strength and different chemical interactions were evaluated statistically by Pearson’s correlation test. The gels with 0.5- to 10-kDa fraction presented the biggest gel strength below 60 °C, and the gels with SPI had better gel strength above 65 °C. At different endpoint temperatures, nonspecific associations decreased in order of MPI mixed with 0.5- to 10-kDa fraction, 10- to 100-kDa fraction, enzyme-hydrolyzed soy proteins, 7S globulin and SPI. Gels with ultrafiltration fractions had higher ionic bonds. Hydrogen bonds fluctuated in small scale below 55 °C and reduced at higher temperature. Hydrophobic interactions increased to maximum before decreasing slowly as the temperature went on. In short, both hydrophobic interactions and ionic bonds had significantly positive correlation with gel strength for mixed gels with enzyme-hydrolyzed soy proteins, whereas for the other four mixed gels, it was hydrophobic interactions and nonspecific associations.

Effect of soy protein isolate on the thermal, mechanical and morphological properties of poly ( ɛ-caprolactone) and corn starch blends

The development of biodegradable polymers is considered to be a good alternative to decrease the volume of the plastic waste disposed into the environment every year. The use of natural polymers as raw materials to develop polymer blends and composites has increased the demand for renewable sources such as starch and soy protein. In this work, the authors prepared and characterized the thermal, mechanical and morphological properties of blends based on poly ( ɛ-caprolactone) and modified corn starch, with added soy protein isolate (SPI) and sorbitol. All samples were processed by extrusion in a single-screw extruder and hot pressing. It was observed that the addition of modified corn starch and SPI were responsible for the reduction of thermal and mechanical properties of the materials, compared to pristine PCL. However, with increasing amounts of SPI and the reduction of starch incorporated into the samples, their properties tend to recover. The insertion of soy protein isolate in the formulations was done with the aim of balancing the C/ N ratio of the blend, which plays a key role in the biodegradation process of these materials.

Sources of phytoestrogen exposure among non-Asian women in California, USA.

We recently described the development of a comprehensive database for assessing phytoestrogen exposure in epidemiologic studies. This paper describes the first application of this database and the primary sources of phytoestrogen consumption in non-Asian women. Four hundred and forty-seven randomly selected African-American, Latina, and white women, ages 50-79 years, residing in California's San Francisco Bay Area and participating as controls in an ongoing population-based case-control study of breast cancer, were included in the present analysis. Average daily consumption of each of seven phytoestrogenic compounds was determined for each woman by combining the values from the new database with food consumption reported on a food-frequency questionnaire. Phytoestrogens in the non-Asian Bay Area diet appear to come primarily from: (1) traditional soy-based foods (e.g. tofu and soy milk); (2) "hidden" sources of soy (e.g. foods containing added soy protein isolate, soy concentrate, or soy flour, e.g. many brands of doughnuts and white bread); and (3) a variety of foods which contain only low to moderate amounts of phytoestrogens per 100 grams but which are frequently consumed (e.g. coffee and orange juice). In the absence of a comprehensive assessment of various phytoestrogens in a wide variety of foods, epidemiologic studies could suffer from the effects of uncontrolled confounding by unmeasured sources of phytoestrogen exposure potentially leading to biased estimates of effect and misinterpretation of findings.

Texture-Structure Relationships in Texturized Soy Protein IV. Influence of Process Variables on Extrusion Texturization

The effects of several variables on texture (as measured by Warner-Bratzler values), extruder pressure, extruder torque, extruder throughput, product moisture level and microstructure of extruded soymeal were investigated using response surface methodology. Variables studied included extrusion temperature, screw speed, and protein and moisture levels of the meal. Protein level and extrusion temperature were found to be the most important factors in determining Warner-Bratzler values, accounting for 64% of the variation. When the effects of protein and moisture were separated by adding soy protein isolate to the feed material 77% of the variation was explained by protein. Warner-Bratzler values increased with increasing protein and temperature levels but while the effects of protein were both linear and quadratic, temperature had predominantly a linear effect Feed moisture had little influence on Warner-Bratzler values at constant protein levels; extruder pressure and torque decreased with increasing feed moisture. Scanning electron microscopy showed that protein level had a pronounced influence on product micro-structure. Increasing protein levels led to a better orientation and contexture of the protein which was in agreement with regression analyses of process parameters and Warner-Bratzler values.