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1.
Changes of isoflavones during processing of soy protein isolates 总被引:7,自引:3,他引:4
C. Wang Q. Ma S. Pagadala M. S. Sherrard P. G. Krishnan 《Journal of the American Oil Chemists' Society》1998,75(3):337-341
Soy protein isolate (SPI) is a widely used food ingredient and is made by extracting soy flour (SF) under slightly alkaline
pH, followed by precipitation, washing, and drying. Soy foods and foods containing soy protein ingredients have great potential
in the prevention of cardiovascular diseases and cancers. These health benefits have been attributed to isoflavones in soy
protein ingredients. However, the current processing techniques were developed many years ago without this knowledge. The
objective of this study was to investigate the mass balance of different isoflavones during manufacturing of SPI and to provide
basic information to assist further development efforts leading to preservation of soy isoflavones in soy protein ingredients.
The study revealed that only about 26% of the total isoflavones in SF remained in SPI. The percentages of total isoflavones
lost during extraction, precipitation, and washing were 19, 14, and 22%, respectively. Washing was the step where most isoflavones
were lost. The isoflavone profile of the SPI was different from that of SF. The former contained much more aglucones (genistein
and daidzein), while the latter had almost none. The high content of aglucones in SPI was probably due to the hydrolysis of
glycosides. 相似文献
2.
Jun Lin Padmanaban G. Krishnan Chunyang Wang 《Journal of the American Oil Chemists' Society》2006,83(1):59-63
The mass balance of saponins during processing of soy protein isolates (SPI) was established, and the effects of precipitating
and washing (P/W) temperatures (0, 10, 25, 40, and 50°C) on the retention of isoflavones and saponins were investigated in
this study. About 41% of total saponins in soy flour (SF) were found to remain in SPI during processing, whereas 42% remained
unextracted in the solid waste. None was detected in the whey or wash water. The study also revealed that only about 27% of
total isoflavones from SF remained in the final SPI when P/W was performed at 50°C. As much as 40% of the total isoflavones
could be retained in SPI when P/W was conducted at 25, 10, or 0°C. When the P/W temperature was 50°C, the percentages of total
isoflavones lost during extraction, precipitation, and washing were 28, 22, and 6%, respectively. When the temperature was
changed to 0°C, the percentages of isoflavones lost during extraction, precipitation, and washing were 28, 11, and 5%, respectively.
The P/W temperatures did not affect the distribution of saponins in different streams during the processing of SPI. Lowering
the P/W temperature did not significantly lower the protein content in SPI unless the temperature was reduced to 0°C. 相似文献
3.
S. Jung B. P. Lamsal V. Stepien L. A. Johnson P. A. Murphy 《Journal of the American Oil Chemists' Society》2006,83(1):71-78
This study investigated the potential of enzymes to increase soy protein extractability without causing protein degradation.
The aqueous extraction of protein was performed from defatted soy flakes on a laboratory-and pilot-plant scale. Yields of
protein and reducing sugars were determined in the alkali extracts obtained with cellulases and pectinase, added alone or
as cocktails. Using 5% (wt/g of protein) Multifect pectinase resulted in the best improvement of protein yields, which were
50 and 17% greater than the controls in laboratory- and pilot-plant-scale trials, respectively. This enhanced protein extraction
was accompanied by an increased reducing sugar content in the aqueous extract compared with the control. Under the conditions
tested, no enzyme cocktail markedly increased the protein yield compared with the use of single enzymes. The solubility curve
for Multifect pectinase-treated soy protein isolate (SPI) was typical of SPI at pH 2–10. Its foam stability significantly
improved, but the emulsification properties declined. Multifect pectinase markedly reduced the viscosity of SPI. SDS-PAGE
showed that the α’ and α subunits of β-conglycinin were modified, and glycoprotein staining showed that these modifications
were probably due to a protease secondary activity in the pectinase preparation. One cellulase and one pectinase were identified
as effective in modifying the protein and reducing sugar extractablity from the defatted soy flakes. 相似文献
4.
L. Jong 《应用聚合物科学杂志》2005,98(1):353-361
Defatted soy flour (DSF) is an abundant renewable commodity and is more economically favorable then soy protein isolate or soy protein concentrate. DSF contains soy protein, soy carbohydrate, and soy whey. The aqueous dispersion of DSF was blended with styrene‐butadiene latex to form elastomer composites. The inclusion of soy carbohydrate increased the tensile stress in the small strain region, but reduced the elongation at break. The shear elastic modulus of the composites showed an increase in the small strain region, consistent with its stress‐strain behavior. The inclusion of soy carbohydrate and soy whey also improved the recovery behavior in the nonlinear region. At small strain, the shear elastic modulus of 30% filled composites at 140°C was about 500 times higher than that of the unfilled elastomer, indicating a significant reinforcement effect generated by DSF. Compared with soy protein isolate (SPI), the stress softening effect and recovery behavior under dynamic strain indicate the addition of soy carbohydrate and soy whey may have increased the filler‐rubber interaction. In general, the DSF composites gave better mechanical properties compared with the protein composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 353–361, 2005 相似文献
5.
Effect of lipids on soy protein isolate solubility 总被引:6,自引:3,他引:6
W. L. Boatright N. S. Hettiarachchy 《Journal of the American Oil Chemists' Society》1995,72(12):1439-1444
Reduced-lipid soy protein isolate (SPI), prepared from soy flour treated so that most of the polar lipids have been removed,
exhibited an increase in protein solubility of 50% over that of the control SPI prepared from hexane-defatted flour. Adding
lipids from a commercial SPI during processing of reduced-lipid SPI decreased SPI solubility by 46%. The 19% decreased solubility
caused by the lipids (primarily phospholipids) was largely recovered by treating the protein with a reducing agent (2-mercaptoethanol).
The balance of protein insolubility, caused by the lipids, was attributed to a smaller lipid fraction (approximately 5% of
the total lipids). Adding lipids during SPI processing contributed to both the formation of oxidized protein sulfhydryls,
incapable of being reduced by 2-mercaptoethanol, and to oxidative deterioration of protein as determined by protein carbonyl
contents. 相似文献
6.
Nicolas A. Deak Lawrence A. Johnson 《Journal of the American Oil Chemists' Society》2006,83(9):811-818
High-sucrose/low-stachyose (HS/LS) soybeans were used to prepare ethanol-washed soy protein concentrate (EWSPC), soy protein
isolate (SPI), and a new low-fiber soy protein concentrate (LFSPC) in which the protein was extracted with alkali to remove
fiber and the protein extract was neutralized and freeze-dired. LFSPC prepared from HS/LS soybeans contained significantly
higher ratios of β-conglycinin to glycinin (1∶1.32) than did EWSPC (1∶1.75) or SPI (1∶1.69), which may have affected functional
properties. The LFSPC were also high in soluble sugars (14.7%) and low in fiber (0.3%) compared with traditional EWSPC (2.9
and 3.4%, respectively) and SPI (1.8 and 0.3%, respectively). For both normal and HS/LS soybean varieties, the LFSPC, especially
when extracted at pH 7.5 as opposed to pH 8.5, had higher denaturation enthalpies than did EWSPC and SPI, indicating less
denaturation had occurred. Water solubilities, surface hydrophobicities, and emulsification properties were highest for the
LFSPC and lowest for EWSPC. The LFSPC also had good foaming properties and low viscosities. These desirable functional properties
of the LFSPC make them unique among alternative soy protein ingredients and highly suitable for industrial applications as
food additives and ingredients. 相似文献
7.
Eduarda M. Bainy Susan M. Tosh Milena Corredig Lorna Woodrow Vaino Poysa 《Journal of the American Oil Chemists' Society》2008,85(6):581-590
This study focussed on the evaluation of thermal denaturation at three different stages during soy protein isolation and the
effect of subunit composition on the formation of heat-induced soy protein gels. Soy protein isolates (SPI) were prepared
from 12 high protein lines, Harovinton variety and 11 derived null-lines which lacked specific glycinin (11S) and β-conglycinin
(7S) protein subunits. Protein denaturation during SPI processing was monitored by differential scanning calorimetry (DSC).
The results showed that hexane extraction of oil from soybean flours at 23 °C or 105 °C did cause changes in protein conformation.
Rheological measurements showed that lines with different subunit compositions and 11S:7S ratio had distinctive gelation temperatures
and resulted in gels with different network structures. All lines formed particulate gels at 11% protein. The 11S:7S ratio
was not correlated to final stiffness, measured as the storage modulus G′, of SPI gels. Lower gelation temperatures were usually observed for 7S-rich lines. The absence of A3 and the combination
of A1, A2 and A4 subunits of 11S fraction may suggest the formation of stiffer gels. A more detailed study of the frequency
dependence of G′ for the various networks formed also indicated that differences in subunit composition influenced the network structures. 相似文献
8.
Soy protein concentrates (SPC) and soy protein isolates (SPI) were produced from hexane-defatted soy white flakes and from
two extruded-expelled (EE) soy protein meals with different degrees of protein denaturation. Processing characteristics, such
as yield and protein content, and the key protein functional properties of the products were investigated. Both acid-and alcohol-washed
SPC from the two EE meals had higher yields but lower protein contents than that from white flakes. Generally, SPC from an
acid wash had much better functional properties than those from an alcohol wash. The SPI yield was highly proportional to
the protein dispersibility index (PDI) of the starting material, so the EE meal with lower PDI had lower SPI recovery. The
protein content in SPI prepared from EE meals was about 80%, which was lower than from white flakes. Nevertheless, SPI from
EE meals showed functional properties similar to or better than those from white flakes. The low protein contents in SPC and
SPI made from EE meals were mainly due to the presence of residual oil in the final products. SPI made from EE meals had higher
concentration of glycinin relative to β-conglycinin than that from white flakes. 相似文献
9.
Nicolas A. Deak Patricia Murphy Lawrence A. Johnson 《Journal of the American Oil Chemists' Society》2006,83(9):803-809
High-sucrose/low-stachyose (HS/LS) soybeans contained lower total concentrations of free sugars (13.3%), less stachyose (0.7%),
and more galactinol (0.7%) (galactopyranosylmyo-inositol) than the control normal soybeans (14.9, 5.1, and 0.2%, respectively).
A low-fiber soybean protein concentrate (LFSPC) process was developed, which is especially suited to HS/LS soybeans, by which
defatted soy flour is merely extracted with alkali to remove fiber and then neutralized and dried to produce the protein-rich
soluble fraction. Two different pH values (7.5 and 8.5) were used in extracting protein, and these LFSPC were compared with
traditional ethanol-washed soy protein concentrate (EWSPC) and soy protein isolate (SPI) prepared from both normal and HS/LS
soybeans. The LFSPC had slightly lower yields of solids and protein (∼70 and ∼81%, respectively) than conventional FWSPC (∼77
and ∼93%, respectively) but much higher than conventional SPI (∼42 and ∼70%, respectively). The LFSPC prepared from HS/LS
soybeans contained significantly (P<0.05) more protein (∼66% protein content) than LFSPC prepared from normal soybeans (∼63%). Total isoflavone contents of the
LFSPC (∼12 μmol/g) were significantly higher than for EWSPC (∼1.5 ìmol/g) or SPI (∼10 μmol/g). The LFSPC prepared from HS/LS
soybeans contained higher sugar contents (∼15%) than either traditional EWSPC (∼2.5%) or SPI (∼1.5%); but the sums of stachyose
and raffinose were only ∼1% for the LFSPC compared with ∼1% for EWSPC and 0.5% for SPI prepared from normal soybeans. 相似文献
10.
A novel pH and ionic strength-sensitive protein-based hydrogel was synthesized via cross-linking ethylenediaminetetraacetic dianhydride-modified soy protein isolate (EDTAD–SPI) with glutaraldehyde. Incorporation of ionizable carboxyl groups into soy proteins increased the net negative charge of the protein and caused extensive unfolding of the protein structure. The EDTAD–SPI hydrogel was capable of imbibing 80-300 g water per g dry gel after centrifuging at 214g, depending on the extent of modification, protein structure, crosslinking density, protein concentration during the crosslinking step, gel particle size, and environ-mental conditions, such as temperature, pH, and ionic strength. The protein concentration used during the crosslinking step was found to be the most important factor affecting the water uptake of the gel. The lower the protein concentration, the higher was the water uptake at 214g. The hydrogel was highly sensitive to pH and exhibited reversible swelling when sequentially exposed to water and 0.15M NaCl. © 1996 John Wiley & Sons, Inc. 相似文献
11.
A membrane-based process to produce protein isolates from seeds of oriental mustard (Brassica juncea) was developed by modifying a method originally developed for rapeseed. The optimized process consisted of extraction at
pH 11, ultrafiltration with concentration factor 4, diafiltration with diavolume 3, and precipitation at pH 5. The process,
based on defatted oriental mustard seed containing 45–50% protein, recovered 81% of the protein in useful products: 47.3%
in precipitated protein isolate (PPI), 3.8% in soluble protein isolate (SPI), and 13% in meal residue. Mass yields were 21.9%
in PPI, 2.8% in SPI, and 38.4% in meal residue. The losses in the system included ∼10% loss of nonprotein nitrogen, and <9%
into permeate and transfer losses. The PPI compared favorably with soy protein isolate in typical meat products in terms of
color, texture, and flavor. The work confirms that oriental mustard is a potentially useful source of edible protein. 相似文献
12.
J. T. Lawhon K. C. Rhee E. W. Lusas 《Journal of the American Oil Chemists' Society》1981,58(3):377-384
The production of food ingredients from undefatted soybeans by aqueous processing and isolation of protein from soy flour
by ultrafiltration membranes has been demonstrated adequately during the past decade. These relatively new techniques offer
significant advantages over conventional soy processing methods. Aqueous processing requires no petroleum-based solvent and
consequently provides increased safety and flexibility of operation (because start-up and shutdown are safe and easy). It
also provides opportunities for removal or deactivation of undesirable constituents of raw materials with appropriate water-soluble
chemicals. It is, however, less efficient in oil extraction, and demulsification is required to recover clear oil when emulsions
form. Ultrafiltration processes recover protein directly from soy flour extracts and thereby avoid generation of the whey
which results from the conventional isoelectric precipitation. These processes have the advantages of increased isolate yield
(as whey proteins are recovered in the isolate), and produce products having enhanced functionality and nitrogen solubility.
The two processing techniques have subsequently been combined to obtain a single procedure with the advantages of each. Extracts
from undefatted soybeans have been membrane processed with and without separating the oil to produce a variety of new soy
protein ingredients. 相似文献
13.
Previous studies have shown that ambient-temperature equilibrium, hexane extraction of soy flour yielded the same amount of
oil as was extracted from soy flakes by conventional high-temperature processing. The oil obtained at ambient temperatures
contained less phospholipid than commercial crude oils obtained by traditional processing. In this study, chemical composition,
flavor and odor of soy flour obtained after oil extraction by the equilibrium procedure were evaluated before and after toasting.
Results were compared with those obtained for commercial untoasted food-grade soy flakes. Chemical and sensory analyses were
performed on soy protein concentrates (SPC) prepared from defatted flour, defatted toasted flour and commercial defatted white
food-grade flakes. SPC were made by acid and ethanol-extraction methods. Ethanol extraction of soy flour produced SPC with
similar protein, lipid and sensory qualities to those obtained from commercial flakes. Acid extraction produced SPC with more
lipid than was obtained by ethanol extraction. Toasted soy flour and flakes had similar sensory properties, as did the SPC
prepared from them. 相似文献
14.
Chromatographic Analysis of the Reaction of Soy Flour with Formaldehyde and Phenol for Wood Adhesives 总被引:2,自引:0,他引:2
Linda Lorenz Charles R. Frihart James M. Wescott 《Journal of the American Oil Chemists' Society》2007,84(8):769-776
The desire to make more biobased and lower-cost bonded wood products has led to an interest in replacing some phenol and formaldehyde
in wood adhesives with soybean flour. Improved knowledge of the soy protein properties is needed to relate resin chemistry
to resin performance before and after wood bonding. To expose the soy protein’s functional groups, it needs to be disrupted,
with minimal hydrolysis, to maximize its incorporation into the final polymerized adhesive lattice. The best conditions for
alkali soy protein disruption were to maintain the temperature below 100 °C and react the soy flour with sodium hydroxide
at pH 9–12 for about 1 hour. A gel permeation chromatography procedure was optimized to determine conditions for selectively
breaking down the high molecular weight soy protein fragments that contribute to high adhesive viscosity. This method and
extraction data were used to evaluate the reaction of the disrupted soy flour protein with formaldehyde and phenol to provide
a stable adhesive. The results were used to develop more economical adhesives that are ideally suited for the face section
of oriented strandboard. 相似文献
15.
Soybean protein meals obtained by various oil extraction methods have different neutral oil content, and they may contain
differnet amounts of polar lipids. Three soy protein meals obtained by different processing methods were extracted by two
solvents consecutively, chloroform/methanol (2:1, vol/vol) and water-saturated butanol, for total lipid analysis. The organic
flour (i.e., ground soybean) containted 15.52% total lipids; the high protein dispersibility index flour from extrusion-expelling
processing and the white flour from conventional solvent extraction contained 11.20 and 1.84% total lipids, respectively.
Organic flour contained more polar lipids than the other two protein meals on a dry-weight meal basis. Chloroform/methanol
extracted most of the lipid from the meals, whereas water-saturated butanol resulted in an extract with more polar lipids
than that from chloroform/methanol extraction. 相似文献
16.
Sang K. Park N. S. Hettiarachchy 《Journal of the American Oil Chemists' Society》1999,76(10):1201-1205
Flexible plastic foams using soy protein isolate (SPI), soy protein concentrate (SPC), and defatted soy flour (DFS) were produced
by interacting proteins with glycerol-propylene oxide polyether triol (polyol), surfactant, triethanolamine (crosslinking
agents), tertiary amine (catalyst), and water (blowing agent). The density, compressive stress, resilience, and dimensional
stability of foams with SPI, SPC, and DFS increased as the initial concentration of soy protein increased. The foam density
increased with increasing weight percentage of SPI, SPC, and DFS. The resilience values of SPI containing foam increased with
the increasing addition of SPI up to a maximum 30% SPI addition. An increase in SPI up to 20% caused an increase in the compressive
stress (225 kPa) in comparison to control polyurethane foam (187 kPa). The control foam and foam containing 20% DFS had a
similar load-deformation relationship. The foam containing 20% SPI and SPC also exhibited a similar shape, but with a higher
compressive stress. The compressive stress of all foams was steeply increased after 55% strain, since the foams completely
collapsed upon compression. 相似文献
17.
Tadeusz Jakubczyk Hanna Haberowa 《Journal of the American Oil Chemists' Society》1974,51(1):120A-122A
Effect of soy flour, soy protein concentrate, and isolate on dough and loaf properties of breads produced from flour, yeast,
salt, and water with no shortening or added improvers was investigated. Wheat flour, rye flour, and mixtures of the two were
included in the studies. Three wheat flours, varying in baking quality and extraction, ash content 0.65 and 0.80%, were used;
1.5, 3, and 5% soy products, flour basis, were added. Water absorption increased 3.8–4.7% at the 3% soy level and 6.1–7.3%
at the 5% level of soy product addition. Dough development time and stability were increased and dough softening reduced.
Dough gassing power increased ca. 7–25%. By using a shorter proofing time, more intensive mixing, and the sponge dough process,
loaves only slightly smaller in volume than the control were obtained at the 3% soy level. Panel evaluations scored bread
highest with 1.5 or 3% soy flour and that with 3 or 5% soy protein concentrate as lowest, but acceptable. Use of 2% lard as
shortening, or 2% lard plus emulsifier, produced soy breads of excellent quality and ca. 25% higher loaf volume than controls. 相似文献
18.
Implications of excess phosphorus (P) in waste streams obtained from soy-based protein preparation processes on the environment and their potential utilization as P-source are two significant understudied areas. Soybean-based protein ingredients for food products retain comparatively enhanced functional properties and are cheaper than other plant-based proteins. Soybean protein can be extracted and utilized as a food ingredient primarily by preparing soy protein concentrates (SPC) and soy protein isolates (SPI) from soybean meal/defatted soy flour (DSF). In a typical soybean processing facility, along with the soy products and soy-protein preparations, the recovery of phosphorus as a coproduct will enhance the economic feasibility of the overall process as the recovered P can be used as fertilizer. In this study, the SPC and SPI were prepared from the DSF following widely used conventional protocols and P flow in these processes was tracked. In SPC production, ~59% of the total P was retained with SPC and ~34% was in the aqueous waste streams. For SPI process ~24% of total P was retained with SPI and ~59% went in the waste solid residue (~40%) and aqueous streams (~19%). About 80%–89% P removal from the waste aqueous streams was achieved by Ca-phytate precipitation. This work demonstrated that in the process of SPC and SPI preparation the phosphorus from the waste aqueous streams can be precipitated out to avoid subsequent eutrophication and the waste solid residue with ~40% P can be reused as a P-fertilizer as other applications of this residue are unspecified. 相似文献
19.
Study of denaturation and composition‐dependent poly(ethylene oxide)–soy protein interactions: Structures and dielectric polarization 下载免费PDF全文
The significance of aggregated protein structures in tuning structures and dielectric polarization of poly(ethylene oxide) (PEO)/soy protein isolate (SPI) films was studied. The aggregated protein structures, subjected to denaturation processes, are expected to alter polymer–protein interactions, leading to diverse material structures, and properties. However, this is still insufficiently understood. In this study, SPI was modified via different denaturation processes including heat, sonication, and pH‐control. According to structural analysis with scanning electron microscope, fluorescence imaging, X‐ray diffraction, and Fourier transformed infrared spectroscopy, both denaturation conditions and SPI content affected PEO–SPI interactions, producing distinctive microstructures of PEO and SPI phases, which subsequently caused different dielectric properties in ferroelectric analysis. Particularly, sonication treated‐SPI distinguished itself by generating a unique parabolic‐like composition dependence of dielectric polarization, in contrast to other modified SPIs. Polymer/protein blends have shown great potential in biomedical and electronic applications, which will be further benefited by the findings in this study. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46561. 相似文献
20.
W. L. Boatright J. St. Pyrek J. Song A. D. Crum 《Journal of the American Oil Chemists' Society》1998,75(11):1651-1655
A previously unidentified component of the lipid extracts from commercial soy protein isolates (SPI) was analyzed by gas chromatography-mass
spectrometry (GC-MS), high resolution mass spectrometry (HRMS), ultraviolet-visible spectroscopy, and GC-Fourier transform
infrared spectrometry (FTIR). All these data, together with mass spectra of derivatives obtained by hydrogenation, indicated
the structure of an unsymmetrical dimethoxystilbene. Subsequently, standard trans-3,5-dimethoxystilbene, synthesized according to established procedures, was found to have identical retention times and spectra
by GC-MS and GC-FTIR with the compound isolated from commercial SPI. Laboratory SPI prepared from Probst, Stressland, and
Burlison variety soybeans contained no detectable amounts of either trans-3,5-dimethoxystilbene or dehydroabietinal. 相似文献