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1.
Steamed black soybeans and black soybean koji, a potentially functional food additive, were subjected to heating at 40-100 degrees C for 30 min. It was found that steamed black soybeans and black soybean koji after heating at 80 degrees C or higher generally showed reduced contents of malonylglucoside, acetylglucoside, and aglycone isoflavone and an increased content of beta-glucoside. A lower reduction in malonylglucoside and acetylglucoside isoflavone but greater reduction in aglycone content was noted in steamed black soybeans compared to black soybean koji after a similar heat treatment. After 30 min of heating at 100 degrees C, steamed black soybean retained ca. 90.3 and 83.8%, respectively, of its original malonylglucoside and acetylglucoside isoflavone, compared to lower residuals of 80.9 and 78.8%, respectively, for black soybean koji. In contrast, the heated black soybeans showed an aglycone residual of 68.0%, which is less than the 80.0% noted with the heated black soybean koji.  相似文献   

2.
Bifidobacteria strains from human origin were screened for the specific activity (beta-glucosidase activity) involved in the metabolism of dietary flavonoids. Five strains with high beta-glucosidase activity were selected for further metabolism analyses (high-performance liquid chromatography separations) of flavonoid glycosides occurring in Phaseolus vulgaris L. (common bean) seeds and seedlings. All selected strains were found to be active in the conversion of kaempferol 3-O-glucoside, daidzin, genistin, and glycitin into their aglyconic forms. No metabolites were detected after the fermentation tests with the diglucosidic compound kaempferol 3-O-xylosylglucoside. In addition, to verify the effective bioavailability of flavonoid aglycones, the degradation rates of daidzein, genistein, glycitein, and kaempferol, following incubation with selected strains, were monitored. The results showed that the five selected strains of bifidobacteria, being active in the biotranformation of flavonoid glycosides occurring in common bean seeds and seedlings, could be considered as probiotic dietary adjuncts to improve the nutritional and health properties of flavonoid-based products, comprising hypothetical common bean food derivatives.  相似文献   

3.
LC/UV/ESI-MS analysis of isoflavones in Edamame and Tofu soybeans   总被引：2，自引：0，他引：2  
High-performance liquid chromatography coupled with ultraviolet and electrospray ionization mass spectrometry (HPLC/UV/ESI-MSD) was applied to the study of isoflavones in both Edamame and Tofu soy varieties, from which the immature fresh soybeans or the mature soybean seeds are consumed, respectively. Positive atmospheric pressure interface (API) MS and MS/MS were used to provide molecular mass information and led to the identification of a total 16 isoflavones, including three aglycones, three glycosides, two glycoside acetates, and eight glycoside malonates. The major isoflavones in soybean seeds were daidzein and genistein glycoside and their malonate conjugates. Trace levels of daidzein and genistein acetyl glycosides were found only in the mature dry soybean seeds. To facilitate quantitative analysis, acid hydrolysis during extraction of soy samples was selected to convert the various phytoestrogen conjugates into their respective isoflavone aglycones, allowing accurate quantitation of total phytoestrogens as aglycones. On the basis of HPLC combined with UV and MS detection, all three targeted soy isoflavone aglycones, daidzein, genistein and glycitein in hydrolyzed extracts were successfully quantified within 25 min with formononetin used as the internal standard. The standard curves of UV detection were fitted in the range of 14.16-29000 ng/mL for daidzein, 15.38-31500 ng/mL for genistein, and 11.72-24000 ng/mL for glycitein. For MS detection, the standard curves were established in the range of 3.54-1812.5 ng/mL for daidzein, 3.85-1968.75 ng/mL for genistein, and 2.93-1500 ng/mL for glycitein. Good linearities (r(2) > 0.999 for UV and r(2) > 0.99 for MS) for standard curves were achieved for each isoflavone. The accuracy and precision (RSD) were within 10% for UV detection and 15% for MS detection (n = 10). Using this method, the phytoestrogen levels of total isoflavone aglycones from 30 soybean seed varieties were then evaluated for confirmation of the technique. Total isoflavones ranged across the varieties from 0.02 to 0.12% in the Edamame varieties, which are harvested while the seeds are still immature, and from 0.16 to 0.25% in Tofu varieties, harvested when the seeds are physiologically mature. While the literature has focused on the isoflavone content of soy products and processing soy, this report provides a reliable analytical technique for screening of authenticated fresh immature Edamame soybeans and Tofu soybeans.  相似文献   

4.
Soybeans were soaked with water for 4 h, steam-cooked, inoculated with the conidia of Aspergillus oryzae, and incubated for 3 days for koji preparation. The koji was then mixed with water-soaked and steam-cooked soybeans (1:2, w/w), ground into paste, and supplemented with 15% ethanol and 12.5% NaCl or 3% ethanol and 6% NaCl for miso fermentation at 30 degrees C. Daidzin, genistin, daidzein, and genistein contents were extracted from the lyophilized and pulverized soybean powder or from the miso homogenate by a developed one-tube procedure and analyzed with an HPLC. After water soaking, daidzein and genistein contents increased markedly, whereas daidzin and genistin contents decreased. Further increases of daidzein and genistein contents and decreases of daidzin and genistin contents were observed after koji mold growth. During fermentation, fungal and lactic acid bacterial (LAB) growth in the miso products was inhibited, whereas soluble protein contents increased much more rapidly in the low-salt miso products supplemented with 3% ethanol and 6% NaCl than the other products. When the 4- and 8-week-fermented miso products were cooked with tofu for sensory evaluation, flavor ratings of the low-salt products were higher than that of a popular commercial product. In both products, the most daidzins and genistins were hydrolyzed after 4 weeks of fermentation. The hydrolytic enzymes contributing to isoflavone transformation originated from soybeans after water soaking and from koji with mold growth. It was of merit that the low-salt fermented products were fairly acceptable in flavor rating and rich in daidzein and genistein contents after 4 weeks of fermentation.  相似文献   

5.
The effect of soybean meal fermented by Aspergillus awamori on the acute lethality of acetaldehyde, pentobarbital sleeping time, and cytochrome P-450 content of the hepatic microsomes was studied in mice. Most of the daidzin and genistin in soybean meal (SBM) were converted into the respective aglycones, daidzein and genistein, by fermentation. In experiment 1, mice were fed isonitrogenic test diets with one of the following five protein sources for 28 d: casein, SBM, fermented and hot-air-dried SBM (FSBM-HD), fermented and freeze-dried SBM (FSBM-FD), or methanol-extracted FSBM-FD (FSMB-FD-R). The acute lethality of acetaldehyde in mice fed the FSBM-FD diet was significantly lower than that in mice fed the SBM, FSBM-HD, or FSBM-FD-R diet. In experiments 2 and 3, mice were fed isonitrogenic test diets with one of the following four protein sources for 28 d: casein, SBM, FSBM-FD, and FSBM-FD-R. The pentobarbital sleeping time was significantly shorter and the cytochrome P-450 content was significantly higher in the mice fed the FSBM-FD diet than the respective value in mice fed the other test diets. In experiment 4, mice were fed one of eight diets which contained different levels of aglycone obtained by varying the proportion of FSBM-FD and FSBM-FD-R, for 28 d. The cytochrome P-450 content in hepatic microsomes increased as the dietary level of isoflavonoid aglycones increased, but there was a saturation phenomenon. These results suggest that soy isoflavonoid aglycones are more potent inducers of cytochrome P-450 than isoflavonoid glycosides.  相似文献   

6.
Profiles of genistein, daidzein, genistin, daidzin, and their acetyl- and malonyl-beta-glycosides were determined in tofu as affected by temperature and time. Tofu was heated in water at 80, 90, and 100 degrees C for 0 (control), 10, 20, 30, and 40 min, and the contents of the isoflavones of interest were quantified using reversed-phase HPLC. Total isoflavone content decreased most likely due to leaching of isoflavones into the water. Because the content of the isoflavones of the genistein series was little affected by the treatments, the decrease in the total isoflavone content was almost exclusively due to a decrease of the daidzein series. Changes in the profile of the daidzein series suggest little decarboxylation of the malonylglycoside to the acetylglycoside, but considerable de-esterification of the malonyl- and acetylglycoside to the beta-glucoside. Strongly temperature dependent decreases of the aglycon suggest possible thermal degradation of daidzein in addition to losses due to leaching.  相似文献   

7.
The soybean isoflavones, daidzein, genistein, and glycitein, were hypothesized to act as cholesterol-lowering components, separate from soy protein. Pure synthetic daidzein, genistein, or glycitein (0.9 mmol/kg diet) or a casein-based control diet was fed to groups of 10 female Golden Syrian hamsters for 4 weeks. Hamsters fed glycitein had significantly lower plasma total (by 15%) and non-HDL (by 24%) cholesterol compared with those fed casein (P<0.05). Daidzein and genistein's effects on these lipids did not differ from the effects of either casein or glycitein. Plasma HDL cholesterol and triglyceride concentrations were not significantly affected by dietary treatments. The percentage of urinary recovery of the ingested dose of each isoflavone was glycitein>daidzein>genistein (33.2%, 4.6%, 2.2%, respectively), with the apparent absorption of glycitein significantly greater than that of the other isoflavones. These data suggest that glycitein's greater cholesterol-lowering effect was due to its greater bioavailability, as reflected in its urinary recovery compared with that of the other isoflavones.  相似文献   

8.
Soybean isoflavone concentrations vary widely, but the contribution of soil fertility and nutrient management to this variability is unknown. Field experiments from 1998 to 2000 on soils with low to high exchangeable potassium (K) concentrations evaluated K application and placement effects on isoflavone concentrations and composition of soybean in various tillage and row-width systems. Soybean seed yield and concentrations of daidzein, genistein, glycitein, leaf K, and seed K were measured. Significant increases in daidzein, genistein, and total isoflavone were observed with direct deep-banded K or residual surface-applied K on low-K soils. Positive effects of K fertilization on isoflavones were less frequent on medium- to high-testing K soils. Both individual and total isoflavones were often positively correlated with seed yield, leaf K, and seed K on low-K soils. Appropriate K management could be an effective approach to increase isoflavone concentrations for soybeans produced on low- to medium-K soils.  相似文献   

9.
Soybean isoflavones have multiple beneficial health effects especially on estrogen-deficient diseases such as menopausal symptoms. In this study, isoflavones were produced from soybean flour, and the extraction and purification parameters were optimized to give a high yield of total isoflavones, about 0.62 mg of aglycones/g of soybean flour, which is >2 times the initial yield. HPLC analysis and MTT cell proliferation assay using MCF-7 cells revealed that the product thus obtained not only contained a high content of isoflavone aglycones but also had estrogenic activity. MTT data also revealed that both genistein and daidzein exhibited estrogenic effects at lower concentrations and antiproliferative effects at higher concentrations, and 1 microM genistein and 10 microM daidzein exerted significant estrogenic activities, which were not more than that of the endogenous level of 17beta-estradiol (E2). The production method developed can be used as a guideline for manufacturing soy isoflavones, and the MTT assay was demonstrated to be suitable for quality control on isoflavone products. The results on the estrogenic properties of isoflavones can be used as reference data for their effective and safe usages in estrogenic therapy.  相似文献   

10.
Genistein, daidzein, and glycitein, as primary isoflavones in soybeans, are reported to have beneficial effects on atherosclerosis, chronic inflammatory diseases, and cancers that are conducted by nitric oxide (NO) injury. The objectives of this study were to investigate the effects and mechanisms of these soy isoflavones on the inducible nitric oxide synthase (iNOS) system in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. Genistein, daidzein, and glycitein dose-dependently suppress NO production (IC(50) = 50 microM) in supernatants of LPS-activated macrophages as measured on the basis of nitrite accumulation. In addition, direct inhibition of iNOS activity, determined by means of the conversion of L-[(3)H]arginine to L-[(3)H]citrulline, and markedly reduced iNOS protein and mRNA levels, evaluated by means of Western blot and RT-PCR, respectively, were found in homogenates of LPS-activated cells treated with each isoflavone. Moreover, genistein was found to have a greater inhibitory effect on NO production but no significant effect on iNOS activity or protein and gene expression to daidzein and glycitein. These observations reveal that the suppression of NO production by genistein, daidzein, and glycitein might be due to the inhibition of both the activity and expression of iNOS in LPS-activated macrophages. The result suggests that soy isoflavones might attenuate excessive NO generation at inflammatory sites.  相似文献   

11.
The isoflavone aglycon and glucoconjugate content of commercially prepared and "home-prepared" high- and low-soy foods selected for use in an on-going nutritional study were measured by LC-MS. The daidzin, daidzein, 6"-O-malonyldaidzin, 6"-O-acetyldaidzin, genistein, genistin, 6"-O-malonylgenistin, 6"-O-acetylgenistin, glycitin, glycitein, 6"-O-malonylglycitin, and 6"-O-acetylglycitin content are expressed in terms of individual isoflavones, total isoflavone equivalents, and milligrams of isoflavones per portion served. Soybeans (774 mg x kg(-1) total isoflavones) and soybean-containing foods had the highest isoflavone content of the foods examined. The low-soy foods all contained very low concentrations (<8 mg x kg(-1) total isoflavones) of the isoflavone aglycons and glucoconjugates. High- and low-soy 11 day rotating menus were constructed from the analyzed foods to deliver 100.0 and 0.5 mg of isoflavones per day, respectively.  相似文献   

12.
Stability of isoflavones during extrusion processing of corn/soy mixture   总被引：3，自引：0，他引：3  
The influence of extrusion processing in the presence of corn on the quantity and quality of genistein, daidzein, and their respective beta-glucoside, acetyl glucoside, and malonyl glucoside derivatives was evaluated. Products of 100% soy (textured) and a blend of 20% soy protein concentrate (SPC) and 80% corn meal (direct-expanded) were extruded, with evaluations before and after extrusion. In addition, a 3 x (3 x 3) split-plot factorial experiment investigated the influence of barrel temperature (110, 130, 150 degrees C), moisture content (22, 24, 26%), and relative residence time (1, 0.8, 0.6) on extruder response and isoflavone profile. The extrusion barrel temperature had the most influence on isoflavone profile, especially decarboxylation of the malonyl beta-glucoside, followed by the moisture content. The amount of extractable isoflavones decreased after extrusion for both the SPC and SPC/corn meal blend when extracted with 80% aqueous methanol but remained approximately the same when first hydrated with water before extraction. However, initially hydrating with water produced enzymatic glycolysis in the unextruded samples, increasing the aglycons dramatically.  相似文献   

13.
Isoflavone phytoestrogens found in soybeans are the most widely studied phytochemicals in human diets and soy infant formulas. The health benefits of the isoflavones daidzein and genistein have been reported, and concerns about potential adverse effects have also been raised. However, the results of direct analysis of isoflavones and their metabolites in biological fluids after consumption of soy-containing diets are scarce. This study describes an LC/MS/MS method for the analysis of isoflavones and their metabolites in the urine of female rats fed diets made with soy protein isolate. Five isoflavones (daidzein, genistein, glycitein, dihydrodaidzein, and O-desmethylangolensin) were identified by comparison with authentic standards. Seventeen conjugates of isoflavones were characterized in the urine, the most unusual being genistein 5-glucuronide and four glucuronide conjugates of reductive metabolites of daidzein. The application of LC/MS/MS to analyze isoflavone metabolites is simple and sensitive, and appears to be an excellent method for determining the bioavailability and metabolism of food phytochemistry.  相似文献   

14.
The isoflavone compositions and concentrations in the leaf, flower, petiole, and stem of 13 red clover cultivars were studied using high-performance liquid chromatography coupled with a diode array and a mass spectrometric detector with negative electrospray ionization. Different cultivars showed significantly different concentrations of individual and total isoflavones. The leaf contained the highest overall concentration, followed by the stem, petiole, and flower. Biochanin A and formononetin were the predominant isoflavones in all cultivars and all parts, along with eight other minor aglycones, daidzein, genistein, glycitein, irilone, orobol, pratensein, pseudobaptigenin, and prunetin, and four minor malonylglycosides, genistein-7-glucoside-6' '-malonate, orobol-7-glucoside-6' '-malonate, formononetin-7-glucoside-6' '-malonate, and biochanin A-7-glucoside-6' '-malonate. The isoflavone compositions and concentrations were also found to be different between red clover parts harvested at the early bud stage and the late flowering stage. Sample storage and handling prior to analysis were also found to be important. Samples in this study were kept at -5 degrees C for a few days before being freeze-dried and were found to contain mainly the aglycones of isoflavones. This may actually be an advantage in that "natural" and more bioactive isoflavones can be obtained without using chemical hydrolysis. Findings in this study therefore provide important information for developing isoflavone-rich red clovers and for optimizing harvest timing and choosing the right part of the red clover plant.  相似文献   

15.
Genistein is the principal soy isoflavone to which the putative beneficial effects of soy consumption have been attributed; however, the possibility of adverse biological effects (e.g., estrogenic, antithyroid) has also been raised. This paper describes development and validation of a simple and sensitive analytical method for the determination of genistein in the blood of rats receiving dietary genistein (<0.5-1250 microg of genistein aglycone/g of chow). The method uses serum/plasma deproteination, liquid-liquid extraction, deuterated genistein and daidzein internal standards, isocratic LC separation, and electrospray mass spectrometric quantification using selected ion monitoring. Extraction efficiency is approximately 85%, the detection limits for genistein and daidzein from 50 microL of rat blood are approximately 5 nM, and the limit of quantification is approximately 15 nM. Interassay precision (relative standard deviation 4.5-4.6%) and intraassay precision (3.3-6.7%) were determined from replicate analysis of a spiked control and an incurred serum sample. The distribution of conjugated and unconjugated forms of genistein in the blood of rats was determined using selective enzyme hydrolysis. The glucuronide was the predominant metabolite (>90%), and only small amounts of the sulfate conjugate and the aglycone were observed at all dose levels. No evidence for additional metabolites was obtained. The 7- and 4'-glucuronide conjugates of genistein were identified using electrospray mass spectrometry and (1)H NMR. Total blood genistein ranged from <15 nM in animals fed soy-free control diet to as high as 8.9 microM in male rats fed 1250 microg of genistein/g of chow and encompasses blood isoflavone levels observed in humans consuming a typical Asian diet and nutritional supplements (0.1-1 microM) and infants consuming soy formulas (2-7 microM).  相似文献   

16.
The soy isoflavones daidzin, glycitin, and genistin were purified from defatted soy flour using preparative-scale reverse-phase HPLC. The stabilities of the three isoflavones at different heating temperatures were investigated. Daidzin, glycitin, and genistin were lost at a rate of 26, 27, and 27% of their original concentration, respectively, after 3 min at 185 degrees C. At 215 degrees C, decreases of daidzin, glycitin, and genistin were 65, 98, and 74% after 3 min and 91, 99, and 94% after 15 min, respectively. The order of the thermal stabilities, from lowest to highest, was glycitin, genistin, and daidzin. Acetyl daidzin and acetyl genistin, daidzein, glycitein, and genistein were produced during heating at temperatures above 135 degrees C. The rate of binding of an acetyl group to form acetyl daidzin and acetyl genistin from daidzin and genistin was higher than the rate of loss of a glucoside group to form daidzein and genistein. However, acetyl daidzin and acetyl genistin decreased sharply at temperatures above 200 degrees C, while daidzein, glycitein, and genistein were relatively stable over 30 min. The stability of daidzein was higher than that of glycitein or genistein.  相似文献   

17.
The reliability of databases on the isoflavone composition of foods designed to estimate dietary intakes is contingent on the assumption that soy foods are consistent in their isoflavone content. To validate this, total and individual isoflavone compositions were determined by HPLC for two different soy protein isolates used in the commercial manufacture of soy foods over a 3-year period (n = 30/isolate) and 85 samples of 40 different brands of soy milks. Total isoflavone concentrations differed markedly between the soy protein isolates, varying by 200-300% over 3 years, whereas the protein content varied by only 3%. Total isoflavone content varied by up to 5-fold among different commercial soy milks and was not consistent between repeat purchases. Whole soybean milks had significantly higher isoflavone levels than those made from soy protein isolates (mean +/- SD, 63.6 +/- 21.9 mg/L, n = 43, vs 30.2 +/- 5.8 mg/L, n = 38, respectively, p < 0.0001), although some isolated soy protein-based milks were similar in content to "whole bean" varieties. The ratio of genistein to daidzein isoflavone forms was higher in isolated soy protein-based versus "whole bean" soy milks (2.72 +/- 0.24 vs 1.62 +/- 0.47, respectively, p < 0.0001), and the greatest variability in isoflavone content was observed among brands of whole bean soy milks. These studies illustrate large variability in the isoflavone content of isolated soy proteins used in food manufacture and in commercial soy milks and reinforce the need to accurately determine the isoflavone content of foods used in dietary intervention studies while exposing the limitations of food databases for estimating daily isoflavone intakes.  相似文献   

18.
Estrogenic activity of glycitein, a soy isoflavone   总被引：35，自引：0，他引：35  
Glycitein (4',7-dihydroxy-6-methoxyisoflavone) accounts for 5-10% of the total isoflavones in soy food products. The biological activity of this compound has not been reported to date, although numerous studies have been performed with the other soy isoflavones, daidzein and genistein. Glycitein was isolated from soy germ to 99% purity. Weaning female B6D2F1 mice were dosed with glycitein (3 mg/day), genistein (3 mg/day), and diethylstilbestrol (DES) (0.03 microg/day) in 5% Tween 80 by gavage for 4 days. A control group received an equal volume of 5% Tween 80 solution daily. The uterine weight increased 150% with glycitein (p < 0.001), 50% with genistein (p < 0. 001), and 60% with DES (p < 0.001) compared with the control group. DES, 17beta-estradiol, and three isoflavones (daidzein, genistein, and glycitein) were examined for their competitive binding abilities with 17beta-((3)H)estradiol to the estrogen receptor proteins of the B6D2F1 mouse uterine cytosol. The concentrations of each compound required to displace 50% of the ((3)H)estradiol at 5 nM in the competitive binding assay were 1.15 nM DES, 1.09 nM 17beta-estradiol, 0.22 microM genistein, 4.00 microM daidzein, and 3.94 microM glycitein. These data indicated that glycitein has weak estrogenic activity, comparable to that of the other soy isoflavones but much lower than that of DES and 17beta-estradiol.  相似文献   

19.
Mice (4-week-old, male ddy) were fed four isonitrogenic diets for 21 days: purified diet (C diet); fermented soybean (400 mg of soy isoflavonoids/kg; FSB); fermented soybean extract (400 mg of soy isoflavonoid aglycones/kg; FSBE); C with indole-3 carbinol (I3C) (2500 mg of I3C/kg; I3C). The I3C and FSB diets significantly increased the cytochrome P-450 content of hepatic microsomes in comparison with the C diet, while the FSBE diet did not. Other mice were fed seven diets for 21 days: C; C with 100 mg or 200 mg of genistein, 100 mg or 200 mg of daidzein, or 100 mg of genistein + 100 mg of daidzein/kg; I3C diet. Genistein and daidzein did not change the liver cytochrome P-450 content. There was no synergistic effect of the combined feeding of genistein and daidzein. The increase in the cytochrome P-450 content with the FSB diet depends on chemicals other than genistein and daidzein. Genistein and daidzein do not induce cytochrome P-450.  相似文献   

20.
The present studies were conducted to determine changes in the quantities of select isoflavones and in the bioactivity (ability to inhibit proliferation of human breast cancer cell lines) of extracts from blends of soy protein and cornmeal during extrusion processing. The extrusion of samples resulted in an average 24% decrease in the concentration of total isoflavones for all samples. Although the amounts of specific genistein-derived and daidzein-derived forms changed following extrusion, the content of the aglycones genistein and daidzein per g sample generally did not change. The extrusion of samples generally resulted in decreased antiproliferative action toward breast cancer cells, although antiproliferative activity was not eliminated. Therefore, extrusion of soy protein/cornmeal-containing foods are likely to retain a considerable portion of their isoflavone content and some of the health benefits associated with soy.  相似文献   

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