Soy Research Today is a free monthly online journal that collates and summarizes the latest research about Soy, including details on soy milk, soy protein, soya bean, benefits, dangers.

Determination of phytoestrogens in dietary supplements by LC-MS/MS.

Clarke DB, Bailey V, Lloyd AS

Department for Environment, Food and Rural Affairs, Central Science Laboratory, Sand Hutton, York, UK.

Labelling data quantifying the exact content of individual phytoestrogen analytes in dietary supplements are generally poor. As these products are commonly used in the management of menopause symptoms, any clinical benefits would be dependent on the exact dosage of isoflavones received. Well-established extraction procedures and updated isotope dilution mass spectrometry liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS) have been used to accurately quantify the concentrations of ten common isoflavones in 35 dietary supplement samples on sale in the UK, Canada and Italy. Concentration-specific ionization suppression is described for biochanin A and formononetin. All supplements contained phytoestrogens. The soya isoflavones (genistein, daidzein, glycitein) were present in all products and the majority also contained the red clover isoflavones (biochanin A, formononetin) and some the Kudzu isoflavones (daidzein, puerarin). The content of total isoflavones per dose ranged from <1 to 53 mg. Trace amounts of coumestrol were found in six products. Other less common analytes, the prenylnaringenins (6-prenylnaringenin, 8-prenylnaringenin, 6,8-diprenylnaringenin) were not found in any of the products. Only 14 of 35 supplements were found to deliver more than or equal to 40 mg day(-1) of aglycone isoflavones, a consensus dose value recognized as delivering therapeutic benefit. Eleven did not match label claims. Six delivered less than 10 mg day (-1) of isoflavones. There has been little improvement in the overall quality of industry labelling in the five years since this was last investigated. Consequently, the public, retailers and healthcare professionals should consider using standardized isoflavone supplements, which are supported by analytical measurements.

Published 14 May 2008 in Food Addit Contam, 25(5): 534-47.
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Articles on Soy published 8 May 2008:

Preparative procedures markedly influence the appearance and structural integrity of protein storage vacuoles in soybean seeds.   J Agric Food Chem, 56(9): 2907-12.

In legumes, vacuoles serve as the final depository for storage proteins. The protein storage vacuoles (PSVs) of soybean contain electron-transparent globoid regions in which phytic acid ( myo-inositol-1,2,3,4,5,6-hexakisphosphate) is sequestered. This paper reports the effect of preparative procedures on the appearance and ultrastructural integrity of PSVs in soybeans. Electron microscopy examination of both developing and mature soybean seeds that were postfixed with osmium tetroxide revealed ... [Abstract] [Full-text]

Articles on Soy published 5 May 2008:

Occurrence and fate of pesticides in four contrasting agricultural settings in the United States.   J Environ Qual, 37(3): 1116-32.

Occurrence and fate of 45 pesticides and 40 pesticide degradates were investigated in four contrasting agricultural settings-in Maryland, Nebraska, California, and Washington. Primary crops included corn at all sites, soybeans in Maryland, orchards in California and Washington, and vineyards in Washington. Pesticides and pesticide degradates detected in water samples from all four areas were predominantly from two classes of herbicides-triazines and chloroacetanilides; insecticides and ... [Abstract] [Full-text]

Nitrogen Fluxes through Unsaturated Zones in Five Agricultural Settings across the United States.   J Environ Qual, 37(3): 1073-85.

The main physical and chemical controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Indiana, Maryland, Nebraska, and Washington from 2004 to 2005. Sites included irrigated and nonirrigated fields; soil textures ranging from clay to sand; crops including corn, soybeans, almonds, and pasture; and unsaturated zone thicknesses ranging from 1 to 22 m. Chemical analyses of water from lysimeters and shallow wells indicate that ... [Abstract] [Full-text]

Articles on Soy published 29 April 2008:

Effect of gastro-intestinal conditions on the growth of Enterococcus mundtii ST4SA, and production of bacteriocin ST4SA recorded by real-time PCR.   Int J Food Microbiol, 123(3): 277-80.

Enterococcus mundtii ST4SA, isolated from soybeans, produces a 3950 Da bacteriocin (bacST4SA) active against a variety of Gram-positive and Gram-negative bacteria, including human pathogens. In this study, the effect of gastro-intestinal conditions on the survival of strain ST4SA and production of bacST4SA was studied. Strain ST4SA was cultured in MRS broth at different pH and in MRS broth supplemented with bile, pancreatic enzymes, and contents of the stomach and small intestine of pigs, ... [Abstract] [Full-text]

Morphological characteristics of sporangiospores of the tempe fungus Rhizopus oligosporus differentiate it from other taxa of the R. microsporus group.   Mycol Res, 112: 547-63.

The fungus Rhizopus oligosporus (R. microsporus var. oligosporus) is traditionally used to make tempe, a fermented food based on soybeans. Interest in the fungus has steadily increased, as it can also ferment other substrates, produce enzymes, and treat waste material. R. oligosporus belongs to the R. microsporus group consisting of morphologically similar taxa, which are associated with food fermentation, pathogenesis, or unwanted metabolite production (rhizonins and rhizoxins). The ... [Abstract] [Full-text]

Articles on Soy published 28 April 2008:

Whole soybean supplementation and cow age class: Effects on intake, digestion, performance, and reproduction of beef cows.   J Anim Sci.

Two experiments were conducted to determine the effects of whole soybean supplementation on intake, digestion, and performance of beef cows of varying age. Treatments were arranged in a 2 x 3 factorial with 2 supplements and 3 age classes of cows (2-yr-old, 3-yr-old, and mature cows). Supplements (DM basis) included: 1) 1.36 kg/d of whole raw soybeans, and 2) 1.56 kg/d of a soybean meal/hulls supplement. Supplements were formulated to provide similar amounts of protein and energy, but a greater ... [Abstract] [Full-text]

SBTX, a new toxic protein distinct from soyatoxin and other toxic soybean [Glycine max] proteins, and its inhibitory effect on Cercospora sojina growth.   Toxicon, 51(6): 952-63.

SBTX, a novel toxin from soybean, was purified by ammonium sulfate fractionation followed by chromatographic steps DEAE-Cellulose, CM-Sepharose and Superdex 200 HR fast-protein liquid chromatography (FPLC). Lethality of SBTX to mice (LD(50) 5.6mg/kg) was used as parameter in the purification steps. SBTX is a 44-kDa basic glycoprotein composed of two polypeptide chains (27 and 17kDa) linked by a disulfide bond. The N-terminal sequences of the 44 and 27kDa chains were identical ... [Abstract] [Full-text]

Articles on Soy published 22 April 2008:

The gap between food-based dietary guidelines and usual food consumption in Belgium, 2004.   Public Health Nutr.

OBJECTIVE: To evaluate the gap between food-based dietary guidelines (FBDG) and the usual food consumption in Belgium.Design and settingInformation on food intake was collected with two non-consecutive 24 h recalls, using the validated software package EPIC-SOFT in combination with a self-administered FFQ. Habitual food intake was estimated by the Nusser method. Physical activity was evaluated according to the International Physical Activity Questionnaire. SUBJECTS: A representative sample of ... [Abstract] [Full-text]

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