Isoflavonas en mujeres menopáusicas

Deglycosylation of isoflavones in isoflavone-rich soy germ flour by Aspergillus oryzae KACC 40247

Aspergillus oryzae KACC 40247 was selected as an efficient daidzein-producing fungus from strains of the genus Aspergillus by using 5% (w/v) soy germ flour (SGF) as an isoflavone-glycoside-rich medium. The culture conditions, including SGF concentration, agitation speed, initial pH, temperature, and time, were optimized as follows: 7% (w/v) SGF, initial pH 6.0, 33 °C, 300 rpm, and 24 h in a 100 mL baffled flask. The determined amount of isoflavone aglycons in SGF using 50% ethyl acetate was the highest among the solvent systems tested and it was 3.7-fold higher than that using 70% methanol. Under the optimized conditions, the content and concentration of daidzein were 134 mg/g of SGF and 9.4 g/L, respectively, with a productivity of 391 ± 2.8 mg/L/h, and those of isoflavone aglycons were 165 mg/g of SGF and 11.5 g/L, respectively, with a productivity of 479 mg/L/h. Optimization of culture conditions increased the content, concentration, and productivity of isoflavone aglycons by 3.1-, 3.0-, and 3.7-fold, respectively. To our knowledge, this is the highest production of isoflavone aglycons reported to date.

Apparent bioavailability of isoflavones in urinary excretions of postmenopausal Malay women consuming tempeh compared with milk

Quantitation of isoflavones in humans is important to establish the benefits of these compounds to the populations. Urinary isoflavones are frequently used as a biomarker of isoflavone bioavailability from food or supplement since urine contains 100-fold higher concentrations of isoflavones. The objective of the present study was to determine and compare the urinary excretions of daidzein (DA), genistein (GE) and equol (EQ) in postmenopausal Malay women following the consumption of tempeh and milk in a calcium absorption study and to test the hypothesis that the excretion of isoflavones following consumption of tempeh maybe higher compared with milk. The amounts of DA (47.06 ± 4.18 μmol/h), GE (33.27 ± 3.71 μmol/h) and EQ (24.35 ± 4.34 μmol/h) excreted in urine following tempeh consumption were significantly higher (P < 0.05) compared with those in milk (3.51 ± 0.62 μmol/h DA, 2.79 ± 0.35 μmol/h GE and 0 μmol/h EQ). Almost all studied postmenopausal Malay women were able to excrete EQ following consumption of 240 g tempeh but only one subject can be classified as an equol producer. We concluded that most postmenopausal Malay women excreted DA, GE and EQ in their urine following tempeh consumption and the amount of the excreted isoflavones were higher compared with those in milk. However, further studies are needed to determine whether longer periods of time are required to capture EQ producers.