, 1999, Genovese and Lajolo, 2002, Irvine et al., 1998, Knight et al., 1998, Kuo and Ding, 2004, Murphy et al., 1997 and Setchell et al., 1997), the only study investigating the contents of both isoflavones and soyasaponins in soy-based infant formulas was conducted in samples acquired in the US market (Murphy et al., 2008 and Murphy et al., 1997). For soy infant formulas sold in the Brazilian market, only data regarding isoflavones contents are available (Genovese & Lajolo, 2002). Since these studies have shown that soy-based infant formulas are very rich in both classes of bioactive compounds,
some concerns related to their potential INCB024360 concentration biological effects on infants have been raised (Kang et al., 2010 and Murphy et al., 1997). Even though soyasaponins are generally considered to have low bioavailability (Hu, Reddy, Hendrich, & Murphy, 2004), there is a need for a more comprehensive description of isoflavones and soyasaponins composition of infant formulas. Considering the paucity of data on the composition of bioactive compounds in soy-based infant formulas, especially
soyasaponins, the aim of this work was to determine the contents of isoflavones and soyasaponins in soy-based infant formulas available in the Brazilian market to estimate the intake of these bioactive compounds by infants. Daidzin, glicitin, genistin, daidzein, glicitein, genistein, selleck soyasapogenol B, soyasaponin B-I, soyasaponin B-II and soyasaponin B-III standards were purchased from Apin Chemicals Limited® (Abingdon, UK). All solvents were HPLC grade from Tedia (Fairfield, OH, USA). HPLC grade water was used throughout
the experiments Regorafenib mw (Milli-Q system, Millipore, Bedford, MA, USA). For the development and validation of the analytical method for the simultaneous analysis of isoflavones and soyasaponins in soy-based foods, a sample of soy fibre (Yoki®) was acquired in a local supermarket in Rio de Janeiro, Brazil. The seven soy-based infant formula samples available in the Brazilian market were purchased in drugstores located in Rio de Janeiro and São Paulo: AlergoMed (comidaMed, Germany), Nan® Soy (Nestlé Infant Nutrition, USA), Nursoy® (Wyeth Nutrition®, Ireland), Aptamil 1 and Aptamil 2 (Danone Nutrition Baby, Argentina) and Isomil® 1 and Isomil® 2 (Abbott Laboratories, Netherlands). Three lots of each brand were obtained and pooled for further analyses. The protein content of the soy-based infant formulas was determined in duplicate using Kjeldahl method for quantification of total organic nitrogen using the conversion factor of 6.25 (AOAC, 2000). Linearity was evaluated using triplicates of six-points standard calibration curves with concentrations ranging between 0.1 to 5.0 μg/ml and 0.5 to 20.0 μg/ml for isoflavones and soyasaponins, respectively. In-house accuracy was assessed by a single-level recovery experiment.