, 2012c). It is clearly shown in Table 4 that the contents of daidzein, genistein and glycitein increased after

2 h of hydrolysis for both experiments. Additionally, it has to be considered that there are other types of isoflavone glucosides in the soy molasses, which can also be converted to other forms at different proportions. http://www.selleckchem.com/products/obeticholic-acid.html The immobilised β-glucosidase presented minimal difference in conversion efficiency of isoflavones compared to the free enzyme, but this result may be explained by the lower enzyme accessibility to the substrate caused by the immobilisation process. This lower isoflavone hydrolysis efficiency exhibited by the immobilised enzyme can be compensated by reuse of the beads. The operational stability of immobilised cells containing β-glucosidase was evaluated at 50 °C using pNPβGlc or soy molasses isoflavones as substrates. In the first cycle the activity with pNPβGlc was 0.26 U/g; followed by 0.12 U/g and 0.04 U/g in the second and third cycles, respectively. The reaction product was not detected in the subsequent cycles. In the first cycle of isoflavone glucosides conversion, the rate of aglycones C59 mw present in the total of isoflavones

was 11.3%, 23.7%, 39.1%, 72.7% and 95.3% with 0, 15, 30, 60 and 120 min of hydrolysis, respectively. There was no change in the concentration of aglycones during the second cycle of hydrolysis. These results indicate that the immobilisation system presents low stability at 50 °C. β-Glucosidase from Paecilomyces thermophila was capable of converting nearly all isoflavone glucosides (above 95%) and malonyl glucosides were little hydrolyzed by this enzyme in soybean flour extract ( Yang et al., 2009).

The results of isoflavone glucoside conversion in soy molasses by intracellular Amobarbital β-glucosidase from D. hansenii UFV-1 are interesting because D. hansenii is a nonpathogenic yeast and it is found in various types of food. The use of immobilised yeast cells in calcium alginate by the food industry makes the enzyme more stable; thus the process is more economical and the conversion of isoflavone glycosides to their aglycone forms is possible, which means that the bioavailability of these compounds in soy molasses will be higher. Intracellular β-glucosidase from D. hansenii UFV-1 was produced, purified, characterised and also immobilised in calcium alginate. This enzyme presents promise for industrial applications since it showed great ability to hydrolyze isoflavone glucosides from soy molasses, in both its free and immobilised forms. The results reported indicate that the D. hansenii UFV-1 β-glicosidase may be used for establishment of a process to improve the nutritional value of soy products by hydrolyzing isoflavones in soy molasses to their aglycon forms.