Soymilk processing with higher isoflavone aglycone content.

The objective of this work was to optimise conversion of β-glucoside isoflavones to aglycones in soymilk processing and to evaluate their thermal stability. The soymilk was assessed for time and temperature effects of incubating supplied to central composite design 2(2). The response functions were investigated for β-glucosidase activity and isoflavone contents. The β-glucosidase activity was reduced through soybean slurry incubation at approximately 64°C and 3.42h. Maximum conversion of β-glucosides into isoflavone aglycones involved soaking the soybeans at 5°C for 14h at a 1:3 ratio (soybean:water, w:v), homogenising them at a 1:8 ratio (soybean soaked:water, w:v) and incubation at 50°C for 2.7h. In evaluation of thermal stability of isoflavones in soymilk at 97°C for 25min, the daidzein and genistein aglycone contents were maintained, the glycitein and β-glucosides contents increased and the malonylglucoside content decreased.

Baú TR ，Ida EI 《-》

The conversion and deglycosylation of isoflavones and anthocyanins in black soymilk process.

The conversion of isoflavones and anthocyanins during black soymilk processing including soaking and heating was investigated. During soaking procedure, the β-glucosidase activity, content of bioactive compounds including daidzein, genistein, delphinidin and cyanidin were significantly increased by deglycosylation reaction. After heating treatment at 90 °C for 1 h, the content of isoflavones β-glucosides including daidzin, glycitin and genistin were increased through a de-esterification reaction from malonyl-glucosides at high temperature. On the contrary, aglycone content including daidzein and genistein were no significant changed, this result indicated aglycones displayed well thermal stability. Moreover, anthocyanins including delphinidin-3-O-glucoside (D3G) and cyanidin-3-O-glucoside (C3G) were converted into delphinidin and cyanidin by glucose removal. HPLC analysis suggested that daidzein, genistein, D3G and C3G were bound with β-conglycinin and glycinin. Our results establish the conversion of bioactive components including daidzein, genistein, delphinidin and cyanidin by deglycosylation during soaking and heating progress and benefit to the production of soymilk.

Hsiao YH ，Hsieh JF 《-》

Evaluation of the isoflavone and total phenolic contents of kefir-fermented soymilk storage and after the in vitro digestive system simulation.

This study aimed to evaluate the isoflavone and total phenolic contents in kefir-fermented soymilk storage and after the in vitro digestive system simulation (DSS). Soymilk was fermented with kefir culture (0.02UC/L) at 25°C for 15h and stored at 4°C for 4days. After the fermentation and storage, the isoflavone and total phenolic contents were quantified by high performance liquid chromatography and spectrophotometry, respectively. The cell viability of lactic acid bacteria and yeast was evaluated. Fermentation promoted an increase of approximately 3log CFU/g cycles of the microorganisms and the storage process did not alter the aglycone isoflavones and total phenolic contents. The content of aglycone isoflavones increased 2-fold, and the total phenolic content increased 9-fold. Therefore, kefir-fermented soymilk is a good source of aglycone isoflavones and phenolics, since the content of these substances was increased significantly after the in vitro digestive system simulation of the product.

da Silva Fernandes M ，Sanches Lima F ，Rodrigues D ，Handa C ，Guelfi M ，Garcia S ，Ida EI ... -  《-》

Transformation of isoflavone phytoestrogens during the fermentation of soymilk with lactic acid bacteria and bifidobacteria.

Chien HL ，Huang HY ，Chou CC 《FOOD MICROBIOLOGY》

Soybean ultrasound pre-treatment prior to soaking affects β-glucosidase activity, isoflavone profile and soaking time.

Ultrasound may convert conjugated isoflavones into their corresponding aglycones, the best form for absorption in the human body. However, ultrasound may also influence the activity of endogenous β-glucosidase. Therefore, the present work evaluated the effects of soybean ultrasound pre-treatment by applying the Box-Behnken design prior to soaking, a step that is important for industries to prepare certain soy products. Furthermore, a multi-response optimisation is provided. The best conditions for soybean ultrasound pre-treatment were established as temperature, X1 = 55 °C; exposure time, X2 = 5 min and ultrasound intensity, X3 = 19.5 W cm-2. Under these conditions, soybeans with higher contents of aglycones were obtained and β-glucosidase activity was kept as high as possible. A second experiment was conducted and confirmed that ultrasound pre-treatment results in a lower soaking time (2 h) to achieve the highest moisture content, lower hardness as well as increased content of aglycones.

Falcão HG ，Handa CL ，Silva MBR ，de Camargo AC ，Shahidi F ，Kurozawa LE ，Ida EI ... -  《-》