β -Glucosidase activity and bioconversion of isoflavones during fermentation of soymilk

Abstract

Lactobacillus rhamnosus C6 culture can be used for the development of functional fermented soy-based products.

α-galactosidase and β-glucosidase Enzyme Activity of Lactic Strains Isolated from Traditional Fermented Foods of West Garo Hills, Meghalaya, India

“…Previously, Hati et al, (2014) reportedGlucosidase activity of six Lactobacillus cultures that exhibited different levels ofGlucosidase activity during their growth under optimal conditions and Lactobacillus rhamnosus C6 showed the highest activity (1.66 U mL−1) among the others. Matsuda et al, (1994) reported L. rhamnosus can be used to increase isoflavone concentrations in fermented soy foods as it possessesGlucosidase activity.…”

“…To prepare soymilk, 100 g of soybeans were soaked for 14-16 h in 1 L of distilled water at room temperature (28 0 C) in a 2 L beaker as stated by Hati et al, (2014). The soak water was drained from the soybeans, which were then blanched at 98 0 C in boiling distilled water for 15-20 min.…”

“…The enzyme assay is based on the principle that when β-glucosidase enzyme acts on the substrate pNPG, it releases pnitrophenol in the medium changing its colour to yellow. One unit of the enzyme activity is defined as the quantity of β-glucosidase action that released one nanomole of pnitrophenol from pNPG per milliliter per min at 37 0 C under the assay conditions (Hati et al, 2014).…”

Changes in phytoestrogen contents and antioxidant activities during fermentation of soybean-powder milks prepared from different soybean cultivars by Lactobacillus plantarum P1201

“…activity of L. plantarum P1201 during fermentation of SPM was determined by measuring the rate of hydrolysis of p-nitrophenyl β-D-glucopyranoside (pNPG) (Sigma Chemical Company) according to the method previously described by Hati et al (2015) with some modifications. At first, the culture was activated at 5% (v/v) in the MRS media at 35°C for 24 h, thereafter was adapted by two successive transfers at 5% (v/v) into SPM and incubated at 35°C for 24 h. Finally, the culture was inoculated at 5% (v/v) into 100 ml of SPM and incubated at 35°C for 60 h. Then 500 μl of 5 mM pNPG (prepared in 100 mM sodium phosphate buffer, pH 7) was added to 5 ml aliquots of each sample and incubated at 35°C for 30 min.…”

“…It was reported that the isoflavone evels in soybean-containing foods, such as fermented soymilk decreased depending on the processing conditions (Hati et al, 2015). Pham and Shah (2007) reported that the total isoflavoneglycoside content in soymilk supplemented with skim powder decreased by approximately 27% from an initial 148.81 mg/100 g to 40.44 mg/100 g after 24 h of fermentation by Bifidobacterium animalis.…”