Kinetics of daidzin and genistin transformations and water absorption during soybean soaking at different temperatures

Abstract

The kinetics of the isoflavones transformations (diadzin, diadzein, genistin and genistein) and moisture content in soaked soybeans were studied in a temperature range of 30-85ºC. The evolution of the moisture was described by Peleg´s model and a modified first order kinetics equation. This last equation was also used to predict the transformation profiles of different isoflavones in the soaked soybeans. The dependency on temperature of the kinetic parameter was modelled by the Arrhenius equation and empirical equations. The measured β-glucosidase activity at different temperatures justifies the experimental profiles of isoflavones conversion.Headline: Isoflavones transformations during soybean soaking at different temperatures.

The mechanism of hydrothermal hydrolysis for glycyrrhizic acid into glycyrrhetinic acid and glycyrrhetinic acid 3- O -mono-β- d -glucuronide in subcritical water

“…It could be concluded that the GL hydrolysis was considered to be first-order reaction. Similar results were mentioned in previous reports Ruen-ngam et al, 2012;Wardhani et al, 2008) The rate constants (k i ) were affected by the temperature, and the results are shown in Fig. 5(a).…”

“…In this reaction, glucuronic acid was a by-product and water was in excess, therefore, glucuronic acid and water were ignored. According to previous reports (Liu, Gao, Xu, Wang, & Yang, 2008;Ruen-ngam et al, 2012;Wardhani, Vázquez, & Pandiella, 2008), the kinetic analysis of GL hydrolysis might be performed based on a general approach of the first order reaction. The rate equations for the three compounds are expressed below:…”

Optimisation of antioxidants extraction from soybeans fermented by Aspergillus oryzae

“…Soybeans and their products are nutritionally rich foodstuff and they contain various amounts of phytochemicals (isoflavones, saponins, phytic acid, phytosterols, Kunitz and Bowman-Birk trypsin inhibitors, phenolic acids) that show functional, antioxidant and radical-scavenging properties (Da Silva Pinto, Lajolo, & Genovese, 2005;Hayes, Bookwalter, & Bagley, 1977;Hubert, Berger, Nepveu, Paul, & Daydé , 2008;Isanga & Zhang, 2008;Pratt & Birac, 1979;Wardhani, Vázquez, & Pandiella, 2008). In some cases the antioxidant effect could be significantly enhanced through fermentation using aspergilli (Esaki, Onozaki, Kawakishi, & Osawa, 1997;Lin, Wei, & Chou, 2006;Romero, Doval, Sturla, & Judis, 2004).…”

Isoflavone Content and Anti-acetylcholinesterase Activity in Commercial Douchi (a Traditional Chinese Salt-fermented Soybean Food)

“…During soaking, the concentration of daidzin-genistin decreases accordingly to the daidzein-genistein formation 24,32 . It was reported that the malonylated isoflavone glucosides were thermally unstable, and were converted into their corresponding isoflavone glycosides and aglycones at the higher temperature 3,28 .…”