Extraction and characterization of low molecular weight bioactive carbohydrates from mung bean (Vigna radiata)

Due to the great interest in obtaining natural bioactive carbohydrates to be used as functional ingredients, a selective microwave assisted extraction (MAE) method was optimized to ensure the exhaustive extraction of inositols and α-galactooligosaccharides (α-GOS) from mung bean. Thereafter, a comprehensive characterization of these compounds was carried out by gas chromatography coupled to mass spectrometry (GC–MS). Apart from free inositols and α-GOS, several glycosyl-methyl-scyllo-inositols and glycosyl-inositols were detected for the first time in this legume. Under optimized MAE conditions (0.5 g dry sample, 2 cycles of 3 min, 50 °C, 10 mL 50:50 ethanol:water, v:v), bioactive carbohydrates yields were similar to those found using solid–liquid extraction (SLE), but with shorter analytical times. Concentrations of bioactive carbohydrates in MAE extracts from samples of different geographical origins ranged between 74.1 and 104.2 mg.g dry sample. MAE was proved a good alternative to SLE to obtain extracts enriched in bioactive carbohydrates.This work has been funded by Fundación Ramón Areces (project CIVP17A2843) and by Ministerio de Economía, Industria y Competitividad (MINECO) of Spain (project AGL2016-80475-R). Authors also thank financial support from the Comunidad Autónoma of Madrid and European funding from FEDER program (project S2013/ ABI-3028, AVANSECAL). C.C.C. thanks MINECO for a predoctoral contract and D.M. thanks CSIC, Fondo Social Europeo and Iniciativa de Empelo Juvenil for a contract.Peer Reviewe