Isolation of individual isoflavone species from soybean by solvent extraction followed by the combination of macroporous resin and aluminium oxide separation

• Published in: Food chemistry Vol. 331; p. 127312
• Main Authors: Hsu, Chen, Wang, Shang-Ta, Wu, Bo-Yuan, Hung, Yu-Ting, Su, Nan-Wei
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 30.11.2020
• Subjects: Aluminium oxide; Aluminum Oxide - chemistry; Extraction; Glycine max - chemistry; Isoflavone; Isoflavones - analysis; Isoflavones - chemistry; Isoflavones - isolation & purification; Isolation; Macroporous resin; Porosity; Resins, Plant; Resins, Synthetic - chemistry; Selective adsorption; Separation; Solvents - chemistry; Soybean; Isoflavone; Aluminium oxide; Separation; Selective adsorption; Soybean; Glycitein, PubChem CID: 5317750; Glycitin, PubChem CID: 187808; Genistin, PubChem CID: 5281377; Daidzein, PubChem CID: 5281708; Isolation; Malonylglycitin, PubChem CID: 23724657; Extraction; Malonylgenistin, PubChem CID: 15934091; Genistein, PubChem CID: 5280961; Malonyldaidzin, PubChem CID: 9913968; Daidzin, PubChem CID: 107971; Macroporous resin
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2020.127312

•The 65% aqueous methanol is the most suitable solvent for isoflavone extraction from soybean.•Isoflavone extract could be separated into glucosides and aglycones by HP20 resins.•Individual isoflavone was further isolated by aluminum oxide chromatography.•Four individual isoflavone products with high purities and an overall remarkable recovery were prepared. Growing interest in the health benefits of soy isoflavones has led to research in the isolation of individual isoflavone species for further application. Herein, we develop a new strategy to isolate daidzein, genistein, daidzin and genistin in soybean. We investigated the impact of solvents used and the extraction time on the extracted isoflavone contents from soybean. A 30-min extraction with 65% aqueous methanol gave a total isoflavone yield of 345 mg/100 g soybean, the highest value among tested conditions. Further, we proposed a two-stage adsorption/desorption chromatography comprising macroporous resin and aluminium oxide to isolate isoflavone. First, HP-20 resin was used to separate the glucosidic and aglyconic forms of isoflavone, then individual species of isoflavone could be isolated using aluminium oxide by specific retention of 5-hydroxy isoflavone. This process achieved overall high recovery (82–97%) and purity (92–95%) of the four isoflavones, which confirms a high separating efficiency for isoflavones from soybean.