Spray drying of the soybean extract: Effects on chemical properties and antioxidant activity

Recent findings that many human chronic diseases are associated with oxidative stresses have instigated the search for dietary antioxidants. Isoflavones, a special phenolic group found in soybean, have been found to act as antioxidant in some model systems. The aim of this work was the evaluation the effects of spray drying on the chemical and biological properties of soybean extract. The total polyphenol contents in the concentrated soybean extract (CSE) and spray dried soybean extract (SDSE) were determined by Folin-Ciocalteau method and HPLC was utilized for the quantification of the genistein, active compound used as a chemical marker. The evaluation of antioxidant activity of CSE and SDSE was assessed by the hydrogen-donor ability to 2,2-diphenyl-1-picrylhydrazyl radical (DPPH center dot). The results indicated that the inlet gas temperature showed significant effect on the total polyphenol, protein and genistein contents of the dried extracts. The SDSE obtained this work showed high antioxidant activity, opening perspectives for its use as food additive and/or ingredient. (C) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.