Optimization of isoflavones extraction from soybeans using full factorial design

This study focuses on the optimization of isoflavones extraction from soybeans cultivated in Quangnam province, Vietnam, using aqueous ethanol solvent extraction. The total isoflavone concentration was determined with six isoflavone standards including daidzin, glycitin, genistin, daidzein, glycitein, and genistein by Reversed Phase HPLC method. The effects of temperature, extraction time, and ratio of solvent to material on the extracted isoflavone content were investigated for use in the experimental planning method with full element 23 and optimization using the Box‐Wilson model. The results of the optimization showed that the optimal conditions of isoflavones extraction from soybeans using ethanol 80% was in temperature of 72.5°C, extraction time of 67.5 min, and solvent to dry soybean ratio of 26.5/1 (ml/g). The maximum amount of isoflavone content obtained from this extraction condition was 1,932.44 µg/g dry matter. Practical applications The extraction of isoflavones from soybeans involves the interaction between various factors including solvent concentration, temperature, extraction time, and ratio of solvent to material. There is a need to study the combined effect of these factors to optimize the extraction conditions within a minimum number of experiments. Hence, this work applies the full factorial design to study the effects of several factors on one or more responses to achieve the optimum extraction condition. This research work is important to obtain the most efficient extraction conditions for isoflavones production without consuming too much efforts on the experimentation. The results attain from this work can contribute to the extension of efficient isoflavones extraction in industrial scale.