Enhanced recovery of bioactive compounds from Trigonella-foenum graecum seeds by ultrasonic-assisted extraction

Abstract

In this study, bioactive rich extracts were obtained from Trigonella-foenum graecum (fenugreek) seeds that are considered to have a rich content of bioactive materials using the ultrasonic-assisted extraction (UAE) method and the recovery of bioactive materials was enhanced by UAE when compared with classical maceration technique (CE). The process conditions ensuring the highest total phenolic (TPC), total flavonoid (TFL) and total saponin (TSC) compounds and antioxidant activity (AA) for both UAE and CE were determined by response surface methodology. Firstly, for CE, the effect of distilled water and ethanol concentration and sample:solvent ratio on AA was investigated. After determination of the optimum solvent mixture ratio in CE (60.938% distilled water, 39.062% ethanol), it was kept constant and effects of the sample:solvent ratio, ultrasonic amplitude and extraction time on the recovery of bioactive materials were investigated for UAE process. UAE enhanced the recovery of TPC, TFL, TSC and AA as 28, 25, 26 and 21%, respectively when compared with CE. This enhancement by UAE was ensured at the half of the extraction time of CE. The optimum process conditions for UAE providing the highest AA values as follows: 13.26 g/L sample:solvent ratio, 54.72% ultrasonic amplitude and 59.71 minutes of extraction time.