RESEARCH ON ULTRASONIC EXTRACTION CONDITIONS OF SOME ANTIOXIDANT ACTIVITY COMPOUNDS FROM LOTUS LEAVES (Nelumbo nucifera) IN NGHE AN PROVINCE

Abstract

The study used response surface methodology to determine the optimal extraction conditions for total phenolic content, total flavonoid and antioxydant activity (DPPH) from lotus leaves (Nelumbo nucifera) with the support of ultrasound waves. The experiment was arranged according to Box-Benhken design, and a model was built to optimize the extraction process of the above objective functions with three factors: extraction temperature (X₁), extraction time (X₂) and ethanol concentration (X₃). The optimal conditions for the technological parameters of the extraction process were determined at an extraction temperature of 71^oC, an extraction time of 50 minutes and a solvent concentration of 44%. The results were as follows: total phenolic content was 45.12 ± 0.15 mg GAE/g, total flavonoid content was 14.04 ± 0.11 mg CE/g and antioxidant activity was 79.15 ± 0.22%.