Optimization of Total Phenolics and Flavonoids from Ginger Using Response Surface Methodology

Abstract

This research aimed to study optimal conditions for solvent extraction of total phenolics, flavonoids and antioxidant activities from ginger (Zingiber officinale). Response surface methodology, Box Behnken design was applied for the experimental design to investigate the optimal conditions. Ranges of operating conditions including chosen as follow: 40-80 %v/v aqueous ethanol concentrations, 30-60°C extraction temperature and 3-6 hours extraction time were chosen. The results from ginger extractions were a) the optimal conditions for extraction of phenolics was 77 %v/v aqueous ethanol concentrations, 60°C extraction temperature and 4.2 hours extraction time, b) the extraction of flavoniods was 80 %v/v aqueous ethanol concentrations, 40°C extraction temperature and 3 hours extraction time and C) the antioxidant activity was 74 %v/v aqueous ethanol concentrations, 49°C extraction temperature and 6 hours extraction time. The maximum contents of the total phenolics, flavoniods and antioxidant activity obtained the optimal conditions were 2.23 % (r2 = 0.93), 2.19 % (r2 = 0.99), and 62.52% (r2 = 0.91), respectively. According to the response surface, the ethanol concentration was a significant factor for the total phenolics extraction. However, for flavonoids and antioxidant activities, the ethanol concentration and temperature were the significant factors.