Response Surface Methodology for Optimization of Mucilage Extraction from Dioscorea alata Tuber

Abstract

Dioscorea alata mucilage (DAM) is a water-soluble polysaccharide and is composed of glucomannan. In this research, mucilages from D. alata were extracted using Response surface methodology (RSM) with a Central Composite Design (CCD) followed by distance-based optimality design, with three independent variables applied, i.e., temperature (4 – 60°C), time (0 – 30 h), and centrifugal speed (1.386 – 22.615×g). The maximum DAM yield was 5.89% ± 0.50%, which was obtained with an extraction temperature of 36.2°C for 13.3 h extraction time and centrifugation at 12,322×g. The regression model from RSM – CCD predicted that the maximum DAM yield was 5.47%, with R2 of 99.59% and adjusted R2 of 97.72%, which shows a significant correlation between the experimental and predicted values. The DAM is a complex material that mainly contains polysaccharides, i.e., β-pyranose forms of glucose and mannose, with low protein content. Water and oil holding capacity of the DAM powder were 8.43 g/g and 5.08 g/g, respectively, which considered as the highest compared to other similar studies. Keywords: Dioscorea alata mucilage, Extraction, Optimization, Response surface methodology, Physicochemical properties