Ultrasound-Assisted Extraction of Starch From Oil Palm Trunk: An Optimization by Response Surface Methodology

Abstract

Higher production of palm oil in Malaysia has resulted in a significant amount of oil palm biomass including oil palm trunk (OPT). OPT has been studied as an alternative starch source. To date, reports on the extraction of starch from OPT using ultrasound-assisted extraction (UAE) are limited. The application of UAE is considered to be a simpler and effective way in starch extraction compared to conventional extraction methods. This study aims to investigate the potential of ultrasound-assisted extraction to extract starch from OPT, and optimization using response surface methodology. A three-factor central composite design (CCD) was designed to determine the effects of variables on response. The three variables involved in the study, namely: sonication temperature (45-65°C), sonication time (30-60 min) and sodium metabisulfite concentration (0.5-1.5% w/v). All of the data were analysed using Analysis of Variance (ANOVA). The R2 value (95.6%) and model (p <0.0001), indicating the acceptability of the model and significance in the interaction between independent variables. At the optimum conditions of 52.84°C temperature, 30.66 min exposure time and 0.58% w/v sodium metabisulfite concentration, the starch yield achieved its optimum value by 34.21%. Therefore, this study proved the potential of UAE in extracting higher OPT starch.