Response surface methodology for microwave-assisted extraction of pectin from cocoa pod husk (Theobroma cacao) mediated by oxalic acid

Abstract

Rather than disposed of as waste, cocoa pod husk has a potential to be the source of natural pectin. An efficient extraction process can provide a sufficient amount of pectin. This study aims to analyze the performance of microwave-assisted extraction to separate pectin from cocoa pod husk mediated by cheaper and milder acidifying agent, oxalic acid. Response surface methodology was performed to investigate the effect of pH, ratio of liquid to solid, and irradiation time on the quantity of pectin extracted. Our model showed that reducing ratio of liquid to solid did not dramatically affect extraction yield. Higher oxalic acid concentration, i.e. lower pH, and prolonged irradiation time increased yield, yet decreased degree of esterification which influences the gelling ability of pectin. This technique also significantly shortened the extraction time compared to conventional method. Our finding complements the application of microwave-assisted extraction as a modern separation technique.