Current status of microwave-assisted extraction of pectin

Abstract

There is an urgent need to develop new pectin extraction processes, as the established commercial extraction process damages the pectin (limiting the potential product applications) and is harmful to the environment. Microwave-Assisted Extraction could offer a sustainable route to pectin extraction from a wide range of food wastes and agricultural residues. We present the current state of the art in Microwave-Assisted Extraction of pectin, including the current understanding of the unique heat and mass transfer mechanisms at play during extraction. We review all of the recent literature, testing the commonly held view that microwave heating offers a general improvement in yield and dramatic reductions in processing time compared with conventional solvent extraction. In most of the literature reviewed, there was no evidence that this is the case. However, there is emerging evidence that Microwave-Assisted Extraction can provide processing advantages under some conditions, and that the feedstock dielectric properties and heating rate are important parameters. Preliminary attempts to scale this technology up have shown promise in terms of pectin yield, quality and Life Cycle Analysis compared with conventional extraction. The next steps should be to test more continuous processing concepts for a wider range of feedstocks, and develop more robust Life Cycle Analysis and technoeconomic models. This is the first review paper to focus on the Microwave-Assisted Extraction of pectin.