Potential application of pulsed electric fields for improving extraction of plant pigments

Abstract

Regarding the potential of pulsed electric field (PEF) to extract pigments from plant tissue, research interest has over the last decade steadily grown with novel findings. PEF has repeatedly been referred to as a novel nonthermal tissue disintegration method that can offer less detrimental changes to tissue and to the extraction of heat-labile pigments. Moreover, it was believed that PEFs can improve the pigment extraction processes and color attributes of some plantbased products. Despite the early evidence, the research on PEF-assisted extraction of plant pigments is still at the development stage and requires better understanding in particular of the effects of different pigments, changes at the cellular level, and favorable extraction strategies. So far, the extractability of the red beetroot betanin through PEF has been most widely studied using aqueous solid-liquid extraction systems. Secondarily, the extraction of anthocyanins from various tissues was proved to be enhanced by the PEF treatment, while less research was carried out on the extraction of oil-soluble pigments, chlorophyll, and carotenoids. This work was conducted mainly to give readers an introductory and fundamental knowledge on plant pigment extraction assisted by PEF in light of recent developments. The first part of the work focuses on the role of PEF treatment in line with general extraction principles. In the final part, specific examples of extracting major plant pigments, namely chlorophylls, carotenoids, betalains, and anthocyanins, from selected research works were introduced; thereby, the approaches, methodologies, and major findings were summarized.