Towards optimisation of the use of 1.02-MHz ultrasound to harvest vacuole-located secondary product from in vitro grown plant cells

The effect of 1.02-MHz continuous wave ultrasound on the kinetics of pigment release from in vitro grown red beetroot cells has been studied in relation to the dissolved gas content and free-radical status of the aqueous-based media used to support cells during sonication. Data presented here show that pigment release from sonicated cells was mediated by cavitational events generated within the support medium alone, and that cavitation-induced free-radicals were intimately associated with the process of product release. These findings are discussed with reference to the optimisation of the use of ultrasound to harvest intracellularly located solute from cultured plant cells, on a non-destructive basis.