Study on enzymatic browning in suspension cultures of licorice cells

Abstract

Enzymatic browning is one of the main obstacles encountered in the establishment of suspension systems of licorice cells. Browning of cells may result in decreased viability, poor growth and even death. The present study investigated the mechanism of browning reactions and the effective controlling methods. The results showed that the cell viability and membrane permeabilization obviously changed when the cells were transferred to liquid medium. The transformation caused rapid increase in the levels of polyphenol oxidase activity and in the production of polyphenols. Osmotic and hydrodynamic stresses arising from liquid culture were regarded as the major causes of enzymatic browning. Ascorbic acid and L-cysteine were found to be the most significant antibrowning agents that could decrease the degree of browning with 55.8% and 52.2%, respectively, at the end of the suspension culture’s lag phase. When cultured with a cycle of 21 days, the maximum biomass of the cells cultured with ascorbic acid and L-cysteine increased with 31.1% and 26.5%, respectively, when compared to the control. These findings may be essential for the development of licorice cell cultures devoted to browning prevention and cell viability maintaining.