Effect of thermosonication on texture degradation of carrot tissue in relation to alterations in cell membrane and cell wall structure

Thermosonication as an alternative to hot water blanching of carrots, the effect of thermosonication on the carrot texture and cell structure required deep investigation. This study was conducted from the aspects of cell membrane, cell water, and cell wall pectin. Results showed that thermosonication at 60 °C significantly increased carrot tissue hardness by up to 10.3% compared with fresh. Rheological curves showed that the carrot tissues remained rigid after thermosonication. Cell membrane permeability was damaged to different extents during processing, inducing bound and immobilized water to migrate to free water and bring intracellular electrolytes to outflow. Thermosonication affected cell structure by altering the characteristics of pectin, including uronic acids and neutral sugar contents, degree of linearity and branching, and degree of methoxylation. The modified pectin can seize more divalent cations such as Ca2+ retained in the thermosonicated carrot cell wall, conducive to preserving the textural property of processed fruits and vegetables.