Estimating pressure induced changes in vegetable tissue using in situ electrical conductivity measurement and instrumental analysis

Pressure-induced textural changes in selected vegetables (carrot, potato, and red radish) were investigated using in situ electrical conductivity measurement. Electrical conductivity of the vegetables was recorded in situ up to 10 min under elevated pressures (200, 400, 600 MPa at 25 °C) using a custom-fabricated experimental setup. The tissue disintegration index (Z) was determined for raw, processed and freeze-thawed samples. The hardness and stiffness of the samples were evaluated using the instrumental texture analyzer. This information was related to the crunchiness index (CI). Pressure treatment increased electrical conductivity values of all the samples as a function of pressure and holding time. Beyond a certain threshold of pressure holding time, the electrical conductivity did not change further. In situ electrical conductivity measurement is a useful tool to document the extent of textural changes during high pressure processing.