Pressure Changes in Oxygen-exchanged, Brined Cucumbers1

Abstract

Abstract A method was developed for determining internal gas pressure changes of pickling cucumbers (Cucumis sativus L.) during brine storage. Internal pressure decreased by 55 mm Hg during the first hour after the control fruit had been submerged in brine and then gradually increased over the next 2 hours to about the level of atmospheric pressure that had existed immediately after brining. With cucumbers that were gas-exchanged before brining, the pressure decreased by a maximum of 145 mm Hg when O2 was the exchange gas, and increased slightly when N2 was the exchange gas. Pressure changes in O2-exchanged cucumbers corresponded with changes in the level of brine that surrounded the fruit, suggesting that liquid entered the fruit as a consequence of the partial vacuum. O2-exchanged, brined cucumbers acquired a translucent, cured appearance, due apparently to filling of the intercellular gas spaces with liquid. Mechanically induced vacuum failed to induce the cured appearance. Respiratory conversion of O2 to CO2 in control and in O2-exchanged fruit, with greater dissolution of the CO2 than the O2 which it replaced, is thought to account for the partial vacuum that develops in brined cucumbers.