Softening Effects of Monovalent Cations in Acidified Cucumber Mesocarp Tissue

Due to the importance of salt as an ingredient in cucumber pickle products, the effect of salt concentration on first-order softening rates during acid storage was determined. Softening rates of unfermented tissue increased as the NaCl increased from 0 to 1.5M, whether or not the tissue was blanched. For unheated, fermented tissue, softening rates increased between 0 and 0.2M NaCl but did not increase above 0.2M NaCl. Changes in the degree of pectin methylation were not highly correlated with changes in softening rates. The ions Li⁺, K⁺, Rb⁺, and Cs⁺ had softening effects similar to Na⁺. An enthalpy of activation of 145 kJ/mole was determined for softening of blanched tissue stored in 1.5M NaCl. This is the first demonstration of a softening effect by monovalent cations in cucumber tissue.