Changes in water potential, osmotic potential, and tissue electrolyte leakage during mass loss in carrots stored under different conditions

Abstract

Mass loss, water potential (ψ), osmotic potential (ψπ) and tissue permeability of carrots (Daucus carota L. cv. Eagle) stored for 30 days at 2 °C and 80% relative humidity (RH) (optimal shelf condition (OSC)), 13 °C and 79% RH (common shelf condition (CSC)), or 13 °C and 31% RH (poor shelf condition (PSC)) were monitored. Carrots at PSC lost the most mass followed by those at CSC and OSC. Total water potential (ψ) and osmotic potential (ψπ) of the carrots at CSC and PSC did not change significantly for up to 6 days, but decreased thereafter. No statistically significant change in ψ and ψπ occurred in carrots at OSC. Relative electrolyte leakage (REL) rapidly increased after 12 days at PSC and after 18 days at CSC, at which point mass loss had exceeded 8% of original weight, considered to be a threshold for quality loss. REL of carrots stored at OSC increased only slightly and the mass loss in these carrots did not exceed 8%. Regression analysis showed that mass loss in carrots was consistently associated with REL; changes in ψ and ψπ were associated with mass loss only when carrots were kept at 13 °C. Thus, REL could be a good indicator of mass loss of carrots under a wide range of shelf conditions. The sharp rise in REL at CSC and PSC occurred when the mass loss exceeded 8%.