Calcium delays senescence-related membrane lipid changes and increases net synthesis of membrane lipid components in shredded carrots
The influence of Ca2+ on firmness and membrane lipid structural components was evaluated during storage of shredded (wound-stressed) carrot tissues (Daucus carota L. ‘Caropak’). During 10 days of storage at 10°C and 95% RH, Ca2+ treatment (applied as 1% w/v CaCl2 upon shredding) provided 6-16% greater firmness retention than did a water control treatment. Calcium accentuated net increases in total phospholipid and monogalactosyldiacylglycerol concentrations after 4 and 10 days of storage, and in acylated steryl glycoside concentrations after 4 days of storage. Calcium partially counteracted a net reduction in steryl glycoside concentration which occurred following 4 days of storage, and prevented an increase in the free sterol : phospholipid ratio following 10 days of storage. Calcium preserved membrane integrity of carrot shreds not only by delaying senescence-related membrane lipid changes, but also by apparently augmenting membrane restructuring processes.