Effect of slicing and storage temperatures on biochemical aspects of membrane integrity in two different genotypes of tomato

Fresh-cut vegetables are subjected to multiple stressing agents: i) slicing that induce cellular decompartmentalization; ii) low refrigeration temperature responsible of chilling injury in the most sensitive products (e.g. tomatoes); iii) storage time which leads the tissue until senescence. In tomato slices, one of the most important issue is membrane that is responsible of several disorders related to the alteration of physiological processes, including ethylene biosynthesis. Electrolyte leakage and thiobarbituric acid reactive substances content of sliced tomatoes increased over time at both storage temperatures (4 and 15°C) compared to intact fruit for the commercial variety (cultivar) Jama used as reference. However, in the tomato Italian landrace Canestrino, electrolyte leakage in sliced fruits increased after 120 h of storage compared to intact tomatoes, whilst thiobarbituric acid reactive substances content rapidly increased over time at both storage temperatures. In the packages, higher values of ethylene content and carbon dioxide concentrations were detected in sliced tomatoes compared to intact fruits for both genotypes. In the most sensitive genotype for slicing (Jama), phospholipase C activities increased in tomato slices after 24 h of storage, while phospholipase D reached higher value only at 168 h after processing at 4°C of storage. The results evidence that the main damage in slices of full ripe tomatoes is more related to cutting, instead of chilling injury due storage temperatures with differences related to the genotype. Slicing enhanced membrane catabolism, ethylene production and enzyme activities of phospholipases with a significant effect of the genotype.