3.4. Colour
Temperature, time and treatment affected juice colour measured as h° (Table 1). The a* value is good parameter for red colour development and the degree of ripening in tomato, while the b* parameter shows yellow discoloration due to chilling injury ( Escriche et al., 1993). Red colour development was enhanced by high temperature when comparing h° for the same treatments and times. These results are in agreement with those obtained for intermittently warmed tomato ( Artés and Escriche, 1994). In general, 2°C maintained the colour close to that at the beginning of the experiment for all treatments. At 10°C, tomato slices under passive or active MAP did not advance in colour compared with the other treatments. The fastest rate of colour development occurred with calcium-treated slices at 10°C.