Effect of hyperbaric pressure and temperature on respiration rates and quality attributes of tomato

Previous work with hyperbaric treatment of tomato focused on application at lower temperature (13. °C). In this work, hyperbaric treatment at varying pressure levels (i.e., 0.1, 0.3, 0.5, 0.7 and 0.9. MPa) at ambient temperature (20. °C) was tested as a potential alternative to conventional refrigerated storage (0.1. MPa at 13. °C) to preserve tomato quality. The experiments were divided into 3 phases: (1) 4 day of hyperbaric treatment, (2) 5 day of post-treatment ripening, and (3) 10 day of post-treatment ripening. Respiration rate (RR) of the tomatoes was continuously monitored during the course of the hyperbaric treatments. Quality attributes were assessed immediately after removal from the hyperbaric treatments and after 5 and 10 day ripening at 20. °C after removal from the treatments. Hyperbaric treatments at ≥0.3. MPa resulted in RR equal or higher than the RR in control fruit (0.1. MPa at 20. °C). The lowest RR was obtained from tomato stored at 0.1. MPa at 13. °C. Hyperbaric treatment at 0.5, 0.7 and 0.9. MPa significantly reduced weight loss, retained color, firmness, total soluble solid (TSS), titratable acidity (TA) and TSS:TA ratio at similar levels as the tomato treated at 13. °C and 0.1. MPa. Firmness after treatment was highest for fruit from 0.1. MPa at 13. °C and from 0.5, 0.7 and 0.9. MPa at 20. °C. The higher firmness advantage declined by 5 day of ripening after treatment, with higher firmness only being retained for fruit from the 0.9. MPa at 20. °C and the 0.1. MPa at 13. °C treatments. After 10 day ripening, firmness was similar for all treatments. Lightness (L*) and hue angle were greater for all treatments compared with the 0.1. MPa at 20. °C treatment. However, only the greater hue angle difference was maintained after 5 day of ripening. After 10 day ripening, no significant differences were found in color attributes. Only 0.1. MPa at 13. °C retained higher soluble solids, lower titratable acidity and higher TSS:TA ratios after treatment and after 5 day ripening. At 10 day of ripening none of the quality attribute differences noted were retained for any of the treatments. These results show that the only consistent effect of hyperbaric treatment at 0.5, 0.7 and 0.9. MPa was to reduce weight loss and enhance firmness retention up to 5 day ripening after treatment. © 2013 Elsevier B.V.