Abstract

Tomato (Solanum lycopersicum L.) is one of the most economically important horticultural crops globally. Consumers value its organoleptic traits but there is general dissatisfaction in terms of quality. One reason for this is inadequate postharvest handling. Tomatoes are susceptible to postharvest chilling injury (PCI), which is a series of complex disorders that occur when fruit are exposed to chilling but non-freezing temperatures below 12.5°C. Damage is initiated during the cold, but symptoms are manifested when the fruit is rewarmed. Therefore there is a need to understand the cascade of events in order to develop indexes that could early detect its occurrence. We are assessing the value of magnetic resonance imaging (MRI) as a tool for non-invasive detection of PCI by comparing it with known indices such as changes at the membrane level (ion leakage), metabolic status (respiration/ethylene evolution rates), and visual evaluations of the fruit (PCI index/objective color). To this end, cherry tomato fruit cv. Sungold were stored at two chilling (2.5 and 5°C) and a control (12.5°C) temperature up to 21 days. After 7, 14 and 21 days, fruit were transferred to 20°C for 1 week to simulate commercial handling. Chilled fruit exhibited changes in respiration, ethylene evolution objective color and chilling injury index consistent with PCI, however ion leakage results were unclear. MRI allowed changes in individual fruit tissue to be differentiated. Together, these results suggest that the disorder was progressive over time, enhanced after rewarming and presented tissue-differential manifestation.