Effect of long-term controlled atmosphere storage on the sensory quality of tomatoes

Tomato (Lycopersicon esculentum Mill.) fruit were harvested at the mature green and pink stages of maturity and held for 60 days at 15degreesC (mature green fruit) or 13degreesC (pink fruit) under three different controlled atmosphere (CA) conditions: 3.2% CO2, 6.4% CO2 or 9.1% CO2, combined in all cases with 5.5% O-2. Mature green fruit were then kept for additional 10 days at 20degreesC to simulate shelf life conditions. Different sensory tests were conducted which included analytical tests (tomato flavour and two flavour descriptors, sweetness and sourness) and affective tests (acceptability). Objective measures (total soluble solids, titratable acidity and TSS/titratable acidity ratio) were also obtained. Control tomatoes showed significantly higher flavour scores, and were sweeter and more acceptable than those exposed to long-term CA storage. Although there were no significant differences in flavour, sweetness and acceptability scores among mature green and pink fruit stored at different gaseous combinations, the acceptability levels were slightly higher in tomatoes stored in 9.1% CO2. The sourness score for tomatoes treated with 9.1% CO2 was significantly lower than that for tomatoes treated with other CO2 concentrations. Although no significant differences were found among the three CA storage treatments, TSS values and TSS/acidity ratios in fruit treated with 9.1% CO2 plus 5.5% O-2 suggested that this combination displayed a better performance for long-term storage (slightly lower ripening rate, and slightly higher tomato flavour and consumer acceptability).