Development of Tomato Aroma Profiles during Low Temperature Storage in Air or CA and Recovery during Shelf Life

Commercial tomatoes are usually harvested before full red ripe color has developed to ensure that they attain the desired color after being exposed to low temperature during distribution. Since the lowest recommended as safe temperature for tomatoes (12.5 °C) was identified based on external appearance (i.e., lack of chilling injury symptoms) we hypothesize that this doesn’t necessarily mean that the volatile composition of the fruit is not significantly altered at 12.5 °C, degrading the flavor profile of the fruit. ’Tasti Lee’ tomatoes were held for 5 or 10 days in air or CA (12% O₂+4% CO₂ or 8% O₂+6% CO₂ at 12.5 °C; 8% O₂+6% CO₂ and 3% O₂+8% CO₂ at 15 and 18 °C). Using GC-MS, we obtained the full flavor profile of fruit both after low temperature storage as well as after shelf life of 2 days in air at 20 °C. In most cases, total volatiles after the shelf life increased significantly both after 5 and 10 days of storage. Lower temperature reduced total volatile production and the CA treatments reduced the effect of storage temperature on the total volatiles. Volatile inhibition at lower temperatures was only temporary since the total volatile amounts recovered during the shelf life period. The  CA inhibited volatile formation during storage compared to air and the recovery during shelf life was less than in the air-stored fruit. However, it was observed that the total amount of volatiles after 5 and 10 days of storage for the more extreme CA treatment at each temperature remained close to initial amounts. The CA storage resulted in limited amounts of 6-methyl-5-heptene-2-one(MHO), a basic tomato flavor compound with a fruity, floral aroma. Air storage resulted in higher amounts of MHO than CA storage with more extreme atmosphere compositions resulting in significantly lower amounts of MHO, which remained close to the initial levels even after 10 days of storage. Also, the temperature effect on MHO production under CA was limited since MHO remained at similar levels after 5 and 10 days of storage. Trans-2-hexanal and cis-3-hexanal, two lipid derived molecules with green, grassy attributes that are significant for tomato flavor, were higher in air storage while temperature had less effect than storage atmosphere. The results suggest that it is important to compare volatile profiles of tomatoes at equivalent ripeness stages when comparing storage treatments, which will be addressed in our future experiments.