THE EFFECT OF HOT AIR TREATMENTS IN AIR OR IN LOW O₂ ATMOSPHERE ON THE QUALITY AND ANTIOXIDANTS OF TOMATO FRUIT

    Tomato fruit is an excellent source of antioxidants. However, the fruit is sensitive to chilling injury (CI). We have determined the effect of forced hot air treatments on the quality, CI, and the contents of some antioxidants. ‘Rapsody’ tomato fruit was exposed to 34ºC for 24 h in air, to 38ºC for 24 h in air, or to 38ºC for 24 h in 5% O₂, all at low RH, and then stored in air at 4ºC or 10ºC for up to 30 d. Fruit exposed to 38ºC at 5% O2 were injured the most, while fruit that were not heated, and those heated in air at 34ºC for 24 h were the least injured. Fruit that were maintained at 10ºC and were previously either not heated, or heated at 34ºC developed the best color when ripened, having the least chlorophyll and the highest lycopene contents. Color developed slowly at 4ºC than at 10ºC. -carotene increased in fruit that were not heated and to a lesser extent in those that were heated in air at 34ºC or 38ºC. Fruit that were exposed to 38ºC in 5% O₂ had lower –tocopherol content and higher peroxidase, ascorbate peroxidase, superoxide dismutase, glutathione reductase, and glutathione S-transferase activity than fruit of other treatments. We conclude that heating of tomato fruit at 34ºC for 24 h caused the least injury and fruit color developed adequately.

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