Changes in reduced ascorbic acid in normal tomato fruits (Lycopersicon esculentum Mill.) during holding at 20°C seem to be related to ripening. No change in reduced ascorbic acid levels from mature green to yellow rin fruits was observed when detached from the plant. Apparently, a reduction mechanism from dehydro to reduced ascorbic acid is active in normal tomatoes but inactive in detached rin fruits. This mechanism was operative in normal and rin fruits left on the plant. Exogenous ethylene (10 ppm) neither affected reduced ascorbic acid levels in normal and rin fruits, nor the total ascorbic acid in normal fruits. Maintenance of initial levels of total ascorbic acid was noted in ethylene treated rin fruits. Similar total ascorbic acid levels were found in normal and rin fruits held on the vine to the red and yellow stages, respectively; and were higher than in comparable fruits held in storage.
Firmness values were determined for isogenic normal and rin tomato fruits (Lycopersicon esculetum Mill.) that were held at 20°C in air or 10 ppm ethylene. Exogenous ethylene induced a slight increase in softening of detached rin fruits but these fruits do not soften as much as normal fruit. A two step sequence for softening is postulated.