Green wrap tomatoes are received at terminal markets by produce houses that have special ripening rooms where temperature is kept at about 70°, with high humidity to prevent wilting or shriveling. Ethylene gas is used by some to hasten ripening. It does not change the nature of the process, merely speeding it up. Some of these repackers have elaborate equipment for sorting and packing.
The tomatoes, on arrival, are shaken out of their paper wraps. Any that have ripened in transit are taken out and packed while the greens go into the ripening rooms. They may have to be sorted over two or three times as ripening progresses.
The ripening process in tomatoes has been rather thoroughly studied. Sando found that tomatoes ripen uniformly, regardless of size, at a certain age, dating from the setting of the fruit. This time, which, of course, varies according to weather conditions, was eight weeks when the studies were made. Ripening is accompanied by an increase in moisture, acids and sugars, with decrease of solids, nitrogen, starch, pentisans, crude fibre and ash. Sugars increase from about a quarter to about half of the dry weight. Chemical analysis did not show differences sufficient to account for the difference in quality between vine-ripened fruit and green fruit ripened in the laboratory. Lack of ventilation seems to be detrimental.
It is commonly held that tomatoes chilled without freezing will not ripen satisfactorily afterward. This belief is discounted by results of Wright and associates and of Platenius who found little effect of low temperatures upon later ripening.
Wright[20] and Platenius[21] have both found that tomatoes should not be stored at low temperatures, 50° to 60° F. being best. Storage is not likely to be satisfactory for more than a month.
Waxing
Waxing of tomatoes by immersion in a dilute water emulsion of paraffine and carnauba waxes is being tried out with very promising results. Waxes are also dissolved in volatile hydrocarbons and sprayed on. Moisture loss and shriveling are materially retarded, and interference with the ripening process is negligible. The wax coating is very thin, adds an attractive gloss and is [entirely harmless].
