Title: Influence of CO2 and O2 on the ripening behavior of tomato fruits at 20 degrees C
Abstract: In this work the influence of O2 and CO2 concentration on the ripening of mature-green tomato fruits (Fukuju No.2) has been studied in terms of CO2 or ethylene production and coloring at 20°C.1. The influence of O2 concentration on the ripening; Eight different atmospheres containing various concentations (21 to 0%) of O2 were used.The patterns of CO2 and ethylene production observed showed the climacteric peak in the fruits held in the O2 concentrations above 14%. Although the concentation of 7% caused the retarding the ripening process, little or no influenced on the patterns of respiration and ethylene production of fruits. On the fruits held in the O2 concentrations under 5%, climacteric rise of respiration and ethylene production was not seen and the development of red color was perfectly inhibited. From these, critical concentration of O2 for ripening can be considered as the 7%.2. The influence of CO2 concentration on the ripening; Eight or five different atmospheres, which the various CO2 concentrations (21 to 0%) were mixed with the O2 levels of 21, 14 and 7%, were used.When O2 concentration was maintained at 21%, the fruits in the mixture gases containing CO2 above 12% were inhibited the ripening processes. The ethylene production from fruits stored in the 9% CO2 was decreased markedly than that of control (21% O2) fruits, but the climacteric rise of ethylene was seen and ripening was finished after 3 weeks in this condition.The influence of CO2 at 14% O2 agreed approximately with the results obtained at 21% O2 levels.When O2 concentration was maintained at 7%, the fruits in the mixture gases containing CO2 above 9% were inhibited the ripeness. In the fruits stored in the mixture gas of 3% CO2 and 7% O2, the climacteric-like rise in ethylene, though the apparent rate of its production was too low to detect, was observed. Also, the ripening was finished after 3 weeks in this atmosphere.From above results, it seem that the ripening is very dependent upon the proper CO2-O2 balance in the storage atmosphere.3. From the standpoint of ripening, the critical concentration for ripening can be considered as a atomsphere containing 7% O2 and 3% CO2.