Stimulation of γ-aminobutyric acid (GABA) production under low O2 and high CO2 conditions (adjusted aerobic atmosphere) at two levels of temperature was studied. Vine-ripened tomato fruits were stored under hypoxic conditions and adjusted aerobic atmospheres as well as in air at 15°C for 12.6 d and at 25°C for 6.6 d. At 15°C, the GABA concentrations of tomato fruits during storage under one adjusted aerobic atmosphere (O2 14%, CO2 8%) were not significantly different from that in air. On the other hand, at 25°C, the tomato fruit GABA concentrations under a second adjusted aerobic atmosphere (O2 11%, CO2 12%) were significantly higher by 72% than that in air 6.6 d from the start of storage. Increased accumulation of alanine under this adjusted aerobic atmosphere supports the observation that these conditions stimulate GABA production. This temperature is 5°C lower than the temperature (30°C) reported to be required to stimulate GABA production. This result is more significant than that reported in the past because the shelf-life of fresh produce including tomato fruits can be prolonged by storage at low temperatures.

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