Physiological responses of tomato fruit to cyclic intermittent temperature regimes
Wahn H., Hammerschmidt S., Artes F., Marquina J., Cano A., and Fernandez-Trujillo J.P.
Postharvest Biology and Technology.Volume 14, Number 3, November 1998 , pp. 283-296.
1998
บทคัดย่อ
Long life tomatoes (Lycopersicon esculentum Mill. cultivar `Durinta') at breaker stage, treated with 0.5 g l-1 iprodione or washed in water, were stored at 9, 12 or 20°C for up to 28 days. Fruit stored at 9°C were warmed to 20°C for 1 day every week, whereas fruit stored at 12°C were cooled to 2°C for 1 day every week. Fungicide treatment reduced decay and pitting on fruit stored more than 3 weeks. At 9°C, a slight synergistic effect on fruit pitting was observed from fungicide alone or fungicide plus intermittent warming. Compared with fruit stored at a constant 9°C, intermittently warmed tomatoes had better surface colour and flavour, were slightly less firm with less severe pitting, and were in better condition both at the end of the storage period and after a 3-day shelf-life. In fruit held at constant 20°C, 9°C or intermittently warmed, increased pectolytic enzyme activity accompanied a fall in respiration rate and ethylene production. In fruit held at a continuous 9°C, polygalacturonase activity was reduced slightly during the third week of storage. Intermittently cooled fruit showed enhanced taste and appearance compared with fruit held at a constant 12°C, but had more decay and pitting after the second cooling treatment. After cooling, slight reductions in L*a*b* Colour Space lightness were detected. During the shelf-life period, tomatoes previously stored continuously for 2 or 3 weeks at 9 or 12°C produced more ethylene and had higher respiration rates. By the third week, ethylene production was severely reduced by cooling at 2°C, but a possible relationship between pitting and non-ripening-dependent ethylene production was indicated. The respiration rate was not affected by the disorder incidence. We conclude that intermittent warming is more beneficial than intermittent cooling because of pitting development at 2°C in intermittently cooled fruit.