Respiration and transpiration characteristics of selected fresh fruits and vegetables

Respiration and transpiration characteristics of mushrooms, strawberries, broccoli and tomatoes were determined under different temperature, atmospheric and humidity conditions in order to get information for modified humidity atmosphere conception. The respiration rate was determined using a static method (scanning method). The transpiration rate was measured using a new method at different relative humidity levels. The respiration rates of all the produce under optimal atmospheres were 40 - 60 % lower than in air. The respiration quotients (RQ) in both air and optimal atmospheres for all produce were lower than 1.0, but were higher in optimal atmospheres. The Q10 values for respiration varied from 2.1 to 3.3. It was shown that the transpiration rate was the sum of inherent, heat-transfer-induced and mass-transfer-induced transpiration. At low relative humidities in the surrounding atmosphere, mass-transfer-induced transpiration was the dominant mechanism for all produce. The better understanding of the respiration and transpiration behavior of produce under different conditions of temperature, atmosphere and humidity obtained in this study will lead to improve storage and modified atmosphere. La respiration et la transpiration du champignon, de la fraise, du brocoli et de la tomate ont ete determinees sous differentes conditions environnementales (temperature, atmosphere et humidite relative) dans le but d\'obtenir des informations indispensables a la conception des emballages sous atmosphere modifiee. Les resultats montrent que la respiration des differents produits a ete reduite de 40 a 60 % par rapport a la respiration initiale dans l\'air. Le quotient respiratoire (RQ) pour tous les produits etudies et sous les deux conditions d\'entreposage est inferieur a 1. Cependant, sa valeur dans les conditions controlees est superieure a celle obtenue dans l\'air. La valeur du Q10 pour l\'intervalle de temperature etudiee varie de 2,1 a 3,3. Il a ete montre que le taux de transpiration est la somme de la transpiration inherente, de la transpiration due au transfert de masse et de celle due au transfert de chaleur. La parfaite connaissance de la respiration et de la transpiration sous differents facteurs environnementaux permettra de maitriser la conception des emballages sous atmosphere modifiee et l\'entreposage des fruits et legumes frais. Keywords : packaging, respiration, transpiration, temperature, relative humidity. Agronomie Africaine Vol. 17 (2) 2005: pp. 103-115