Effect of temperature and storage on açaí (Euterpe oleracea) fruit water uptake: simulation of fruit transportation and pre-processing

Introduction. Açaí is a common palm in the Amazon River basin, from which a much-appreciated drink is prepared in the North of Brazil. Despite the strong increase in the drink market, some basic questions about the fruit postharvest physiology have not been properly studied. Our paper presents results about the fruit water absorption at different temperatures and times of storage, which may help the development of more efficient procedures for fruit transport and processing. Materials and methods. The experiments began approximately 3 h after harvest of fruits collected early in the morning. In a first experiment, to evaluate the effect of temperature on water absorption, fruits were submitted to five treatments: 0 °C, 6 °C, 12 °C, 26 °C and 39 °C. Each treatment was applied to 50 fruits, with four repetitions. Fruits from each lot were put into a beaker with water at the temperature of the selected treatment. Lots were weighed before immersion and every 10 min up to 60 min. The fruit relative increase in mass (dMasserel) was calculated according to experiment time. In a second experiment, to evaluate the effect of storage, fruits collected at the same spot were immediately stored in the lab at 10 °C under relative air humidity of 81% to 87%. After (5, 6 and 7) days of storage, the dMasserel curves were determined. Results and discussion. Between 0 °C and 26 °C, the absorption reaches an asymptote after 30 min, and at 39 °C, the absorption continues to increase for a longer period. The maximum (dMasserel) regarding the temperature was fitted by a parabole, with a minimum at 13 °C. Fruits stored at 10 °C presented an increase in the absorption rate after the fifth day. Conclusion. Our data suggest that: (i) water absorption is minimum at 13 °C; (ii) the imbibition rate is temperature-related, and (iii) fruit stored at 10 °C, and relative humidity 81% to 87%, increases its water absorption rate at the end of the shelf-life time (5th day). Introduction. Le « palmier pinot » est un palmier commun dans le bassin amazonien ; son fruit est à la base d’une boisson très appréciée au nord du Brésil. Malgré une forte progression de ce marché, certaines questions fondamentales sur la physiologie après-récolte du fruit n'ont pas encore été correctement étudiées. Notre document présente des résultats sur l'absorption d'eau par le fruit à des températures et des durées de stockage différentes ; ils pourraient aider à développer des procédures plus efficaces pour le trans