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

Abstract

Introduction. Acai 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 pro- perly studied. Our paper presents results about the fruit water absorption at different tempe- ratures 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 (dMasse rel ) was calculated according to experiment time. In a second experiment, to eva- luate 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 rea- ches an asymptote after 30 min, and at 39 °C, the absorption continues to increase for a longer period. The maximum (dMasse rel ) 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). Brazil / Amazon river / Euterpe oleracea / fruits / fruit pulps / beverages / storage Effet de la temperature et du stockage sur l'absorption d'eau par le fruit d'Euterpe oleracea : simulation de transport et de pretraitement du fruit.