Caracterização físico-química de diferentes variedades de amêndoa (Prunus dulcis) e efeito das condições de armazenamento

Abstract

Almond (Prunus dulcis) is a traditional crop in Portugal, being well represented in Trásos-Montes region. Thus, the main objectives of the present work were to characterize some almond producers, in relation to their varieties, type of harvest and transport applied and storage conditions, as well as to determine the main problems observed during the storage. Moreover, it was also studied the physicochemical and microbiological properties of some varieties produced by them, namely: French, Spanish and Portuguese varieties. Furthermore, it was also proposed to carry out a preservation study of peeled almonds (mixture of molar varieties), where the effect of relative humidity (RH) (60, 70 and 80%) at constant temperature (25°C) was studied during the storage. After the application surveys, it was detected that most of the producers (42%) were between 60 and 69 years old. More than half of the producers (63%) have almond groves with areas lower than 10 ha and 53% of the orchards are more than 11 years old. The origins of the cultivated varieties are Spain, France and Portugal, highlighting the Ferraduel and Ferragnès (both French). More than half of the producers (63%) do manual harvesting, and the fruit is stored at room temperature, without control of RH. Approximately 53% of the producers mentioned that they had no problems during storage or did not answer this question. However, the producers who indicated problems, the main one was the appearance of pests (26%). Some significant differences were observed in the 19 analyzed samples, in terms of physic (mass, size, number of fruits per kg, number of double seeds in 25 fruits), chemical (moisture, fat, protein, crude fiber, ash and oxidative stability) and microbiological parameters (microrganisms at 30 °C, molds and yeasts, total coliforms and Escherichia coli). The Portuguese varieties when compared to the foreign ones did not stand out. Regarding the microbiological quality, the majority of the samples were acceptable or satisfactory, none with an unacceptable number of E. coli. Regarding the storage trials, it was observed that throughout the storage the almonds maintained a visual and physical appearance similar to that observed at the beginning (day 0), regardless of the RH applied. Concerning the nutritional composition, no significant differences were detected either for the storage period or for the RH applied. The results indicated that it is necessary to continue the storage test for a longer period ofvii time, in order to be able to verify possible differences between the RHs and to define the best one for the transportation of peeled almonds.