Resumo

DIAZ-AYALA, Felipe; ALVAREZ-GARCIA, G. del Socorro  e  SIMA-MOO, Efraín. Drying kinetics of slices of nopal (Opuntia ficus indica) cladodes in a convective transversal flow dryer. Agrociencia [online]. 2015, vol.49, n.8, pp.845-857. ISSN 2521-9766.

Opuntia ficus-indica, also known as nopal, is a cactus which grows on arid and semiarid lands of America. Dehydrated nopal is an alternative for food preservation, but drying times of cladodes are very long. The objective of this study was to evaluate dry kinetics of nopal thin slices, of 4 mm thick, 140 mm long and 17 mm wide. We conducted the drying process in a convective cross flow tray dryer at 35 °C, 45 °C and 60 °C and air velocities of 1 m s^-1, 1.5 m s^-1 and 2 m s^-1, under laboratory conditions. Results indicated that the effect of air temperature on the drying time of nopal slices was higher than the air velocity (p≤0.05). The drying time for nopal in thin slices was remarkably lower (99 %) compared to that for whole cladode (p≤0.05 and 50 % lower for cylindrical 25 mm nopal pieces previously reported. Further, the experimental data of drying curve of nopal slices were fitted to different thin layer models and the Midilli model with empirical constants was the best describing the of nopal slices drying. ANOVA analysis indicated that all the tests were significant (p≤0.05) for all drying temperatures and velocities evaluated.

Palavras-chave : Food drying; nopal cladode drying; drying kinetics of cactus; thin layer drying; drying time.

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