Influence of power density and geometry of young cactus cladodes (Opuntia ficus-indica (L.) Mill.) on intermittent microwave drying kinetics

Due to its multiple uses, the production and consumption of nopal have increased worldwide in recent years. The influence of power density (60.3 to 538.9 W g-1 intemperizados en suelos y sedim ntos db) on the intermittent microwave drying of young cladodes, of different sizes, was studied. In general, all drying treatments showed a sigmoid shape and three drying periods: heating (I), constant rate (II) and falling rate (Bi d g d ti od li g f sl d bi t rs f tot l p t l hydro b n thering i il (III). Empirical models were used to model drying kinetics. However, although they had a good fit (R2 from 0.965-0.998) they do not exactly represent the changes between drying periods. According to microstructural analysis of dried samples, the water was and sediments) transferred from the inside to the surface of the cladode by te sides, where there is cuticle o epidermis (which was removed S.A Medina-Moreno, S. Huerta-Ochoa, C.A. Lucho-Constan ino L. Aguilera-Vazquez, A. Jimenez-by the thorn quitting process). It was determined that the drying rate in period II depends exclusively on the power density applied Gonzalez y M GutierrezRojas and not on the cladode's geometry. However, in period III the data of effective diffusivity (Deff , 2.20x10-6 to 5.59x10-5 m 2 2 9 C i i b i nci p io d d b f s ond a id s-1) showed that the drying rate is affected by the size and thickness of cladodes.