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The present work examined the effect of air drying conditions on drying kinetics of cactus/brewer's grains mixture fermented with Lactobacillus plantarum HG328248. The drying kinetics was performed in a convective dryer for three air temperatures (40, 50 and 60 °C) and three air velocities (0.7, 1.0 and 1.3 m/s). Four mathematical models were tested to fit the drying curves. The Page model seemed the most appropriate to describe experimental data. The experimental drying curves showed two periods: that at constant rate and that of falling rate. The air temperature was the main factor in controlling the drying rate. The characteristic drying curve equation was determined. The influence of air drying conditions on color, water activity and microbiological quality of the fermented product was also studied. The temperature affected these parameters more significantly than air velocity. All dehydrated products had a satisfactory microbiological quality and consequently could be introduced in ruminant feed.

The aim of this work was to study the effect of air drying process on the dehydration kinetics of sardine muscles ( Sardina pilchardus ). Experimental drying kinetics were measured at five air temperatures (40, 50, 60, 70 and 80 °C), two relative humidity and at a constant air velocity of 1.5 m/s. The sardine drying kinetics were accelerated by increasing air temperature and were showed down when increasing air humidity. Moisture desorption isotherms of sardine muscles were determined at three temperatures (40, 50 and 70 °C) by using the static gravimetric method. The equilibrium moisture contents of sardine muscles were used to treat mathematically the experimental drying kinetics. Experimental drying kinetics and desorption isotherms of sardine muscles were described by using empiric models available in the literature. Eight models (GAB, BET, Henderson–Thompson, Modified Chung & Pfost, Modified Halsey, Oswin, Peleg and Adam & Shove models) were compared in order to describe the desorption isotherms. The Peleg model showed the best fitting of experimental data. For the drying kinetics, the Page model allowed a better fitting than the Newton and the Henderson and Pabis models. The Page model was thus used for simulating the drying kinetics of sardine muscles between 40 and 80 °C.

In the present work, a diffusion-based model was adopted to represent the convective drying behavior of cylindrical banana samples, taking into consideration the shrinkage along drying. The developed model simulated a significant number of situations resulting from the variations of some operating conditions. The temperatures tested were 50, 60, 67 and 70 °C, the air velocities were 3, 4 and 4.5 m/s and the relative humidity range of the drying air was from 3.5 to 11.5%. The calculated drying curves were compared to the experimental ones in order to determine apparent moisture diffusivity. An empirical equation was suggested, describing the apparent moisture diffusivity within the banana versus product temperature and local moisture content. A good agreement was found between experimental and calculated drying kinetics.

Desorption isotherms of sardine muscles were determined at three temperatures (25, 35 and 50 °C) for a water activity range varying from 0.10 to 0.75. Gravimetric static methods using saturated salt solutions were used (continuous and discontinuous measurements). Six models were taken from the literature to describe experimental desorption isotherms. The OSWIN model shows the best fit of the experimental data. The net isosteric heat of desorption and the isosteric heat of desorption were determined by using the CLAUSIUS–CLAPEYRON equation. The isosteric heat of desorption decreases continuously with the increase of the equilibrium moisture content. A mathematical correlation was established between the isosteric heat of desorption and equilibrium moisture content.