Solar drying was carried out on three independent trays, for each studied variety. The curves show that
drying during the night edge not but there is a deceleration. Drying takes again the morning with a speed
(slope of the curve masses – time) higher than in the end of the day. For the three varieties solar drying is
rigorously identical during the first two days of drying, the difference appears at the end of the drying
where the variety Irwin dries slightly more quickly. The variety with low water content (Pink Zatopec)
does not dry more quickly than the others. The time of average solar drying is from 2 to 3 days. However
at the end of 24:00 of drying, 75% of water are eliminated for all the varieties. A first improvement of
solar drying would be to bring a contribution of heat at the end of the drying. Figure 2 gives the evolution
of the water content of the same variety of tomatos (Anna Russian) according to time for three
thicknesses of the slices: 4 mm, 6 mm and 8 mm. The curve of the fig.2 then shows us that the thickness
influences the speed of drying, the increase the time of drying is a direct resultant of the increase
thickness of the slices to be dried. On the basis of drying with 0.5% of water content bases dries, one
notes 65 mn for the slice of 4 mm, 200mn for that of 6 mm and almost 350 mn for that of 8 mm what
shows the importance of cutting (thickness of the slices with dried).
The loss of mass is function of the mode of drying and the temperature applied. These curves take the
same forms as those described by Desmorieux [3], Bimbenet and al. [4]. The variation of the duration of
drying according to the temperature is explained by the fact why the rise in temperature involves an
increase in the intensity of the transfer of heat [4].