We notice that this οE colour variation depends on several factors such as the temperature to which the samples
are directly exposed, the temperature of the drying air and the duration of the operation. The largest colour difference
οE=37.68 was obtained when we used 2 panels. The smallest difference οE =22.64 was obtained with a sample dried
with the help of one panel during 3 hours for οE=24.13 the drying time equals 2h 45mn therefore we may conclude
that the hybrid solar drying of the potatoes slices with panel induces a considerable colour changes in all tested cases.
Any decision to make in the way of defining eventual good criteria must refer to consumer preference and industrial
post treatment of the dried product.