In this paper, we propose an optimized process for farm product convective drying. Above and beyond the influence of the air parameters on foodstuff convective drying, this work shows that product internal parameters ...In this paper, we propose an optimized process for farm product convective drying. Above and beyond the influence of the air parameters on foodstuff convective drying, this work shows that product internal parameters and drying proceedings must be taken into account during the evaluation of their convective drying. Results indicate that okra maturity influences its convective drying. It dries faster when it is too young or when it is advanced age. Drying time of okra of 1, 2, 3, 4 and 5 days old is respectively 580 min, 780 min, 990 min, 1200 min and 850 min. Also, one observes that considering okra on its three zones according it length, i.e. its base, middle and extremity parts have not the same resistance to transfers during convective drying. These three zones have respectively 400 min, 520 min and 600 min of drying time. Okra cut reveals a major importance on its convective drying evaluation. The longitudinal cut di-viding okra on four parts, sliced with 5 mm and 10 mm of thickness and the whole okra put respectively 150 min, 200 min, 280 min and 400 min for their drying. At last, three (03) different constituents of okra, namely, the skin, the seeds and central material behave differently during convective drying. The drying time of the central material, the seeds and the skin is about 70 min, 150 min and 190 min respectively, against 400 min for the whole okra.展开更多
In this paper the influence of sample initial size on their convective drying at 80°C using convective dryer is determined. Results prove that initial size must be taken into account when drying process was estim...In this paper the influence of sample initial size on their convective drying at 80°C using convective dryer is determined. Results prove that initial size must be taken into account when drying process was estimated. This influence is limited by its form of cut. Comparing cubic form and parallelepiped (slice) one;results seem to show that thickness is the most important parameter governing the transfer phenomena during foodstuff convective drying. Three slices with thickness of 0.5 cm and surface area of 17, 82 and 112 cm2 respectively, dry better than cubic sample with a = 1 cm or a = 2 cm of arrest and having respectively 6 and 24 cm2 of surface area. All things seem to show that initial surface is not only the essential parameter;but also the thickness of the sample must be taken into account. Indeed, all of the samples with equal thickness (0.5 cm) and different exchange surfaces dry at the same time, about 210 min, comparing with cubic form 1 cm of arrest and 6 cm2 of surface and drying time of 230 min. A new parameter noted Dc called characteristic diameter is so considered to bridge the gaps. It is defined to be the diameter of the biggest sphere we can cut into a sample. This parameter is independent of form of the sample, and time increase with characteristic diameter increasing.展开更多
文摘In this paper, we propose an optimized process for farm product convective drying. Above and beyond the influence of the air parameters on foodstuff convective drying, this work shows that product internal parameters and drying proceedings must be taken into account during the evaluation of their convective drying. Results indicate that okra maturity influences its convective drying. It dries faster when it is too young or when it is advanced age. Drying time of okra of 1, 2, 3, 4 and 5 days old is respectively 580 min, 780 min, 990 min, 1200 min and 850 min. Also, one observes that considering okra on its three zones according it length, i.e. its base, middle and extremity parts have not the same resistance to transfers during convective drying. These three zones have respectively 400 min, 520 min and 600 min of drying time. Okra cut reveals a major importance on its convective drying evaluation. The longitudinal cut di-viding okra on four parts, sliced with 5 mm and 10 mm of thickness and the whole okra put respectively 150 min, 200 min, 280 min and 400 min for their drying. At last, three (03) different constituents of okra, namely, the skin, the seeds and central material behave differently during convective drying. The drying time of the central material, the seeds and the skin is about 70 min, 150 min and 190 min respectively, against 400 min for the whole okra.
文摘In this paper the influence of sample initial size on their convective drying at 80°C using convective dryer is determined. Results prove that initial size must be taken into account when drying process was estimated. This influence is limited by its form of cut. Comparing cubic form and parallelepiped (slice) one;results seem to show that thickness is the most important parameter governing the transfer phenomena during foodstuff convective drying. Three slices with thickness of 0.5 cm and surface area of 17, 82 and 112 cm2 respectively, dry better than cubic sample with a = 1 cm or a = 2 cm of arrest and having respectively 6 and 24 cm2 of surface area. All things seem to show that initial surface is not only the essential parameter;but also the thickness of the sample must be taken into account. Indeed, all of the samples with equal thickness (0.5 cm) and different exchange surfaces dry at the same time, about 210 min, comparing with cubic form 1 cm of arrest and 6 cm2 of surface and drying time of 230 min. A new parameter noted Dc called characteristic diameter is so considered to bridge the gaps. It is defined to be the diameter of the biggest sphere we can cut into a sample. This parameter is independent of form of the sample, and time increase with characteristic diameter increasing.
