TY  - SER
AU  - Abdel-Galil,H.S.
AU  - EL-Nakib,A.A.
TI  - Effect of natural convection solar drying on quality of peppermint
KW  - Peppermint
KW  - Quality
KW  - Food
KW  - Solar drying
N1  - Includes references
N2  - The main objective of this research work was to investigate the effect of two different natural convection solar drying systems on quality of two species of peppermint namely: mentha pepperita and mentha vridis. Two different natural convection solar drying systems namely: direct (a) and indirect (b) systems were designed and constructed with respect to their ability to dry peppermint and other medicinal plants. Both of the solar air heater and the drying cabinet were oriented to face the south direction and tilted with an optimum tilt angle at noon. The obtained results indicated that the air temperature in the dryers increased above ambient (36.4oC) by maximum values of 14.2oC and 9.6oC for dryers (a) and (b), respectively. The daily average thermal efficiencies for dryers (a) and (b) were 36.60% and 35.70%, respectively. Dryer (a) achieved the fast rate of peppermint moisture content reduction as compared with dryer (b). On the basis of the effective collector areas, the estimated moisture removal rates were 3.57 and 3.53 kg .m-2 .day-1 for dryers (a) and (b), respectively. The water loss from mentha pepperita (72.4% w.b.) was higher than that lost from mentha vridis (65.2% w.b.). The oven drying method gave the lowest essential oil and chlorophylls A and B contents as compared with the solar drying methods. The essential oil content of dried peppermint was slightly higher for dryer (a) as compared with dryer (b), while chlorophylls A and B contents were slightly higher for dryer (a) as compared with dryer (b). The total costs of drying one tone of peppermint for the two different drying systems (a) and (b) were 52.4 And 96.7 L.E/tone, respectively. Dryer (a) may be recommended to use by small farmers for drying peppermint, medicinal plants and other agricultural products
UR  - http://nile.enal.sci.eg/EALE/2008/MJAE/2508/2/513.pdf
ER  -