SOLAR DRYING PROCESS OF ‘DELLAHIA’ PRICKLY PEAR (Opuntia ficus indica) FROM NORTHERN MOROCCO AND EFFECT OF ALTITUDE ON PHYSICO-CHEMICAL CHARACTERISTICS OF DRIED FRUITS

In this study, we processed the solar drying of the fruits picked up from two sites localized in northern Morocco at a different altitude, Mestassa (119 m) and Targuist (1034 m), the geographic areas of this study. The drying process was carried out in the city of Meknes in October. Fruits were cut in small discs of 5mm and 10mm and dried until their water content reached approximately 4.79%. Then we analyzed the drying kinetics based on the diffrence in the sample size. A significant relation was observed in terms of drying time and sample size. 25% of the drying time was saved with 5mm thick samples. No significant difference was noticed between samples from both sites about the drying kinetic. We have also processed some physico-chemical characteristics of dried fruits : ash content (ranged from 1.06 ± 0.13 to 1.09 ± 0.01%), neutral detergent fiber content, NDF (ranged from 14.2 ± 2.57 to 14.6 ± 2.71%) ; total polyphenols content, TPC (ranged from 100.6 ± 16.59 to 110.51 ± 9.34 mg GAE/g of dry weight); total flavonoids content, TFC (ranged from 18.76 ± 0.08 to 19.12 ± 0.04 mg RE/g of dry weight); antioxidant capacity using ORAC assay (with IC50 ranged from 0.2397 ± 0.018 to 0.2242 ± 0.014 mg/mL). No significant difference was observed between samples about their ash content, organic matter, NDF and TFC while significant difference was found about their TPC and antioxidant capacity. Then the effect of altitude on these parameters has been discussed. Samples from the highest altitude (Targuist : 1034 m) present the highest TPC and TFC but reversely present the lowest antioxidant capacity.