Convective Hot Air Drying of Pomegranate Peel and Study its Physcio-chemical Properties

The aim of the present study was to determine the drying characteristics of pomegranate peel and its physicochemical and functional properties of pomegranate peel powder (PPP). Pomegranate peel were dried at different temperatures i.e. 40°C, 50°C, 60°C in convective hot air dryer and powdered. Drying experiments were performed at constant air velocity of 2.0 m/s and thickness of 5 mm for pomegranate peels. The drying time decreased with increase in drying air temperature. Drying models i.e. Newton, Page, Henderson and Pabis, Logarithmic and Verma were fitted to the experimental data on moisture ratio with respect to time. The Verma model fitted well r² ≥ 0.996 and MSE ≤ 1.79910^-3 among all the models tested for the experimental data. Effective diffusivity from this study was 1.65×10^-8, 1.975×10^-7 and 1.90×10^-7during the drying temperature of 40°C, 50°C and 60°C respectively. The activation energy E_a for moisture diffusion was found to be 6.205 kJ/mole .Average Moisture content of 7.94 to 10.49 % (db) was observed, while average percent ash, fiber, protein and fat contents were 2.75to 3.19 %, 13.21 to 17.53 %, and 3.08 to 4.37 % and 1.80 to 2.20 % respectively. The ascorbic acid, bulk density, water holding capacity, oil holding capacity, colour L, a, and b was in the range of 6.01 to 6.75 mg/g, 0.51 to0.80 g/c, 2.43 to 2.69 ml/g, and 0.91to 0.98 ml/g respectively in the experimental temperature range studied. The ascorbic acid decrease, bulk density increase, water holding capacity decreases, oil holding capacity also decreases. The colour “L” value increases with increases in temperature.