Effect of Hybrid Solar Drying Method on the Functional and Sensory Properties of Tomato

Abstract

A hybrid solar dryer, direct solar energy dryer and open sun drying under the climatic conditions of Yola, Nigeria was used to dry tomato slices. The effect of these drying methods on the functional and sensory quality of the dried tomatoes was examined. The functional properties of the dried tomatoes slices were significantly different (p<0.05). In open sun dried tomatoes, the bulk density ranged from 0.56 – 0.62 g/ml, water absorption index (WAI) 436.33 – 475.67 gH2O/sample, water solubility index (WSI) 6.00 – 14.00, specific volume 1.61 – 1.78 ml/g and wettability 10.33 – 13.33 s for 4 – 8 mm thick tomato samples. For solar dried tomatoes, the bulk density ranged from 0.52 – 0.57 g/ml, the WAI ranged from 412.00 – 454.00 gH2O/sample, the water solubility index (WSI) range was 12.33 – 16.67, specific volume range was 1.73 – 1.90 ml/g and wettability ranged from 5.85 – 10.63 s for 4 – 8 mm thick tomato samples. For the hybrid dried tomatoes, the bulk density ranged from 0.50 – 0.54 g/ml, the WAI values ranged from 386.00 – 436.00 gH2O/sample, the WSI 14.67 – 18.00, specific volume range was 1.84 – 1.99 ml/g and wettability 5.80 – 8.44 s for 4 – 8 mm thick tomato sample. The organoleptic properties showed that the tomatoes dried by hybrid drying method was superior in terms of acceptability test than those dried using direct solar energy and a photovoltaic (PV) solar panel tomato products. Conclusively, good quality shelf stable dried tomato slices could be produced using hybrid drying method.