Evaluation of drying methods on the content of some bio-actives (lycopene, -carotene and ascorbic acid) of tomato slices

Tomato (Solanum lycopersycum L.) is one of the most important vegetables worldwide. As it is a relatively short duration crop and gives a high yield, it is economically attractive. Thus, the objective of this study was to evaluate the effect of drying method on the quality of the dried tomatoes based on three parameters viz; lycopene, s-carotene and ascorbic acid contents. Thirty-six kilograms of tomatoes were sorted, cleaned, blanched and divided into three equal portions of 12 kg each. The tomatoes were sliced into 4, 6 and 8 mm, then sun, solar and hybrid dried, respectively. The value of lycopene content obtained for sun dried tomatoes ranged from 23.89 to 18.77 mg/100 g, solar dried ranged from 24.51 to 22.56 mg/100 g and hybrid dried ranged from 25.12 to 24.65 mg/100 g. The average value of β-carotene content obtained for sun dried tomatoes ranged from 4.12 to 3.72 mg/100 g, solar dried ranged from 4.94 to 4.25 mg/100 g and hybrid dried ranged from 4.98 to 4.65 mg/100 g. The values of ascorbic acid obtained for sun dried tomatoes ranged from 17.04 to 5.60 mg/100 g, solar dried ranged from 23.73 to 13.37 mg/100 g and hybrid dried ranged from 29.20 to 24.82 mg/100 g. Hybrid dried tomatoes slice showed higher retention of lycopene, s-Carotene and ascorbic acid than both the solar and open sun dried methods.  Key words: Tomato, hybrid-photovoltaic dryer, solar dryer, sun drying, lycopene, β-carotene and ascorbic acid.