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Effects of different solar drying methods on 'Galiang Bird' Chilli (Capsicum frutescens Linn.)
Author(s)
Assawarachan, R.
Date Issued
June 30, 2015
Type
Article
Abstract
Thin-layer drying behavior of 'Galiang bird' chilli (Capsicum frutescens Linn.) undergoing three different solar drying methods, namely, direct solar drying, indirect solar drying and hybrid solar-thermal drying, was investigated. The convection solar dryer is an indirect forced convection solar dryer consisting of a solar air collector and a drying cabinet, while the hybrid solar dryer consists of a solar collector, reflector, electrical heater and air circulation system. Upon drying it was found that to reach a final moisture content of 0.1428 gwater/gdry matter at 60, 70 and 80°C, the drying time in the hybrid solar dryer was 5.83, 4.17 and 2.81 h, respectively. On the other hand, it took 16.5 h with convection solar drying and 23.5 h with direct solar drying. Dried product color was best maintained by hybrid solar drying at 60°C, which yielded the highest a∗value (red color). The experimental data were fitted to four drying models, namely, Newton, Page, Henderson and Pabis and Logarithmic. The suitability of the models was assessed by comparing the coefficient of determination (R2), reduced chi-square (x2) and root-mean square error (RMSE). It was found that among the tested models, Page model was the most appropriate for prediction because it provided the highest R2 and lowest x2 and RMSE. According to these results, the Pagemodel was the most suitable model in describing the various different solar drying behavior of 'Galiang bird' chilli.
Citation
Acta Horticulturae, 1088, 595-598, 2015