The purposes of this research were to develop and to test performance of mini heat pump dryer for slice banana. Drying chamber of 0.48×0.47×0.39 m3 was designed and it could contain three trays. The three trays had dimension of 0.33×0.409 m2. A blower with 174.6 W motor of air condition was modify and could adjust flow rates of three levels for air cycle system in dryer. The air system had bypass air at evaporator. The refrigerant of R-134a and four main parts were used in the heat pump system. The four main parts were a 497 W hermetic compressor a 1800 W condenser an expansion valve and a 1300 W evaporator. Experiments for test performance of the mini heat pump dryer used close loop air system an evaporator bypass air of 60 % a temperature of 60 oC and various flow rates of 0.117 0.128 and 0.140 m3/s. Slide bananas of 400-500 g had an initial moisture content of 244-281 %dry basis and were dried until final moisture content lower than 6.24±0.007 %dry basis. It was found that the flow rates of 0.117 0.128 and 0.140 m3/s had coefficients of performance (COPh) of 3.32±0.066 3.88±0.031 and 4.24±0.08 respectively and had specific moisture extraction rates (SMER) of 184.5±11.85 186.2±8.17 and 200.1±21.34 g/kWh respectively. The flow rate at 0.140 m3/s was the best condition because it had high specific moisture extraction rate.

This research aimed to investigate the suitable method to product osmotically dehydrated banana peels and determine its shelf life as well as consumer acceptation. It was found that the proper method was the slow osmotic dehydration process with 30 40 and 50% of syrup (sucrose solution). This method led to the highest appearance color and flavor scores as accessed by the consumer. Therefore the slow osmotic dehydration process was selected for further study relating to the ratio between salt and malic acid (3:2 3:3 and 2:3 of syrup weight). The result show that no differences in appearance color flavor and texture scores were found among treatments however the sample treated with salt and malic acid in the ratio of 3:3 obtained the highest taste score. Thus the suitable process to produce the osmotically dehydrated banana peels was slow process with salt and malic in the ratio 3:3. According to the shelf life study the sample (100g) packed in metallic foil still compiled with Thai community standard of fruit and vegetable products during 12 weeks of storage under 25-30 °C. In addition the consumers also accepted the selected osmotically banana peel product.

This research is to develop and experiment the hybrid solar dryer by using cultivated banana as the ingredient in the experiment. The objective is to design create and test the hybrid solar dryer that using heat energy with infrared heater. The result from the experiment of drying cultivated banana at night-time by using heat energy from infrared heater is found that at night-time experiment cultivated bananas moisture is decrease more than at day-times experiment for 61.25 %. The temperature inside the hybrid solar dryer at night when using heat energy from infrared heater is at 49.1-55.0°C. Using heat from sunlight together with infrared heater cause the cultivated bananas moisture to decrease better approximately 27 % when compare to drying with heat energy by only sunlight.