Rice Grain Physical and Chemical analysis from Paddy Drying by Using a Solar Tunnel Dryer at Prathum Tani, Thailand

This paper presents the RD31 rice grain physical and chemical analysis from paddy drying by using a solar tunnel dryer. RD31 paddy was dried in a compact solar tunnel dryer, with a drying chamber volume in the size of 0.113 m(3) and 2.112 m(2) flat plate collectors. The experiment was performed on May 15, 2014 at Faculty of Industrial Technology Vallaya Alongkorn Rajabhat University Pathum Tani Thailand. The samples for testing were three varieties of Thai rice namely RD31 (from the farm), RD31 (dried in a solar tunnel dryer), and Prathum Tani 1 (from the market). The test consists of RD 31 dried by a solar tunnel dryer; the moisture content was reduced to about 14 wt. %. Then 3 varieties of rice were milled and sent to the laboratory for analyzing physical and chemical properties, repeated 3 times. The results showed that the average drying temperature was 67.75 degrees C. The paddy moisture reduction content was estimated from 49.96 to 14.64 MC (% w. b.) within 6 hours. All dimensions of RD31, dried by using solar tunnel dryer milled rice were closely related to those of the Prathum Tani 1, purchased from the market. The ratio of length to width of 3 samples: RD31 (raw rice), RD31 (dried in solar tunnel dryer), and Prathum Tani 1 (from the market) were 3.54, 3.47, and 3.44, respectively. 3 rice grain varieties were slender. The yield percentage was 60%, 75 %, and 70 %, respectively. Results from chemical test showed that the alkaline spreading value were 4-5, 3, and 2, respectively. The quality of the RD31 rice grain dried in a solar tunnel dryer passed the Thailand Ministry of Agriculture rice quality standard