3. Results and discussion
3.1. Microstructure of the dried rice noodle
Surfaces of the dried rice noodles were different; more pores formed on the side opposite to the tray (the rough surface) while a reduced presence of pores developed on the side in contact with the tray (the smooth surface) (Fig. 1). Evaporation of water was easier from the rice noodle surface not in contact with the tray, resulting in a larger presence of pores. This evidence was presented for the first time here using SEM analysis. The amount, size and the depth of the pores of both noodle surfaces were reduced with increasing NaCl concentration. This suggested that the noodle surface became smoother with the presence of NaCl. The cross-section of dried rice noodle without NaCl revealed that the dried rice noodle structure was dense and compact. This result was consistent with the cross-section of dried rice noodle reported by Kongkiattisak and Songsermpong (2012). An increase in the NaCl concentration had no effect on the internal structure of dried rice noodle.