Result and Discussion
Optimum heating time for rice cracker
The study of optimum heating time was carried out at 150-155oC and sampling was conducted every 2 min. It was found that moisture content and water activity decreased with time (Figure 1). Generally, if water activity is less than 0.6, microorganisms cannot grow and some chemical reactions will be reduced. At 14 min, the moisture content was 5.07% and water activity was 0.59. However, this water activity was near the border line, hence heating time was set at 16 min resulting in water activity of 0.31 ± 0.01.