The purpose of this thesis was to assess the temperature effect on saccharification reaction. During baking, maltose content of sweet potato is increasing due to saccharification of starch. Saccharification in sweet potato is an amylase reaction on pasted starch and baking temperature and time are key factors that influence the final content of maltose. Heating will increase degree of starch pasting to favorite saccharification but also the deteriorate activity of amylase. In this study, we developed a constant temperature heating apparatus, which is is monitored by the plate thermal couples and the temperature is controlled by PID controller written in Labview software, for heating sweet potato slice. Under the well-controlled process, a better temperature-time relationship of saccharification will be understood. In the experiment, baking temperatures are controlled from 60°to 90°C in 10°C difference and durations of heating are from 5 to 30 minutes in 5 minutes difference. Results show that the highest maltose conversing was observed at 80°C. On the other hand, activity of amylase decrease after 5 minutes baking but the decreasing trend become smooth after 10 minutes. Furthermore, when baking temperature becomes higher, the degree of pasting starch become higher even with short baking time. In conclusion, the degree of pasting starch is more influential than the activity of amylase in saccharification reaction during baking.