Relationship between saliva and starch
Saliva is helpful to digest starch
Put bread crumbs into two test tubes with the same amount.Inject 2ml salivary amylase into NO.1 tube,and inject 2ml clean water into NO.2 tube,then mix each tube evenly,and then put the two tubes into 37℃ water for 5-10 minutes.Take the tubes out,drop two drops of iodine into each of them,shake evenly.NO.1 tube does not change into blue,but NO.2 tube does.