Question

Amylase and starch are mixed and placed at 0 degrees. after the iki test, the solution turns black. a benedict's test yields a negative result. was the starch digested? how do you know?

Answer 1

The starch is not digested.

Amylase is the enzyme that digest starch to Maltose

In iki test, which is also iodine test, it is a test for presence if starch. It turns iodine color from brown to black. Therefore, we know that starch still exist if the color turns black.

Second, benedicts test is a test for reducing sugars, such as glucose or Maltose. Negative results mean no Maltose is detected. So, we can also figure out that no Maltose is produced.

Therefore, the original starch still exists and the product Maltose does not exists, so starch is not digested.