The leaf on the right shows a positive test for starch in the areas which contained chlorophyll, and a negative test for starch in the areas which lack chlorophyll. This is evidence that ...

Test the leaf for starch using the 4-step starch test. Make another drawing of the leaf. In this drawing show the areas of the leaf that tested positive and those that tested negative for starch.

If it leaves a bright yellow stain ... If the mixture turns blue, it indicates starch, meaning the turmeric may be impure. This test is helpful because it ensures you’re using high-quality ...