Question

Why does the Lugol’s test (iodine test) give dark blue color of amylase- starch
mixture after boiling of this mixture?

Answer 1

Once amylose is added, it forms another CT complex, Here, the amylose acts as a charge donor and the polyiodide as an acceptor. This complex absorbs light of a different wavelength than polyiodide, and the color turns dark blue.