Milk and Starch solution are capable of showing "Tyndall effect" because these are colloidal solutions.

A colloid is a kind of solution in which the size of solute particles is intermediate between those in true solutions and suspensions. Due to the relatively smaller size of particles, as compared to that of a suspension, the mixture appears to be homogeneous. But actually, a colloidal solution is a heterogeneous mixture, for example, milk. Because of the small size of colloidal particles, we cannot see them with naked eyes. But, these particles can easily scatter a beam of visible light known as "Tyndall effect".