As Turmeric is a reddish-yellow rhizome. The more prominent yellow color is due to the presence of the xanthophyll pigment, while the reddish-orange color comes from carotene pigment.

When turmeric is dissolved in water and a pinch of lime is added to it, the organic acids are neutralized by alkaline lime. 

Thus, as a result, the yellow xanthophyll is suppressed an orange-red carotene pigment becomes more prominent. So turmeric turns red in color.

Exposure of turmeric powder or turmeric water to quick lime neutralizes any of the two phenolic protons and triggers the conversion of the original benzenoid structure with yellow appearance into a quinoid structure with red colour. 

That is why turmeric water, when mixed with quicklime, turns red.