Why does adding lemon juice to a blueberry smoothie make it change color from purple to pink?

Acidity Explanation:

Acidity plays a crucial role in changing the color of a blueberry smoothie from purple to pink when lemon juice is added. Blueberries are naturally purple in color due to the presence of anthocyanin pigments. These pigments are responsible for the purple hue of blueberries.

When lemon juice, which is acidic, is added to the blueberry smoothie, it reacts with the anthocyanin pigments in the blueberries. The anthocyanin pigments are sensitive to changes in pH levels, and when they come into contact with acidic substances like lemon juice, they change color. In this case, the purple anthocyanin pigments in the blueberries shift to a pink hue, resulting in the change of color in the smoothie from purple to pink.

The change in color is a visual indicator of the chemical reaction taking place between the acidic lemon juice and the anthocyanin pigments in the blueberries. The higher acidity in the lemon juice alters the pH levels in the smoothie, leading to the color transformation. This phenomenon is commonly observed in food science and is a simple yet fascinating example of how acidity can impact the color of food items.