Why does chopped turmeric turn brown in air exposure?

Question

Learn why fresh chopped turmeric turns brown when exposed to air. Discover the science of oxidation and how to keep it bright and yellow.

Answer 1

Chopped turmeric turns brown upon air exposure due to oxidation of its curcuminoids, the compounds responsible for its vibrant yellow color and antioxidant properties. This reaction is accelerated by light and heat.

Detailed Explanation:

Turmeric's characteristic yellow hue comes from compounds called curcuminoids, primarily curcumin. When turmeric is chopped, the increased surface area exposes these curcuminoids to oxygen in the air. This exposure triggers an oxidation reaction. Oxidation is a chemical process where a substance loses electrons. In the case of turmeric, the curcuminoids lose electrons when they react with oxygen. This change in the chemical structure of the curcuminoids alters their light-absorbing properties, causing them to appear brown instead of yellow. The browning is similar to what happens when you cut an apple and it turns brown; it's a natural chemical reaction. The rate of browning is influenced by factors like temperature and light intensity. Higher temperatures and brighter light can speed up the oxidation process.

Pro Tip:

To minimize browning, store chopped turmeric in an airtight container in a cool, dark place. You can also add a squeeze of lemon juice, as the acidity can help slow down the oxidation process.