Why does stored urad dal develop dark patches?

Question

Learn what causes dark patches on stored urad dal. Discover if it's a sign of moisture damage, mold, or simply a natural aging process.

Answer 1

Urad dal develops dark patches during storage due to enzymatic browning and oxidation of phenolic compounds present in the dal's seed coat. This process is accelerated by moisture, heat, and exposure to air.

Detailed Explanation:

Urad dal, like many other legumes, contains phenolic compounds. These compounds are naturally present in the seed coat and contribute to the dal's color and antioxidant properties. When urad dal is stored, several factors can trigger enzymatic browning:

1. Enzyme Activation: Enzymes like polyphenol oxidase (PPO) are naturally present in the dal. These enzymes become active when the dal is exposed to moisture.

2. Oxidation: In the presence of oxygen, PPO catalyzes the oxidation of phenolic compounds. This reaction leads to the formation of quinones, which are highly reactive.

3. Polymerization: The quinones then polymerize to form melanins, which are dark-colored pigments. These melanins are responsible for the dark patches you see on the urad dal.

4. Moisture and Heat: High moisture levels and elevated temperatures accelerate these enzymatic reactions, leading to faster browning. Improper storage conditions exacerbate the problem.

The dark patches don't necessarily mean the urad dal is spoiled or unsafe to eat, but they can affect its appearance and potentially its flavor.

Pro Tip:

To prevent dark patches, store urad dal in an airtight container in a cool, dry place away from direct sunlight. Adding a few dried red chilies or neem leaves to the container can also help absorb moisture and deter pests, further preserving the dal's quality.