Quercetin is a flavonoid found in many fruits, vegetables, and grains. It is known for its antioxidant properties and potential health benefits, including anti-inflammatory and anti-cancer effects. Quercetin contributes to the sensory characteristics of foods, providing a bitter taste. It is commonly found in onions, apples, berries, and tea. Its role in food includes enhancing flavor and providing health benefits, making it significant in both culinary and nutritional contexts.