...Sweet is one of the five main tastes. It has smooth and round notes in its flavor profile. Sweet is a naturally occurring flavor in many foods, including fruits, berries, winter squashes, sugarcane, and honey. The sweet taste in these foods is due to a higher sugar content. Sweetness is characteristic of desserts and is used as an accent in savory foods.
...Sour is one of the five main tastes. It is tart and bright, sometimes with a mouth-puckering quality. Sour is a naturally occurring flavor found in many foods, including citrus, vinegar, various dairy products, and certain fruits. Sour is used to enhance a dish or drink and is used as both a main and complimentary flavor.