D-Limonene

Limonene is a clear, colorless liquid hydrocarbon classified as a cyclic monoterpene, and is the major component in oil of citrus fruit peels. The D-isomer occurring more commonly in nature as the fragrance of oranges is a flavoring agent in food manufacturing. It is also used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products. The less common L-isomer is found in mint oils and has a piney, turpentine-like odor. (source)