Vegetable was very dull, typically comprising mainly some staple product made from rice, rye, barley, wheat, millet or maize. The addition of vegetable matter provided some variety to the diet. The staple diet of the Aztecs in Central America was maize and they cultivated tomatoes, avocados, beans, peppers, pumpkins, squashes, peanuts, and amaranth seeds to supplement their tortillas and porridge. In Peru, the Incas subsisted on maize in the lowlands and potatoes at higher altitudes. They also used seeds from quinoa, supplementing their diet with peppers, tomatoes, and avocados. In Ancient China, rice was the staple crop in the south and
Vegetable oil refining oil, known as a triterpene, which is transformed into alkanes by a different process. Based on its feedstock green diesel could be classified as biodiesel; however, based on the processing technology and chemical formula green diesel and biodiesel are different products. The chemical reaction commonly used to produce biodiesel is known as transesterification. Vegetable oil and alcohol are reacted, producing esters, or biodiesel, and the coproduct, glycerol. When refining vegetable oil, no glycerol is produced, only fuels. Various stages of converting renewable hydrocarbon fuels produced by hydrotreating is done throughout energy industry. Some commercial examples of vegetable oil refining are