Agave nectar (more accurately called agave syrup) is a sweetener commercially produced from several species of agave, including Agave tequilana (blue agave) and Agave salmiana. Agave syrup is sweeter than honey and tends to be less viscous. Most agave syrup comes from Mexico and South Africa. To produce agave syrup from the Agave americana and A. tequilana plants, the leaves are cut off the plant after it has been growing for seven to fourteen years. The juice is then extracted from the core of the agave, called the piña. The juice is filtered, then heated to break the complex components (the polysaccharides) into simple sugars.[citation needed] The main polysaccharide is called inulin or fructosan and is mostly fructose. This filtered juice is then concentrated to a syrupy liquid, slightly thinner than honey. Its color varies from light- to dark-amber, depending on the degree of processing. Agave salmiana is processed differently from Agave tequiliana. As the plant develops, it starts to grow a stalk called a quiote. The stalk is cut off before it fully grows, creating a hole in the center of the plant that fills with a liquid called aguamiel. The liquid is collected daily. The liquid is then heated, breaking down its complex components into fructose and glucose and preventing it from fermenting into pulque. An alternative method used to process the agave juice without heat is described in a United States patent for a process that uses enzymes derived from the mold Aspergillus niger to convert the inulin-rich extract into fructose. Aspergillus niger, a fungus commonly used in industrial fermentations, is "generally recognized as safe" (GRAS) by the U.S. Food and Drug Administration.