Sodium benzoate glycine "N"-acyltransferase into hippuric acid. In combination with ascorbic acid (vitamin C, E300), sodium benzoate and potassium benzoate may form benzene. When tested by the FDA, most beverages that contained both ascorbic acid and benzoate had benzene levels that were below those considered dangerous for consumption by the World Health Organization (5 ppb). Most of the beverages that tested higher have been reformulated and subsequently tested below the safety limit. Heat, light and shelf life can increase the rate at which benzene is formed. Research published in 2007 for the UK's Food Standards Agency (FSA) suggests that certain artificial colors,
Vitamin C and also regenerator of other antioxidants. Plants use multiple pathways to synthesize vitamin C. The major pathway starts with glucose, fructose or mannose (all simple sugars) and proceeds to L-galactose, L-galactonolactone and ascorbic acid. There is feedback regulation in place, in that the presence of ascorbic acid inhibits enzymes in the synthesis pathway. This process follows a diurnal rhythm, so that enzyme expression peaks in the morning to support biosynthesis later on when mid-day sunlight intensity demands high ascorbic acid concentrations. Minor pathways may be specific to certain parts of plants; these can be either identical to the vertebrate pathway