Capsaicinoids: Occurrence, Chemistry, Biosynthesis, and Biological Effects

Capsaicinoids are a family of secondary plant non-toxic alkaloid metabolites that occur in chili peppers. This chapter aims to present an updated account of the occurrence, chemistry, biosynthesis, and biological properties of capsaicinoids as an important family of phytochemicals from fruits and vegetables. All of the identified capsaicinoids in the Capsicum fruits are vanillylamides of branched fatty acids, with 9-11 carbons, of which capsaicin (II) and dihydrocapsaicin (III) occur in quantities greater than 80%. The biosynthesis pathway of capsaicin follows two distinct pathways. One pathway runs through the synthesis of vanillylamine moiety via phenylpropanoid shikimate/arogenate. The second leads through the branched fatty acid moiety derived from L-valine. The pungency of chili peppers is assessed by sensory analysis. The most commonly used method is the Scoville test. This assay is based on a sensory panel of some individuals who are asked to record the pungency intensity of a given sample.