**3. Chemistry and pungency**

The pungency of *Capsicum* pods is mainly attributed to the presence of a group of closely related compounds called capsaicinoids. Capsaicinoids refer to a group of pungent alkaloids that accumulate in the placenta of matured *Capsicum* pods [12]. Chemically, these are acid amides of vanillylamine with C9–C12 branched-chain fatty acid. All capsaicinoids possess a common 3-hydroxy-4-methoxybenzylamide (vanilloid) skeleton, but differ in their hydrophobic alkyl side chain. Differences in the side chain include saturation of the carbon carbon double bond, absence of a methyl group and also changes in the length of hydrocarbon chain [13]. Some important capsaicinoids are capsaicin, followed by dihydrocapsaicin, nordihydrocapsaicin, homodihydrocapsaicin, and homocapsaicin. Capsaicin and dihydrocapsaicin together account for approximately 80% of total capsaicinoids content of *Capsicum* pods. These two compounds are the most important and potent members of capsaicinoids family [14]. The chemical structures of capsaicinoids are displayed in **Figure 2**.

Most of the *Capsicum* species cultivated in India contain around 1% of capsaicinoids, but *Capsicum chinense* L. (*Bhut Jolokia*) and *Capsicum frutescens* (*Dhan Jolokia*) possess around 2–4% of capsaicinoids [15]. However, though seven different indigenous varieties of *Capsicum* are found to be cultivated in the Assam state of India, the *Bhut Jolokia* and *Dhan Jolokia* have been documented to be the most potential *Capsicum* varieties in terms of their capsaicinoids content and level of pungency [16]. The capsaicinoids content (%) of indigenous *Capsicum* varieties of India is depicted in **Table 2**.

It is noteworthy that the capsaicinoids content is a measure of the degree of hotness or the level of pungency of *Capsicum* pods. However, it is also responsible for medicinal properties as well as for the nutritional value of *Capsicum* spice. The Defense Research Laboratory, Tezpur, India reported that the potential of the *Bhut* 

#### **Figure 2.** *Chemical structures of capsaicinoids.*


#### **Table 2.**

*Capsaicinoids content (%) of indigenous* Capsicum *varieties of India [15, 16].*

*Jolokia* is comparable with that of the Red Savina Habanero of Mexico in terms of Scoville Heat Units (SHUs) [17]. The pungency of *Bhut Jolokia* was recorded 855,000 SHU, while it was 577,000 SHU for Red Savina Habanero. Studies at the New Mexico State University also reported that *Bhut Jolokia* possessed 1,001,304 SHUs, whereas Red Savina had 248,556 SHUs [18]. In September 2006, the *Bhut Jolokia* was officially recognized as the world's hottest *Capsicum* variety measuring over 1,000,000 SHUs according to the Guinness Book of World Records [19].
