Capsaicin pungency

The widespread use of the terms pungent or bite component, capsaicin pungency or sensory pungency has tended to be confusing. To recognise the cause and effect relationship clearly, the stimulant should be identified only by its common or chemical... 

Suzuki T, Fujiwake H, Iwai K (1980) Intracellular localization of capsaicin and its analogues, capsaicinoid, in Capsicum fruit. 1. Microscopic investigation of the structure of the placenta of Capsicum annuum var. annuum cv. Karayatsubusa. Plant Cell Physiol 21 839-853 Ohta Y (1963) Physiological and genetical studies on the pungency of Capsicum IV. Secretory organ, receptacles and distribution of capsaicin in the Capsicum fruits. Jap J Breed 12 179-183... 

Chemesthesis. The term chemesthesis has been introduced to classify thermal and painful sensations experienced in the mouth (26). Chemesthesis refers to a chemical sensibility (mouthfeel) in which certain chemicals direcdy activate nerve fibers at the level of the basal membrane in the mouth. The sensations are analogous to similar effects at the skin surface where there is a close anatomical and functional relationship. Sensations include the "hot" of capsaicin and piperine, which are active components of chili and pepper, the coolness of menthol and the irritation of chemicals such as salt at high concentrations [FIGURE 4]. Some of the descriptive terms used to make qualitative distinctions in food sensations include pungency, freshness, tingling, burning and sharpness. 

The second most common capsaicinoid is dihydrocapsaicin (DC). Capsaicin and DC together make up 80 -90% of the capsaicinoids found in the fruit. The minor capsaicinoids include nordihydrocapsaicin (NDC) [dihydrocapsaicin with (CH2)5 instead of (CH2)6], homocapsaicin (HC) [capsaicin with (CH2)5 instead of (CH2)4], and homodihydrocapsaicin (HDC) [dihydrocapsaicin with (CH2)7 instead of (CH2)6]. The pungencies of these five pure compounds in Scov-ille Units (SU) are as follows ... 

All these aspects have been recently studied in two publications (10.13). which standardized the dilution test for pungency and clearly established correlations with the estimates of total, and even individual, capsaicinoids. These papers also review the earlier attempts at standardisation. Two approaches are possible use of a fairly homogenous panel to determine the threshold pungency response due to the stimuli or use of a general panel to determine the average threshold of the panel for the stimuli. The second value will have wider applicability in use situations but the first value should be useful for correlative work. The two methods approach one another when panels are screened and trained to avoid all bias factors, and when carefully planned dilution levels, details of panel procedure, treatment of data, and expression of results are adopted. In fact, the results published in the two independent studies (10.13). show close values, 17+0.9 million for natural capsaicinoids and 16.1+0.6 million for pure capsaicin and dihydrocapsaicin. 

Hence, in such samples, it is necessary to know the pungency of the individual capsaicinoids. Recent careful determinations of the pungency thresholds of individual capsaicinoids have shown that the two major components, capsaicin and dihydrocapsaicin, have the same pungency, while the minor related components and the synthetic compounds have only about half, or less, of their pungency (10.24) (Tables II and III). 

The pungency of chilli is measured in multiples of 100 units, from the bell pepper at zero Scoville units to the incendiary Habanero at 300,000 Scoville units. One part of chilli heat per 1,000,000 drops of water rates as only 1.5 Scoville units. The substance that makes a chilli so hot is capsaicin. Pure capsaicin rates over 15,000,000 Scoville units The Red Savina Habanero has been tested at over 577,000 Scoville units (Padilla and Yahia, 1998). Tiwari et al. (2005) identified the hottest chilli variety in the world. A special variety of chilli, Nagarhari, grown in Tezpur (Assam) has been found to possess a pungency of... 

It is interesting to discuss the SEE of capsaicin next, directly after the discussion of the SEE of vanillin. Capsaicin is an amide (containing isoprene units) derivative of vanillin. Ten parts per milhon can be detected by tasting. Capsaicin is the compound responsible for the pungency (heat) of Jalapena and other peppers. It is the pungent principle in fruit of various species of Capsicum Solanaceae. 

There is evidence indicating that the structure-activity requirements for excitation and inhibition are different for capsaicin analogues. Thus, the incorporation of certain long chain fatty acids in capsaicin analogues resulted in desensitising and analgesic activity but also decreased pungency. [56]. 

Urban [20] described a capsaicin-analogue compound (SDZ 249-665), with antinociceptive and anti-hyperalgesic activity as well as reduced pungency. In addition, it does not cause bronchoconstriction or changes in blood pressure. 

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