Capsaicinoids synthetic

The threshold values obtained by this improved procedure for the different capsaicinoids and some synthetics are given in Table X. These values were used to calculate actual pungency of capsicum extract from the gas chromatographic determination of individual capsaicinoids, and a significant correlation with sen-sorily estimated pungency was found (See later, Figure 3). 

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). 

However, the values by any of these methods measuring total capsaicinoids would give a low correlation with pungency, when there are high proportions of the Cb and Cio capsaicinoids, or when there is gross adulteration with synthetics. The detection... 

The estimation of individual components and different synthetics was effectively achieved by gas chromatography after simple silylation (10). Figure 2 shows the separation obtained, clearly away from other volatiles in a capsicum extract. The individual capsaicinoids were quantitated in relation to vanillyl octanamide as the internal standard chosen, because it eluted just prior to the capsaicinoids and the response factors of the capsaicinoids with reference to this standard were close to unity. The standardised conditions were as follows Silylation with N,0-bis (trimethylsilyl)-trifluoroacetamide in tetrahydrofuran gave clear rapid reaction at room temperature. The silylated extracts were injected directly on to a stainless steel column of 2 m x 3 mm, filled with 3% SE-30 on Chromosorb-GHP, (100-120 mesh) the column temperature was programmed from 170° to 215°C at 4°/min. and held at 215°C for 10 minutes. The injection port temperature was important for rapid volatilisation of all the components without decomposition, and was fixed at 200°C. The flame ionisation detector temperature was kept at 250°C, and nitrogen flow at 20 ml/min. The percentages of the individual capsaicinoids were calculated from the areas of the peaks, the response factors, and the weight and area of the reference compound. 

It is, therefore, clearly possible to evaluate by instrumental methods the quantity of synthetics present as adulterants in a sample of capsicum extract or oleoresin, to determine individual capsaicinoids or total capsaicinoids, and to predict the pungency of the capsicum preparations. 

Figure 1. Tracings of separation of total capsaicinoids of capsicum extracts and reference pure compounds by paper chromatography Spot (1) red capsicum Spot (2) natural capsaicinoids pure Spot (3) green capsicum fresh and Spot (4) synthetic capsaicin (C) color (F) fat, and (Cv), capsaicinoids/capsaicin ((27) and...

The combination of these elements generates the diversity of capsaicinoids reported to date. Generally, the major constituent of the capsaicinoid soup are capsaicin (la) and its dihydroderivative (lb). Commercial capsaicin potvder is an approximately 5 1 mixture of capsaicin and dihydrocapsaicin, while analytical (>95 %) capsaicin contains mainly nonivamide as impurity. Despite its trivial name of synthetic capsaicin, nonivamide is a natural trace constituent of capsicum oleoresin, and concentration >3 % are indicative of adulteration [26]. The addition of nonivamide to capsicum oleoresin has been detected in products from both the food and the pharmaceutical markets. Some of them have been found to contain exclusively nonivamide, even though capsaicin is the only individual constituent of capsicum oleoresin to be approved by the FDA for human use [26]. 

Since hot pepper is important for the food and the pharmaceutical industries, a range of different methods have been developed for the analysis of capsaicinoids in plant material and finished products. The separation of CPS (la) and nonivamide (11) is especially challenging, since these compounds have similar behavior in many chromatographic conditions. Since synthetic nonivamide is the most common adulterant of capsicum oleoresin, various strategies have been suggested to overcome this problem. Capillary GC does not require previous derivatization of capsaicinoids, but its separatory power seems lower than that of HPLC, currently the most popular technique for the quantization of capsaicinoids. GC is, however, the method of choice for the analysis of the acyl moieties of capsaicinoids as methyl esters. These can be directly produced from capsaicinoids by oxidative N-dealkylation with DDQ (2,3-dichloro-5,6-dicyanobenzoquinone), followed by alcoholysis of the resulting amides with methanol in the presence of an acidic resin (Scheme 4.4) [41]. 

Other capsaicinoids are available. Pelargonic acid vanillylamide (PAVA or nonivamide), shown in Figure 12.10, is a synthetic form of capsaicin. Nonivamide was first synthesized by Nelson (1919). Nonivamide was originally found to be a minor component in Capsicum annum peppers (Constant and Cordell, 1996) however, the majority of PAVA is derived from synthesis rather than extraction from natural plant sources. As a result, the composition and concentration of PAVA can remain consistent (Haber et al, 2007). 

Apart from the organoleptic determination of pungency (Scoville heat units [239]), the capsaicinoids are determined quantitatively, photometrically or singly best with HPLC (e.g. [240, 241, 242]). The quantitative determination of pelargonic acid vanil-lylamide, which is available synthetically and, therefore, prone to adulteration, is of special importance. This substance is only present in small amounts in genuine mixtures. 

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