It has always disappointed me as an inorganic chemist, that every
first year student can tell you the formula and structure of
salt, but not even at the postgraduate level will you find many
students that have any idea at all about what is in pepper!
A wealth of information is available from the Northern
Carolina Cooperative Extension Service on growing commercial
includes Bell peppers and pim(i)ento (the pepper).
A recent paper in J. Sci. Food Agric., 1995, 67, 189-196 by
S.M. van Ruth, J.P. Roozen and J.L. Cozijnsen, describes flavour
components in Bell peppers.
Out of 47 compounds identified, 12 could be detected by
assessors at a sniffing port on a GC. A simulation of their GC is
shown as a sensitive map GC/MS, and the MS files can be
downloaded in JCAMP-DX format by selecting the appropriate
The 12 compounds were:
other compounds found in reasonable quantities were:
- 3 (2220) 2-Methylpropanal
- 9 2-Methylbutanal MS
- 10 3-Methylbutanal
- 13 (2370) 2,3-Butanedione
- 15 (3382) 1-Penten-3-one
- 19 (2557) Hexanal MS
- 25 (2540) Heptanal
- 29 β-Ocimene
- 35 trans-3-Hepten-2-one
- 39 Dimethyltrisulfide
- 45 (3132) 2-isobutyl-3-methoxypyrazine PDB
- 47 (3639) β-Cyclocitral
The numbers on the left are the peak numbers identified in their
GC, the numbers in brackets are the FEMA codes (Flavor and
Extract Manufacturers' Association of the USA).
- 14 (3098) Pentanal
- 21 1-Methyl-1H-pyrrole
- 23 (3584) 1-Penten-3-ol
- 26 (2633) (R)-(+)-Limonene
- 36 cis-2-Heptenal
- 40 (2782) Nonanal PDB
- 42 (2805) 1-Octen-3-ol
- 44 (2362) Decanal PDB
The structure of capsaicin, one of the chemicals giving the
pungent flavour, is shown above.
The compound described as the character imparting compound in
Bell peppers is
2-isobutyl-3-methoxypyrazine. This very powerful odourant has
a threshold in water of 1 part in 1012.
Jamaica is well known for hot peppers such as "Scotch Bonnet".
Work is in progress on establishing a hotness scale for these
peppers and more on this later.
In the meantime, check out these links on
spices and chiles, the
fire and spice page.
An article in Chem and Eng News, March 4, 1996, pps30-31,
outlines the novel use of hot peppers as an additive to bird seed
to make it unpalatable to squirrels. Apparently birds are not
affected by the heat but the squirrels avoid the birdseed treated
with sufficient pepper to give a 20,000 Scoville heat unit.
Copyright © 1995-2014 by Robert John
Lancashire, all rights reserved.
Return to Chemistry, UWI-Mona,
Created and maintained by Prof. Robert J.
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.
Created Feb 1995. Links checked and/or last modified
8th August 2014.