DRYING OF HOT PEPPERS
David R.McGaw1, Edward Commissiong1, Rosalie Holder1,
Nigel Seepaul1 and Anderson Maxwell2
1. Department of Chemical Engineering, University of the West Indies,
St Augustine, Trinidad and Tobago
2. Department of Chemistry, University of the West Indies, St Augustine,
Trinidad and Tobago
KEYWORDS: Hot Peppers, Drying Characteristics, Volatile losses, Retained
fixed oils
ABSTRACT
Pungent peppers belonging to the family Solanaceae and classified as the
variety Capsicum annum L. Var. Annum (also known as Scotch Bonnet and Bell
peppers) are widely cultivated in the Caribbean. They are renowned for
their flavours, which originate from both the volatile oil and the fixed
oil, and are marketed both as fresh and dried products. The fixed oil gives
rise to the heat or pungency in the peppers, the major component of which,
capsaisin, is also used in pepper sprays.
Since there is no reported work on the drying characteristics of these
types of peppers, nor on the effect of drying on the retention
characteristics of the flavour components, a programme of work has been
carried out to investigate both these aspects. Thus whole peppers were
dried in both oven and vacuum driers, with the flavour components being
trapped out during vacuum drying. Drying times to reach a moisture content
of 18% w.b. for atmospheric oven drying reduced from 166 hours at 45°C down
to 11.5 hours at 60°C. Drying times for vacuum drying were generally lower,
reducing from 33 hours at 40°C down to 20 hours at 50°C. Application of
reported drying equations showed Page's equation to give the best fit for
both types of drying.
Volatile oils were driven off in the drying process, their compositions,
as measured by Gas Chromatography (GLC) being similar to those reported in
the literature. The fixed oils were characterised using Nuclear Magnetic
Resonance Spectrometry (NMR), with the quantity of the major component,
i.e. the capsaicinoids being quantified by High Performance Liquid
Chromatography (HPLC). The capsaicinoid contents of the dried peppers had
higher equivalent values than any others reported in the literature.
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