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Piperine determination in pepper ( Piper nigrum L.) and its oleoresins—a reversed‐phase high‐performance liquid chromatographic method
Author(s) -
Wood A. B.,
Barrow Maureen L.,
James D. J.
Publication year - 1988
Publication title -
flavour and fragrance journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.393
H-Index - 70
eISSN - 1099-1026
pISSN - 0882-5734
DOI - 10.1002/ffj.2730030202
Subject(s) - piperine , chemistry , pepper , chromatography , piper , high performance liquid chromatography , solvent , pungency , piperaceae , organic chemistry , traditional medicine , medicine , food science
A reversed‐phase high‐performance liquid chromatographic (HPLC) method for the selective determination of piperine, in pepper or its oleoresins, is described and evaluated. It employs a fully‐capped, bonded C 18 stationary phase (ODS‐2) and an acetonitrile ‐ aqueous acetic acid mobile phase, with ultraviolet (UV) detection. Piperine is extracted from ground pepper by refluxing 3h with ethanol (96% v/v), whilst homogenized oleoresins are simply dissolved in the same solvent. At all stages, light must as far as possible be excluded from the solutions, so as to minimize the photoisomerization of piperine. Quantitation, based on peak areas, is achieved by reference to purified piperine as external standard. Results obtained for a range of samples at four different detection wavelengths showed virtual wavelength‐independence, indicating a good degree of peak purity. All samples were also analysed by the ISO spectrophotometric method (ISO 5564, 1982), which invariably yielded higher results because of the contributions from other pepper alkaloids (e.g. piperyline and piperettine) to the UV absorption. Since some of these other alkaloids are believed to contribute to the pungency of pepper, the HPLC method is proposed as complementary to the spectrophotometric method, rather than as a replacement for it. The HPLC method gave results with relative standard deviations less than ±3% for black or white pepper, and piperine values between 75.8% and 90.9% of those yielded by spectrophotometry. Given suitable standards, its use could perhaps be extended to cover the quantitation of other pepper alkaloids, two of whose peaks were tentatively identified. Limited experiments on the use of a synthetic capsaicinoid as an internal standard for piperine determination gave encouraging results, and suggested that piperine might be determined satisfactorily with this means of standardization used in conjunction with an automatic injection system, provided that light could be adequately excluded from solutions awaiting injection.