摘要:

AbstractA 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 C18stationary 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 awaiti

ISSN:0882-5734    

DOI:10.1002/ffj.2730030202

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractEssential oil extracted from Comptonia peregrina (L.) Coulter (sweet fern) harvested in the lake Saint‐Jean area (Québec) has been analysed using GC‐MS and Kovats indices techniques. The main identified products are (E)‐2‐hexenal (16.8–19%), β‐caryophyllene (10.7‐13.3%), 1,8‐cineole (9‐10%), myrcene (5‐7%), and linalol (4‐5.4%). More than fifty constituents, mainly oxygenated compounds, are reported for the first tim

ISSN:0882-5734    

DOI:10.1002/ffj.2730030203

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe literature reports few studies ofSequoiadendron giganteumBuchh. leaf oils. The essential oil was obtained by steam distillation from a natural population approximately 110 years old on the one hand and of a young population of two origins (France and the USA) on the other hand.Fifty‐two constitutents were identified by GC‐MS. The myrcene content is higher in the young population than in the mature

ISSN:0882-5734    

DOI:10.1002/ffj.2730030204

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractEssential oils obtained from the aerial parts ofThymus mongolicusandT. quinquecostatuswere analysed by GC and GC‐MS. The main constituents of the oils were linalol, carvacrol, and geranyl acetat

ISSN:0882-5734    

DOI:10.1002/ffj.2730030205

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe chemical composition of eleven mint species, grown in Piedmont (North West Italy) in 1985 and 1986 were studied in relation to environmental factors. Thermoperiod and rainfall were measured and correlated with qualitative and quantitative oil composition changes. Temperature and rainfall changes were found to affect the oil composition of some of them, particularly peppermint. The degree of adaptation and some genetic considerations were also discussed.

ISSN:0882-5734    

DOI:10.1002/ffj.2730030206

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe chemical composition of the ginger oils (obtained by hydrodistillation) of fresh and dried rhizomes of Nigerian origin were investigated by means of a combination of column chromatography, high resolution gas chromatography (GC) and GC‐MS. The essential oils contained mainly mono‐ and sesqui‐terpenoids of which geranial, neral, 1,8‐cineole, zingiberene, β‐bisabolene and β‐sesquiphellandrene were the major components. Among the 54 constituents identified, (E)(E)‐α‐farnesene, viridiflorol and (E)(E)‐farnesal have not been found

ISSN:0882-5734    

DOI:10.1002/ffj.2730030207

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe essential oil isolated from rhizomes ofAmomum pavieanumPierre&Gagnep., which are used as seasoning agent in Thailand, was analysed by capillary GC. Forty‐one components of the oil were identified, among which were many trace components. The identity of the components was confirmed by GC‐MS using an ion trap detector. The oil was characterized by a high content of methylchavicol (9

ISSN:0882-5734    

DOI:10.1002/ffj.2730030208

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractEight essential oil components added to growth media at concentrations ranging from 50 to 400 ppm were studied with respect to their inhibitory effects against 10 common food‐borne bacteria at two inoculum levels. The growth of the bacteria in culture media containing 50 ppm carvacrol or 100 ppm cuminaldehyde with 2.0% sodium chloride, 0.05% ascorbic acid or 0.5% sucrose in various combinations was also determined. Of essential oil components tested, carvacrol, thymol and cuminaldehyde were inhibitory at some concentrations, except againstPseudomonas aeruginosa. The inoculum level had little effect on the inhibition. Pair combinations were not effective on any bacteria. Carvacrol or cuminaldehyde, when used in combination with sodium chloride and ascorbic acid, exhibited an enhanced inhibitory effect on certain bacteria. Thus, some combinations completely inhibited the growth of Ps.aeruginosa. Bacillus cereusalso showed some sensitivity to these combination

ISSN:0882-5734    

DOI:10.1002/ffj.2730030209

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0882-5734    

DOI:10.1002/ffj.2730030210

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0882-5734    

DOI:10.1002/ffj.2730030201

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY