摘要:

AbstractStable isotope dilution assays were developed for 14 important odourants of roasted coffee. The following amounts (mg/kg) were found in the Arabica (I) and the Robusta (II) coffees: 2‐furfurylthiol (1.08 I, 1.73 II), methional (0.24 I, 0.095 II), 3‐mercapto‐3‐methylbutyl formate (0.13 I, 0.115 II), 2‐ethyl‐3‐5‐dimethylpyrazine (0.33 I, 0.94 II), 2,3‐diethyl‐5‐methylpyrazine (0.095 I, 0.31 II), guaiacol (4.2 I, 28.2 II), 4‐vinylguaiacol (64.8 I, 177.7 II), 4‐ethylguaiacol (1.63 I, 18.1 II), vanillin (4.8 I, 16.1 II), (E)‐β‐damascenone (0.195 I, 0.205 II), 4‐hydroxy‐2,5‐dimethyl‐3(2H)‐furanone (109 I, 57 II), 3‐hydroxy‐4,5‐dimethyl‐2(5H)‐furanone (1.47 I, 0.63 II), 5‐ethyl‐3‐hydroxy‐4‐methyl‐2(5H)‐furanone (0.16 I, 0.085

ISSN:0882-5734    

DOI:10.1002/ffj.2730100102

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

Abstract[2H6]‐3‐Mercapto‐3‐methylbutyl formate was synthesized to be used as internal standard in the quantification of the corresponding unlabelled thiol which belongs to the character impact flavour compounds of roasted coffee.1H‐NMR,13C‐NMR and mass spectra are given and compared with those of the unlab

ISSN:0882-5734    

DOI:10.1002/ffj.2730100103

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe release of aromas during eating of mint‐flavoured sweets was investigated by collecting volatiles in the expired air from the noses of human subjects (nosespace) on Tenax and determining the amounts of eleven key volatiles by GC‐MS. The variation in aroma release was first measured by analysing the amounts of the volatiles from one person who chewed mints on four separate occasions. No attempt was made to standardize eating patterns. There was some variation in theamountsof volatiles in the four replicates but thepatternof volatiles was similar. The degree of similarity was assessed by expressing each volatile as a percentage of the total peak area (normalization) which reduced the variation between replicates as measured by the coefficient of variation. Aroma release on chewing was then tested using nine people who ate mints on four occasions. All the aroma profiles showed a similar pattern and normalization of the data again improved the degree of similarity between the profiles of the assessors. When mints were sucked rather than chewed, the aroma profiles showed greater variation, probably due to greater differences in the way individuals suck and the associated airflow through the mouth and nose. Using headspace analysis of whole mints, crushed mints and mints crushed in water (to simulate the hydration of mints in the mouth), it was clear from the volatile profiles, that crushing increased the amounts of volatiles in the headspace but the addition of water changed the volatile profile. A methanolic extract of mints was also prepared and analysed to give an estimate of the total volatile content. Analysis of the aroma profiles using pattern recognition software indicated the degree of similarity and showed that the crushed mint in water profile was most similar to nosespace profile, although not similar enough to be an adequate mo

ISSN:0882-5734    

DOI:10.1002/ffj.2730100104

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractEssential oils were isolated fromArtemisia abrotanumL.,A. absinthiumL.,A. albaTurra,A. annua, L.,A. campestrisL. ssp.campestris, A. campestrisL. ssp.borealis(Pallas) H. M. Hall et Clements,A. chamaemelifoliaVill.,A. genipiWeber,A. glacialisL., A.petrosaBaumg. ssp.erianthaTen.,A. umbelliformisLam.,A. vallesiacaAll.,A. verlotiorumLamotte,A. vulgarisL., growing spontaneously in the north‐west Italian Alps. GC‐MS analyses were carried out in order to determine the percentage composition of the oils. The data obtained were statistically processed in order to partition the species according to their oil composition. The results showed the presence of two main groups of plants. The first group composed ofA. genipi, A. umbelliformisandA. petrosawas characterized by the presence of α‐thujone, while camphor and 1,8‐cineole characterized the oil of the remainin

ISSN:0882-5734    

DOI:10.1002/ffj.2730100105

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA fully automated HPLC‐HRGC‐MS(ITD) system was used for the analysis of the terpene hydrocarbon fraction of eight essential oils: bergamot, lemon, mandarin, sweet orange, bitter orange, grapefruit, clementine and Mexican lime. The system allows the isolation by LC of the hydrocarbon fraction followed by transfer into the GC and identification of the single components by MS(ITD).LC‐GC‐MS coupling gives more accurate results than those obtained from GC‐MS analysis of the whole essential oil. The results obtained were compared with those reported in the literature, and represent a reference for the characterization of the citrus essen

ISSN:0882-5734    

DOI:10.1002/ffj.2730100106

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe essential oil ofMinthostachys spicata(Benth.) Epl. was obtained by hydrodistillation from aerial parts of the plant in a 0.53% yield related to the dry weight. The composition of the oil was analysed by gas chromatography and gas chromatography‐mass spectrometry. The oil was found to contain 54.7% oxygenated monoterpenes, the major compounds being menthone (14.5%), 2‐hydroxy‐p‐menth‐1‐en‐3‐one (12.5%) and pulegone (9.7%). Spathulenol (4.9%) was the principal oxygenated sesquiterpene. There were few monoterpene hydrocarbons (3.2%) with limonene as the main component of this fraction. β‐Caryophyllene (4.9%) and viridiflorene (3.5%) were the most abundant sesquite

ISSN:0882-5734    

DOI:10.1002/ffj.2730100107

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractEssential oils obtained by hydrodistillation of green and blackPiper nigrumL. berries of Indian origin were analysed by GC and GC‐MS methods and compared with reported constituents of Sri Lankan green and black pepper oils. The monoterpene hydrocarbons of Indian oils are similar to those of corresponding Sri Lankan oils but the oils differ in the make‐up of their sesquiterpene and oxygenated components. β‐Pinene and caryophyllene occur in all oils, sabinene in Sri Lankan oils only and car‐3‐ene in none of the oils. Salzer's recommendation that the ratio of (sabinene + β‐pinene + car‐3‐ene)/caryophyllene ‘as a suitable pepper oil characteristic’ requ

ISSN:0882-5734    

DOI:10.1002/ffj.2730100108

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA method to deterpenate sweet orange and lemon oils by supercritical fluid extraction (SFE) with carbon dioxide combined with use of silica gel as adsorbent is described. The composition of the oxygenated fractions obtained by SFE was compared to that of deterpenated oils obtained by vacuum distillation, and to that of cold‐pressed oils. The deterpenated products obtained by SFE show qualitative composition and quantitative ratios between oxygenated compounds near to those of original oil

ISSN:0882-5734    

DOI:10.1002/ffj.2730100109

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0882-5734    

DOI:10.1002/ffj.2730100110

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0882-5734    

DOI:10.1002/ffj.2730100111

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY