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To establish whether fishy off-flavour observed in cows' milk in Sweden is due to abnormal concentrations of trimethylamine (TMA) in milk, 15 milk samples from 13 cows of the Swedish Red and White breed (SRB) were analysed for this compound using dynamic headspace (DHS) gas chromatography (GC). A mass selective detector (MSD) was used for the qualitative and a flame ionization detector (FID) for the quantitative analyses. Further confirmation was obtained using a solid phase microextraction (SPME) followed by GC-olfactometry (GC-O) and GC-NPD (nitrogen and phosphorus detector). Samples were also evaluated by a two-person organoleptic panel for the presence of fishy off-flavour. Results showed that the seven milk samples with a fish-like taint contained >1 mg TMA/kg milk, whereas, with a single exception, the seven samples that were judged to be normal did not contain this compound. Furthermore, there were indications of a dose-dependent relationship between TMA concentration and fishy off-flavour score.

The current review lists a total of 126 chiral compounds described in the literature for at least 21 different cheese varieties: 30 alcohols, 8 ketones, 2 aldehydes, 20 esters, 20 lactones, 27 carboxylic acids, 13 hydrocarbons (8 terpenes), 4 furanones, and 2 amines. Of these only a few authentic reference compounds are commercially available. All these data are compiled in seven tables.

This paper examines the distribution of mono- and sesquiterpene secondary metabolites in 47 plants present in grazing areas from which cheeses are produced. In total, 54 terpenoid volatiles, derived from both highland and lowland plants, were obtained by a gaseous purge-and-trap system without the use of organic solvents and then identified by automated GC/MSD-FID analysis using mass spectral libraries, retention indices, and data acquired by the authors with authentic substances. Single ion monitoring proved valuable in identifying overlapping compounds with similar spectra for the subsequent semiquantitative determination of compositions. These are displayed as radar plots. It is suggested that flavor/aroma differences in cheeses produced from animals grazing in different areas and seasons arise from species (n = 38), phenological stages (n = 8), locations (n = 4), and seasonal variation in terpenoids present (the most common were trans-β-ocimene, limonene, and trans-β-caryophyllene). This hypothesis is...

The objective was to determine the influence of the season of manufacture and the ripening time on the volatile terpenoids and benzenoids of La Serena cheese made in summer, winter and spring, using a plant coagulant. Ewes were fed with formulated feed in summer, grazing on natural pastures in winter and spring. Most terpenoids and benzenoids present in cheese were observed in the formulated feed (mainly terpenes), and in the Cynara cardunculus extract (mainly benzenoids). The enantiomeric α(+){plus 45 degree rule}α(-)-pinene ratio changed during ripening. γ-Curcumene, α-humulene, ethyl benzene and propyl benzene and all xylene isomers decreased, while α-terpineol, verbenone, benzyl alcohol, 2-phenyl-ethanol, benzoic acid methyl ester, and the phenolic compounds increased significantly during ripening. Safranal, geranyl acetone, γ-curcumene and α-curcumene were more abundant in spring than in winter cheeses. Alkyl benzenes and other benzenoids were significantly more abundant in summer than in winter or spring cheeses. © 2007 Elsevier Ltd. All rights reserved.

The aim of this study was to characterise the volatile flavour compounds in a Gruyere-type cheese manufactured from pasteurised milk using different strains of Lactobacillus casei. These strains were used as non-starter cultures to manufacture the different cheeses. A dynamic headspace extraction technique, purge and trap, coupled to gas chromatography-mass spectrometry (GC-MS), and solvent assisted flavour evaporation (SAFE) in combination with GC-MS and GC-olfactometry (GCO) were used to determine the volatile aroma compounds formed after 180 days of ripening. The purge and trap method revealed aldehydes and ketones, such as 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and 2,3-butanedione, as well as dimethyl disulfide and dimethyl trisulfide among other compounds, which have been described earlier as key aroma compounds of Gruyere and Cheddar cheeses. Free fatty acids were not detected by the purge and trap extraction method. On the other hand, the analysis of the SAFE extract revealed intense signals for propanoic, butanoic, 2- and 3-methylbutanoic acid as well as pentanoic acid and hexanoic acid. Less volatile, more polar odorants, such as the caramel-like 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone, but also the mushroom-like smelling 1-octen-3-one were detected in the SAFE extract by GCO, however, not using purge and trap GC-MS.