Borneol represents the main constituent of the essential oil. This is an interesting fact because in the literature no other variety of thyme was reported to contain more than 8% of borneol, and generally the level is around 2 to 3% of the t o t a l essential oil. Adulteration of Provence thyme by Moroccan thyme might be detectable by determining the quantity of borneol. We are now studying T. satureioides to establish whetlier the borneol content of all samples is consistently higher than 20%.In fraction no. 4, two new compounds were idehtified: trans-4-thujanol and bornyl acetate.Fraction no. 5 revealed peaks already known, and from fraction no. 6, camphor was characterized by its infrared spectrum. The presence of this compound was assumed by several workers, but to date, no evidence has been presented. It is noteworthy that this particular variety of thyme contains a large amount of camphor, 2.6%, giving a noticeable note of camphor to the essential oil.In fraction no. 7, no new components were identified. The chromatogram of the whole essential oil on a Carbowax 20M glass capillary column ( Figure 2) shows that all the main constituents were identified. Analysis of several other samples of T. satureioides revealed this Using a modified Likens and Nickerson extraction procedure followed by low temperature/high vacuum distillation, representative samples of aroma volatiles were obtained from beef both while boiling by microwave radiation and by conventional means. Separation of the components of the isolates was achieved by gas chromatography and the majority of the components identified using combined gas chromatography-mass spectrometry. Odor assessments were made of the separated volatile components. A comparative study was undertaken of the effect on the volatile components of boiling for different periods of time conventionally and by microwave heating.The flavor of meat has been extensively studied and the literature frequently reviewed (Dwivedi, 1975;Herz and Chang, 1970; Patterson, 1974;Rhodes, 1974;Wasserman, 1972). Many factors pre-slaughter, at slaughter, and post-mortem (including cooking procedure) may influence the final flavor (Herz and Chang, 1970; Patterson, 1974). Uncooked meat has little odor and only a blood-like, metallic taste and it is generally agreed that desirable meat flavor is developed during cooking. Two types of cooked meat flavor have been distinguished, a "meaty" flavor believed to originate from the lean and a "species" flavor which characterizes different animal species and which derives from the fat tissue. Nevertheless, lean meat contains 4 4 % intramuscular fat which is sufficient to give rise to the characteristic species flavor (Patterson, 1974).

No abstract

Samples of beef sirloin from a 12 month old steer were aged in a vacuum wrap for up to 4 weeks and analysed for sensory and chemical properties of boiled beef aroma. Total organic volatiles extracted increased with ageing period, the rate of increase accelerating as ageing proceeded. Odour descriptions by a trained panel of 12 members indicated a trend from weak, bland and unappetising (no ageing) to strong, savoury, appetising and roasted after 4 weeks of ageing, coinciding with increased concentrations of alkanes, benzenoid compounds, furans, pyrroles, pyridines and pyrazines. These sensory differences were not significant at the 5 % level. A significant burnt, toasted off-odour which may be attributed to certain alkenes, ketones and alcohols, was associated with the sample aged for 3 weeks and was probably due to ageing at a higher oxygen tension than the others.

Sensory properties of the aroma of cooked beef were analyzed using an odor quality assessment technique based on, though not identical with, that of Persson et al. (1973a) (J. Food Sci. 38: 386). Detailed odor descriptions were obtained for beef samples cooked conventionally and by microwave radiation for different periods of time. Several differences in aroma characteristics were observed. In general, odor qualities rated highly for the aroma of microwave cooked beef were shown to be either associated with "meaty boiled" aroma or else to have negative correlation with the quality "meaty roast."