Headspace Components Research Articles

Studies on characterization of Blue cheese flavour

AbstractA variety of 20 Blue cheese samples of different quality have been used for flavour quality characterization. Sample evaluation included a sensory profile method with 15 attributes and instrumental methods such as the determination of free fatty acids, head space components by gas chromatographic analysis, determination of methyl ketones, acetaldehyde, diacetyl, acetoin, and a few summarizing group tests.Correlation analysis revealed a lot of high correlation coefficients being discussed as to their importance in detail. Only small correlation coefficients could be found between single attributes and total flavour impression thus demonstrating the complexity of the sensation. Application of cluster and discriminant analysis revealed indices which can be used for describing the intensity of 8 sensory attributes successfully. Total flavour impression can be calculated from data for fatty acids, methyl ketones, acetaldehyde, and pH‐value. There are relations with respect to cheese ripening time, too. The use of rapid tests for group determinations seems to be more limited in some cases.

Changes in onion (Allium cepa L.) flavour components resulting from some post‐harvest processes

AbstractThe effect of the following processes on the flavour of the product as compared with that of fresh onion has been investigated: pickling, canning, boiling and frying under domestic conditions, dehydration in hot air and by freeze‐drying and freezing. Flavour assessments were based on determination of pyruvate, thiolsulphinate and volatile components in headspace, gas‐liquid chromatograms as well as sensory testing in certain cases. All the methods of flavour assessment led to the conclusion that these processes were accompanied by large flavour losses. Quantitative estimates of the losses, varied with the analytical method in question, but were in general of the order of 90 to 95%. Freeze‐drying gave a product which retained more of the characteristic flavour components of fresh onion, as judged by sensory tests, than the other processes and in this case the taste threshold test indicated a flavour loss of 95%, pyruvate (PE) a loss of 25%, thiolsulphinate 26% loss and gas‐liquid chromatography a loss of total peak area of 57%. Evidence that onions are consumed mainly for their flavour rather than as a source of nutrients in the classical nutritional sense is discussed and other factors which influence the flavour strength of the vegetable are reviewed.

FLAVOR QUALITY IN EXPLOSION PUFFED DEHYDRATED POTATO. 2. Flavor Contribution of 2‐Methylpropanal, 2‐Methylbutanal and 3‐Methylbutanal

SUMMARY– Headspace vapor components previously associated with the intensity of an off‐flavor in explosion puffed dehydrated potatoes were added to potatoes lacking the off‐flavor to determine the flavor contribution of these compounds. 2‐Methylpropanal produced a characteristic wet fur flavor note while 2‐ and 3‐methylbutanal modified this flavor and contributed burnt flavor notes. While these flavor notes resembled some elements of the puffing off‐flavor, the total off‐flavor at its normal intensity could not be simulated by combinations of these compounds in potato at realistic concentrations. Acetone, which is also present in the headspace vapor of explosion puffed dehydrated potatoes, was found as a major headspace component of fresh boiled potatoes. This compound and smaller amounts of 2‐ and 3‐methylbutanal were produced in overcooked fresh potatoes which lacked the puffing off‐flavor.