Interactions between methyl ketones and beta-lactoglobulin: sensory analysis, headspace analysis and mathematical modelling

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Affinage et qualite du gruyere de Comte. V. Influence de l'affinage sur la teneur en composes volatils

Vingt-quatre fromages de type Gruyere de Comte ont ete analyses. Ces fromages proviennent d'une meme fromagerie et correspondent a 6 groupes de 4 fromages issus d'une meme fabrication, a savoir, 3 fabrications d'hiver et 3 fabrications d'ete. Les 4 fromages sont affines dans 4 caves differentes. 103 composes ont ete identifies avec certitude, appartenant aux classes de composes suivantes: des hydrocarbures aliphatiques et terpeniques, des methylcetones saturees et insaturees, des aldehydes satures, des alcools primaires et secondaires satures, des esters et des lactones. Une analyse de variance univariable montre que l'effet saison est preponderant, ce qui est confirme par une analyse en co…

A new approach to studying sponge cake aroma after storage in treated paper and plastic packaging by direct gas chromatography–olfactometry (D-GC–O)

The objective of this study was to use D-GC–O to compare the global odour of a sponge cake flavoured with either a ‘viennoiserie’ aromatic note or a simplified mixture of aroma compounds (used for physicochemical studies), then stored in a glass packaging (inert and impermeable) or in pouches made with treated papers or with plastic packaging, in accelerated ageing conditions (high temperature and relative humidity gradient). After 1 week of storage, the flavoured sponge cake headspace was SPME-extracted directly into the packaging and analysed by D-GC–O. The sponge cake global odour was better retained if plastic film rather than treated-papers was used, for both flavourings. Changes in th…

Influence of packaging on the aroma stability of strawberry syrup during shelf life

Different types of packaging (glass bottle, PVC, and PET) were compared for the preservation of aroma quality of a strawberry syrup during shelf life. Esters, alcohols, and aldehydes were analyzed by solid-phase micro-extraction (SPME) and solvent extraction. During storage, hydrolysis of esters in acids and alcohols led to a modification of the aroma profile which can be explained by the replacement of “fruity” and “fresh” notes by “dairy note” in the syrup. Aroma compounds that are responsible for fruity notes, such as methyl cinnamate, methyl anthranilate, and methyl dihydrojasmonate, were strongly reduced after 90 days. This could be explained by a selective interaction of these compoun…

Solid Phase Microextraction (SPME) of Orange Juice Flavor:  Odor Representativeness by Direct Gas Chromatography Olfactometry (D-GC-O)

The sensorial quality of solid phase microextraction (SPME) flavor extracts from orange juice was measured by direct gas chromatogrphy-olfactometry (D-GC-O), a novel instrumental tool for evaluating odors from headspace extracts. In general, odor impressions emerging from SPME extracts poorly resembled that of the original orange juice. In an attempt to improve the sensorial quality of extracts, sample equilibration and exposure times were varied on Carboxen/polydimethylsiloxane (CAR/PDMS) and divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibers. Best sensorial results were obtained with the DVB/CAR/PDMS fiber exposed for the shortest time; a trained panel of eight assess…

Role of pulp in flavor release and sensory perception in orange juice

This work elucidates the role of suspended solids in sensorial perception and flavor release in orange juice. The coarsest pulp (insoluble particles with a diameter of2 microm) accounted for two major physicochemical effects in orange juice samples: it retained large amounts of aroma compounds, including terpenes and aldehydes, and modified the rheological properties of the juice matrix. These phenomena strongly affected the chemical composition of the vapor phase in the juice samples. On the other hand, orange juice cloud (finest insoluble particles with a diameter of2 microm) also showed a strong retention effect on ethyl butanoate or hexanal, probably due to the occurrence of molecular i…

Determination of key odorant compounds in freshly distilled Cognac using GC-O, GC-MS, and sensory evaluation

This aim of this work was to identify the odorant compounds responsible for the typical sensory descriptors attributed to freshly distilled Cognac spirits, not matured in barrels. Panelists were first selected and trained for gas chromatography−olfactometry. Among the 150 volatile compounds identified by gas chromatography−mass spectrometry analysis, only 34 are mainly responsible for the odors detected in the spirits. The “butter” descriptor is explained by the presence of diacetyl, the “hay” descriptor by nerolidol, the “grass” descriptor mainly by Z-3-hexen-1-ol, but also by other compounds, the “pear” and “banana” descriptors by 2- and 3-methylbutyl acetates, the “rose” descriptor by 2-…

Change in the aroma quality of a sponge cake during storage in flexible packaging films evalued by D-GC-O