9 research outputs found
Aroma volatile compounds of coffee: role in authenticity, traceability and well-being of consumers
No full textAroma volatile compounds of coffee: role in authenticity, traceability and well-being of consumers
No full textGC-MS aroma characterization of coffee and vegetable matrices: focus on 3-Alkyl-2-Methoxypyrazines
No full textQuantitatively unravelling the effect of altitude of cultivation on the volatiles fingerprint of wheat by a chemometric approach
No full textGC-MS aroma characterization of vegetable matrices: Focus on 3-alkyl-2-methoxypyrazines
No full text3-Alkyl-2-methoxypyrazines (MPs) are a very important class of volatile organic compounds (VOCs), intensively characterizing the aroma of several food products including fruits and vegetables. Due to the very low orthonasal sensory threshold, low amounts of MPs may act as key positive or negative aroma compounds. The analysis of these volatiles in foods is then remarkably important, and it may be very challenging as confirmed by the scarce literature focused on MPs, particularly with respect to quantitative data. In the attempt to fill this gap, in this work, presence and quantification of MPs in four different vegetables, namely, green bell pepper (Capsicum annuum L. var grossum), green pea (Pisum sativum L. and Pisum spp), carrot (Daucus carota subsp sativus), and cucumber (Cucumis sativus L.) have been investigated. Two different volatile extraction techniques (solid phase microextraction [SPME] and simultaneous distillation-extraction [SDE]) in conjunction with VOC qualitative analysis by gas chromatography-mass spectrometry (GC-MS) methods were applied. Solid phase microextraction coupled with GC-MS in single ion monitoring (SIM) mode showed the best performances in sensitivity to detect MPs on the different vegetable matrices. Therefore, a headspace (HS) SPME-GC-MS quantitative method was developed and optimized, and dominant MPs quantified. 3-Isopropyl-2-methoxypyrazine (IPMP), 3- sec-butyl-2-methoxypyrazine (sBMP), and 3-isobutyl-2-methoxypyrazine (IBMP) have been detected and quantified in all the vegetables. 3-Isopropyl-2-methoxypyrazine was the prevalent MP in peas and cucumber while IBMP in bell pepper. These MPs were detected for the first time in carrot and cucumber. Finally, sBMP has been confirmed to be the most important MP in carrot. The developed method allowed to characterize the VOC pattern and, in particular, to quantify MPs in four vegetables. Results highlight the feasibility of further applications of the analytical approach to determine MPs in other food matrices where an excessive amount of these aromas may negatively affect their flavor (eg, coffee)
Could environmental effect overcome genetic? A chemometric study on wheat volatiles fingerprint
No full textA unifying approach to wheat beer flavour by chemometric analyses. Could we speak of ‘terroir’?
No full textRaw materials are recognized to affect the sensory profile of ‘Blanche’ craft beers and their ‘terroir’. Two common wheat (Triticum aestivum, L.) were harvested in three experimental fields with different pedo-climatic conditions and altitudes, and then used for beer production. The taste and flavour of wheat beers were analysed by sensory (panel and consumer test) and SPME GC-MS analyses. Panel dataset was processed by multivariate statistical analyses: a principal component analysis (PCA) revealed that formulation was the main source of variation of sensory profile in wheat beers and a generalized Procrustes analysis (GPA) showed how wheat origin affected the sensory profiles of wheat craft beers based on the consensus among panelists. Moreover, a partial least-squares discriminant analysis (PLS-DA) on VOCs permitted to discriminate and characterize beers selected by a panel-driven approach. By comparing panel and VOCs results, it was possible to highlight that higher altitudes of wheat cultivation determine an increase of pleasant notes such as fruity and herbal. A PCA on consumer test data confirmed that formulation was the main factor affecting liking scores and that the preferences were affected by age, involvement and frequency of use. An internal preference map combining panel and consumer data suggested that the majority of preferences are driven by a few key sensory attributes. Differences in liking among the considered beers revealed two main consumer groups
Volatiles profile of ‘Blanche’ wheat craft beer as affected by wheat origin: A chemometric study
No full textDetermination of 3-Alkyl-2-Methoxypyrazines in Green Coffee: A Study to Unravel Their Role on Coffee Quality
No full textAlthough a high concentration of some 3-alkyl-2-methoxypyrazines in green coffee has been associated with an
off-flavor described as potato taste defect (PTD) or “peasy” defect, affecting the product quality, the natural concentration of these compounds in good quality coffee beans has never been the subject of a detailed study. 3-Isobutyl-2-methoxypyrazine (1), 3-sec-butyl-2-methoxypyrazine (2), 3-isopropyl-2-methoxypyrazine (3) concentrations were determined on a range of selected, good quality green coffees of different botanical species (arabica and robusta) and geographical origin. The presence of the three methoxypirazines was confirmed in all samples; the concentration of compound 1 was significantly higher than those of compounds 3 and 2, showing a geographical-origin-dependent variability. This whole set of experimental data was then used as a reference to ascertain the PTD occurrence in “suspected PTD” and insect-damaged samples. Compound 3 was the main indicator of defectiveness, with a main variability in its concentration in insect-damaged samples, suggesting that the insectinduced damage is not a sufficient condition to induce the off-flavor. The analysis in fresh potatoes, carried out to disclose the origin of the term used to describe the PTD in coffee, showed a very low concentration of 3-alkyl-2-methoxypyrazines. However, the relative prevalence of compound 3 on the total of 3-alkyl-2-methoxypyrazines could be related to thecharacteristic “potato” flavor frequently evoked to describe the sensory perceived defect in coffee
