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Il laboratorio sensoriale della Fondazione Mach. Studi sulla qualità dei prodotti e sulle risposte dei consumatori
No full textNosespace analysis by PTR-ToF-MS for the extravirgin olive oil characterization
No full textIntroduction:
Extravirgin olive (EVO) oil aroma and taste influence consumer preferences. Volatile organic compounds (VOCs) release from food within oral cavity is a complex process. Nose-space (NS) analysis should unravel the retro-nasal olfaction processes happened during olive oil tasting. Proton Transfer Reaction-Mass Spectrometry with Time-of-Flight analyser (PTR-ToF-MS) was already successfully applied for NS analysis of apples [2], cereal bars [3], coffee [4,5].
Methods:
In this study 2 Italian EVO oils were used: commercial vs home made (Lago di Garda, TN). Pure oil, oil mixed with tomato sauce, oil on bread prepared for each EVO oil were used for headspace (HS) and NS measurements by PTR-ToF-MS 8000. The samples were presented to 8 assessors in duplicate. For NS sampling a glass nose-piece with silicone rubber tube was fitted into assessors’ nostrils and connected to PTR-ToF-MS. The method for HS analysis was described elsewhere [6].
Results:
26 out of 319 mass peaks of NS dataset displayed signal related to olive oil, tomato or bread aroma. Peaks related to human metabolism were eliminated. The individual profiles differed in peak intensity and duration. However it was possible to distinguish the two types of EVO oils. HS data confirmed diversity of the oils. Home-made EVO oil in all products was characterized by significantly higher concentrations of mass peak 99.081 tentatively identified (t.i.) as (E)-2-hexenal associated to a green-leaf and fruity flavor [1]. Commercial EVO oil was richer in t.i. pentanal, acetic acid, butanal, and several esters which are reported as oxidation products of olive oil [7]. The samples of olive oil on bread showed the best performance (higher signals intensities) for all panellists due to an increased release surface area, prolonged presence in mouth, increased interaction with saliva and mucosal surfaces. Adding tomato sauce to olive oil decreased the olive oil aroma release in NS and contaminated it with tomato aroma.
Conclusions
NS analysis performed by PTR-ToF-MS discriminated different EVO olive oils. HS and NS data were consistent. The next steps are the optimization of sample preparations, tasting protocol, and the improvement of PTR-ToF-MS sensitivity by applying an ion funnel.
The optimized methods will be applied to study different EVO olive oils within the project “VIOLIN” aiming to the valorisation and promotion of Italian EVO oils.
Novel Aspect:
For the first time NS analysis was applied for olive oil profiling taking into consideration individual perception and the combination with different food matrices
Barriere socio-culturali, psicologiche, sensoriali ed affettive nel panorama dell’innovazione alimentare in Italia: sviluppo di questionario
Full text linkInfluenza di compost di origine diversa sulla crescita di essenze test in coltura protetta
No full textL’accettabilità delle mele a polpa rossa e la sua relazione con la neofobia, fiducia nell'innovazione ed emozioni
No full textEsplorazione della scala della neofobia verso le tecnologie alimentari (FTNS) nel consumatore italiano
Full text linkDesigning an online survey to uncover sociocultural, psychological, sensory, and affective barriers in italy's food innovation landscape
No full textHandling individual differences in preference mapping models
No full textIn this work we discuss an extension in preference mapping of the method proposed in Endrizzi et al. (2011) for accommodating both population averages and individual differences in the same model. The method, based on average estimates and residuals, is a combination of ANOVA, PCA and PLS-DA, which are well-known techniques that can be run in almost all statistical software packages. Main attention will be given to the relation between the double centered residual matrix which highlights differences between consumers in their relative position as compared to the average consumer values and the standard centering in preference mapping. This approach has been found particularly useful for highlighting differences in preference pattern among the consumers. Furthermore, the interpretation and the segmentation, that is here taking place based on differences in acceptance pattern, are graphically oriented. In addition, some possible alternatives to the generally used validation method in PCA are suggested. The approach is then illustrated using the data-set from a consumer study of berry fruit juices (Endrizzi et al.,2009), showing that when individual differences are analysed by the present method, interesting results regarding individual differences in response pattern were detected.
Endrizzi, I., Menichelli, E., Johansen, S. B., Olsen, N. V., & Næs, T. (2011). Handling of individual differences in rating-based conjoint analysis. Food Quality and Preference, 22, 241-254.
Endrizzi I., Pirretti G., Caló D.G., Gasperi F. (2009). A consumer study of fresh juices containing berry fruits. Journal of the Science of Food and Agriculture, 89, 1227-1235
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