Elisabetta Moneta

Attitudes, habit, sensory and liking expectation as determinants of the consumption of milk

A total of 111 subjects took part in a survey in which attitudes, habits, surveyed ratings of liking and of sensory attributes, and consumption frequency of the three types of milk, skimmed, semi-skimmed and whole fat, were studied. The frame of reference for design and analysis was based in part on the Fishbein and Ajzen model of reasoned action. Habit was found to be more important than attitude in the prediction of the behavioural intention. Liking was more important than intention for predicting behaviour with the exception of semi-skimmed milk for which the intention was equally important, whereas the inclusion of surveyed ratings of sensory/hedonic components for milk into the model failed to improve the prediction of attitude. The relationships between beliefs, evaluations and attitudes were examined.

Use of electronic nose and trained sensory panel in the evaluation of tomato quality

In this paper the performances of an electronic nose based on metalloporphyrin-coated quartz microbalance sensors and of an experienced panel of seven human assessors in the evaluation of gases derived from degradation reactions in tomatoes are presented and discussed. The performances are measured in terms of the capability of both systems to distinguish between samples of different quality coming from conventional and organic production systems. The study deals with the application of pattern recognition techniques based on either multivariate statistical methods (PCA, GPA) or artificial neural networks using a self-organising map (SOM). The response pattern of the sensor array and the sensory data are analysed and compared using these methods. Similarities in the classification of the data by electronic nose and human sensory profiling are found.

Electronic nose and sensorial analysis: comparison of performances in selected cases

Abstract Sensorial analysis based on the utilisation of human senses, is one of the most important and straightforward investigation methods in food analysis. It provides a unique information about the ‘food–man interaction’. Nevertheless, human senses, when considered as instruments, show several problems of reproducibility, stability and difficulties of expression, making it very hard to compare results between different panels. The electronic nose has been proven to be sufficiently accurate as an artificial approximation of the human olfaction apparatus when applied to well defined problems in food analysis. In this paper results obtained for tomato pastes and milk analysis, comparing a panel of tasters and an electronic nose will be presented and discussed.

Sensory evaluation of walnut fruit

Abstract The paper provides an in-depth examination of the sensory differences between cultivars of walnut fruit (Juglans regia L.) from different countries. Eighteen samples, belonging to three clonal cultivars, plus some other genetic selections, collected from five European countries (France, Greece, Italy, Portugal and Spain) were analyzed for their sensory characteristics by a panel trained in Descriptive Analysis (DA). Fifteen descriptors were selected to describe the fruits, covering the following attributes: external appearance of the shell and kernel, colour, visual, manual and oral texture, taste and flavour. Principal Component Analysis (PCA) adequately reduced the multidimensional structure of the data and distinguished the regions of origin of the walnut samples more effectively than the cultivars. Generalized Procrustes Analysis (GPA) was also included to describe relationships between samples and to evaluate assessor performance.

Qualitative data analysis for an exploratory sensory study of grechetto wine

Grechetto is a traditional white-grape vine, widespread in Umbria and Lazio regions in central Italy. Despite the wine commercial diffusion, little literature on its sensory characteristics is available. The present study is an exploratory research conducted with the aim of identifying the sensory markers of Grechetto wine and of evaluating the effect of clone, geographical area, vintage and producer on sensory attributes. A qualitative sensory study was conducted on 16 wines, differing for vintage, Typical Geographic Indication, and clone, collected from 7 wineries, using a trained panel in isolation who referred to a glossary of 133 white wine descriptors. Sixty-five attributes identified by a minimum of 50% of the respondents were submitted to a correspondence analysis to link wine samples to the sensory attributes. Seventeen terms identified as common to all samples are considered as characteristics of Grechetto wine, 10 of which olfactory: fruity, apple, acacia flower, pineapple, banana, floral, herbaceous, honey, apricot and peach. In order to interpret the relationship between design variables and sensory attributes data on 2005 and 2006 wines, the 28 most discriminating descriptors were projected in a principal component analysis. The first principal component was best described by olfactory terms and the second by gustative attributes. Good reproducibility of results was obtained for the two vintages. For one winery, vintage effect (2002-2006) was described in a new principal component analysis model applied on 39 most discriminating descriptors, which globally explained about 84% of the variance. In the young wines the notes of sulphur, yeast, dried fruit, butter, combined with herbaceous fresh and tropical fruity notes (melon, grapefruit) were dominant. During wine aging, sweeter notes, like honey, caramel, jam, become more dominant as well as some mineral notes, such as tuff and flint.

Comparison of multivariate methods of analysis to evaluate panellists' performance

Abstract To evaluate the effectiveness of training, performance monitoring of assessors is necessary. This study shows how multivariate statistical analysis may be used to explore the effect of training in improving assessors ability. Ten non-experienced assessors were asked to measure descriptive flavour and texture parameters in brands of frozen and canned peas. Sensory evaluations were made before and after training. Principal Component Analysis (PCA) and Cluster Analysis (CA) were carried out to explore the homogeneity of behaviour among panellists.

EEG Frontal Asymmetry Related to Pleasantness of Olfactory Stimuli in Young Subjects

It is widely known, in neuroscientific literature, that the brain prefrontal cortex activity asymmetry is closely linked with the pleasantness emotion experienced by the subject during a sensorial stimulation. Thus, from the electroencephalographic (EEG) signal it is possible to estimate the approach/withdrawal index, and this index has been largely investigated and validated in scientific literature, regarding visual and acoustic stimuli. In this work, we present an innovative study aimed to prove, in a systematic way, that such brain AW index is actually correlated with the “pleasant” or “no-pleasant” perception also of olfactory stimuli, conveniently produced by standardised methods in the sensory specific scientific literature. In particular, we recorded the electroencephalographic (EEG) signal from a group, gender balanced, of 24 healthy and no-smokers subjects during the perception of ten different smells, presented by means of the “Screening test-odour identification” set (Sniffin’ sticks, Burghart). The cerebral AW indexes of all the subjects, for each odorous stimulus, were compared with the appreciation numeric score assessed by the subject during the experiment, by performing a statistical correlation test. Findings show that it is possible to evaluate the pleasantness or no-pleasantness of odorous substances by means of the analysis of EEG signals collected during the presentation of such substances, making way for new applications of such measure kind in experimental environments more and more ecological, as the typical ones of the marketing research areas.

Nutraceutical Improvement Increases the Protective Activity of Broccoli Sprout Juice in a Human Intestinal Cell Model of Gut Inflammation

Benefits to health from a high consumption of fruits and vegetables are well established and have been attributed to bioactive secondary metabolites present in edible plants. However, the effects of specific health-related phytochemicals within a complex food matrix are difficult to assess. In an attempt to address this problem, we have used elicitation to improve the nutraceutical content of seedlings of Brassica oleracea grown under controlled conditions. Analysis, by LC-MS, of the glucosinolate, isothiocyanate and phenolic compound content of juices obtained from sprouts indicated that elicitation induces an enrichment of several phenolics, particularly of the anthocyanin fraction. To test the biological activity of basal and enriched juices we took advantage of a recently developed in vitro model of inflamed human intestinal epithelium. Both sprouts’ juices protected intestinal barrier integrity in Caco-2 cells exposed to tumor necrosis factor α under marginal zinc deprivation, with the enriched juice showing higher protection. Multivariate regression analysis indicated that the extent of rescue from stress-induced epithelial dysfunction correlated with the composition in bioactive molecules of the juices and, in particular, with a group of phenolic compounds, including several anthocyanins, quercetin-3-Glc, cryptochlorogenic, neochlorogenic and cinnamic acids.

Characterization of volatiles and identification of odor-active compounds of rocket leaves

The volatile profile of crushed rocket leaves (Eruca sativa and Diplotaxis tenuifolia) was investigated by applying Headspace Solid-Phase MicroExtraction (HS-SPME), combined with GC-MS, to an aqueous extract obtained by homogenization of rocket leaves, and stabilized by addition of CaCl2. A detailed picture of volatile products of the lipoxygenase pathway (mainly C6-aldehydes) and of glucosinolate hydrolysis (mainly isothiocyanates), and their dynamics of formation after tissue disruption was given. Odor-active compounds of leaves were characterized by GC-Olfactometry (GC-O) and Aroma Extract Dilution Analysis (AEDA): volatile isolates obtained by HS-SPME from an aqueous extract and by Stir-Bar Sorptive Extraction (SBSE) from an ethanolic extract were analyzed. The most potent odor-active compounds fully or tentatively identified were (Z)- and (E)-3-hexenal, (Z)-1,5-octadien-3-one, responsible for green olfactory notes, along with 4-mercaptobutyl and 4-(methylthio)butyl isothiocyanate, associated with typical rocket and radish aroma. Relatively high odor potency was observed for 1-octen-3-one, (E)-2-octenal and 1-penten-3-one.

A comparison between an electronic nose and human olfaction in a selected case study

An electronic nose is now becoming available as a commercial product. Nevertheless its performances are not fully understood and interpreted. Also the differences between electronic noses and the human olfaction have not yet been sufficiently studied. This is an important issue in many industrial sectors, such as food analysis. In this paper a comparison between the performances of an electronic nose and a panel of human tasters is presented in a selected case (tomato paste). An extensive set of tools for data analysis was available. A number of chemometrics based methods (principal component analysis and cluster analysis) and neural networks (feedforward backpropagation trained networks, self organizing maps, adaptive resonance theory based networks) have been utilized to analyze electronic nose data in order to extract the relevant information. The electronic nose and the human panel show strong similarities but the former displays a more concise classification capability for the data.