Fac-simile Scheda Linee di Ricerca - Federalimentare
Fac-simile Scheda Linee di Ricerca - Federalimentare
Fac-simile Scheda Linee di Ricerca - Federalimentare
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Dati pubblicati inerenti il tema <strong>di</strong> ricerca:1. Ulrici, A.; Manzini, D.; Foca, G.; Masino, F.; Franchini, G.C; Antonelli A. (2005) Analisimultivariata <strong>di</strong> immagini <strong>di</strong>gitali per la valutazione del colore <strong>di</strong> matrici alimentari<strong>di</strong>somogenee. Ingre<strong>di</strong>enti Alimentari, 19(3), 22-29.Questo lavoro descrive un nuovo metodo automatizzato per la classificazione <strong>di</strong> matrici alimentari eterogeneesulla base delle comuni fotografie <strong>di</strong>gitali a colori. La caratteristica più innovativa <strong>di</strong> questo approccio consistenella capacità <strong>di</strong> identificare autonomamente gli aspetti che risultano essere maggiormente utili per laclassificazione degli alimenti esaminati. Ciò significa in<strong>di</strong>viduare le variabili più significative per laclassificazione dei campioni analizzati in maniera cieca, ovvero senza la necessità <strong>di</strong> effettuare alcunaassunzione a priori sulla natura della matrice alimentare considerata. L’approccio prevede <strong>di</strong> rappresentare ilcontenuto in colore <strong>di</strong> ogni immagine <strong>di</strong>gitale sotto forma <strong>di</strong> un segnale, che noi abbiamo chiamatocolorigramma, il quale consiste essenzialmente nella sequenza delle curve <strong>di</strong> <strong>di</strong>stribuzione dei tre valori <strong>di</strong> coloreRosso, Verde e Blu, nonché <strong>di</strong> vari parametri da essi derivati. I colorigrammi così ottenuti possono quin<strong>di</strong> essereanalizzati me<strong>di</strong>ante un algoritmo <strong>di</strong> classificazione e selezione <strong>di</strong> variabili chiamato WPTER. In questo lavoro sipresenta l’applicazione <strong>di</strong> tale approccio su una serie <strong>di</strong> campioni <strong>di</strong> pesto alla genovese. Questo tipo <strong>di</strong>con<strong>di</strong>mento, soprattutto a causa della degradazione della clorofilla, tende a presentare una grande variabilità <strong>di</strong>colore, che risulta però <strong>di</strong>fficile da quantificare con meto<strong>di</strong> tra<strong>di</strong>zionali <strong>di</strong> analisi a causa dell’aspetto eterogeneo.2. Masino, F.; Ulrici, A.; Antonelli. A. (2008) Extraction and quantification of main pigments inpesto sauces. Eur. Food Res. Technol., 226, 569-575.Pesto is a widely <strong>di</strong>ffused Italian pasta sauce, whose main ingre<strong>di</strong>ent is basil. Since its appearance is a key factorfor marketing, the determination of its pigment content is of fundamental interest. To this aim, a method for thedetermination of pesto pigments by C18-HPLC is proposed. Only β-carotene was determined <strong>di</strong>rectly by Visspectrophotometry,as a consequence of sample purification over a silica cartridge. The proposed method isreliable allowing, for the first time, an easy determination of chlorophylls, pheophytins, lutein and β-carotene ina complex matrix such as pesto. The results show great <strong>di</strong>fferences in pigment composition among the samples,with pheophytins as the main components. Only non-thermally processed product show appreciable chlorophyllcontent as a consequence of the <strong>di</strong>fferent production technique. Principal Component Analysis performed on thepigment contents showed great variability among the <strong>di</strong>fferent samples.3. Masino, F.; Foca, G.; Ulrici, A.; Arru, L.; Antonelli, A. (2008) A chemometric study of pestosauce appearance and of its relation to pigment concentration. J. Sci. Food Agr. 88, 1335-1343.Pesto sauce is a typical example of a food matrix in which aspect is of key importance to the final judgment ofthe consumer, and whose color strongly depends on the production process and on the ingre<strong>di</strong>ents. In view ofthis, the aim of the present work is to evaluate the possibility of quantifying the variability of visual aspect of<strong>di</strong>fferent brands of pesto sauce, and its relation to the concentration of the main pigments. Sensory evaluation ofthe appearance of 12 commercial pesto samples was carried out by a panel of 16 assessors who evaluatedquantitatively six visual attributes, suitably defined for the description of pesto aspect. A quantitative estimate ofthe performance of the panel was carried out by means of both univariate and multivariate–multiwaychemometric tools (parallel factor analysis, PARAFAC). In ad<strong>di</strong>tion, the relationship between the mean sensoryscores values and the concentrations of chlorophylls, pheophytins and carotenoids was investigated by principalcomponents analysis (PCA). Both PCA and PARAFAC showed good clustering of the samples and asatisfactory degree of homogeneity of the assessors. Data analysis showed that assessors fundamentally agreeabout the main visual characteristics of pesto sauces, which are partly correlated with the concentration values ofthe main pigments.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento <strong>di</strong> Scienze e Tecnologie Agroalimentari, Università degli Stu<strong>di</strong> della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it252
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