196,391 research outputs found
Il consumatore celiaco e le valutazioni sensoriali dei prodotti senza glutine : un caso studio : il pane in cassetta
No full textA rise in celiac consumers has increased interest of food companies towards research and development of food substitutes, which are more sensorily acceptable.
The aim of this study was to provide a sensory, chemical-physical characterization of six types of gluten-free sliced bread.
Products were evaluated by ten trained judges using the sensory profile method, and 17 descriptors were identified. Results from 3-factor Analysis of Variance (ANOVA) with 2-way interactions allowed us to identify significant differences in all descriptors between the six types of bread, invariability of samples in replicates and optimal repeatability of judges' responses. Subsequently, mean values obtained from sensory profiles were processed together with results from chemical-physical analyses by Principal Component Analysis (PCA). Data processing allowed us to identify the most significant sensory and analytical variables as follows: six sensory attributes (i.e., adhesiveness, fermented odour, cheese odour, salty taste, fermented flavour, cheese flavour) and four instrumental variables (i.e., acidity and Hunter's colorimetric coordinates a, b, L with respect to bread crumb), thus confirming that considerable differences did exist between the different types of gluten-free bread considered.
Results from this study point to the importance of investigating thoroughly the sensory aspect, which has often been underestimated, of specific food products destined to celiac consumers. However, no research is available in the literature, where sensory aspect of gluten-free products is given the same attention as both nutritional and safety characteristics. And yet sensory information is an essential aspect, as visual, olfactory, gustatory characteristics are known to be closely related to liking and choice of food products.
Identification of the most significant sensory variables representative of gluten-free sliced bread may also help to develop new products to meet requirements of this consumer target, which is steadily increasing
Al-Spinel-sulphide bearing dikes and the fate of chromium in marginal reaction zones at Balmuccia
No full textThe Balmuccia peridotite massif is one of the subcontinental mantle peridotite bodies intruded in the mafic-ultramafic Ivrea-Verbano complex in the Western Alps, Northern Italy. The Balmuccia body consists of dominant foliated lherzolites crosscut by several generations of pyroxenite dikes, approximately belonging to an earlier “Cr-diopside suite” and a later “Al-augite suite”. These dike suites are interpreted as mineral segregations from melts which percolated into the lherzolite, refertilized it and caused focused dunitization of the host peridotite. Our study is focused on some thin, cm- to dm-thick pale grey-violet dikes presumably belonging to the late-stage Al-augite suite and intersecting the lherzolite mass at its eastern margin, near the intrusive contact with the Ivrea-Verbano complex. These dikes often show a spotted texture due to the segregation of abundant coarse vitreous black spinel phenocrysts. The mineral assemblage is both Al- and sulphide-rich. The silicate-oxide assemblage includes dominant clinopyroxene (diopside-augite) and blue-green, transparent Al-rich spinel, with minor Ti-rich Na-K pargasite amphibole, Al-bearing orthopyroxene (enstatite), accessory Ti-rich phologopite and plagioclase and rare olivine (intergrown with spinel droplets). Abundant Fe-Ni-Cu sulphides (pentlandite, phyrrotite, chalcopyrite and bornite) are widely disseminated across the dikes both as mm-sized polyphase nodules interstitial to the silicate-spinel matrix and as tiny, locally extremely abundant drop-like inclusions in spinel. Assemblages containing bornite exclusively occur as inclusions in spinels, which host a redox-dependant equilibrium pentlandite-chalcopyrite-bornite association. The richness in Ni sulphides copes with the scarcity of olivine in this association and is one of the interesting features of these dikes. Another curious feature involves the margins of the dikes. The contacts with the host lherzolite are sharp but not tectonic and are characterized by lateral passage from dike-related undeformed to lherzolite-related, variably foliated assemblages (olivine, ortho- and clino-pyroxenes, fine-grained dark brown spinel and rare amphibole). A visual inspection of the host lherzolite/grey dike contact zones showed a peculiar, progressive change in colour of the spinel from dark brown, in “distal” position, to green transparent near the dike margin. That was the most visible evidence of the interaction between lherzolite and intruding dikes, as an actual reaction zone is not easy to recognize texturally. Analytical transects across these mm- to cm-sized “contact zones” by means of microprobe showed that there may be a cryptic reaction zone. The lherzolite phases do record some changes in major element composition, and in particular spinel, pyroxenes and amphibole show variations in Chromium concentration, among others. Across the reaction zones lherzolite spinel vary their Cr content from about 19 wt% Cr2O3 to <1%. They also decrease their Fe2+ content whereas Al and Mg are enriched. Clinopyroxene shows a variable “response” to this reaction zone as it shows a tendency to Cr depletion coupled with Ti enrichment and fluctuations in alkalis. Accessory amphibole crystals in lherzolite show a trend of Cr depletion and Ti enrichment as well as a variability in Al and Na contents towards the dike margin. Cr is rather low in lherzolite orthopyroxene, however it shows a tendency to Cr and Mg depletion (and Fe enrichment) towards the dike contact. Olivine tends to be more forsteritic in a distal position. Ongoing and future analytical investigations are aimed to characterize and verify the meaning and the extent of this Cr-depleting Al-enriching and dike-lherzolite metasomatic interaction. Of particular interest is the fate of Cr, one of the economic elements enriched (after mobilization from a source) in relation to metasomatic processes, e.g., dunitization, affecting peridotites
CIP-stabilized virtual elements for diffusion-convection-reaction problems
No full textThe Virtual Element Method (VEM) for diffusion-convection-reaction problems is considered. In order to design a quasi-robust scheme also in the convection-dominated regime, a Continuous Interior Penalty approach is employed. Due to the presence of polynomial projection operators, typical of the VEM, the stability and the error analysis requires particular care-especially in treating the advective term. Some numerical tests are presented to support the theoretical results
Intervento
No full textIntervento introduttivo della sessione, da Nello presieduta, dedicata a «Giuseppe Toniolo promotore di iniziative sociali»: le Settimane sociali (Taccolini M.), il carteggio con Medolago Albani (Trezzi L.), le origini del cattolicesimo democratico (Campanini G.), l'Associazione internazionale per la protezione legale dei lavoratori (Maifreda G.)
Selecting the most relevant brain regions to classify children with developmental dyslexia and typical readers by using complex magnocellular stimuli and multiple kernel learning
No full textIncreasing evidence supports the presence of deficits in the visual magnocellular (M) system in developmental dyslexia (DD). The M system is related to the fronto-parietal attentional network. Previous neuroimaging studies have revealed reduced/absent activation within the visual M pathway in DD, but they have failed to characterize the extensive brain network activated by M stimuli. We performed a multivariate pattern analysis on a Region of Interest (ROI) level to differentiate between children with DD and age-matched typical readers (TRs) by combining full-field sinusoidal gratings, controlled for spatial and temporal frequencies and luminance contrast, and a coherent motion (CM) sensitivity task at 6%-CML6, 15%-CML15 and 40%-CML40. ROIs spanning the entire visual dorsal stream and ventral attention network (VAN) had higher discriminative weights and showed higher act1ivation in TRs than in children with DD. Of the two tasks, CM had the greatest weight when classifying TRs and children with DD in most of the ROIs spanning these streams. For the CML6, activation within the right superior parietal cortex positively correlated with reading skills. Our approach highlighted the dorsal stream and the VAN as highly discriminative areas between children with DD and TRs and allowed for a better characterization of the “dorsal stream vulnerability” underlying DD
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