1,720,958 research outputs found
Alimenti arricchiti con probiotici e prebiotici
No full textIl primo obiettivo di questa tesi di dottorato è stata la formulazione di una mozzarella Fiordilatte simbiotica attraverso un rivestimento di alginato di sodio commestibile come veicolo di probiotici (Lactobacillus rhamnosus ) e di frutto-oligosaccaridi prebiotici (FOS). Gli obiettivi di questo studio sono stati la valutazione della capacità della tecnica di rivestimento di intrappolare il microrganismo senza alterarne la vitalità e il monitoraggio della vitalità microrganismo durante l'intero periodo di conservazione . A questo scopo , prove di shelf life sono state condotte a tre diverse temperature di stoccaggio (a 4°C, la normale temperatura di refrigerazione, a 9°C in condizioni di moderato abuso termico e a 14°C, in condizioni di abuso termico) per valutare la qualità microbiologica, sensoriale e funzionale della mozzarella. Pertanto, sono stati monitorati sia i microorganismi di deterioramento e sia i batteri probiotici. I risultati hanno dimostrato che la vitalità dei batteri lattici presenti nel prodotto funzionale è rimasta oltre il limite imposto (107 CFU/g) per l'intero periodo di conservazione in tutte le prove sperimentali con i valori intorno a 4,52 x 107 CFU/g a 4°C, 3,42 x 107 a 9°C e 4,62 x 107 a 14°C. Inoltre , l'aggiunta di sostanze probiotiche e prebiotiche nel rivestimento ha provocato un leggero effetto antimicrobico contro Pseudomonas spp. ed Enterobacteriaceae, che ha a sua volta migliorato il sapore finale del prodotto e prolungato la sua durata commerciale. Il secondo obiettivo di questa tesi è stata l'ottimizzazione di hamburger di manzo arricchiti con frutto-oligosaccaridi (FOS) , inulina e schiuma proteica a base di crusca d’avena. Le diverse formulazioni di hamburger di manzo funzionali sono state ottimizzate dal punto di vista sensoriale mediante un panel addestrato composto da dieci membri . Una volta ottimizzata la formulazione da un punto di vista sensoriale, è stata valutata l'influenza degli ingredienti prebiotici sulle caratteristiche chimiche, fisiche, nutrizionali e tecnologiche degli hamburger di carne. Dai risultati, si è constatato che la combinazione sia dei FOS che dell’inulina, con la schiuma a base di crusca può risultare una strategia interessante per minimizzare la perdita di composti prebiotici durante la cottura. La concentrazione di fibre in tutti i campioni di carne sviluppati, è risultata essere molto superiore al livello minimo imposto (3 g di fibre per 100 g di prodotto alimentare) per un alimento prebiotico. I risultati hanno dimostrato anche che l’aggiunta delle sostanza prebiotiche ha migliorato le caratteristiche tecnologiche e sensoriali degli hamburger. ABSTRACT IN ENGLISH The first objective of this PhD thesis was the formulation of a symbiotic Fiordilatte cheese with an edible sodium alginate coating as carrier of probiotic (Lactobacillus rhamnosus) and prebiotic fructo-oligosaccharides substances (FOS). The objectives of this study are the evaluation of the coating technique to entrap the microorganism without altering its vitality and the monitoring of the microorganism vitality during the entire storage period. To this aims, shelf life tests were conducted at three different storage temperatures (4°C as refrigeration temperature, 9°C as moderate thermal abuse and 14°C as thermal abuse) to assess the microbiological, sensory and functional quality of cheese. Therefore, both spoilage and probiotic bacteria were monitored. Results proved that viability of lactic acid bacteria in the functional product remained over the imposed limit (107 CFU/g) for the entire storage period in all the experimental trials with counts accounting for about to 4.52 x 107 CFU/g at 4°C, 3.42 x 107 at 9°C and 4.62 x 107 at 14°C. Furthermore, the addition of probiotic and prebiotics substances in the coating provoked a slight antimicrobial effect against Pseudomonas spp. And Enterobacteriaceae that improved the final taste of the product and prolonged its shelf life. The second goal of this thesis the optimization of beef burgers enriched with fructo-oligosaccharides (FOS), inulin and an oat bran loaded protein foam. The various formulations of functional beef burgers were optimized from a sensory point of view by means of a panel of ten trained members. Once the formulation has been optimized, the influence of the prebiotic ingredients on chemical, physical, nutritional and technological characteristics of meat burgers was assessed. From the results, it was found that combinations of both FOS and inulin, respectively combined with oat bran loaded foam are an interesting way to minimize the loss of prebiotic compounds during cooking. The concentration of fibers was found to be much higher than the minimal imposed level (3 g of dietary fiber for 100 g of food product) for prebiotic food, in all developed meat samples. Results also suggest that prebiotic addition to meat also improved the technological and sensory characteristics of investigated burger
Microencapsulated Lactobacillus reuteri combined with modified atmosphere as a way to improve tuna burger shelf life
No full textIn this study, tuna burgers were subjected to a bio-preservation treatment combined with modified atmosphere packaging (MAP) in order to prolong the shelf life. After L. reuteri production of reuterin, the antimicrobial compound was microencapsulated and then added to tuna burger formulation. Reuterin content was analysed before and after the spray drying treatment, thus assessing its final concentration. Then, the effects of spray-dried reuterin on tuna burgers quality were investigated with success on samples packaged under both ordinary and MAP conditions. The efficacy of bio-control was evident in all the samples. For burgers stored in air, a shelf life of about 7.63 days was recorded for the active samples with respect to the 5.78 days of the reuterin-free samples. Under MAP, a similar reuterin effectiveness was recorded but a general shelf life improvement was reached, accounting for about 13 days in the active samples and 12 days in the reuterin-free samples
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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