1,721,167 research outputs found
Soluble sugars and polysaccharides
No full textDuring sourdough fermentation, important changes in the carbohydrate fraction occur due to enzymatic and metabolic reactions of both yeasts and lactic acid bacteria involved in the process. Indeed, the production of several metabolites depends on the availability of soluble carbohydrates either initially present in the flour or resulting from the hydrolysis of starch or other polysaccharides.
For the determination of soluble sugars and polysaccharides, enzymatic kits, often based on official methods of analysis, recognized by the scientific community are available. The high specificity of enzymes enables the analysis of complex matrixes without complicated sample preparation techniques and little interferences which, on the contrary, might occur during chromatographic coelution. Nevertheless, although enzymatic assays favor the analysis of several samples in relatively little amount of time, the higher costs of analysis per sample compared to lab-developed methods tip the scale in favor of the latter.
Whereas soluble sugars can be easily extracted and separated through high performance liquid chromatography, starch quantification needs to be preempted by its hydrolysis to glucose. As for dietary fibers, the hydrolysis of proteins and starch precedes filtration of insoluble fiber and precipitation of soluble fiber in ethanol. Their content is then evaluated by weighing after drying. In this chapter, the chromatographic method for mono-, di-, and oligosaccharides, the enzymatic hydrolysis of starch, and the analysis of dietary fibers according to official methods will be described
Pane gluten-free da semola di grano duro: caratterizzazione integrata e confronto con pani senza glutine commerciali - Parte I, materiali e metodi
No full textCharacterization of the Bread Made with Durum Wheat Semolina Rendered Gluten Free by Sourdough Biotechnology in Comparison with Commercial Gluten-Free Products
No full textDurum wheat semolina was fermented with sourdough lactic acid bacteria and fungal proteases aiming at a complete gluten hydrolysis. The gluten-free (GF) semolina, added with naturally GF ingredients and structuring agents, was used to produce bread (rendered GF bread; rGFB) at industrial level. An integrated approach including the characterization of the main chemical, nutritional, structural, and sensory features was used to compare rGFB to a gluten-containing bread and to 5 commercial naturally GF breads. High-performance liquid chromatography was used for free amino acids (FAAs), organic acids, and ethanol analysis. A methanolic extract was used for determining total phenols and antioxidant activity. The bread characterization also included the analysis of dietary fibers, mycotoxins, vitamins, and heavy metals. Beyond chemical analysis, nutritional profile was evaluated considering the in vitro protein digestibility and the predicted glycemic index, while the instrumental texture profile analysis was performed to investigate the structure and the physical/mechanical properties of the baked goods. Beyond the huge potential of market expansion, the main advantages of durum wheat semolina rendered GF can be resumed in the high availability of FAAs, the high protein digestibility, the low starch hydrolysis index, and the better technological properties of bread compared to the commercial GF products currently present on the market. Vitamins, minerals, and dietary fiber profiles are comparable to those of gluten-containing wheat bread. Also the sensory profile, determined by a panel test, can be considered the most similar to those of conventional baked goods, showing all the sourdough bread classic attributes
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
Investigation of the nutritional, functional and technological effects of the sourdough fermentation of sprouted flours
No full textIn recent years, recommendations on whole grains consumption have been added to the overall dietary guidelines of many countries around the world. Despite the many benefits on human health, whole grains contain several anti-nutritional factors which decrease their nutritional quality leading to a poor use in human diet. Here, an integrate biotechnological approach, combining germination and sourdough fermentation with selected lactic acid bacteria, was set-up in order to improve the functional and nutritional quality of wheat, barley, chickpea, lentil and quinoa grains. Sourdough fermentation with Lactobacillus rossiae LB5, Lactobacillus plantarum 1A7 and Lactobacillus sanfranciscensis DE9 further enhanced the nutritional and functional features of sprouted flours by means of increased peptides, free amino acids and γ‐aminobutyric acid concentrations, and decreased phytic acid, condensed tannins, raffinose and trypsin inhibitory activity. Sensory appreciable wheat breads fortified with the fermented sprouted flours were manufactured and characterized, showing high protein digestibility and low starch availability
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