1,721,104 research outputs found
A technological solution to recover volatile compounds and modulate the aroma profile during fermentation
No full textThe food system approach: new challenges for education, research and industr
A Technological Solution to Modulate the Aroma Profile during Beer Fermentation
No full textDuring the production of fermented alcoholic beverages, such as wine or beer, the loss of aroma active compounds (AACs) has a significant impact on the overall product aroma. This paper presents the results of an experimental technique in which a condenser was placed on the top of the fermenter in order to reduce such losses. AAC concentrations in beers produced in this way were compared with a control produced without a condenser. There were two main findings: (i) some AACs could be recovered during fermentation and (ii) the technique stimulated the de novo synthesis of esters from carboxylic acids and alcohols. In particular, the production of ethyl esters from the reaction between ethanol and organic acids and the production of acetates from the reaction between acetic acid and alcohols were demonstrated. Consequently, the addition of the condenser changed the final aroma of the beverage. The effect was confirmed by a panel test and AAC quantitation using HS-SPME-GC-MS. The technique could be used by brewers as a tool to modulate the flavor and aroma of beer
A Condenser to Recover Organic Volatile Compounds during Vinification
No full textVolatile compounds are lost during grape must fermentation owing to escaping carbon dioxide, which ultimately affects the wine’s aroma. An innovative condensation device was designed to trap organic volatile compounds that would otherwise be lost. Trials were performed on Sangiovese and Syrah grapes and involved continuous condensation of vapor (condensed fractions, CFs) escaping from fermentation tanks. Daily measurements were taken of the ethanol content and volatile compound composition of CFs. An average of 1.3g of CF per kilogram of fermenting must was recovered, corresponding to a theoretical yield of condensed product of about 0.37%. Mean ethanol content was about 24% by volume, while the total organic volatile compound concentration was about 1200 mg L−1. Predominant compounds were alcohols and esters of secondary origin, with four compounds (ethyl octanoate, 1-propanol, ethyl acetate, and 2, 3-butanediol) accounting for more than 88% of the final concentration. The CF volatile profile changed as a function of fermentation time. CFs were added back to their respective wines for sensory evaluation and were statistically shown to be detectable at a rate of 1‰
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
The effect of ripening time on the chemical, textural, volatile and sensorial traits of Bicep femoris and Semimembranosus muscles of the Slovenian dry-cured ham Kraški pršut
No full textThe effect of two ripening times (12 or 16 months) on the chemical, physical, volatile and sensorial properties of Biceps femoris (BF) and Semimembranosus (SM) muscles of Kraski prsut, was studied. Both muscles showed lower water content and higher proteolysis index at 16 than at 12 months. BF had lower lipid contents and higher moisture, salt percentage and proteolysis index than SM. In SM, a decrease of MUFA with time was observed. A higher quantity of total fatty acids was observed for SM than for BF. General increases in hardness, cohesiveness, chewiness and gumminess were observed over time in both muscles. Higher values of force decay coefficient and lower values of hardness, cohesiveness, gumminess and chewiness were found for BF than for SM. Eighty-seven volatile compounds were tentatively identified in both muscles and were more abundant at 16 than at 12 months. Aldehydes were the predominant group followed by acids, alcohols, esters, hydrocarbons, ketones and furans
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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