1,720,996 research outputs found
Processed kaolin particles film, an environment friendly and climate change mitigation strategy tool for Mediterranean vineyards
No full textForeseen climate change points to shifts in viticultural production patterns worldwide, leading to some major impacts in the economy of the wine industry. In a climate change scenario, combination of water scarcity, high temperature, and radiation and salinity, experienced in many regions will be strengthened, worsening the negative effects on plant growth, berry composition, and yield. Hence, the interaction between several factors, such as terroir features, climate, grapevine stress responses, and management practices used, represents a real challenge for sustainable Mediterranean viticulture. The processed kaolin particle film (PKPF) application in vineyards has been renowned as a favorable short-term strategy for sustainable mitigation of adverse abiotic summer stress. Nevertheless, the mechanisms underlying stress alleviation by PKPF application continue minimally discussed, and far from consensus on its effects on different variables, including berry composition and wine quality. This short review illustrates some of the main PKPF functions and evaluates its impact on leaves and berry traits
Chapter 9 - Processed kaolin particles film, an environment friendly and climate change mitigation strategy tool for Mediterranean vineyards
No full textForeseen climate change points to shifts in viticultural production patterns worldwide, leading to some major impacts in the economy of the wine industry. In a climate change scenario, combination of water scarcity, high temperature, and radiation and salinity, experienced in many regions will be strengthened, worsening the negative effects on plant growth, berry composition, and yield. Hence, the interaction between several factors, such as terroir features, climate, grapevine stress responses, and management practices used, represents a real challenge for sustainable Mediterranean viticulture. The processed kaolin particle film (PKPF) application in vineyards has been renowned as a favorable short-term strategy for sustainable mitigation of adverse abiotic summer stress. Nevertheless, the mechanisms underlying stress alleviation by PKPF application continue minimally discussed, and far from consensus on its effects on different variables, including berry composition and wine quality. This short review illustrates some of the main PKPF functions and evaluates its impact on leaves and berry traits
A survey on wines from organic viticulture from different European countries
No full textA survey was carried out on a thousand wines from organic viticulture from different European countries. Analytical data were collected about the most used quality control parameters (e.g. alcoholic strength, reducing sugars, total acidity and pH, volatile acidity, malic and lactic acid, free and total sulfur dioxide), as well as regarding some compounds harmful for human health, such as ochratoxin A and biogenic amines. The results collected on quality control parameters were generally in agreement with the values normally detectable for conventional wines. Total sulfur dioxide was lower than 110-120mg/L in the most of the samples and no significant correlation was found between sulfite levels and other parameters. Ochratoxin A (OTA) seemed not a generalized problem for organic wine productions: its concentration was below the European legal limit, in the 95% of the samples analyzed; nevertheless, the risk of OTA pollution seemed higher in certain southern European regions. On the other hand, biogenic amines (BA) appeared a serious problem for organic winemaking and high concentrations were found in many of the analyzed wines. They seemed connected with a bad management of malolactic fermentation, being generally associated with high pHs and volatile acidities. © 2013 Elsevier Ltd
Chitosan from mushroom by-products: sustainable extraction process and winemaking application
No full textChitosan is a biopolymer industrially obtained from the deacetylation of chitin, the second most abundant polysaccharide on earth, after cellulose. It is extracted from various terrestrial and marine resources, including insects, grasshoppers, shrimps, crabs, lobsters, squids, and fungi. Chitosan has a polycationic character due to the free amine groups along its chemical backbone, and depending on its deacetylation degree (dd) and molecular weight (mw), it shows variable properties that differ from those of other natural polysaccharides. It is an outstanding polymer with low toxicity, high biodegradability, chelating, anticoagulant, antioxidant, and antimicrobial activities. Fungal chitosan from aspergillus niger is the only type accepted in winemaking to avoid any potential concerns about allergenicity because of the crustacean raw material. The addition to wines is currently aimed at controlling unwanted microbial growth, particularly brettanomyces spp., preventing iron and copper casses, and removing heavy metals and ochratoxin a. The addition of fungal chitosan in musts and wines has also been successfully authorized for fining and clarification purposes to reduce turbidity by precipitating suspended particles or proteinaceous matter. The recommended doses of chitosan range from 10 g/hl to 500 g/hl for microbial control, iron and copper haze prevention, and heavy metal and contaminant reduction. This limit is set at 100 g/hl only for fining purposes. The conventional production of chitin and chitosan involves deproteinization, demineralization, decolorization, and deacetylation steps. Acid, alkaline, or enzymatic processes are commonly performed. However, these methods are long-time consuming, low-efficient, and require large volumes of solvents and hazardous chemicals. Several greener strategies and technologies have been proposed. Subcritical water technology is one of the most promising and versatile processes. Subcritical water extraction (swe) is usually conducted at temperatures ranging from 100 to 374°c, under sufficient pressure to keep water in a liquid state. Swe offers several advantages, including fast reaction rates, the replacement of acids/bases with a more environmentally sustainable solvent, and its properties can be finely modulated. Moreover, the identification of new undervalued and unexploited biomasses, such as edible mushroom by-products, should also be promoted for eco-friendlier chitosan production. In the present work, a sustainable extraction process with subcritical water from mushroom (pleourotus ostreatus) by-products was performed. Swe allowed a 4.5-fold increase in extraction yield and a 4-fold reduction in process time. The chitin and chitosan were characterized and compared with conventional ones. Significant effects were pointed out on some chemical properties, such as deacetylation degree, crystallinity index, and chromatic properties, according to the adopted subcritical conditions. The swe chitosan was also studied for winemaking purposes. Several experimental trials were performed at different dosages (0-100 g/hl), on several unstable white wines, aimed to point out significant interactions with proteins, polyphenols, and aroma compounds. Positive effects were highlighted on some analytical indices related to wine protein stability, and a significant decrease in unstable proteins was detected, for both chitinases and thaumatin-like proteins (tlps). The swe chitosan didn’t affect the chromatic characteristics of wines or the total polyphenol content. Moreover, the chromatographic analysis of volatile compounds showed no significant effects on the main chemical classes. Further research is already undergone, aimed at deeply investigating the effect of subcritical water at different conditions on the chitosan polymeric structure and its functionality for winemaking applications
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
Approccio elettroanalitico per lo studio di antiossidanti ad uso enologico
No full textLa voltammetria ciclica è una potente tecnica elettroanalitica per lo studio di molecole antiossidanti. Questa tecnica è
stata utilizzata per valutare il comportamento di alcuni antiossidanti enologici. Anidride solforosa, acido ascorbico, glutatione
e derivati di lievito sono stati confrontati in diverse concentrazioni, per valutare la loro capacità di proteggere la
(+)-catechina, in vino modello. I prodotti testati hanno dimostrato attività diverse, legate non solo alle loro specifiche caratteristiche
antiossidanti, ma anche alla concentrazione media che hanno nel vino. Il lavoro svolto dimostra il potenziale
di questa tecnica analitica per lo studio dei meccanismi di ossidazione in ambito enologico
Acidification and pH Control in Red Wines
No full textThis chapter focuses on the management of acidic fraction and pH control in red wines. The main traditional strategies for chemical acidification and deacidification are discussed, including the use of acidic musts from low maturity grapes, as well as the addition of tartaric acid, malic, lactic, and citric acid, potassium bicarbonate, and calcium carbonate. Less common practices, such as deacidification by the addition of other salts, are also examined, together with new technologies, such as electrodialysis and the use of ion exchange resins. The effects of these techniques on wine pH as well as their impact on wine composition, stability, and sensory characteristics are considered, focusing on the problems of red wine processing. Finally, the main laboratory techniques for pH and acidity measurements are overviewed
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
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