Phenolic compounds are bioactive substances present in a large number of food products including wine. The importance of these compounds in wine is due to their large effect on the organoleptic attributes of wine. Phenolic compounds play a crucial role in the colour as well as mouthfeel properties of wines. UV-visible spectroscopy appears as a suitable technique for the evaluation of phenolic compounds' properties and content. The ability of the phenolic ring to absorb UV light and the fact that some of the phenolic substances are coloured compounds, i.e. show absorption features in the visible region, make UV-visible spectroscopy a suitable technique to investigate and quantify grape and wine phenolic compounds. A number of analytical techniques are currently used for phenolic quantification. These include both simpler approaches (spectrophotometric determinations) as well as more complex methodologies such liquid chromatography analysis. Moreover, a number of spectroscopy applications have also been recently reported and are becoming popular within the wine industry. This chapter reviews information on the UV-visible spectral properties of phenolic compounds, changes occurring during wine ageing and also discusses the current UV-visible based analytical techniques used for the quantification of phenolic compounds in grapes and wine.

Phenolic compounds are of crucial importance for red wine color and mouthfeel attributes. A large number of enzymatic and chemical reactions involving phenolic compounds take place during winemaking and aging. Despite the large number of published analytical methods for phenolic analyses, the values obtained may vary considerably. In addition, the existing scientific knowledge needs to be updated, but also critically evaluated and simplified for newcomers and wine industry partners. The most used and widely cited spectrophotometric methods for grape and wine phenolic analysis were identified through a bibliometric search using the Science Citation Index-Expanded (SCIE) database accessed through the Web of Science (WOS) platform from Thompson Reuters. The selection of spectrophotometry was based on its ease of use as a routine analytical technique. On the basis of the number of citations, as well as the advantages and disadvantages reported, the modified Somers assay appears as a multistep, simple, and robust procedure that provides a good estimation of the state of the anthocyanins equilibria. Precipitation methods for total tannin levels have also been identified as preferred protocols for these types of compounds. Good reported correlations between methods (methylcellulose precipitable vs bovine serum albumin) and between these and perceived red wine astringency, in combination with the adaptation to high-throughput format, make them suitable for routine analysis. The bovine serum albumin tannin assay also allows for the estimation of the anthocyanins content with the measurement of small and large polymeric pigments. Finally, the measurement of wine color using the CIELab space approach is also suggested as the protocol of choice as it provides good insight into the wine's color properties.

Climate change refers to an alteration in the state of the climate that can be identified by changes in the mean and the variability of its properties. Climate change reflects abnormal variations in the Earth's atmosphere and subsequent effects on other parts of the planet, such as on crop lands, reducing the annual yield. The objective of this paper was to contribute to a better understanding of the scientific knowledge in climate change and his effect concerning agriculture, as well as to investigate its evolution through the published papers. Items under study were obtained from Web of Science (WOS) platform from Thomson Reuters. A bibliometric and social network analyses was performed to determine indicators of scientific productivity, impact and collaboration between authors, institutions and countries. A subject analysis taking into account the key words assigned to papers and subject areas of journals was also carried out. A total of 1,471 articles were included in the selected subject categories in WOS since 2005 until 2014. The most productive journals were Agricultural and forest Meteorology, Forest Ecology and Management, and Agriculture Ecosystems & Environment. Excluding climate or climatic change, the most frequent keywords have been CO2, Adaptation, Model, Temperature and Impact. The network of collaboration between countries shows the central position of the United States, together with other leading countries such as China, Canada, Australia, Germany, and United Kingdom. This work has provided helpful insights into the climate change research in Agricultural subject areas, wich had grown steadily during the last decade. The network of collaboration between institutions and countries involve both centres from developed and developing countries, and it is noteworthy the cooperation between US and China. Highly cited papers reveal the concern on emerging climate change risks for forest, the impact on forest ecosystems, the effect on plant diseases and adaptation options.

There have been a substantial number of studies suggesting possible health benefits from polyphenols in wine, especially red wine. These hypothetical effects, in addition to those of alcohol, are attributed by many to antioxidant and anti-inflammatory effects of the polyphenols. The aim of this paper was to map the scientific research on wine and health by using bibliographic analyses of papers published during the period 2002-2011. Papers were published in 535 different journals and in 106 different subject categories, the most productive journals being the Journal of Agricultural and Food Chemistry, Food Chemistry and Molecular Nutrition, and Food Research, and the most productive subject category being food science and technology. Institutions in the main network of collaboration between centers were primarily located in France, Italy, and the United State. The number of papers on the medicinal use of wine has been dramatically rising in recent years because of the increased awareness of its importance in modern society. We emphasize the large distribution of information among numerous journals and the multidisciplinary nature of the topic. In the network of co-words, we observe the central role played by the terms "resveratrol", "wine", and "polyphenols".

The volatile and phenolic composition of Chenin blanc wines made with different skin contact treatments was studied. One batch of grapes was used to make a dry white wine according to two different treatments, namely pre-fermentative skin contact and complete fermentation on the skins. A white wine fermented without any skin contact was used as control. Fermentation on the skins and skin contact before fermentation led to significantly lower levels of terpenes, esters, acids and thiols, and the highest significant levels of alcohols and phenolic compounds. However, this effect was less pronounced in wines with skin contact before fermentation. Sensory analysis of all the experimental wines was also performed. The results showed a significant shift from the sensory attributes of fresh and tropical fruits of the control Chenin blanc wines towards riper fruit notes in the skin contact treatments. This observation was correlated with the length of the skin contact period. Possible reasons to explain the results observed in this study are discussed.