Browsing by Author "Aleixandre-Tudo, Jose Luis"
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- ItemBasic in-mouth attribute evaluation : a comparison of two panels(MDPI, 2018-12-21) Mihnea, Mihaela; Aleixandre-Tudo, Jose Luis; Kidd, Martin; Du Toit, WesselAstringency is often difficult to evaluate accurately in wine because of its complexity. This accuracy can improve through training sessions, but it can be time-consuming and expensive. A way to reduce these costs can be the use of wine experts, who are known to be reliable evaluators. Therefore, the aim of this work was to compare the sensory results and the panel performance obtained using trained panelists versus wine experts (winemakers). Judges evaluated twelve red wines for in-mouth basic perception (sweet, sour, bitter, astringent, and burning sensation) following the same tasting protocol and with the samples being presented in two different tasting modalities. Panels’ performance and relationship between the chemical composition and the sensory perception were investigated. Both panels showed similar consistency and repeatability, and they were able to accurately measure the astringency of the wines. However, the significant correlations between sensory scores and chemical composition varied with the panel and the tasting modality. From our results, we could see that winemakers tended to discriminate better between the samples when the differences were very small.
- ItemBibliometric and social network analysis in scientific research on precision agriculture(Indian Academy of Sciences, 2018-11-10) Aleixandre-Tudo, Jose Luis; Castello-Cogollos, Lourdes; Aleixandre, Jose Luis; Aleixandre-Benavent, RafaelPrecision agriculture (PA) is used to improve agricultural processes. A better understanding of PA as well as the evolution of the research status through the available literature are reported and discussed in this study. The Web of Science (WoS) was used to obtain the research records under study. Indicators of scientific productivity, collaboration between countries and research impact were evaluated through a social network analysis. The keywords included in the publications and subject areas under which the research was published were also evaluated through subject analysis. A total of 2027 articles were analysed from 1994 to 2014. The most productive journals were ‘Computers and Electronics in Agriculture’ (n = 191) and ‘Precision Agriculture’ (n = 110). The most frequent keywords were ‘management’ (n = 243), ‘yield’ (n = 231), ‘soil’ (n = 198) and ‘variability’ (n = 190). The collaboration network showed the United States occupying a central position, in combination with some leading countries such as Brazil, Germany, People’s Republic of China, Canada, Australia and Spain. A steady increase in PA research was identified during the last decade, which was even more sharp between 2010 and 2014. The increased importance of PA research has recently led to the birth of specific journals such as Precision Agriculture. The increasing number of journals that publish articles related to the topics included in the WoS must also be considered. The network analysis identified a number of developed countries in the hotspot of international collaboration.
- ItemEffect of skin contact before and during alcoholic fermentation on the chemical and sensory profile of South African Chenin Blanc white wines(South African Society for Enology and Viticulture, 2015) Aleixandre-Tudo, Jose Luis; Weightman, C.; Panzeri, V.; Nieuwoudt, Helene; Du Toit, W. J.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.
- ItemInfrared spectroscopy and chemometric applications for the qualitative and quantitative investigation of grapevine organs(Frontiers Media S.A, 2021-09-03) Van Wyngaard, Elizma; Blancquaert, Erna; Nieuwoudt, Hélène; Aleixandre-Tudo, Jose LuisThe fourth agricultural revolution is leading us into a time of using data science as a tool to implement precision viticulture. Infrared spectroscopy provides the means for rapid and large-scale data collection to achieve this goal. The non-invasive applications of infrared spectroscopy in grapevines are still in its infancy, but recent studies have reported its feasibility. This review examines near infrared and mid infrared spectroscopy for the qualitative and quantitative investigation of intact grapevine organs. Qualitative applications, with the focus on using spectral data for categorization purposes, is discussed. The quantitative applications discussed in this review focuses on the methods associated with carbohydrates, nitrogen, and amino acids, using both invasive and non-invasive means of sample measurement. Few studies have investigated the use of infrared spectroscopy for the direct measurement of intact, fresh, and unfrozen grapevine organs such as berries or leaves, and these studies are examined in depth. The chemometric procedures associated with qualitative and quantitative infrared techniques are discussed, followed by the critical evaluation of the future prospects that could be expected in the field.