Browsing by Author "Pavez C."

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    Astringency sub-qualities of red wines and the influence of wine–saliva aggregates
    (Blackwell Publishing Ltd, 2021) Brossard N.; Gonzalez-Muñoz B.; Pavez C.; Bordeu E.; Gonzalez-Muñoz B.; Ricci A.; Paola Parpinello G.; Wang X.; Chen J.; Osorio F.
    © 2021 The Authors. International Journal of Food Science & Technology published by John Wiley & Sons Ltd on behalf of Institute of Food, Science and Technology (IFSTTF)Astringency is a sensory attribute, related to the quality and mouthfeel of red wines. However, the origin of astringency sub-qualities, such as the typical drying astringency found in immature grapes, is still unknown. Astringency of red wines with similar tannin content but different astringency sub-qualities, from different harvest dates, is studied. Astringency was characterised in terms of friction coefficient, polyphenol content, sensory analysis and tannin/salivary–proteins aggregates characterisation. A different evolution during ripening was found for both Cabernet Sauvignon and Carménère, and tannin–protein aggregates showed differences in size, shape and surface. The velvety sub-quality appears to be related to aggregates with low precipitation, and with specific surface characteristics as roundness and Feret diameter. Results from this work propose an effect of aggregates on sensory perception and opens the possibility to explore their effect on oral lubrication.
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    High prevalence of SARS-CoV-2 detection and prolonged viral shedding in stools: A systematic review and cohort studyElevada detección de SARS-CoV-2 y prolongada excreción viral en deposiciones: Estudio de cohorte y revisión sistemática
    (2022) Diaz L.A.; Chahuan J.; Alvarez M.; Pavez C.; Candia R.; Monrroy H.; Espino A.; Pizarro M.; Riquelme A.; Garcia-Salum T.; Levican J.; Almonacid L.I.; Valenzuela G.H.; Serrano E.; Ferres M.; Salinas E.; Medina R.A.; Fuentes-Lopez E.; Riquelme A.; Reyes D.; Ortiz J.; Rada G.; Valderrama S.; Budnik S.; Gandara V.; Gallardo A.; Seydewitz M.F.; Cofre C.; Rada G.; Ortiz L.; Rada G.; Toro A.; Ortega M.; Ortega M.
    © 2022 Elsevier España, S.L.U.Objectives: To: 1. Describe the frequency of viral RNA detection in stools in a cohort of patients infected with SARS-CoV-2, and 2. Perform a systematic review to assess the clearance time in stools of SARS-CoV-2. Methods: We conducted a prospective cohort study in two centers between March and May 2020. We included SARS-CoV-2 infected patients of any age and severity. We collected seriated nasopharyngeal swabs and stool samples to detect SARS-CoV-2. After, we performed a systematic review of the prevalence and clearance of SARS-CoV-2 in stools (PROSPERO-ID: CRD42020192490). We estimated prevalence using a random-effects model. We assessed clearance time by using Kaplan–Meier curves. Results: We included 32 patients; mean age was 43.7 ± 17.7 years, 43.8% were female, and 40.6% reported gastrointestinal symptoms. Twenty-five percent (8/32) of patients had detectable viral RNA in stools. The median clearance time in stools of the cohort was 11[10–15] days. Systematic review included 30 studies (1392 patients) with stool samples. Six studies were performed in children and 55% were male. The pooled prevalence of viral detection in stools was 34.6% (twenty-four studies, 1393 patients; 95%CI:25.4–45.1); heterogeneity was high (I2:91.2%, Q:208.6; p ≤ 0.001). A meta-regression demonstrates an association between female-gender and lower presence in stools (p = 0.004). The median clearance time in stools was 22 days (nineteen studies, 140 patients; 95%CI:19–25). After 34 days, 19.9% (95%CI:11.3–29.7) of patients have a persistent detection in stools. Conclusions: Detection of SARS-CoV-2 in stools is a frequent finding. The clearance of SARS-CoV-2 in stools is prolonged and it takes longer than nasopharyngeal secretions.
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    Red wine astringency: Correlations between chemical and sensory features
    (Academic Press, 2022) Pavez C.; Gonzalez-Munoz B.; O'Brien J.A.; Bordeu E.; Brossard N.; Gonzalez-Munoz B.; O'Brien J.A.; Laurie V.F.; Osorio F.; Nunez E.; Vega R.E.
    © 2021 The AuthorsThirty-seven red wines from different varieties, origins, and styles were characterized to identify the chemical parameters that better correlate with wine astringency. Principal Component Analysis showed that tannin content was the most important parameter influencing overall astringency and its sub-quality dryness, followed by polyphenolic content, color index and, to a lesser extent, pH and alcoholic degree. Given that astringency is a textural sensation caused by the interaction between salivary proteins and tannins, a comparison between two tannin precipitation assays (i.e., methylcellulose, MCP; and Harbertson-Adams assays, HA) were performed to evaluate their ability as estimators of red wine astringency. Results of the sensory correlations showed that MCP and HA have a different behavior toward intensity of astringency and dryness, mainly influenced by the tannin concentration. HA exhibited a sigmoidal behavior with a better astringency predictive performance at low and mid tannin concentration range, whilst MCP showed a linear behavior with a better performance at high tannin concentration range.
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    Wine astringency: more than just tannin–protein interactions
    (John Wiley and Sons Ltd, 2022) Gonzalez-Munoz B.; Garrido-Vargas F.; Pavez C.; Bordeu E.; O'Brien J.A.; Brossard N.; Gonzalez-Munoz B.; Garrido-Vargas F.; O'Brien J.A.; Osorio F.; Chen J.
    © 2021 Society of Chemical Industry.Red wines are characterized by their astringency, a very important sensory attribute that affects the perceived quality of wines. Three mechanisms have been proposed to explain astringency, and two theories describe how these mechanisms work in an integrated manner to produce tactile sensations such as drying, roughening, shrinking and puckering. The factors involved include not only tannins and salivary proteins, but also anthocyanins, grape polysaccharides and mannoproteins, as well as other wine matrix components that modulate their interactions. These multifactorial interactions could be responsible for different sensory responses and therefore need to be further studied. This review presents the latest advances in astringency perception and its possible origins, with special attention on the interactions of components, their impact on oral perception and the development of astringency sub-qualities. Future research efforts should concentrate on understanding the mechanisms involved as well as on the limiting factors related to the conformation and stability of the tannin–salivary protein complexes. © 2021 Society of Chemical Industry.