Publications by authors named "Esperanza Valdes-Sanchez"

The influence of applying hydrostatic high pressure (HHP) to red grape pomace cv. Tempranillo was studied to obtain an ingredient rich in bioactive compounds for the manufacture of food products. Four treatments were investigated: (i) 600 MPa/1 s; (ii) 600 MPa/300 s, and other two treatments with 2 cycles of HHP: (iii) 2 cycles of 600 MPa/1 s; and (iv) 1 first cycle of 400 MPa/1 s and a second cycle 600 MPa/1 s.

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White wine pomace, a by-product from winemaking, was stabilized after the application of thermal blanching (with the aim of deactivating the polyphenoloxidase enzyme), milling, and processing by hydrostatic high-pressure treatment (with the aim of reducing initial microbial loads while preserving phenolic compounds content). The valorized pomace (VP) ingredient was added at different proportions to pork burgers (0.5%, 1%, and 3% /) to improve their preservation, and the effect was compared to those produced by sulfites and with a control (without sulfites or VP).

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Polyphenolic characterization of minority red grapevine varieties is a key factor to improve varietal recovery and promotion. This work focuses on determining phenolic family content and anthocyanin (AN) profiles of 28 different red grape varieties during 2018 and 2019 vintages in Galicia (Northwest of the Iberian Peninsula). Most of these varieties are considered "minority varieties" in this region.

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The applicability of front-face excitation-emission fluorescence spectroscopy to compare grape water extracts of two consecutive sampling dates, corresponding with two maturation stages, and subjected to full irrigation and non-irrigation, was carried out. The decomposition of the obtained three way grape samples was initially analyzed by means of parallel factor analysis (PARAFAC). A tentative identification of fluorophores was done by matching PARAFAC score values with HPLC measurements.

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Phenolic extracts from cv Tempranillo grapes subjected to water stress and irrigation treatment, both of them with high and low crop load, were analyzed by front-face fluorescence. Excitation-emission matrices (EEMs) were analyzed by means of unsupervised parallel factor analysis (PARAFAC), PARAFAC supervised by linear discriminant analysis, and discriminant unfolded partial least-squares. All algorithms allowed to differentiate between water stress and irrigation grape samples when the fluorescence maxima region of catechin and epicatechin, and resveratrol was considered.

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