Browsing by Subject "Ripening"

Now showing 1 - 3 of 3
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    Combining high-power ultrasound and enological enzymes during winemaking to improve the chromatic characteristics of red wine
    (Elsevier, 2021-12-28) Pérez Porras, Paula; Bautista Ortín, Ana Belén; Jurado, Ricardo; Gómez Plaza, Encarna; Tecnología de Alimentos, Nutrición y Bromatología; Facultad de Veterinaria
    Several techniques have been used by the winemaking industry to facilitate the extraction of grape phenolic compounds during the maceration process. Interest in innovative techniques such as high-power ultrasound (US) has increased in recent years, replacing more traditional techniques such as the addition of pectolytic enzymes (E). This study evaluates the combined effect of ultrasound and enological enzymes, used at semi-industrial scale at the time of crushing, on the chromatic characteristics of red wine. Variables such as the timing of enzyme addition and the ripening state of the grapes were considered. The results showed that ultrasound had a greater effect than enological enzymes when used alone, especially when the ripest grapes were used. The results also indicate that, when added after sonication, the enzymes favored the US effect, enabling the contact time necessary to achieve a wine with chromatic characteristics similar to those resulting from a traditional maceration process to be reduced by 4 days. Carried out on a semi-industrial scale, the study demonstrates that the adequate combination of these two techniques can optimize the maceration process both in terms of time and the wine organoleptic characteristics, making the technique of special interest for industrial application.
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    Fingerprinting of volatile organic compounds and discrimination of pear samples by gas chromatography-ion mobility spectrometry
    (Elsevier, 2025-05-20) Giménez Campillo, Claudia; Pastor Belda, Marta; Campillo Seva, Natalia; Arroyo Manzanares, Natalia; Viñas López-Pelegrin, Pilar; Química Analítica
    The pear contains many volatile organic compounds that are responsible for its distinctive aroma, flavour and texture. The aim of this work was to develop, optimise and validate an analytical method for the determination of volatile compounds in pears using headspace gas chromatography coupled to ion mobility spectrometry. A total of 254 samples from four cultivars were analysed, and a partial least squares discriminant analysis model using 93 markers allowed differentiation between cultivars with 100 % accuracy and a Q2 of 0.878. Additionally, a total of 227 Ercoline pears collected at different stages of ripening were analysed. For the first time, a predictive model based on 75 markers was used to determine pear ripeness, achieving 100 % accuracy and a Q2 of 0.856. A total of 22 compounds were identified and quantified in the samples and key compounds were determined for each cultivar and ripening stage.
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    Formation of carboxylated and decarboxylated betalains in ripening grains of Chenopodium quinoa by a dual dioxygenase
    (Oxford University Press, Society for Experimental Biology, 2022-04-07) Henarejos Escudero, Paula; Martínez-Rodríguez, Pedro; Gomez-Pando, Luz Rayda; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular "A"
    Chenopodium quinoa (quinoa) is a pseudo-cereal that forms part of the cultural heritage of Andean countries, and its grains have high nutritional value and potential health benefits. Betalains are nitrogenous water-soluble pigments and bioactive molecules that contribute to these health-promoting properties. Betalains are restricted to plants of the order Caryophyllales, to which quinoa belongs. A new family of betalains has been discovered in the form of unconventional decarboxylated pigments. Here, we show that these pigments accumulate in ripening quinoa grains of fluorescent nature, and are putatively based on a dopamine-cleaving activity. This study describes for the first time the purification and molecular and functional characterization of a 4,5-dopamine extradiol dioxygenase enzyme from plants. It is a monomeric protein with a molecular mass of 34.5 kDa characterized by chromatography, electrophoresis, and time-offlight mass spectrometry. We demonstrate that this key enzyme has a dual function in a square-shaped biosynthetic pathway towards the formation of both carboxylated and decarboxylated pigments. Enzyme kinetic properties are characterized for the production of 6-decarboxy-betalamic acid and 3,4-dihydroxy-l-phenylalanine-derived betalamic acid, the two structural units of plant pigment in nature. The profile of multiple betalains present in quinoa grains has been reproduced in one-pot bioreactors containing the novel enzyme and two competing substrates