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Assessment of grape pomace phenolic composition and anthocyanin profile
Get PDFOnly AbstractGrape pomace is the major solid by-product generated during winemaking process, representing a current environmental problem, its reintroduction into the food technology circuit being among the main objectives of sustainable horticulture. Among the recoverable compounds left from grape processing, phenolic compounds remain the most valuable. Grape pomace resulted from the winemaking of three Vitis vinifera L. cultivars for white (Pinot gris) and red (Cabernet Sauvignon and Merlot) wine was naturally dried (protected from direct sunlight, wind and moisture)
Evaluarea compoziției fenolice și a profilului de antociani al tescovinei de struguri
Get PDFOnly AbstractTescovina de struguri reprezintă principalul subprodus generat în procesul de vinificație, reprezentând în prezent o problemă de mediu, reintroducerea acestor deșeuri în circuitul tehnologiilor alimentare fiind unul dintre principalele obiective ale horticulturii durabile. Dintre compușii recuperabili regăsiți în tescovină ca urmare a procesării strugurilor, compușii fenolici rămân cei mai valoroși.
Tescovina rezultată în urma procesării strugurilor a trei soiuri Vitis vinifera L. pentru vinuri albe (Pinot gris) și roșii (Cabernet Sauvignon și Merlot) a fost uscată în condiții naturale (protejată de lumina directă a soarelui, vânt și umiditate)
Evaluation of phenolic composition of red grape dried pomace - a sustainable source of bioactive compounds
Get PDFAbstract.Grapes are one of the most produced crops worldwide with an estimated production of about 79 million tons, approximately 75% of grapes being used for wine production, out of which 20–30% represents waste products [1]. Winemaking waste, mainly as grape pomace (grape skins, pulp seeds and stalks) and wine lees, represent an important environmental issue, their recovery and reintroduction into the food technology circuit is one of the main objectives of sustainable horticulture. Among the recoverable compounds from grape pomace, phenolic compounds remain the most valuable, showing great potential from both the nutritional and therapeutic point of view [2]. Phenolic substances are concentrated in the skin and seeds, i.e. exactly that part which remains as pomace after their processing. After winemaking, due to their poor extraction during the process, about 70% of phenolic compounds remain in the grape pomace (anthocyanins, proanthocyanidins, phenolic acids or stilbenes).
Material and methods. The purpose of the current study was the assessement of phenolic compounds content and composition from grape pomace resulted as waste from the winemaking of cosmopolitan Vitis vinifera L. varieties Cabernet Sauvignon, Merlot and Pinot gris (Copou-Iasi wine center, NE of Romania). After grape crushing and destemming, the maceration was conducted for 72 hours, followed by pressing (pneumatic press), the pomace being recovered and dried under natural conditions. For the extraction, the dried pomace was ground (< 0.2 mm) and three successive extractions with 80% ethanol with 0.1% HCl were performed. pH differential method (anthocyanin assay) and Folin-Ciocalteu reagent (total phenolics) were used.
Results. The total phenolic content of the dried pomace varied from 1.34±0.03 to 1.97±0.10 g/ 100 g as gallic acid, while the anthocyanin content was between 327.58±1.52 (Pinot gris) and 890.32±3.81 mg/100 g (Cabernet Sauvignon). Total flavonoid content (Dowd method) was higher in Cabernet Sauvignon dry pomace, up to 653.48±2.31 mg/100 g as quercetin. The ratio between catechins (vanillin reaction), as monomeric flavanolic units, and proanthocyanidins, as polymerized flavanols (Bate-Smith assay) was determined, showing the high degree of polymerization of the grape pomace tannins. The polyphenolic index (D280) varied widely depending on the variety, between 26.66 and 47.28.
Conclusions. The high amount of polyphenolic compounds extracted demonstrate that grape pomace, even in dry state, is a valuable and accessible source of bioactive metabolites for the food and pharmaceutical industries, with a huge functional potential still insufficiently exploited
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variația unor caracteristici biochimice la unele organe verzi ale viței de vie (Vitis vinifera L.) în funcție de înălțimea de creștere
No full textThe purpose of the study was to evaluate and establish
therelationships between some biochemical featrures of leaves collected from
the top, middle and bottom of the vine stock in the phenophase of grapes
tehnological mathurity. The determinations included analysis of the moisture
and total dry matter, total polyphenolic compounds and peroxydase activity.
The concentration of photosynthetic pigments and the ratios between them was
also determinated. The varietys ana lysed were Fetească albă, Fetească Regală,
Grasă de Cotnari, Tămâioasă românească and Frâncușă from Iași vineyard.
The highest total polyphenolic content, was registrated in the top leaves while
the middle collected leaves recorded a increased level of photosynthetic
pigmentsdepending on variety and growing height
Effects of exogenous growth regulators on agrobiological, technological and physiological characteristics of an interspecific grapevine cultivar
No full textThe use of interspecific grapevine cultivars offers new perspectives for sustainable viticulture. Although the application of exogenous plant hormones has become widespread in recent years, data regarding the response of interspecific grapevine cultivars to treatments with biostimulants are scarce. The aim of the study was to evaluate the effect of different doses of gibberellic acid (GA3) (25, 50 and 100 mg L−1), applied by spraying the inflorescences in the late flowering phenophase, and of the complex product Cropmax® (1.0, 2.5 and 5.0 mL L−1) applied by spraying the leaves in three different phenophases, on the phenology, fertility, physiological characteristics, grape yield and quality of the interspecific table grape cultivar Moldova (Guzal kara × Seyve-Villard 12-375), growing in temperate climate conditions (N-E Romania). The application of GA3 at 50 mg L−1 increased the plant productivity (36%), promoted fruit growth and rachis elongation, improved the percentage of the marketable yield (by 5.5%), balanced the sugar/acidity ratio, but affected the synthesis of phenolic compounds. Foliar application of Cropmax® at 2.5 mL L−1 significantly improved the berry diameter, and sugar and anthocyanin accumulation, but grape acidity remained high. All treatments allowed the normal development of plant phenophases and grape maturation, but GA3 application slightly extended the number of days of the annual biological cycle of the Moldova hybrid cultivar (up to 5.5 days), probably due to a temporary variation in the physiological parameters (except for stomatal conductance), as determined in mature leaves after the application of the exogenous growth regulator
Studii privind extracţia compuşilor fenolici din coardele de viţă de vie
Get PDFÉtant donné que la taille de la vigne produit chaque année une grande quantité de déchets inutilisables, le but de cette étude était d'évaluer le potentiel des baguettes de vigne à être utilisées comme source naturelle de composés bioactifs pour les industries alimentaire, pharmaceutique et cosmétique. Afin d'optimiser les procédures d'extraction phénoliques, les baguettes de vigne de raisin de Cabernet Sauvignon ont été extraites avec diverses concentrations d'éthanol (0, 50, 70, 90 et 96%) et d'hydroxyde de sodium 1N, dans un rapport matière végétale/solvant de 1:10. Pour purification ultérieure sur des cartouches C18SPE préconditionnées, les surnageants ont été concentrés à sec dans un évaporateur rotatif sous vide. Après avoir déterminé la concentration optimale en solvant, le temps (<300 min) et la température (20, 40, 60 °C) nécessaires pour maximiser l'extraction des composés phénoliques ont été testés. La concentration la plus élevée en polyphénols a été obtenue lorsque l'extraction a été réalisée sur des baguettes de vigne broyées (particules <0,5 mm), avec une solution d'éthanol 70%, 4 heures à 60 °C. Après application de températures élevées, l'activité antioxydante et le pouvoir réducteur ferrique des extraits sont restés élevés(94,01% de DPPH nettoyé). Les résultats de la recherche indiquent que les baguettes de vigne sont sources durables de composés polyphénoliques avec fonction sanogène, actuellement inexploitées au potentiel technologique et économique réel
Evaluarea conținutului de acid clorogenic şi total fenolic din boabele uscate de cafea verde (Coffea canephora)
No full textChlorogenic acids are a group of cinnamic acid derivatives with
biological effects mostly related to their antioxidant and antiinflammatory
activities. This paper aims to determine the chlorogenic acid (CGA) and total
phenolic (TP) concentration in various solvent extracts of green coffee beans
(Coffea canephora syn. Coffea robusta). Also, the influence of brewing time
(water at 90 °C) on the extraction of CGA was analyzed. 70% methanol and
70% 2-propanol were the most effective solvents in extraction of CGA from
dried grinded green coffee beans of C. canephora (34.80±0.21 mg CQAE/g d.w.
and 31.20±0.32 mg CQAE/g d.w., respectively). The most important CGA
concentration was registered after 10 to 15 minute of coffee brewing
(38.20±0.24 mg CQAE/g d.w.), when CGA represents approximately 45% of
total phenolic compounds. Data obtained are useful both for experts from the
food (functional food) and pharmaceutical industry, and also for traders and
consumers
Studiu privind implicarea relației guaiacol peroxidaza-compuşi fenolici în degradarea pigmenților asimilatori din frunzele Vitis vinifera L.
No full textPrevious research highlighted that chlorophyll and some carotenoids are
bleached by the action of oxidative enzymes such as peroxidases in the presence of
phenolic compounds. In the present investigation, leaves of 11 Vitis vinifera L.
varieties (in blooming phenophase), were assayed for their chlorophyll (a+b) and
carotenoid (x+c) concentration and their degradation after 30 days of cold (6°C)
and dark storage. Peroxidase activity (EC 1.11.1.7) and total phenolic content (TP)
of leaves were initially determined. We found an important linear correlation
between peroxidase activity (PA) and the percentage of total chlorophyll (Chl)
degraded (R2=0.9243; p<0.05), and also a positive statistically significant
relationship between PA and TP concentration (R2=0.8389; p<0.05). Analyzing by
fractions, the most important coefficient of determination was registered for the
relationship PA – % of Chl a degraded (R2=0.8389; p<0.05), with a poor
correlation for PA – % of Chl b degraded and PA – % of carotenoid degraded
relationships. Experimental data obtained indicates that peroxidase might be
involved in chlorophyll bleaching in the presence of phenolic compounds, and might
mediate in a lesser extent leaf carotenoids degradation
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