Mihai Lucian Lung

Phenolic Substances, Flavor Compounds, and Textural Properties of Three Native Romanian Wine Grape Varieties

In this work, the chemical compositions and texture characteristics of three native Romanian wine grape varieties (Fetească regală, Fetească alba, and Fetească neagră) were studied. We assessed the distinct characteristics directly linked to their phenolic compositions, volatile profiles, and mechanical properties and compared these characteristics with those of Pinot noir grapes. The effect of the growing zone was also evaluated. Various spectrophotometric indices directly related to the phenolic compositions of berry skins and seeds were determined. The detailed phenolic compositions (anthocyanins, hydroxycinnamoyl tartaric acids, and stilbenes) of the skins were determined using high-performance liquid chromatography methods. Free and bound volatile compounds in the berries were quantified by gas chromatography/mass spectrometry. The textural properties of the skins and seeds were measured by instrumental texture analysis. The results showed high diversity among the varieties and zones that affected the enological potential. Among the white varieties, Fetească albă grapes could be less susceptible to browning as a consequence of their lower trans-caffeoyltartaric acid concentration, whereas Fetească regală grapes from Cluj had the highest concentrations of total free and bound volatile compounds, particularly terpenes and norisoprenoids. Among the red varieties, Fetească neagră was identified as a promising variety to be exploited in the future for its particular phenolic characteristics, particularly those grapes grown in Mica. Nevertheless, Fetească neagră grapes grown in Cluj had the highest total glycosidically bound terpene concentrations. Finally, differences in the mechanical and/or acoustic properties of the skins and seeds could strongly influence the kinetics and completeness of phenolic compound extractions.

Researches Regarding the Influence of Special Green Works on Evolution of Ripening in Four Varieties of Grapes for Wine from Vineyard Târnave

This paper was done in order to establish the influence of special green works (grapesthinning, partial deleafing and grapes bagging) on ripening evolution at the varieties: ‘MuscatOttonel’, ‘Neuburger’, ‘Traminer roz’ and ‘Sauvignon blanc’, in ecoclimatic conditions of TA¢rnaveVineyard. The grapes ripening was observed starting with 19th August, after dough ripening. Severaldeterminations were conducted regarding sugars accumulations, acidity and the weigh of 100 berries,at a one week interval (the 19th of August, 29th of August, 5th of September and 12th of September).Out of the methods known for sugars determinations within the must (refractometric method,densymetric method and chemical method) it was used the refractometric one. The principle of themethod is based on the determination of the dry matter percent within the must by using therefratometer. The content of sugars is then calculated with the aid of the corresponding tables. Theresult is expressed in g/l (sugar grams/must litres). Titration in the presence on phenolphthalein wasused to determine the total acidity within the must. The acidity is expressed in g/l H2SO4. Variant 2(deleafed) of ‘Traminer roz’ accumulated the highest sugars content. The acidity decreases with thesugars concentration. An important decrease is observed in the first period of maturation (19th ofAugust- 5th of September), excepting the ‘Neuburger’ variety, which had an acidity decrease duringthe 5th- 12th of September period.