Browsing by Author "Belancic, A"

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    Aromatic potential of certain Muscat grape varieties important for Pisco production in Chile
    (2000) Agosin, E; Belancic, A; Ibacache, A; Baumes, R; Bordeu, E; Crawford, A; Bayonove, C
    Pisco is noted for its fruity, Muscat aroma. However, numerous different grape varieties, bearing distinct aromatic profiles, are used in the production of this unaged wine distillate. Hence, this work provides a quantification of the most significant terpenes (linalool, nerol and geraniol), and other aromatic components of the main aromatic grape varieties found in the Pisco-producing region of Chile. Moscatel de Alejandria and Moscatel Rosada both proved to be highly aromatic while the terpene profiles of two little-grown varieties, Early Muscat and Moscatel Amarilla, indicate that these could contribute much to the aroma of Pisco.
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    Influence of sun exposure on the aromatic composition of Chilean Muscat grape cultivars Moscatel de Alejandria and Moscatel rosada
    (AMER SOC ENOLOGY VITICULTURE, 1997) Belancic, A; Agosin, E; Ibacache, A; Bordeu, E; Baumes, R; Razungles, A; Bayonove, C
    The effect of sun exposure on the aromatic composition of two Muscat grape cultivars, Moscatel de Alejandria and Moscatel rosada, was monitored over two seasons. Fully exposed and artificially shaded clusters permitting 20% (shaded) and 50% (semi-shaded) sun exposure were used to assess the impact of shading in fruit aroma composition. Both cultivars contained similar levels of total free terpenols (2100 mu g/L), although Moscatel de Alejandria was richer in total bound terpenols. The highest concentration of free terpenols was obtained from the semi-shaded treatment, although for Moscatel de Alejandria, the resulting difference between exposed and semi-shaded treated grapes was negligible. Shaded grapes had the lowest concentration of terpenols, with poor Muscat typicity. The content of one of the most important terpenols from the aromatic perspective, linalool, appeared to be the most sensitive to sun exposure. Berry temperature appeared to be critical for maximizing monoterpene levels and muscat flavor in the fruit.
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    Rigorous dynamic modeling and simulation of wine distillations
    (ELSEVIER SCI LTD, 2004) Osorio, D; Perez Correa, R; Belancic, A; Agosin, E
    A novel simulation strategy for dynamic distillation of complex mixtures, such as wine, is proposed and evaluated in terms of computing efficiency and accuracy. The model developed describes wine distillation as a multicomponent reactive batch distillation process. The simulation approach transforms the system of differential algebraic equations (DAE) into a set of ordinary differential equations, by pre-solving the algebraic equations and replacing them with artificial neural networks.
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    β-glucosidase from the grape native yeast Debaryomyces vanrijiae
    (2003) Belancic, A; Gunata, Z; Vallier, MJ; Agosin, E
    Six hundred ten yeast colonies isolated from various vineyards in Chile were screened for the presence of a beta-glucosidase activity as well as the resistance to glucose and ethanol inhibition. Among them, Debaryomyces vanrijiae was found to produce high levels of an extracelular beta-glucosidase which was tolerant to glucose (K-i = 439 mM) and ethanol inhibitions. The enzyme (designated DV-BG) was purified to apparent homogeneity,respectively, by gel filtration, ion-exchange, and chromato-focusing techniques. Its molecular weight was 100 000, and its pl 3.0, optimum pH, and temperature activities were 5.0 and 40 degreesC, respectively, and had a V-max of 47.6 mumol min(-1) mg(-1) and a K-m of 1.07 mM. The enzyme was active against different beta-D-glucosides including glucosidic flavor precursors. The disaccharidic flavor precursors were not substrates for the enzyme. When added to a Muscat grape juice, the concentration of several monoterpenes increased as the consequence of its hydrolytic activity.