Browsing by Author "Baumes, R"

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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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    Synthesis and stable isotope dilution assay of ethanethiol and diethyl disulfide in wine using solid phase, microextraction. Effect of aging on their levels in wine
    (2002) Majcenovic, AB; Schneider, R; Lepoutre, JP; Lempereur, V; Baumes, R
    Ethanethiol and diethyl disulfide (DIEDS) most often occurred at levels above their olfactive threshold in wines with nauseous sulfur-linked smells. As ethanethiol is very oxidizable and chemically reactive, a stable isotopic dilution analysis of both ethanethiol and its disulfide in wines using solid phase microextraction and GC-MS was developed. The latter involved the determination of the proportion of DEDS formed by oxidation of the thiol during the analysis conditions, which was obtained by the use of two differently labeled disulfide standards. An original synthesis of labeled ethanethiol standards in conditions minimizing oxidation was developed, and the corresponding labeled diethyl disulfides were obtained from these thiols. This analytical method Was used to follow the levels of these sulfur compounds during aging in a young red wine spiked with ethanethiol and added with enological tannins, with or without oxygen addition. The total levels of these two sulfur compounds were.,shown to decrease steadily after 60 days of aging, up to 83%. The effect of oxygen sped this decrease, but the effect of enological tannins was very slight. Residual ethanethiol was detected in its disulfide form from similar to36% in the nonoxygenated wines to 69% in the oxygenated samples.