Browsing by Author "Von Baer, D."

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    FLAVONOL PROFILES FOR VARIETAL DIFFERENTIATION BETWEEN CARMENERE AND MERLOT WINES PRODUCED IN CHILE: HPLC AND CHEMOMETRIC ANALYSIS
    (SOC CHILENA QUIMICA, 2011) Vergara, C.; Von Baer, D.; Mardones, C.; Gutierrez, L.; Hermosin Gutierrez, I.; Castillo Munoz, N.
    Wine differentiation is an important issue for the Chilean winemaking industry, especially for the Carmenere variety, which was rediscovered in this country around 20 years ago. Authentication parameters are required for this wine due to its frequent confusion with Merlot. The concentration of anthocyanins, shikimic acid, and the principal flavonols found in wine allowed some varietal differentiation between Carmenere and Merlot wines. Myricetin and quercetin are the most concentrated flavonols in wine in which they are present in free and conjugated forms. These compounds are responsible for important wine antioxidant properties. In the present work, using only the concentrations of free and conjugated quercetin and myricetin, differentiation between Carmenere and Merlot varieties was better achieved. Flavonol profiles of wine produced in Chile were studied with HPLC-DAD-ESI-MSn. An overview of the concentration range of flavonols present in 248 Chilean red wines is presented, finding that the mean concentration of the sum of total myricetin and total quercetin were higher in Carmenere (81.5 mgL(-1)) and Merlot (78.9 mgL(-1)) than in Cabernet Sauvignon (53.9 mgL(-1)) wines. These mean levels were higher than the majority of the concentrations reported in the literature. The chemometric analysis shows that the ratio of total quercetin/total myricetin combined with the concentration of free myricetin allowed the varietal differentiation between Carmenere and Merlot wines.
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    Tribromophenol and pentachlorophenol uptake from sawdust to horticultural products
    (TAYLOR & FRANCIS LTD, 2009) Mardones, C.; Von Baer, D.; Silva, J.; Ruff, A.; Gutierrez, L.; Berg, A.
    This paper presents a study of the uptake of 2,4,6-tribromophenol (TBP), pentachlorophenol (PCP), and its metabolite pentachloroanisole (PCA) from contaminated sawdust from the forest industry in horticultural products such as apples, raspberries, and fodder maize for cattle feed. The samples were obtained from Bio-Bio Province in South Chile between 2002 and 2006. The analytical parameters of the methodology applied to the different matrices are presented and discussed. The chromatographic method was applied to determine the residues in 413 horticultural product samples. Eleven per cent of fodder maize samples showed detectable or quantifiable levels of PCP, TBP or PCA, 3% of samples presented quantifiable levels, although the concentrations surpassed the maximum allowed concentrations for vegetables (10 mu g kg-1) in only two samples. Traces of TBP were detected in eight samples, PCA was detected in 15, and PCP in 14 samples. Based on these results, a risk analysis was performed, indicating a low probability, 0.4% for PCA, 1.6% for TBP and 1.9% for PCP, to find concentrations higher than the allowed maximum. For apples and raspberries, no residues of these compounds were detected. These results indicate that those cultivars directly exposed to sawdust, like fodder maize, could contain detectable residues in several samples. To confirm this observation, a field assay was performed on fodder maize cultivated in the presence of sawdust artificially contaminated with 30 mg of TBP and/or PCP under controlled conditions. The results showed that under the experimental conditions used in the study, TBP can be transferred from sawdust to the plant, with an uptake rate of 0.04% from the TBP applied initially with sawdust but not to the corn ear. Also, the degradation of PCP to PCA was observed in the soil.