Browsing by Author "Devarajan, Y. S."

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    Electronic Nose Evaluation of the Effects of Canopy Side on Cabernet franc (Vitis vinifera L.) Grape and Wine Volatiles
    Devarajan, Y. S.; Zoecklein, Bruce W.; Mallikarjunan, Kumar; Gardner, D. M. (American Society for Enology and Viticulture, 2011-03-01)
    The effect of grapevine canopy side (north versus south and east versus west) on grape and wine volatiles of Cabernet franc was evaluated during two growing seasons using two electronic nose systems based on conducting polymers and surface acoustic waves. Data from three sampling dates per season from both electronic noses were compared with physicochemistry and wine aroma sensory evaluations. Univariate and multivariate statistical analyses generally indicated grape physicochemistry indices could not differentiate consistently (p > 0.05) between canopy sides across growing seasons and sampling dates. Both electronic nose (ENose) systems provided complete discrimination of canopy sides for grapes and wine using canonical discriminant analysis. On average, the surface acoustic wave-based ENose explained <50% of variation for grapes and <60% for wine using the first principal component, compared to >80% for the conducting polymer-based ENose. Wine aroma sensory evaluation differentiated canopy sides in three of four evaluations.
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    Monitoring Effects of Ethanol Spray on Cabernet franc and Merlot Grapes and Wine Volatiles Using Electronic Nose Systems
    Zoecklein, Bruce W.; Devarajan, Y. S.; Mallikarjunan, Kumar; Gardner, D. M. (American Society for Enology and Viticulture, 2011-09-01)
    The ability of two electronic nose systems (conducting polymer and surface acoustic wave-based) to differentiate volatiles of grapes and wines treated with an aqueous ethanol spray (5% v/v) at veraison was evaluated. Ethanol spray induced fruit ethylene production immediately posttreatment, which then declined progressively. The electronic nose evaluations of grape volatiles were compared with Cabernet franc and Merlot physicochemistry and with wine gas chromatographic and aroma sensory data. Canonical discriminant and principal component analysis found that both electronic nose systems and the physicochemical measures (Brix, TA, pH, color intensity and hue, total phenols, glycosides, and berry weight) were able to discriminate between ethanol-treated and untreated grapes and wines for both cultivars. Grape physicochemical treatment differences were due mainly to variations in hue, phenolic-free glycosides, and total phenols. Aroma sensory evaluations using a consumer panel differentiated between ethanol treatments and controls for Merlot, but not for Cabernet franc wines.