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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Production and Genetic Improvement Research Unit » Research » Research Project #438671

Research Project: Evaluation of Combined Effects of Grape Maturity, Alcohol Concentration & Long Term Maceration on Flavor & Mouthfeel Profile of Cabernet Sauvignon

Location: Horticultural Crops Production and Genetic Improvement Research Unit

Project Number: 2072-21000-057-012-G
Project Type: Grant

Start Date: Aug 1, 2020
End Date: Oct 31, 2022

Objective:
To explore the sensory evaluation of wines and method development for proanthocyanidins.

Approach:
Two sensory methods will be applied to assess the flavor profile of each treatment. The first method, descriptive analysis, will evaluate the differences among the intensities of various taste and aroma attributes. The second method, temporal dominance of sensation (TDS), will describe how the taste and mouthfeel attributes change over the course of a single sip. Combined, this research will lead to a complete picture of maceration effects on the flavor profile of Cabernet Sauvignon wine. Each method requires the use of trained panelists to objectively evaluate the set of experimental wines. A panel of 8-12 people will be recruited. Descriptive analysis begins with panel members meeting as a group to generate consensus terminology describing the flavor attributes of the experimental wines, with each flavor attribute clearly defined. During subsequent training session panelists will become familiar with rating the intensity of each attribute in the experimental wines. Once training is complete, the panel will shift to data collection. Each panelist will taste the experimental wines in triplicate using a randomized service order. Evaluation sessions will occur in individual tasting booths under red light and wines will be presented in black glassware to mask possible color differences. Treatment effects on the intensity of specific taste and flavor attributes will be evaluated using analysis of variance with factors of judge, replicate, maturity, alcohol content, along 2-way and 3-way interactions. Principal component analysis will be used to establish relationship among treatments and combinations of sensory descriptors. Results will indicate how the flavor profile of wines can be impacted by the application of extended maceration in conjunction with harvest decision. Upon completion of collecting the descriptive analysis data the panel will the transition to measuring the temporal aspect of the experimental wines. The method presents a list of attributes and asks which attribute is perceived as most dominate. Sweetness, sourness, bitterness, hotness, and astringency will be assessed for their temporal dominance changes in each wine, and all wines will be evaluated in triplicate by each panelist. Method training begins by presenting taste standards for discussion. After discussion of each sensation the panelist is directed to an individual booth and given instructions on the use of the Compusense data capture software. TDS curves will be constructed and extracted curve parameters will be related to chemical measures. Results will indicate the flavors and aromas that distinguish the wines, allowing for those flavors to be statistically related to the measured chemistry. Phloroglucinolysis will be performed. Cacao polymers will be purified and used to validate new methodology. HPLC-QToF will be used to evaluate tannin (proanthocyanidins) polymer sizes and standards of proanthocyanidins will be used to calibrate the instrument. The new methodology will be compared to phloroglucinolysis which is a standard method for characterizing grape and wine tannins.