Location: Horticultural Crops Research2010 Annual Report
1a. Objectives (from AD-416)
Objective 1: Determine effects of water management on wine grape productivity and fruit maturity. Objective 2: Integrate the development and use of analytical methods for the evaluation of phenolic compounds and other chemical indicators of quality in fruit, fruit products, and wine. Objective 3: Determine effects of vineyard and vine microclimate on fruit development, vine productivity, and fruit quality, particularly phenolic compounds.
1b. Approach (from AD-416)
Our fundamental approach for conducting the proposed research is based on interdisciplinary work toward grape production systems and connecting production practices to the quality of the harvested fruit or value-added fruit products. Although each team member is responsible for a distinct experimental focus, overall goals and responsibilities of the contributors overlap because the interactions among system processes and properties transcend disciplines. Formerly 5358-21000-034-00D (11/08).
3. Progress Report
During the past year, a variety of sample preparation methods were evaluated for their influence on food quality component identification and quantification (i.e. phenolics, free amino acids, ammonia, sugars, organic acids). Selected preparation methods were employed for analyses on research projects that included determining grapevine leafroll associated viruses or altered vine nutrient treatments effects upon fruit, dehydrated vs. fresh Lamiaceae products, etc. In 2010, under objective 3A, we successfully controlled and monitored the temperature of grape clusters directly in the vineyard over the entire 5-month fruit development cycle. Fruit samples were collected at intervals for chemical analysis of the compounds that are associated with fruit quality in grapes. Micrometeorological data from this set of experiments were summarized and shared with our university collaborator. Under objective 3B, we drafted the code for a dynamic deterministic model of cold hardiness in grapevine buds during dormancy. The code was debugged and an initial set of model parameters was set by trial-and-error. Progress on this project has been interrupted due to a staffing vacancy. A second year of data was collected for project Objective 1 from field trial sites to investigate the effect of well-watered or water-deficit growing conditions on wine grape vine productivity and berry composition at maturity. Prior results suggested that foliar application of white, clay particle film increased vine productivity under well-watered conditions. This trend was investigated further this season by measuring the yield and maturity of fruit harvested from vines with and without particle film under deficit or well-watered conditions. Multi-year funding in support of research under Objective 1 was awarded from the American Vineyard Foundation and the Specialty crop block grant program. A description of ongoing collaborations between ARS and University scientists in projects under Objective 1 were featured in Agricultural Research magazine. Previous season data describing the effect of vine water deficit on berry tissue components and berry weight uniformity at maturity were analyzed and submitted for publication.
1. Sample preparation and analytical methods impact analysis results. Different analytical and sample preparation methods provide different results. Sample preparation is an often-overlooked step that is vital to the outcome of analyses of chemical compounds. Method conditions require exactness to permit researchers and industry laboratories to directly compare results. ARS researchers in Corvallis, OR defined the relationship between grape samples prepared by a method common in industry (juicing) to chemically extracted samples (typical of a research setting). Free amino acids and ammonia, calculated as YAN (yeast assimiable nitrogen) were evaluated in juices and extracts from an established vine nutrient study; YAN values are crucial for wineries to ensure healthy alcoholic and malolactic fermentations. ARS researchers in Corvallis, OR also demonstrated to a major herb company that blanching and cultivar selection could improve their herb product’s phytochemical retention, and how their current commercial product was potentially an additional source of phytochemicals for U.S. consumers.
2. Continuous monitoring system. ARS Ssientists in Corvallis, OR demonstrated that a continuous monitoring system in vineyard trellises, denoted the 'trellis tension monitor' (TTM) provided estimates of grapevine yields that were more accurate than those compiled by the juice processing industry using their static sample approaches. We subjected the juice processors' data and the TTM data to three methods of calculating yield estimates. On average across 10 commercial juice grape vineyards, TTM data produced more accurate estimates of actual yield than did the long-established, partially subjective protocols of the juice processors. Regardless of calculation method, there was high vineyard to vineyard variability in the accuracy of the yield estimate. TTM may be a useful adjunct to the traditional, labor-intensive practices that are required to estimate yield in vineyards; the TTM also provides nearly continuous information on the size of the crop, something that is not possible with the industry standard methods that rely on infrequent collections of fruit samples by hand.
3. Water deficit affects weight and tissue composition of grapes. The weight and tissue composition of red-skinned wine grape berries are of economic interest because the skin and seed of the berry contain different phenolic compounds that differentially affect wine sensory attributes. Water deficit is a production tool used with red-skinned wine grapes to conserve water and enhance berry attributes for wine production. ARS researchers at Parma, Idaho determined that vine water deficit increased up to 27% the proportion of seed to total berry fresh weight but had no effect on berry size uniformity. Results reveal a crucial relationship between water conservation and potential wine style because the ratio of seed to total berry fresh weight impacts sensory attributes.Lee, J., Scagel, C.F. 2010. Chicoric acid levels in commercial basil (Ocimum basilicum) and Echinacea purpurea products. Journal of Functional Foods. 2:77-84.