ARS | Publication request: Vine Water Status Influences Volatile Composition of Merlot Wine

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 27, 2009
Publication Date: July 9, 2009
Citation: Qian, M.C., Fang, Y., Shellie, K. 2009. Vine water status influences volatile composition of Merlot wine. Journal of Agricultural and Food Chemistry. 57:7459-7463.

Interpretive Summary: Irrigation management is one of the most important inputs for production of wine grapes in arid regions. Water is a non-renewable, natural resource with limited availability, and the amount that is applied to the vine during fruit growth and maturation has a direct influence on grape composition. A primary objective of irrigation in red wine grape production is to provide an amount of water that supports a leaf canopy sufficient to ripen an economically feasible quantity of fruit on the vine and a level of water stress that will stimulate production of berry and seed components associated with wine quality. In this research, we evaluated the influence of vine water status during berry development on the aroma profile of the wine by producing replicated lots of wine from vines provided with differing amounts of water throughout the growing season. The study was conducted on the red wine cultivar Merlot over a three year period within a commercial vineyard in southwestern Idaho. The vines were supplied with 100 or 35% of their estimated water requirements. Sixty kg of fruit harvested from field trial plots were fermented in 100L stainless steel tanks. Thirty aroma-active compounds in the wines were quantified using an analytical technique called stir bar sorptive extraction-gas chromatograph-mass spectrometry (SBSE-GC-MS). The results demonstrated that despite annual differences in amount of all aroma volatiles, in each of three years of this study, deficit irrigation during berry development had a consistent effect on the aroma composition of the wine, especially on C13 norisoprenoids. Wine produced from deficit irrigated vines had an increased amount of beta-damascenone and a decreased amount of beta-ionone relative to wine produced from well-watered vines.

Technical Abstract: Water status during berry development directly affects vine physiology and secondary metabolism of the plant. The impact of vine water status during berry development on the wine aroma profile of Merlot was investigated in this study. Own-rooted Merlot vines grown in a commercial vineyard in Idaho were supplied throughout berry development with 100 or 35% of their estimated crop evapotranspiration needs. Wines were produced from 2002, 2003 and 2004 growing seasons. Thirty aroma-active compounds in the wines were quantified using stir bar sorptive extraction-gas chromatograph-mass spectrometry (SBSE-GC-MS) technique. The results demonstrated that despite annual differences in amount of all aroma volatiles, in each of three years of this study, deficit irrigation during berry development had a consistent effect on the aroma composition of the wine, especially on C13 norisoprenoids. Wine produced from deficit irrigated vines had an increased amount of beta-damascenone and a decreased amount of beta-ionone relative to wine produced from well-watered vines.