Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2011
Publication Date: 3/10/2011
Citation: Lee, J., Steenwerth, K.L. 2011. Rootstock and vineyard floor management influence on 'Cabernet Sauvignon' grape yeast assimilable nitrogen (YAN). Food Chemistry. 127:926-933.
Interpretive Summary: Grape nitrogen (N) compounds are essential for a healthy fermentation. This study explored how two rootstocks (110R and 420A) and three vineyard floor management techniques (1- resident vegetation that was tilled, 2- barley planted then mowed, and 3- barley planted then tilled) affected 'Cabernet Sauvignon' grape N content and composition.
Technical Abstract: This is a study on the influence two rootstocks (110R, high vigor; 420A, low vigor) and three vineyard floor management regimes (tilled resident vegetation – usual practice in California, and barley cover crops that were either mowed or tilled) had upon grape nitrogen containing compounds (mainly ammonia and free amino acids recalculated as YAN), sugars, and organic acids in 'Cabernet Sauvignon' clone 8. A significant difference was observed in some of the free amino acids between rootstocks. In both sample preparation methods (juiced or chemically extracted), 110R rootstock grapes were significantly higher in SER, GLN, THR, ARG, VAL, ILE, LEU, and YAN compared to 420A rootstock grapes. Differences in individual free amino acid profiles and concentrations were observed between the two sample preparations, which indicate care should be given when comparing values from dissimilar methods. No significant differences among vineyard floor treatments were detected, which suggests that mowing offers vineyard managers a sustainable practice alternative to tilling, without negatively effecting grape nitrogen compounds, sugars, or organic acids.