1a.Objectives (from AD-416):
Identify and evaluate vineyard practices within the Pacific Northwest that produce high quality fruit and fruit products.
1b.Approach (from AD-416):
Both parties will examine vine characteristics and major chemical components responsible for any differences, or similarities, between differing vineyard practices. We will use simple spectrophotometric methods in addition to more complex analytical methods (HPLC), to better understand qualitative and quantitative effects on grape phytonutrients.
Sample preparation is an often-overlooked step that is vital to the outcome of compound analyses. Different analytical and sample preparation methods provide different results. Method conditions require exactness to permit researchers and industry laboratories to compare and discuss results. We contrasted data and defined the relationship between grape samples prepared by a method common in industry (juicing) to chemically extracted samples (typical of a research setting). Since berry skin contributed to actual yeast assimilable nitrogen (YAN), wineries that determine YAN from mainly the pulp fraction (juice) may underestimate YAN and as a result add more (artificial) N supplement than is required for a healthy red wine fermentation (whole berry fermentations). Extraction procedure should be taken into consideration when comparing grape YAN. This research was conducted in support of objective 305 1B Perennial Crops.