Malolactic fermentation (MLF) is important in the production of wines as it reduces acidity through the conversion of malic acid to lactic acid. However, successful MLF can be difficult to achieve due to yeast antagonism of the bacterium responsible for
the secondary fermentation, Oenococcus oeni. In particular, yeast produced sulfur...
To provide a possible alternative for the antimicrobial action of sulfur dioxide in winemaking, and address the issue of stuck fermentations, I studied the efficacy of chicken lysozyme (EC 3.2.1.17) as an antimicrobial in grape juice. Two different forms of lysozyme were used: native lysozyme (NL), that is known to...
The impact of yeast on the aroma and flavor of Vitis vinifera L. cv. 'Pinot Noir' wine was investigated. Due to the presence of naturally occurring yeast and bacteria on grapes and wine equipment, and the influence these microorganisms have on wine, a means of eliminating microorganisms from grape must...
Sensory properties of four important volatile sulfur compounds, dimethyl disulfide (DMDS), diethyl disulfide (DEDS), methanethiol (MeSH) and ethanethiol (EtSH), were determined in base Oregon Pinot noir wine in order to understand their impacts on wine aroma. Detection thresholds of these four compounds in base wine were determined first. All four...
Winter provides many opportunities for viticulture and enology programming across Oregon, the Pacific Northwest and beyond. The vines, although dormant, need pruning and the winery operations continue. This month, we’ve decided to focus on important considerations in both the vineyard and winery. An article on pruning operations by Dr. Patty...
It is often perceived that late maturity of grape gives a more complex aroma
profile to Pinot noir wine, however, there is little understanding of the basic flavor
chemistry of grape maturity on wine aroma. The aroma contributing compounds in
Pinot noir were first identified by aroma extract dilution analysis...
The objective of this project was to investigate the effects of refrigeration storage and processing technologies on the quality and nutraceutical benefit of blackberries. 'Marion' and 'Evergreen', the two major blackberry varieties in Oregon, were evaluated in this study. For refrigeration storage, fresh fruit were packed in clam-shell containers right...
Representing the most common flavonoid consumed in the American diet, the flavanols and their polymeric condensation products, the proanthocyanidins, are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies and supplements. Their presence in food affects food quality parameters including astringency, bitterness, sourness, sweetness, salivary viscosity,...
As the 2009 growing season comes to a close, we prepared this newsletter to provide information on several viticulture and enology issues important to the Oregon winegrape industry. We begin with the most immediate topic of this season – wine production with Dr. James Osborne and importance of wine superstars...
This study investigated how manipulating vineyard nitrogen status, irrigation levels and cultivation practices would effect nutrient composition, and anthocyanin and phenolic accumulation in Pinot noir juice and wine from a commercial Willamette Valley Oregon vineyard. Pinot noir fruit was sourced from a vineyard trial in the Benton Lane Vineyard, located...