Angel Morales, Gabriela Del Carmen (2011-08). Health Benefits and Quality of Texas Red Wines. Doctoral Dissertation. Thesis uri icon

abstract

  • Processing techniques for red wines and their potential health benefits have intensively been investigated, however, information relevant to the grape and wine industry in Texas is less frequently available. The overall objective of this work was to investigate the reduction of 3-alkyl-2-methoxypyrazines that can affect the quality of Texas wines and to study the health benefits of Texas wines. The methods used include SPME-GC-MS and molecular bioassays. The first objective was to demonstrate the anti-inflammatory potential effect of red wine polyphenols from Black Spanish wine (Vitis aestivalis hybrid) in colonic human fibroblast cells. Results show that an extract prepared from Black Spanish wine decreased gene expression and activation of NF-kB transcription factor and target proinflammatory cytokines and cell adhesion molecules. Induction of microRNA-126 (miR- 126) by wine extract was found to be one of the underlying molecular mechanism by which wine extract decreased vascular cell adhesion molecule (VCAM-1) and inflammation in colon cells. These mechanisms may be relevant to the prevention of iv inflammatory bowel disease (IBD) that may increase the risk for colon cancer. The second objective was to investigate the role of the green june beetle (GJB ) as exogenous source of MPs other than the multicolored Asian Lady beetle (Harmonia axyridis). Over the last decade, the green june beetle has been suspected to be a source of MPs based on intermittent reports from Texas growers of an atypical aroma and flavor reminiscent of crushed green June beetles (GJB). Specifically the North region of Texas seems affected. Results demonstrated GJB as source of 3-isopropyl-2- methoxypyrazine, where one GJB could elevate MPs above sensory perceptible levels in 4.3 gallons of wine. The incorporation of GJB to the winemaking process may contribute negatively to the sensory properties of Texas wines and therefore should be strictly controlled. The third objective was to explore the potential effect of micro-oxygenation treatment and accelerated aging techniques relevant for the state of Texas in the reduction of 3-Isobutyl-2-methoxypyrazine (IBMP), and 3-isopropyl-2-methoxypyrazine (IPMP) levels as determined by SPME-GC-MS. Results show that MPs were not affected by MOX or oak interaction. Although the data suggest that MOX and oak exposure do not directly affect MPs concentration. The fourth research objective was to explore the potential effect of three commercial available yeast strains, BM45, K1, and D80, on MPs levels in Black Spanish wines. Black Spanish wines were fermented with MB45 strain resulted in the highest amount of MPs. Conversely K1 and D80 yeast strains reduced IBMP levels in comparison with the control. An increase in IBMP was not expected. However it has been demonstrated that amino acids valine and leucine are MPs precursors. If Vitis v aestivalis hybrid grapes contained a similar methyltransferase enzyme found in Vitis vinifera grapes and S. cerevisiae contained similar IPMP biosynthesis pathway found in Pseudomonas perolens BM45 may have led to the increased IBMP observed in the fermentation. In addition we evaluated MPs levels of wines fermented over 20 days with a chemical defined grape juice medium containing a concentration of yeast available nitrogen of 200 mg N/L. Data suggest that wines fermented with BM45 and D80 yeast strains reduced IBMP but K1 yeast did not show any effect in comparison with the control. In addition MPs were evaluated in the yeast mannoproteins fraction. Results show the presence of IBMP in low concentration below the method detection limit. This data demonstrate for the first time that yeast mannoproteins binds IBMP. to evidence for interactions between mannoproteins secreted by the D80 yeast strain and IBMP. This work will provide valuable information regarding the potential health benefits of Vitis aestivalis hybrid grapes and reduction

publication date

  • August 2011