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 of MPs and thus improving the quality of
Texas wines
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2011-08-9824 |
| Date | 2011 August 1900 |
| Creators | Angel Morales, Gabriela Del Carmen |
| Contributors | Mertens-Talcott, Susanne |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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