Enhancing the natural folate level in wine using bioengineering and stabilization strategies

Area of Science:

• Enology
• Nutritional Biochemistry
• Yeast Genetics

Background:

• Folate deficiency is associated with various diseases, particularly in individuals with alcohol-induced metabolic alterations.
• Understanding folate content and stability in wine is crucial for nutritional considerations.

Purpose of the Study:

• To investigate factors influencing folate concentration and stability in commercial wines.
• To enhance folate levels in wine through yeast bioengineering.
• To identify key genes involved in folate biosynthesis in wine yeast.

Main Methods:

• Analysis of folate content in commercial wines across different varieties.
• Assessment of folate stability post-opening, correlating with phenolic and sulfite levels.
• Yeast bioengineering to overexpress folate biosynthesis genes (e.g., FOL2).
• Confirmation of gene function through overexpression studies.
• Addition of ascorbate to stabilize enhanced folate levels.

Main Results:

• Folate content in wine is primarily determined by the yeast strain, not wine color (red vs. white).
• Folate stability in opened wine did not correlate with total phenolic or sulfite content.
• Overexpression of the FOL2 gene in yeast significantly increased wine folate levels, identifying it as the rate-limiting step.
• Overexpression of other folate biosynthesis genes (ABZ1, ABZ2, DFR1, FOL1, FOL3) did not affect wine folate content.
• Ascorbate addition effectively stabilized the increased folate levels in wine.

Conclusions:

• Wine yeast selection is critical for natural folate content.
• Yeast bioengineering offers a viable strategy to fortify wine with folate, with FOL2 as a key target gene.
• Ascorbate is an effective additive for ensuring folate stability in fortified wines, enhancing their nutritional value.