Institute of Nutritional and Food Sciences, Molecular Food Technology , University of Bonn , Endenicher Allee 19b , D-53115 Bonn , Germany.
Viticulture and Enology Research Center , California State University , 2360 E. Barstow Ave , Fresno , California 93740 , United States.
J Agric Food Chem. 2019 Oct 2;67(39):10913-10920. doi: 10.1021/acs.jafc.9b03519. Epub 2019 Sep 18.
Copper in grape musts can influence the fermentation efficiency of during winemaking. The present study revealed the impact of glutathione addition on yeast strains with variable copper sensitivity. The antioxidant glutathione increased yeast vitality and fastened sugar metabolism at copper concentrations up to 0.39 mM. A significant accumulation of acetaldehyde at high copper concentrations was mitigated by the addition of 20 mg L glutathione. Low recovery of glutathione added implicated a complexation of both compounds. Specific alcohol dehydrogenase (ADH) activity was inhibited or reduced in the enzyme extracts of the copper-stressed yeast cells. The activity was restored in fermentations with glutathione at a copper concentration of 0.16 mM. At low copper concentrations, glutathione decreased ADH activity presumably due to complexation of essential copper amounts. Results provide important information on the use of glutathione as an antioxidant in winemaking to counteract negative effects of copper-rich musts on copper-sensitive yeast strains.
葡萄汁中的铜会影响葡萄酒酿造过程中的发酵效率。本研究揭示了添加谷胱甘肽对铜敏感性不同的酵母菌株的影响。抗氧化剂谷胱甘肽可提高酵母活力并加速糖代谢，在铜浓度高达 0.39 mM 时仍有效果。添加 20mg/L 谷胱甘肽可减轻高铜浓度下乙醛的大量积累。添加的谷胱甘肽回收低表明两者发生了络合。铜胁迫酵母细胞的酶提取物中特定的醇脱氢酶（ADH）活性受到抑制或降低。在铜浓度为 0.16mM 的谷胱甘肽发酵中，酶活性得到恢复。在低铜浓度下，谷胱甘肽降低 ADH 活性可能是由于必需铜量的络合。研究结果为在酿酒过程中使用谷胱甘肽作为抗氧化剂提供了重要信息，以抵消富含铜的葡萄汁对铜敏感酵母菌株的负面影响。
