Ascorbic acid (AH₂) is frequently included in wheat bread recipes to strengthen dough. We report here that its use increases dough extensional viscosity. However, its dough strengthening effect upon AH₂ addition is more pronounced in yeasted dough samples than in its non-yeasted counterpart. This was unexpected as compressed yeast contains free glutathione (GSH) which decreases dough extensional viscosity. Additional tests showed that small levels of added GSH positively impacted the dough strengthening effect of AH₂. However, AH₂ did not compensate for the detrimental effect of higher levels of GSH. We hypothesize that the combined effect of GSH and AH₂ may be the result of the timing of the reactions in which they are involved and/or may relate to the coupled oxidation/reduction reactions between GSSG and free cysteine. We conclude that yeast and its associated GSH are important determinants of the state of the redox couples in wheat flour-based bread dough. The choice and dosage of yeast can therefore influence the efficiency of dough improving agents.

抗坏血酸 (AH ₂ ) 经常包含在小麦面包配方中以增强面团。我们在此报告它的使用会增加面团的拉伸粘度。然而，它对添加AH _{2 的}面团强化效果在发酵面团样品中比在非发酵面团样品中更显着。这是出乎意料的，因为压缩酵母含有游离谷胱甘肽 (GSH)，这会降低面团的拉伸粘度。其他试验表明，少量添加 GSH 对 AH ₂的面团强化效果有积极影响。然而，AH ₂并没有补偿较高水平 GSH 的不利影响。我们假设 GSH 和 AH ₂的联合作用可能是它们参与的反应时间的结果和/或可能与 GSSG 和游离半胱氨酸之间的耦合氧化/还原反应有关。我们得出结论，酵母及其相关的谷胱甘肽是小麦面粉面包面团中氧化还原对状态的重要决定因素。因此，酵母的选择和用量会影响面团改良剂的效率。