Iron and copper salts have complex olfactory and gustatory properties including a metallic flavor component that is decreased by nasal occlusion. To examine the sensory properties of ferrous sulfate and copper sulfate, a trained descriptive panel evaluated these compounds at equal molarity and perceived equal intensity with and without nasal occlusion. Ferrous sulfate exhibited a metallic taste and metallic aftertaste and copper sulfate exhibited a more pronounced metallic aftertaste. Metallic sensations were decreased by nasal occlusion, which in the absence of any orthonasal metallic smell, implies that the sensations were retronasally perceived volatiles in the nose open condition. Ferrous sulfate showed a larger effect of nasal occlusion. A second experiment isolated ferrous sulfate solutions from oral contact via a plastic barrier. In comparison to a condition in which oral contact was allowed, intensity ratings were decreased. This result is consistent with the hypothesis that rinses with solutions of metal salts, particularly ferrous sulfate, generate volatile lipid oxidation products in the mouth that are perceived retronasally as metallic flavors.

中文翻译：

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鼻塞和口腔接触对金属盐味觉的影响

铁盐和铜盐具有复杂的嗅觉和味觉特性，包括因鼻塞而减少的金属风味成分。为了检查硫酸亚铁和硫酸铜的感官特性，一个训练有素的描述小组评估了这些化合物的等摩尔浓度和感知强度，有无鼻塞。硫酸亚铁表现出金属味和金属余味，硫酸铜表现出更明显的金属余味。鼻塞会降低金属感觉，在没有任何正鼻金属气味的情况下，这意味着感觉是在鼻子打开状态下鼻后感知的挥发物。硫酸亚铁对鼻塞的影响更大。第二个实验通过塑料屏障从口腔接触中分离出硫酸亚铁溶液。与允许口腔接触的情况相比，强度等级降低。该结果与用金属盐溶液，特别是硫酸亚铁溶液冲洗会在口腔中产生挥发性脂质氧化产物的假设一致，这些产物在鼻后被感知为金属风味。