Psychophysics of Divalent Salts and Metallic Taste

描述（由申请人提供）：二价盐（如钙和铁）的感官特性在化学感官方面的文献中很少受到关注。鉴于美国人口老龄化和骨质疏松症的流行，膳食钙不足是一个日益关注的问题，并且正在通过越来越多的钙强化食品来解决。缺铁是第三世界的一个持续问题，影响着全世界数十亿人。了解二价盐（如钙和铁）的感官特性将增加味觉和嗅觉方面的知识基础，并可能有助于设计具有可接受的感官特性的食品和补品。本文主要分为两个部分提出了研究计划。首先，二价盐的心理物理表征将解决元素周期表中第二组的定性和强化特性，包括钙，在味觉传导的各个步骤中的积极参与者，以及镁和钡。在钙和镁的初步研究中，经常用“金属”这个词来描述味道。多价卤化物的这种性质很少受到关注，但定性研究表明，它是由一种经鼻后感知的挥发性物质产生的。也就是说，金属味可能是一种气味，而不是真正的味道。这与食品化学文献一致，表明金属离子如铁和铜可以催化脂质氧化产生非常强效的气味化合物。第二个研究项目旨在表征铁盐和铜盐的感官特性，它们在口腔中产生复杂的感觉。仪器感官关联将用于识别和表征由硫酸亚铁与人类唾液混合产生的挥发性化合物，并将这些化合物与已知的脂质氧化产物进行比较，这些化合物已知在食品化学文献中识别出“金属”气味。与电味觉的金属感觉报告类似，我们将进行研究。人们感兴趣的一个主要问题是，金属味本质上是嗅觉、味觉还是触觉，还是三者的某种结合。

DESCRIPTION (provided by applicant): Sensory properties of divalent salts such as those of calcium and iron have received scant attention in the literature on the chemical senses. Given the aging of the US population and the prevalence of osteoporosis, dietary calcium insufficiency is a growing concern and is being addressed by an increasing number of calcium fortified food products. Iron deficiency is a continuing problem in the third world, affecting billions of people worldwide. Understanding the sensory properties of divalent salts such as those of calcium and iron will add to the knowledge base in the senses of taste and smell and may help the engineering of foods and supplements with acceptable sensory properties. A program of research is proposed here in two main sections. First, psychophysical characterization of divalent salts will address the qualitative and intensive properties of Group II of the period table including calcium, an active participant in various steps of taste transduction, as well as magnesium and barium. In preliminary research with calcium and magnesium, a frequent taste descriptor was the term "metallic." This property of multivalent halides has received little attention but qualitative work suggests that it results from the production of a volatile substance that is perceived retronasally. That is, metallic taste may be a smell and not a true taste. This is consistent with literature from food chemistry suggesting that metallic ions such as iron and copper can catalyze the production of very potent odor compounds from oxidation of lipids. The second program of research aims to characterize the sensory properties of iron and copper salts, which produce complex sensations in the oral cavity. Instrumental-sensory correlations will be brought to bear on the identification and characterization of volatile compounds produced from mixing ferrous sulfate with human saliva, and comparison of these compounds to known lipid oxidation products known to smell "metallic" as identified in the food chemistry literature. A parallel to the reports of metallic sensations from electric taste will be investigated. A primary question of interest is whether metallic taste is olfactory, gustatory or tactile in nature or some combination of the three.