Guest Steve, Essick Greg, Young Mike, Phillips Nicola, McGlone Francis
Center for Neurosensory Disorders, School of Dentistry, University of North Carolina, Chapel Hill, NC, United States.
Physiol Behav. 2008 Mar 18;93(4-5):889-96. doi: 10.1016/j.physbeh.2007.12.006. Epub 2007 Dec 23.
A feeling of mouth dryness occurs from actual drying of the oral surfaces or from sampling astringent substances such as polyphenols (e.g., tannins in brewed tea and wine), which bind proline-rich proteins in saliva to reduce its lubricity. Here we investigated the interactions between physical drying and the effect of polyphenols on the subjective state of oral hydration. Twelve subjects rated the perceived wetness/dryness of their mouth using a labeled magnitude scale, after the mouth was dried with air for 35 s, or the subjects waited for an equal period of time during which the mouth was not dried. Subsequently, 1.5 mL volumes of an astringent solution (5 g L(-1) tannic acid in distilled water), distilled drinking water, or a sweet solution (40 g L(-1) sugar in mango tea with no tannins) were introduced into the mouth. After swishing and swallowing, the subject rated the wetness of the mouth for 4.3 min. The liquids were found to differ in their ability to wet the mouth (p<0.0001). The least wet sensations were reported for the astringent solution, on average; however, the differences among liquids were not equally pronounced at all times during the observation period (p<0.02). When the mouth was normally hydrated (i.e., had not been dried), the wetting effectiveness of the three liquids, based on the ratings, differed most greatly immediately after they had been received and swallowed. In contrast, when the mouth was dried, the liquids did not differ at this time. That the astringent solution did not have less wetting effectiveness in the dried mouth was attributed to the absence of precipitable salivary proteins. The findings suggest that the refreshment value of astringent drinks, based on their perceived wetting effectiveness, may vary with the state of oral hydration.
口腔表面实际干燥或接触诸如多酚类（如冲泡茶和葡萄酒中的单宁）等收敛性物质时会产生口干的感觉，这些物质会结合唾液中富含脯氨酸的蛋白质，降低其润滑性。在此，我们研究了物理干燥与多酚对口腔水合主观状态的影响之间的相互作用。12名受试者在口腔被空气吹干35秒后，或在等待相同时间（期间口腔未被吹干）后，使用标记量值量表对口腔的干湿感觉进行评分。随后，将1.5毫升的收敛溶液（蒸馏水中5克/升单宁酸）、蒸馏水或甜味溶液（芒果茶中40克/升无糖单宁的糖）引入口腔。漱口并吞咽后，受试者对口腔的湿润度进行4.3分钟的评分。发现这些液体在湿润口腔的能力上存在差异（p<0.0001）。平均而言，收敛溶液引起的湿润感觉最少；然而，在观察期内，不同液体之间的差异并非在所有时间都同样明显（p<0.02）。当口腔正常水合（即未被干燥）时，根据评分，三种液体在刚被接受和吞咽后，其湿润效果差异最大。相比之下，当口腔被干燥时，此时这些液体之间没有差异。收敛溶液在干燥口腔中没有较低的湿润效果，这归因于不存在可沉淀的唾液蛋白。研究结果表明，基于其感知的湿润效果，收敛性饮料的提神价值可能会因口腔水合状态而有所不同。
