Introduction

Taste perception is affected by trigeminal stimuli, i.e., capsaicin. This has been studied at suprathreshold concentrations. However, little is known about taste perception at threshold level in the presence of low concentration of capsaicin. The aim of the study was to explore whether taste sensitivity for sweet, sour, salt, bitter, and umami is modulated by the presence of capsaicin in the peri-threshold range.

Methods

Fifty-seven adults (age range 19–85 years; 32 women) with functional gustation participated in the study. Based on their perception of phenylthiocarbamide (PTC), the group was stratified into non-tasters (n = 20) and tasters (n = 37). Threshold for sweet (sucrose), sour (citric acid), salty (sodium chloride), bitter (quinine-hydrochloride), and umami (sodium-glutamate) tastes was estimated using a single-staircase paradigm (3-alternative forced choice; volume per trial 0.1 ml) with or without 0.9-µM capsaicin added. This capsaicin concentration had been determined in pilot studies to be in the range of oral perception thresholds.

Results

The addition of capsaicin produced lower taste thresholds for sweet, sour, salty, and bitter but not for umami. In contrast, neither PTC taster status nor sex affected these results.

Conclusion

The current results indicate that a low concentration of capsaicin increases gustatory sensitivity.

Implications

The current findings provide evidence supporting different effects of capsaicin on taste perception at threshold level. It has implications for boosting taste sensitivity or flavor enjoyment with low concentration of capsaicin.

中文翻译：

---

用辣椒素刺激阈下三叉神经可增加人类的味觉敏感性

介绍

味觉受三叉神经刺激，即辣椒素的影响。这已经在超阈浓度下进行了研究。然而，在存在低浓度辣椒素的情况下，对阈值水平的味觉知之甚少。该研究的目的是探索对甜味、酸味、盐味、苦味和鲜味的味觉敏感性是否受阈值范围内辣椒素的存在调节。

方法

57 名有功能性味觉的成年人（年龄范围 19-85 岁；32 名女性）参与了这项研究。根据他们对苯硫脲 (PTC) 的看法，该组被分为非品尝者 ( n  = 20) 和品尝者 ( n  = 37)。甜味（蔗糖）、酸味（柠檬酸）、咸味（氯化钠）、苦味（盐酸奎宁）和鲜味（谷氨酸钠）的阈值是使用单阶梯范式（3-替代强制选择；体积每个试验 0.1 毫升）添加或不添加 0.9-µM 辣椒素。该辣椒素浓度已在试点研究中确定在口腔感知阈值范围内。

结果

辣椒素的添加降低了甜味、酸味、咸味和苦味的味觉阈值，但不会产生鲜味。相比之下，PTC 品尝者身份和性别都不会影响这些结果。

结论

目前的结果表明，低浓度的辣椒素会增加味觉敏感性。

影响

目前的研究结果提供了支持辣椒素在阈值水平上对味觉感知的不同影响的证据。它对提高低浓度辣椒素的味觉敏感性或风味享受有影响。