J. Future Foods | 有效量化柠檬酸诱导的咸味感知改变以及其口腔唾液生化机制

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Abstract

感官研究中常遇到不同味觉的相互现象，但如何量化一种呈味物质对另一种味觉感知的影响程度仍然需要探索，尤其是从口腔加工的角度。本研究利用了这样一种思路，通过比较相同的心理物理量下的浓度差异来评估不同味觉交互影响的程度大小。以柠檬酸作为酸味呈味物质，以氯化钠作为咸味呈味物质，我们将咸味感知强度变化（change of salty taste intensity，CSI，mmol/L）定义为单纯咸味刺激溶液样品与酸—咸刺激溶液样品中的咸味感知的最小可觉差（just noticeable difference，JND，mmol/L）之差。由此可知，CSI绝对值越高，影响作用越明显；同时，当CSI＞0时，呈酸物质对咸味有正向的增强感知作用，当CSI＜0时，呈酸物质对咸味有负向的抑制感知作用。依此在16名年轻健康受试者的感官实验中我们发现，当二元溶液体系（柠檬酸—氯化钠）中柠檬酸浓度较低（0.05和0.09 mmol/L）时，咸味感知增强（平均CSI为0.93 mmol/L），但随着柠檬酸浓度在0.14至0.40 mmol/L范围内持续增加，这种效应逐渐从增强咸味感知转变为抑制咸味感知（CSI亦相应持续下降），这种可量化的呈味物质对味觉感知的影响程度是首次被报告和验证。研究还发现，受试者的非刺激唾液样本中的半胱氨酸蛋白酶抑制剂（cystatin SN）浓度与咸味识别阈值呈现显著负相关，它也是影响CSI的最显著因素之一；而受试者的非刺激唾液样本中的碳酸酐酶VI（carbonic anhydrase VI）浓度虽然也与咸味识别阈值存在显著负相关，但在多元回归分析中并未显示对CSI的显著影响。

Results and Discussion

当氯化钠和柠檬酸在同一刺激物体系中发生味觉交互作用时，柠檬酸对咸味强度感知的或增强或抑制的往往是建立在个体明确味觉属性的感知的情况下。因此，这里利用不同刺激体系的同一心理强度感知变化所需的氯化钠浓度改变量来描述柠檬酸对咸味感知强度的改变。先后测试受试者的咸味识别阈值和咸味识别阈值上的第一个最小可觉差（JND），由此计算CSI为：

CSI = JND PS -JND SS

其中，CSI为柠檬酸—氯化钠刺激体系中柠檬酸对咸味感知强度影响的量化值（mmol/L），JNDSS为柠檬酸—氯化钠刺激体系中咸味识别阈值上的第一个JND（mmol/L），JNDPS为纯氯化钠刺激溶液中咸味识别阈值上的第一个JND（mmol/L）。

图1 酸味对咸味感知强度的改变的量化计算示意图

图2 咸—酸刺激体系中受试者的CSI变化：随柠檬酸浓度增加，咸味感知的增强作用逐渐转变为持续增加的抑制作用

将受试者的唾液流率、pH、钠离子浓度、总蛋白质浓度、半胱氨酸蛋白酶抑制剂浓度和碳酸酐酶VI浓度等非刺激唾液的生理生化特性和柠檬酸 – 氯化钠刺激体系中的CSI量化值采用逐步回归的多元线性回归，发现具有统计显著性的唾液生化因素为受试者非刺激唾液中的半胱氨酸蛋白酶抑制剂浓度以及感官实验中使用的样品的柠檬酸浓度，拟合方程为 CSI = –11.15 × Citric acid concentration – 0.01 × Cystatin SNconcentration + 3.52（R 2 ＝0.411，P＜0.001）

Conclusion

根据这些结果，本研究建立了评估二元味觉交互作用影响程度的量化方法，并由此证实了柠檬酸浓度依赖的咸味感知改变现象，并初步探索了这种味觉改变感知可能的唾液生化机制。

第一作者

姜宏男：男，硕士研究生。本科毕业于长春工业大学，硕士毕业于浙江工商大学。参编书籍章节一部，参与科技部十三五重点研发计划项目研究工作，发表SCI论文一篇。

通信作者

王鑫淼：女，副教授、硕士生导师，2016年加入国内唯一、国际领先的食品口腔加工实验室。主要科学研究领域为食品物性，食品感官，口腔生理与吞咽等。主持和参与国家、省部级项目及横向课题多项。发表论文二十余篇，参编英文书籍章节十余部。

Evaluation and salivary biochemistry associations of sour-salty taste interaction

Hongnan Jianga,b, Ye Chena,b, Jianshe Chena,b, Louise Dyeb,c, Xinmiao Wanga,b,*

a Laboratory of Food Oral Processing, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China

b Zhejiang-UK Joint Laboratory of Food Sensory Science, Zhejiang Gongshang University, Hangzhou 310018, China

c School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK

*Corresponding author.

Abstract

Taste interaction is a well-known phenomenon in sensory studies, but how to quantify the magnitude of the effect of one tastant on other taste attribute(s) is still largely unsolved, let alone further explorations from a salivary biochemistry perspective. Upon acquiring the individual taste threshold and evaluating the just noticeable difference (JND), this study firstly established a quantitative method to assess the magnitude of taste interaction in a binary taste mixture by evaluating the concentration difference upon psychologically-comparable stimulation. The change of salty taste intensity (CSI) was therefore defined as the subtraction of JND using sour-salty taste stimulant from JND using pure salty taste stimulant, with a dimension of concentration in mmol/L. CSI was then used to demonstrate how citric acid affected salty taste perception in a salty - sour binary taste mixture in 16 young and healthy participants. Concentrations of citric acid used in the binary taste mixture were 0.05, 0.09, 0.14, 0.24 and 0.40 mmol/L, respectively, and results showed that salty taste perception was enhanced (average CSI of 0.93 mmol/L) when the citric acid concentration was low (at 0.05 and 0.09 mmol/L), but with an increasing concentration of citric acid ranging from 0.14 to 0.40 mmol/L, this effect gradually turned from enhancement to suppression of salty taste perception (correspondingly a continuously decreasing CSI all the way down to an average of –2.94 mmol/L). It was also found that cystatin SN concentration in participants’ unstimulated saliva samples was significantly negatively correlated with salty taste threshold (with and without the presence of citric acid), and it was one of the most significant factors affecting CSI, as shown in multiple regression analysis. Carbonic anhydrase VI concentration in participants’ unstimulated saliva samples was also found to be significantly negatively correlated with salty taste recognition (with and without presence of citric acid), but it did not pose significant effect on CSI. From these results, this study had not only demonstrated a citric acid concentration-dependent salty taste perception phenomenon based on a proposed methodology to quantitively assess the taste interaction in binary taste mixtures, but also showed how salivary biochemical properties (cystatin SN and carbonic anhydrase VI) might have been associated with salty taste perception during food oral processing.

Reference:

JIANG H N, CHEN Y, CHEN J S, et al. Evaluation and salivary biochemistry associations of sour-salty taste interaction[J]. Journal of Future Foods, 2024, 4(4): 376-382. DOI:10.1016/j.jfutfo.2023.11.010.

文章编译内容由作者提供

编辑：梁安琪；责任编辑：张睿梅

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