椒麻风味增强咸味感知的作用机制研究

Reducing salt has become a major concern for public health and nutrition on account of the health risks from excessive salt intake. However, the loss of salty for food will affect consumer acceptance and consumption habits and thus it is difficult to implement the strategy of salt reduction effectively. The previous research found that pungency flavor evoked by chili pepper and Sichuan pepper could affect human's salty perception significantly. That is, it is possible to use the effect of sensory interaction to achieve the goal of salt reduction without affecting the taste. Nevertheless, it was unknown that how the salty perception was affected and how the mechanism of action of salty perception was enhanced by the trigeminal nerve flavors. For the purpose, the study will take Chinese characteristic pungency flavor as the research object, and focus on the taste stimulation and sensory response of brain activities. The food sensory and psychophysical methods were firstly used to investigate the sensory interaction between salty and pungency, and establish a dose-response quantitative model. Then the functional magnetic resonance imaging (fMRI), electroencephalography (EEG) and common spatial pattern algorithm were used to quantitatively analyze the enhancement regularity of salt signal in brain and the effect of emotional mechanism on the signals of salty-related brain regions. The study will provide a scientific basis for the new strategy of salt reducing by utilizing the effect of sensory interaction, and has important theoretical and practical significance for the design of food flavor and the application of sensory mechanisms to influence food selection and reduce the health risks.

膳食多盐存在健康风险，减盐成为公共营养健康重大关注。但盐减味失会影响消费者对减盐食品的接受性及其消费习惯，而使许多减盐策略难以有效实施。现有研究和前期基础发现辣椒辣感和花椒麻感均能显著影响人对咸味的感知，即有可能利用感觉交互作用来实现减盐不减咸。但这些三叉神经风味如何影响咸味感知，存在着怎样的增强作用机制尚未阐明。本研究以我国特色风味—椒麻为研究对象，以味物质刺激与味感觉响应大脑活动为核心，运用食品感官和心理物理学实验方法在考察麻—咸交互作用及其剂量效应关系的基础上，通过采用fMRI、EEG等脑成像及脑电技术结合算法应用来分析麻对咸感大脑关键响应区域的激活以及麻—咸情绪激发对咸味感知的影响及其规律，以期阐明椒麻风味增强咸感的作用机制。本研究将为利用三叉神经风味与食品基本味之间的交互来实现减盐的新方略提供科学基础，对食品风味设计及运用感觉机制影响食物选择降低健康风险具有重要理论与实践意义。

膳食多盐存在健康风险，减盐成为公共卫生与营养健康的重大关注。现有减盐策略成效并不十分显著，寻找一种不影响消费接受性的减盐策略十分必要。椒麻是我国特色风味，文献中曾有过花椒可以部分替代食盐的报道，但对其具体的增咸规律及作用机制并不明确。为解决上述问题，本研究从椒麻与咸味的感觉交互作用、基于脑区分析的椒麻风味增强咸感的感知机制以及基于脑电分析的椒麻风味增强咸感的情绪机制等三方面展开研究。主要得到以下结论：通过分析比较四类常用标度区分差异的一致性与重复性，发现gLMS与15 cm线性标度组合使用可得到准确的麻感语义标度及其对应参比系。采用上述标度法评估了椒麻增咸的影响因素及其增咸规律，结果显示阈限麻、低麻、中麻和高麻背景下对应的咸味感知响应幂指数分别为0.638、0.590、0.636及0.693，其中，低麻和中麻具有显著的增咸趋势，其中，低麻背景下的高敏组具有最佳增咸减盐效果，最大减盐量可达38.61%。进一步采用EEG探究了椒麻增咸作用机制，ERP和时频分析结果显示，感觉相关的早期正成分潜伏期并未发生变化，晚期正成分的潜伏期自417 ms延长至462 ms。时频分析结果表明多数咸味ROI增强发生在晚期（0.4s之后），wPLI指标显示，在椒麻—咸味混合刺激后，不同电极点在1s之后的θ频段，α频段及低频γ频段神经振荡活动的耦合程度较高，椒麻增强咸味的神经转导为“层次整合”模式。进一步采用相对差异评分法及自主开发的中国人面部情绪数据库探究了椒麻感知与情绪加工的关系，并基于fMRI探究了椒麻溶液刺激后的脑部神经响应。针对fMRI功能像数据的复杂网络分析，结果表明与基本味觉可以形成相对有序、结构化的编码不同，椒麻带来的多个脑区间非结构化协同编码调控了咸味感受性。本研究不仅为实现减盐的新方略提供科学基础，对椒麻食品的研发、工艺改良与质量控制等具有指导意义，而且对食品风味设计及运用感觉机制改善食物选择、降低健康风险具有重要理论与实践价值。