基于动物偏好指数与电子舌评价关联的中药涩味整体量化表征方法研究

Quantification of astringency for traditional Chinese medicine based on animal preference index and electronic tongue

目前的涩味表征主要采用感官评价,具有高度的主观性与模糊性,缺少客观、统一、量化的评价指标,不利于涩味强度的精准表征。为此,该文建立了基于动物偏好指数与电子舌评价体内外关联的中药涩味整体量化表征方法。首先,采用涩味标准物鞣酸进行双瓶喜好实验的方法学优化及验证,确定标准实验动物为140~180 g的雌性大鼠,得到鞣酸浓度-动物偏好指数的函数关系Y=ln(1.682 6-0.441 66X),r=0.997 3。然后,利用优化后的方法对典型涩味中药诃子、矮地茶、青果、儿茶、大腹皮进行评价,计算其2 g·L^(-1)时的涩味强度分别相当于0.56,0.29,0.24,0.34,0.25 g·L^(-1)鞣酸的涩度。最后,采用电子舌进行验证,将其主成分分析(PCA)图中欧氏距离与样品偏好指数及换算的鞣酸浓度分别进行pearson相关分析,发现具有较高的相关性。上述体内、体外实验结果相互佐证,共同表明由动物偏好指数换算得到的结果客观、真实、可靠。该方法的建立,为中药涩味的精准量化以及掩味效果的客观评价提供了可靠的工具,也为药品、食品领域其他味觉的量化评价提供了新的思路与范例。

Current evaluation method for astringency is mainly focused on human sensory evaluation. However,it is subjective,vague,and short of assessment indicators for objective quantification. In this paper,the quantification method for astringent intensity of traditional Chinese medicine was established based on the animal preference index and electronic tongue in vitro and in vivo. Firstly,the standard substance of astringency,tannic acid,was used for the methodology optimization and validation of two-bottle preference test. It was determined that the standard experimental animals were female rats of 140-180 g. The functional relationship between concentration of tannic acid and preference index was obtained Y = ln（ 1. 682 6-0. 441 66X）,r = 0. 997 3. Then the typical astringent Chinese herbs Chebulae Fructus,Ardisiae Japonicae Herba,Canarii Fructus,Catechu,and Arecae Pericarpium were evaluated by the optimized method. Their corresponding concentration of tannic acid was converted by the concentration-preference index relationship through preference index. Their astringency was equivalent to 0. 56,0. 29,0. 24,0. 34,0. 25 g·L^（-1）tannic acid. Finally,the results were verified by electronic tongue. The correction analysis between Euclidean distance in PCA and preference index and concentration of tannic acid converted by samples showed a high correlation through pearson correlation analysis. The above results indicated that the method was objective,true and reliable. The method provided a reliable tool for the quantification of astringency and evaluation of taste masking effect for Chinese medicines,and also offered a new idea and model for the quantification of taste in the pharmaceutical and food fields.