| As a bitter substance in beer,iso-a-acid gives beer a refreshing bitter taste,which is one of the core factors affecting beer taste.Therefore,it is of great significance to study the relationship between the concentration of iso-a-acid and the intensity of human bitter taste.However,at present,due to the complex structure and immature purification process of iso-a-acid,the sensory research of iso-a-acid is relatively less.Moreover,when the concentration of iso-a-acid was changed,the change of bitterness was not clear.At the same time,there are few studies on the taste sensor for the detection of the concentration of Iso-a-acid solution.Therefore,the purpose of this paper is to clarify the relationship between the concentration of iso-a-acid and the taste intensity and to realize "quantitative detection of the concentration of iso-a-acid solution".First of all,this paper establishes a reproducible and stable sensory evaluation method of bitterness to construct the curve of different intensity of bitterness,and also establishes the corresponding quantitative standard method of bitterness.Secondly,by applying the artificial lipid membrane to the self-designed screen-printed electrode,a kind of bitterness sensor which can detect the quantitative value of bitter feeling was established.Next,a quartz crystal microbalance bitterness sensor based on artificial lipid membrane was prepared.Finally,by culturing taste stem cells in vitro,the feasibility of using taste stem cells instead of sensory organs to evaluate and detect bitter substances was discussed.The main research work and conclusions were as follows:(1)In this paper,iso-a-acid is taken as the research object and bitterness as the research taste,so as to establish a relatively simple and repetitive sensory evaluation method and mathematical statistics method for measuring the threshold of iso-a-acid detection and the intensity of sensory difference.On this basis,the sensory difference intensity curve of the bitter taste of iso-a-acid was established,and the logarithmic relationship between the concentration and sensory difference intensity was obtained,specific formula was as follows:S=21.65 lg(C)-4.75.The sensory difference intensity curve of the bitter taste of iso-a-acid,the curve between the quantitative value of the bitter taste of iso-a-acid and the logarithm of sample concentration was further established,thus realize the quantification of the bitter taste of iso-a-acid(2)Only by optimizing the formulation of PVC artificial lipid membrane and applying it to the self-designed screen printing electrode,can a low-cost,single use bitterness sensor be successfully prepared.Moreover,the sensor not only realizes the quantitative determination of the concentration of iso-a-acid solution(the correlation coefficient is 0.96),but also realizes the mutual transformation between the absolute value of the potential difference of iso-a-acid and the quantitative value of bitterness(the correlation coefficient is 0.99).Even,the cleaning conditions of the sensor(50%ethanol solution,500 rpm,cleaning for 60 s)were explored.And the repeatability(more than 4 times of continuous use),service life(more than 3 days of continuous use),specificity(no response to other taste substances)and storage time(more than 20 days)of the sensor were evaluated.Furthermore,the PVC artificial lipid membrane prepared in this experiment was applied to the quartz crystal microbalance sensor to realize the quantitative determination of the concentration of iso-a-acid solution(the correlation coefficient is 0.99)(3)Based on the 3D culture of taste bud cells in vitro,taste stem cells which can differentiate into three kinds of taste bud cells were successfully cultured and characterized.Based on the taste stem cells,the standard curve of bitterness sample concentration and chemoluminescence was established,the specific formula was as follow:y=21726x-13007(correlation coefficient 0.99).The relationship curve between the concentration of bitter sample and the impedance value of the prepared cell sensor(correlation coefficient 0.98)was established by AC impedance method. |
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