| 2-(4-methoxyphenoxy)propionic acid has a significant sweet taste inhibit,was approved by China in 2000 into the GB2760,as a food additive used in food production.At the same time,2-(4-methoxyphenoxy)propionic acid is also used in many countries and regions.Such as Europe,the United States and Brazil.This paper belongs to the research content of the National Natural Science Foundation of China.The molecular modification of 2-(4-methoxyphenoxy)propionic acid was carried out to explore the effect of molecular structure on sweet taste inhibit.And it seeks more modified substances with high efficiency sweet taste inhibit,low cost and no bad smell,which were applied to production.And it provides some reference for the mechanism of sweet taste inhibit.In this experiment,the sweet taste prediction model of electronic tongue machine was built by least square method to explore the feasibility of using electronic tongue to predict the actual sweet taste of substances.The inhibit rate of 2-(4-methoxyphenoxy)propionic acid on different sweeteners was determined to further verify the feasibility of using electronic tongue to explore the effect of sweet taste inhibit.Then 2-(4-methoxyphenoxy)propionic acid substituted and esterified derivatives were synthesized by Williamson reaction and esterification reaction and characterized by NMR 、 IR.The effect of different sweetener types,sweetener concentration and derivative concentration on the sweet taste inhibit of different derivatives was investigated by using electronic tongue technology,and the effect of adding derivatives on other tastes was further studied.The experimental results are as follows:(1)The establishment of an electronic tongue method to evaluate the sweet taste effect.A regression prediction model of sucrose,maltose alcohol,fructose,glucose artificially perceived sweetness value and electronic tongue measured sweetness value was established.The correlation coefficient range of fitting model was 0.98642~0.98951,which indicated that the electronic tongue machine sweetness measurement and taste sensory sweetness value had a good positive correlation.The Rc、Rcv、Rp range is 0.973~0.997,the RMSE、RMSECV and RMSEP range is 0.078~0.679,which indicates that the predicted value is very close to the actual measured value and the model accuracy is high.It is feasible to use electronic tongue to measure the sweetness value to reflect the actual sweetness of the senses.Electronic tongue was used to explore the sweet taste inhibit law of 2-(4-methoxyphenoxy)propionic acid.The experimental results were consistent with the Mathlouthi study,and the feasibility of using electronic tongue to explore the sweet taste inhibit law was further verified.(2)The sweet inhibit effect of 2-(4-methoxyphenoxy)propionic acid substituted derivatives.It was found that the sweet inhibit rate of 25% sucrose reached the maximum when most of the substituted derivatives were added at 1.4‰.Among them,2-(2-methylphenoxy)propionic acid and 2-(3-propylphenoxy)propionic acid inhibited the best and the worst,respectively.In terms of different substitution positions and kinds of substitution groups,the sweet inhibit rate of methyl substituted derivatives is higher than that of ethyl and propyl substituted derivatives,and the inhibit rate of para-substituted derivatives is higher than that of ortho and inter-substituted derivatives.The sweet taste inhibit rules of each substituted derivative are as follows: methyl > ethyl > propyl,intermediate substitution,methyl > propyl,ortho substitution,methyl > propyl > ethyl.At the same time,the methyl and ethyl substituted derivative modifiers of 2-(4-methoxyphenoxy)propionic acid can induce weak bitter taste,while the propyl substituted derivatives of 2-(4-methoxyphenoxy)propionic acid will induce strong bitter taste.(3)Sweet inhibit of 2-(4-methoxyphenoxy)propionate derivatives.Through single factor experiment,it was found that 2-(4-methoxyphenoxy)propionic acid esterified derivative had no obvious sweet taste inhibit effect,and the best sweet taste inhibit effect was 2-(4-methoxyphenoxy)propionic acid isopropyl ester.But its sweet inhibit rate is not more than 5,other esterification derivatives will even appear sweetening reaction.It shows that carboxyl group is very important to realize the sweet taste inhibit of 2-(4-methoxyphenoxy)propionic acid,and the destruction of carboxyl group structure will lead to the loss of sweet taste inhibit effect and even increase sweetness.After adding ester derivatives,the bitter and astringent taste of sucrose solution increased and the sour taste decreased,but neither of them had a great effect on the taste of sucrose solution itself. |
