【作者】 李小奎；

【导师】 邓少平； 陈忠秀；

【作者基本信息】 浙江工商大学 ， 食品科学， 2009， 硕士

【摘要】 甜味剂作为生活中常用的添加剂,在食品科学领域占有重要的地位。然而,基于实验条件的限制和甜味感觉的特殊性,人们至今没有完整理解甜味分子的感受机理。本文以合成的多羟基富勒醇作为人工化学甜味受体,通过测定多羟基富勒醇与典型甜味剂之间相互作用的荧光动力学和热力学参数,并将其与甜味剂感官甜度进行相关性研究,以确立人工甜味化学受体可行的实验研究模型。本课题研究的内容有:（1）多羟基富勒醇的合成。多羟基富勒醇采用四丁基氢氧化铵（TBAH）催化法合成,通过红外、核磁和荧光表征了富勒醇分子的光谱性质。在实验中发现富勒醇水溶液的自聚集现象,并利用透射电镜、Zeta电位/粒径和荧光方法详细阐述了自聚集的机理,这一现象的发现为后期将其作为人工化学受体,用于甜味识别方面的研究提供了方法学的基础。（2）人工化学受体甜味识别的荧光光谱研究。根据荧光滴定实验,首先确立多羟基富勒醇的浓度为1×10^-5mol/L,获得不同甜味剂复合物的荧光特性增强曲线。在滴定初期富勒醇-甜味剂的结合比为1:1,并且得到25℃和50℃下的结合常数K值,通过经典热力学公式获得相互作用的热力学参数。分别利用荧光光谱动力学和热力学参数对感官甜度进行回归,拟合方程式如下:Lg S=0.031265A₁-16742.4t₁-0.02632A₂-14100.1t₂+1.84666;Lg S=352.173+1.28×10⁵k₁+7.91×10⁵k₂+1.7434×10⁴ln（k₂/k₁）-0.54495△H+0.012167△G₁;相关系数R值分别达到0.9943和0.9998,表明荧光动力学和热力学参数均能较好地识别甜味剂的感官甜度。（3）人工化学受体甜味识别的DSC量热研究。根据富勒醇-甜味剂分子复合物的DSC曲线,利用非线性最小二乘法拟合得到了体系的相转变温度T_m等热力学参数,并将其与感官甜度值之间进行回归,得到了相关性方程式:Lg S=-0.9931T_m+0.015123△H+0.000243△H_v-2.40197n+0.1803T_1/2-4.70375△S;相关系数R=0.9956,意味着DSC实验获得的热力学参数可以应用于感官甜度的识别。本论文从受体-配体作用的化学本质出发,以多羟基富勒醇为人工化学甜味受体,利用荧光光谱和DSC扫描量热为实验技术手段,基于经典热力学理论,得到了荧光光谱动力学和热力学参数与感官甜度的相关性拟合方程,确认了多羟皋富勒醇作为人工甜味化学受体的可行性,建立了相应的实验模型,为后续的系统研究奠定了基础。更多还原

【Abstract】 By way of the additive used in daily life frequently,sweeteners occupy important status in food science field.However,because of the restriction of experiment condition and particularity of sweet taste,people can’t understand the sweetness mechanism of the sweetness molecules up to the present.In this paper,we used fullerenols as artificial sweet taste chemoreceptor,via determined fluorescence kinetics and thermodynamic parameters of the interaction between fullerenols and typical sweeteners, correlated these parameters with the sweeteners’ sensory sweetness,and established an artificial sweet taste chemoreceptor model which is feasible to have a research.The main research work is as follows:（1） Synthesization of Multi-hydroxylized fullerenols.The artificial sweet taste chemoceptor was catalysed by tetrabutylammonium hydroxide （TBAH）,the spectrum properties of fullerenols were characterized by FT-IR、NMR and Fluorescence.The phenomenon of self-aggregation of fullerenols appeared in water solution during the experiment,the mechanism of self-aggregation was expatiated by TEM、Zeta Potential/Size and fluorescence.This conclusion settled the methodological basic for it used as an artificial sweet taste chemoreceptor in the latter sweet recognition study.（2） A Study on sweet recognition of artificial sweet taste chemoreceptor by Fluorescence Titration Method.Based on the fluorescence titration experiment,the concentration of fullerenols to be ascertained was 1×10^-5 mol/L firstly,then we got the fluorescence specific-increase curves of different sweet compounds.The binding proportion was 1:1 during initial stages of titration,the binding constants at 25℃and 50℃were achieved, it could obtained thermodynamic parameters by classical thermodynamic formulas,then had fitting it with the logarithm value of sensory sweetness intensity,polynomials are as follows:LgS=0.031265A₁-16742.4t₁-0.02632A₂-14100.1t₂+1.84666;LgS=352.17+1.28×l0⁵k₁+7.91xl0⁵k₂+1.74xl0⁴ln（k₂/k₁）-0.55△H +0.012△G₁;The corresponding correlation coefficients were 0.9943 and 0.9998,it meaned that could recognize sensory sweetness by the method of fluorescence kinetics and thermodynamics perfectly.（3） A study on the sweet recognition of artificial sweet taste chemoreceptor by Differential Scanning Calorimetry（DSC）.Based the DSC calorimetry curves of fullerenols-sweeteners supramolecular compounds,gained the transition temperature（T_m） and other thermodynamic parameters by NONLINEAR LEAST SQUARE METHOD.We used these parameters fitting for the sensory sweetness, received the correlate equation:Lg S=-0.9931T_m+0.015123△H+0.000243△H_v-2.40197n+0.1803T_1/2 -4.70375△S+0.012△G₁;the correlation coefficient R=0.9956,it tells us that DSC thermodynamic parameters also can used in recognize sensory sweetness. Started from the chemical essence of receptor-ligand,taken fullerenols as artificial sweet taste chemoreceptor,used fluorescence spectrum and DSC as experiment technique means,based on classical thermodynamic theory at the same time,obtained the correlation fitting equation between parameters and sensory sweetness,the feasibility of taken fullerenols as artificial sweet taste chemoreceptor was verified, established the correspond experiment model,and settled the foundation for the further systematically study.更多还原