【作者】 张丹；

【导师】 田明磊；

【作者基本信息】 长江大学 ， 材料与化工， 2023， 硕士

【摘要】 番茄红素(Lycopene,LYC)是番茄中蕴含的对人体有益的物质之一,它并不单独在自然界中存在,人体也不能通过自身合成番茄红素,因此更好的分离提取番茄红素自然成为了本论文的关键。玉米醇溶蛋白(Zein)可从玉米中提取获得,是一种天然易得的材料。Zein在成膜的情况下脆性大且力学性能极差,而单独制备的粒状材料用于吸附综合性能又较差,在响应绿色化学号召的情况下,采用绿色的离子液体修饰剂进行改性以Zein为主的吸附材料。离子液体具备优异的物理化学性质,非常适用于分离提纯方面的实验。因此从废弃的番茄中去提取番茄红素,同时采用绿色材料作为吸附剂,既可以使得资源更大的利用,保护环境,同时也有助于人体健康方面医疗的发展。本论文中选用了多种离子液体对Zein进行改性,并将获得的改性后材料应用于废弃番茄中番茄红素的吸附分离。根据实验条件以及操作的简单性和精确性,该论文采用高效液相色谱法对吸附分离出的番茄红素含量进行检测。本论文的主要内容包括以下几个方面:(1)以Zein为主要材料,采用合成的离子液体进行修饰,离子液体选用三种不同碳链长度的烷基咪唑离子液体。第一阶段的材料是不添加离子液体但通过不同的有机酸、盐及多糖等添加到Zein中合成初步的材料,从而观察其机械性能和疏水性的改变,最后通过扫描电子显微镜(SEM)优化得到以Zein为主的基础材料。(2)第二阶段的材料是在第一阶段得到的基础材料条件下,采用离子液体修饰,得到Zein@BIM-IL、Zein@PIM-IL和Zein@HIM-IL,通过傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TGA)和SEM等表征的方法以及单因素影响的情况下得到最优化的材料,但有两个材料在吸附性能相差不大则进一步在响应曲面优化的情况下,最终得到最优吸附材料的离子液体合成的比例为3:7。(3)第三阶段的材料是在之前的实验结果下,采用硅胶修饰的离子液体对材料深入的改性从而得到Zein@Si-IL-37、Zein@HIM-Si-IL和Zein@PIM-Si-IL这三种材料,通过同样的表征手段以及单因素影响因素的探讨,选择出Zein@Si-IL-37作为最优的吸附材料应用到实际样品中,最后利用高效液相色谱检测实际样品废弃番茄中番茄红素的含量。实验证明硅胶修饰的咪唑离子液体改性后的玉米醇溶蛋白材料疏水性改善以及机械性能提高,孔隙增大,吸附效果更好,吸附更加的稳定。实验的结论是Zein@Si-IL-37作为最优的吸附材料,在温度为20℃左右,溶液浓度为0.001mg/mL-0.005mg/mL,吸附时间为2h时,对番茄红素的吸附效果最好。(4)针对上述合成的吸附材料后,第五章中考虑将玉米醇溶蛋白和壳聚糖进行复合,形成一种新型环保的多孔吸附材料,壳聚糖可从天然的甲壳素中获得,其含量较多也易提取,将其复合呈粉末状的吸附材料,通过少量的离子液体、戊二醛和表面活性剂等改善了材料的吸附性能,通过FT-IR、TGA和SEM等表征的方法得到最优化的材料,结合高效液相色谱对吸附的番茄红素性能进行评估,从而更好的吸附番茄红素,最后使用溶剂洗脱将番茄红素与材料分离,实现材料的二次利用,有效的运用到实际样品中。实验结论是该复合材料在中性溶液环境下,吸附浓度在0-0.03mg/mL,吸附时间在30-40min条件下,对番茄红素的吸附最佳。更多还原

【Abstract】 Lycopene(LYC)is one of the beneficial substances contained in tomatoes for human body.LYC cannot exist alone in nature,and human body is impossible to synthesize it.Therefore,separation and extraction of lycopene naturally become the key technology of this paper.Zein is a natural material which can be obtained from corn.Zein has high brittleness and poor mechanical properties in the case of film formation,while the granular materials prepared separately have poor comprehensive performance for adsorption.Under the requirement of green chemistry,zein based adsorption materials are immobilized with green ionic liquid modifiers.Ionic liquids have excellent physical and chemical properties,making them very suitable for experiments in separation and purification.Therefore,extracting lycopene from discarded tomatoes and using green materials as adsorbent can not only protect the environment by recycling the resources,but also contribute to the development of medical treatment in human health.In this paper,a variety of ionic liquids were selected to modify zein,and the modified materials were applied to adsorb and separate lycopene from discarded tomatoes.According to the experimental conditions and the simplicity and accuracy of the operation,the amount of isolated lycopene was detected by HPLC.The main content of this paper includes the following aspects:(1)Zein was used as the main material and modified with several synthesized ionic liquids,which consisted of three alkyl imidazole ionic liquids with different carbon chain lengths.First stage,the preliminary materials were synthesized,and the changes in mechanical properties and hydrophobicity were observed by using different organic acids,salts,and polysaccharides as additives without ionic liquids.A basic material mainly composed of zein is optimized through scanning electron microscopy(SEM).(2)Base on the basic material obtained in the first stage,the materials in the second stage were modified with ionic liquids,resulting in Zein@BIM-IL,Zein@PIM-IL and Zein@HIM-IL.The optimal material was obtained through characterization methods such as Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TGA),and SEM.And the influence of single factors on adsorption performances of these three materials were investigated.However,two of the materials(PIM-IL and HIM-IL)obtained similar adsorption performance.Hence,further optimization was assisted by response surface method(RSM)and the optimal ratio of these two ILs was 3:7.(3)Based on the previous experimental results,the third stage of the material is further modified using silicone modified ionic liquids to obtain Zein@Si-IL-37,Zein@HIM-Si-IL and Zein@PIM-Si-IL.These three materials were selected through the same characterization methods and the exploration of single factor influencing factors Zein@Si-IL-37.Finally,the content of lycopene in discarded tomatoes was detected by HPLC.Experiments have shown that the hydrophobic and mechanical properties of zein materials modified with silica gel modified imidazole ionic liquids are improved,with larger pores and better adsorption effect,resulting in more stable adsorption.The conclusion of the experiment is Zein@Si-IL-37 as the optimal adsorption material.When the temperature is about 20 ℃,and the solution concentration is between 0.001mg/mL and 0.005mg/mL,after 2h adsorption the material can adsorb the highest amount of lycopene.(4)Base on the adsorption mechanism,a new type of environmentally friendly porous adsorption material,zein and chitosan,was formed and synthesized in this stage.Chitosan can be obtained from natural chitin,which has a high content and is easy to extract.The complex adsorption material was prepared and a small amount of ionic liquid,glutaraldehyde,and surfactants are used to improve the adsorption performance.Through FT-IR,TGA,SEM and other characterization methods were used to obtain the optimized materials,and the performance of lycopene adsorbed was evaluated in combination with HPLC.Finally,solvent elution was used to separate lycopene from the materials,so as to realize the secondary utilization of materials and effectively apply them to actual samples.The experimental conclusion is that the composite material has the best adsorption of lycopene under the conditions of neutral solution environment,adsorption concentration of 0-0.03mg/mL,and adsorption time of 30-40 min.更多还原