微流控芯片技术制备花青素微乳的机制研究

Being easily oxidized and unstable, such reasons of anthocyanins which belong to food functional pigment, limit its application in food processing. Preparing the functional pigment emulsion can protect its stability and extend its storage．The microemulsion processing by traditional method cannot reach uniform and controllable particle size, microfluidic chip can effectively solve the liquid - solid mixed problem, control the size and distribution of microemulsion. This program planned to use Cyanidin 3-sophoroside as the raw material, which is a kind of monomeric anthocyanin with a high content in blueberries, microfluidic chip technology was used to prepare anthocyanins microemulsion. Verify how do common environmental factors impact the stability of the embedding Cy-3-soph by dynamic degradation process, anthocyanins antioxidant activity, and oil phase aggregation concentration testing. The microstructure of anthocyanins can be analyzed by scanning electron microscopy. The viscoelastic properties of particles can be determined by rheometer. The cyanidin content can be tested by HPLC. The interaction way of anthocyanins and emulsifier can be analyzed by spectrometry combination with quantitative structure-activity relationships (QSAR)，including stereoscopic effect, hydrophobic interactions and electric effect on the microemulsion areas and the size of the self-emulsifying system. On basis of the research results, we can conclude the mechanisms that microfluidic chip technology preparing for anthocyanins microemulsion. Our research can provide theoretical basis of the application of microemulsion in processing food functional pigment products.

花青素等功能性色素由于易氧化、稳定性差等原因，限制其在食品加工中的应用。将花青素制备成微乳具有保护其稳定性，延长贮藏期的特点。传统方法加工的微乳无法达到粒径均一可控，微流控芯片可以控制微乳的大小和分布，有效解决液体－固体间的混合问题。本项目拟以蓝莓中含量较高的单体花色苷—矢车菊素-3-槐糖苷(Cy-3-soph)为原料，利用微流控芯片技术制备花青素微乳，从降解动力学过程、花青素抗氧化活性及乳化剂聚集浓度三方面来研究常见环境因素对包埋Cy-3-soph稳定性的影响。利用电镜技术直观分析微乳的微观结构，流变仪测定微乳的粘弹特性，HPLC法测定矢车菊素在微乳中的含量变化。定量构效关系结合光谱法分析微乳中花青素与乳化剂的相互作用方式(包括空间立体效应、疏水效应、电性效应对乳化体系形成的影响)，以此探讨和推断微流控芯片技术制备花青素微乳的机制。本课题的研究可为实现微乳在色素加工中的应用提供理论依据。

花青素等功能性色素由于易氧化、稳定性差等原因，限制其在食品加工中的应用。将花青素制备成微乳具有保护其稳定性，延长贮藏期的特点。传统方法加工的微乳无法达到粒径均一可控，微流控芯片可以控制微乳的大小和分布，有效解决液体－固体间的混合问题。本项目以从蓝莓提取分离所得到高纯度的矢车菊素-3-槐糖苷（Cy-3-soph）为研究对象，探索出微流控芯片技术制备粒径均匀Cy-3-soph微乳的最佳方法：采用50%的聚乙二醇二丙烯酸酯（PEGDA）作为分散相，肉豆蔻酸异丙酯作为油相（连续相），吐温80复配司盘80作为复合表面活性剂，无水乙醇为助表面活性剂(表面活性剂∶助表面活性剂∶IPM= 4：2：4) ，且Km = 2：1，HLB = 7.5 时，连续相与分散相流速分别为3.0、1.0 μL/min 时形成的油包水型（W/O）微乳液面积较大。利用肉豆蔻酸异丙酯/吐温80复配司盘80/无水乙醇/水微乳体系对Cy-3-soph进行增溶，结果表明每克W/O型微乳可溶解Cy-3-soph 5720 μg，气相顶空技术测定微乳的包封率在70%以上。温度、光照、湿度和留样观察试验均表明，微乳中Cy-3-soph保留率要高于Cy-3-soph溶液。低浓度NaCl、含量低于9%的葡萄糖和蔗糖对Cy-3-soph微乳液的稳定性无显著影响; DPPH自由基清除实验、ABTS实验和超氧阴离子清除实验发现，花青素微乳的体外抗氧化活性明显高于花青素溶液。荧光光谱法、紫外-可见吸收光谱法、红外光谱法和动态激光散射技术研究表明微乳中乳化剂与Cy-3-soph 宏观结合方式为静电作用力。透射电镜下观察制备的花青素微乳为球状液滴，粒径在0.07μm左右，以此探讨和推断微流控芯片技术制备花青素微乳的过程。采用聚乙二醇二丙烯酸酯（PEGDA）作为微乳原材料，使用紫外光源照射 PEGDA 微乳液滴使其发生光聚合反应而固化。通过控制连续相与分散相流速，制得的花青素微乳单分散性好， 变异系数低于 5%。. 基于微流控芯片辅助制备花青素微乳，可提高微乳制备技术中的操作稳定性，降低生产成本，最终为包括蓝莓花青素在内的各种植物功能性色素加工技术开展和应用提供理论支持。