不同干燥方式下叶蛋白辣椒素微胶囊理化特性研究

Effects of Different Drying Methods on Properties of Leaf ProteinCapsaicin Microcapsules

含有丰富蛋白资源的辣椒叶长期作为农业废弃物被掩埋和焚烧造成了严重的环境污染与资源浪费,同时辣椒素作为优质的天然生物抗菌物质因强烈的刺激性气味限制了其开发与应用。基于微胶囊技术方法以植物辣椒叶中提取的蛋白质为壁材,辣椒素为芯材,采用喷雾干燥和真空冷冻干燥法制备了叶蛋白辣椒素微胶囊,并利用扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪、热重分析仪、激光粒度仪及高效液相色谱技术对不同干燥方式下叶蛋白、辣椒素及其微胶囊的理化特性进行表征。结果表明:微胶囊在不同干燥方式下微观结构差异显著,喷雾干燥下微观结构呈球状,结构完整,而真空冷冻干燥下呈片状结构,形态不一;X射线衍射分析表明不同干燥方式得到的微胶囊均呈弥散衍射型特征峰,证明了辣椒素被完全装载到叶蛋白中,且在样品制备的过程中没有形成晶体;傅里叶变换红外光谱分析表明不同干燥方式下辣椒素包埋过程均没有产生新的化学键,其未与叶蛋白发生化学反应;热重分析表明,不同干燥方式得到的微胶囊热稳定性均有所提高,且叶蛋白的热稳定性低于辣椒素,保证了辣椒素的成功释放;粒径分析表明喷雾干燥法所制备的微胶囊粉末D_(90)为70.2μm,明显小于真空冷冻干燥方式下的微胶囊粒径,更易于包埋物的释放;微胶囊包埋率在喷雾和真空冷冻干燥条件下分别为90.38%和85.43%,表明喷雾干燥法对制备叶蛋白辣椒素微胶囊具有优异性。

Pepper leaves,which are rich in protein resources,have been buried and burned as agricultural wastes for a long time,causing serious environmental pollution and resource waste.At the same time,capsaicin,as a high-quality natural biological antibacterial substance,has restricted its development and application due to its strong pungent smell.Therefore,based on the method of microcapsule technology,the protein extracted from the leaves of the plant pepper was used as the wall material and capsaicin as the core material.The leaf protein capsaicin microcapsules were prepared by spray drying(SD)and vacuum freeze drying(FD)methods,and the SEM and X-ray diffractometer(XRD),Fourier transform infrared(FITR)spectrometer,thermogravimetric(TG)analyzer,laser particle size analyzer and high performance liquid chromatography(HPLC)technology were used to characterize the physical and chemical properties of leaf protein,capsaicin and their microcapsules under different drying methods.The SEM results showed that the microcapsules had significant differences in their microstructures under different drying methods.The microstructures under SD were spherical and complete,while under FD were sheet-like structures with different shapes.XRD analysis showed that the microcapsules all showed characteristic peaks of diffusion diffraction pattern by different drying methods,which proved that capsaicin was completely loaded into leaf protein,and no crystals were formed during sample preparation.FTIR analysis showed that no new chemical bond was produced in capsaicin embedding under different drying methods,and no chemical reaction occurred with leaf protein.TG analysis showed that the thermal stability of microcapsules obtained by different drying methods was improved,and the thermal stability of leaf protein was lower than that of capsaicin,which guaranteed the successful release of capsaicin.The particle size analysis showed that the D_(90) of the microcapsule powder prepared by SD method was 70.2μm,which was significantly smaller than the particle size of the microcapsules in the FD mode,and it was easier to release the embedded matter.The embedding rate of microcapsules was 90.38%and 85.43%respectively under SD and FD conditions,which indicated that SD method had excellent properties for the preparation of leaf protein-capsaicin microcapsules.