Preparation Of Capsaicin Microcapsules By Complex Coacervation

Capsaicin is the spicy and active ingredient of Chilies. Which has manyfunctions，such as analgesis, bacteriostasis, anti-cancer, regulating the blood fat,losing weight, antifatigue, etc. But its strong pungency limits the application in allfields. Microencapsulation provides several advantages by improving the physicalproperties of core, shielding taste and smell, controling release and sustaining releasepossibilities. Complex coacervation occurs under mild conditions and simpleoperation, whose products shows great thermostability and effective resistance to highhumidity. In this paper, capsaicin was microencapsulated using complex coacervationof gelatin and CMC, nontoxic transglutaminase(TG) is the cross-linking agent. Theelectric charges of gelatin and CMC, quantitative method of capsaicin, preparationprocessing, physical and chemical properties, and storage stability were studied.The charges of CMC and gelatin brought in different pH were tested, and theresults showed that isoelectric point (IEP) of gelatin which used in experiment is 5.08,the gelatin shows positive charge under IEP, and negative charge above IEP, on theother hand, the CMC always puts out negative electric charge. The ultravioletspectrophotometry and high performance liquid chromatography were compared toensure quantitative method for capsaicin, both are up to the requirements of this topic,at last, the Ultraviolet spectrophotometry was chosen as the quantitative measure ofcapsaicin in view of its wide application.To discuss the influence of wall material concentration, gelatin/CMC rate,core/wall rate, and pH to the preparation, using the yield and efficiency ofmicroencapsulation as indexes. The process conditions were optimized by orthogonalon the base of single factor test. The optimal conditions which are: the concentrationof wall material 1%, rate of gelatin/CMC 9:1, rate of core/wall 1:1, pH 4.6. Underthese parameters, the encapsulation yield and efficiency are 92.53% and 91.23%,respectively.The physical and chemical properties of capsaicin microcapsules werestudied．The moisture is 3.46%, the repose angle is 43.8°, and the loading efficiency is45.63%; The microcapsule particle and microstructure was valued by scanningelectron microscope and shows that an irregular spherical structure and integralsurface, and has the mean diameter of 100μm; FT-IR spectrum proved that the coacervate is formed successfully. Thermogravimetricanalysis(TGA) showed that thegelatin-CMC protects the core to some extent, and the thermal stability ofmicrocapsules by complex coacervation has been increased.