Preparation And Controlled Release Characterization Of Allicin-load Microcapsule

The mass propagation and metabolism of Microorganisms is one of the main causes of food spoilage. In order to keep food fresh and tasty, the traditional food packaging materials are mainly through passive isolating from the permeation of gas, water or microorganisms to keep food in an environment of low oxygen concentration in the low water activity (Aw), to control the propagation of microorganisms. However, a kind of packaging material with the function of antimicrobial controlled releasing, currently one of the frontier of research in international active packaging materials area, is different from the traditional food packaging material. The principle of keeping food fresh of controlled releasing antimicrobial packaging material mainly depends on continuously adding antibacterial antioxidants and other active substances to packaged food surfaces, which can achieve the goal of keeping food’s flavor and prolong the duration of on-shelf. This thesis takes allicin-loaded microcapsules as the research object to study the effects of controlled release of microcapsule in different environments. It has also provided a new way to study the active antimicrobial packaging materials.This experiment chooses allicin, which has strong volatile and excellent antibacterial effect, as antibacterial agent, using the current popular technology of emulsification/cross-linking to prepare microcapsules, guided by the electrostatic adsorption principle of the positive and negative ions of chitosan and sodium alginate. In the process of this experiment, allicin is firstly wrapped in sodium alginate/chitosan microcapsule, by controlling the oil-water ratio, the content of the surfactant, the concentration of calcium chloride, sodium alginate and chitosan as well as the pH parameters of reaction system, and then will get allicin microcapsules with uniform particle size, good sphericity, high encapsulation efficiency and drug-loading rate. It studies the drug release rate of microcapsule in different release medium, meanwhile, prelimilarily discusses allicin microcapsules in the application of antimicrobial packaging materials.The specific research results are as follows:by way of microemulsion, the fat-soluble allicin solubilization into the alginate aqueous phase of the system, the formation of O/W microemulsion with an average particle size of the microemulsion is13.7nm, narrow distribution (PDI=0.34). When allicin content is150μg/mL and 200μg/mL, its Staphylococcus aureus inhibition zone sizes is14±0.84mm、18±0.54mm. The optimum conditions for Preparation of microcapsules containing allicin are:sodium alginate concentration of1.5%, calcium chloride concentration of4.5%, chitosan concentration of1.0%, chitosan and alginate pH4.5. Under these conditions, the drug loading ratio and encapsulation efficiency ratio is61.4%and78.1%(alginate/allicin=2/3) respectively; the cumulative increase ratio increases from50.6%to81.9%in6hours (pH1.2～pH7.4), and declines from78.9%to72.3%in6hours in NaCl release media (1.0mol/L～4.0mol/L, pH=6.8). In the cassava starch-PVA water soluble film, when microcapsules content of1%, an increase in arllic content of microcapsules,the inhibition zone size against Candida albicans of38±0.04mm、44±0.16mm、50±0.22mm。In this experiment, lipophilic drugs were put into pH sensitive sodium alginate/chitosan microcapsule in the form of microemulsion, which can achieves the purpose of high encapsulation efficiency and drug-loading rate as well as good controlled release effect in different pH environments. The prepared microcapsule, taking allicin with strong volatile and broad-spectrum antibacterial effects as antibacterial agent, has good bacteriostatic action on the Staphylococcus Aureus and Candida Albicans. This study lays a foundation of obtaining practical control release antibacterial packaging materials, as well as providing a new way of thinking to do research on other active packaging materials.