The Research On Extraction And Microencapsulation Of Acorn Polyphenols And The Character Of Microcapsule

Acorn polyphenols with unique biological activity, especially its antioxidant and bacteriostasis, have a broad prospect of application in food, medicine, health products and cosmetics industries and other fields. However, because acorn polyphenols are vulnerable to light, oxygen, temperature, acid and alkaline and other environmental conditions which accelerate oxidative degradation, its applications have been limited greatly. The microencapsulation of acorn polyphenols can not only protect its activity from external conditions, but also raise its stability in storage and applications.In this paper, extraction technology of acorn polyphennols using the methods of organic solvent and ultrasound-assisted two-phase aqueous system was studied, and then acorn polyphenols was microencapsuled by spray-drying, and the microencapsulated wall composition, process parameter, physical and chemical characteristics and the properties of storage of microencapsulated acorn polyphennols was studied. The main results are listed as follows:The optimum conditions for the extraction of acorn polyphenols with organic solvent were as follows:acetone concentration60%, extracting temperature60℃, material-solvent ratio1:20, extracting time0.5h, under the optimum conditions, the extraction ratio of polyphenols is10.63%;with ultrasound-assisted two-phase aqueous system, the optimum conditions were as follows:acetone concentration80%, amount of (NH4)2SO40.16g/mL, ultrasonic time25min, material-solvent ratio1:45(W/V); the extraction ratio of polyphenols is13.52%.Encapsulated wall material composition of acorn polyphenols was studied.The encapsulated wall material was to be optimized with microencapsulation efficiency as the index, and the optimum wall material composition was that maltodextrin:(3-cyclodextrin was4:1,amount of gum Arabic7.5%, anthocyanin:wall material is1:3, the microencapsulation efficiency of acorn polyphenols is94.29%±0.51%.On the basis of determination of encapsulated wall material, the processing parameter of spray-drying was investigated and optimized.The optimum processing conditions were as follows:concentration of feeding material25%,feeding speed200mL/h, outlet temperature180℃,under the conditions, the microencapsulation efficiency is94.52%±0.53%. The physical and chemical characteristics of polyphennols microcapsules were investigated and analyzed.The results showed that microcapsules was milky, pure smell, no other-off flavor and the particle was uniform, texture is exquisite.The moisture content, repose angle, solubility of microcapsules were2.94%,41.3°,93.25%. This suggested that microcapsules had great superiorities, such as easy preservation, good solubility and fluidity.The properties of storage of polyphennols microcapsules were studied. Compared with the condition in light, the reservation rate of microcapsules in avoid light was higher dramatically than in light. The microcapsules stored stably in4℃,25℃,40℃,but the stability decreased in60℃dramatically. Compared with the anaerobic condition, the reservation of rate of microcapsules in the aerobic condition was lower significantly. The effect of NaHSCO3on the stability of polyphenols microcapsules is not significant, but on the polyphenols is significant. The stability of both microcapsules polyphenols and polyphenols decreased dramatically in H2O2solvent system.The higher the concentration of Reductant and oxidizer were, the more significantly the influence was.