Preparation And Characterization Of Glyceryl Arachidonate Double-Walled Microcapsules

Arachidonic acid is one of n-6 series polyunsaturated fatty acids, its physiological functions are important for human body and the main existence form is glyceryl arachidonate, oxidation and acidification of glyceryl arachidonate is incidental by environmental factors out of body or gastric juice in body, the intake experience is bad that metamorphic products are Harmful and the odor is unpleasant. On the other hand, glyceryl arachidonate is viscous liquid at room temperature, transport and storage is difficult. Mixing of oil-soluble glyceryl arachidonate and water-soluble substances is difficult; the application of arachidonic acid in the food industry is limited. The main objective of this thesis is finding a technology that can resolve these problems.Take dextrin and MSF-231 (modified starch that lab-made) as wall material, and glyceryl arachidonate as core material, one-walled microcapsules was prepared by spray drying; Hydroxypropyl methyleellulose phathalate and parts of one-walled microcapsules were microcapsulated second time and formed into enteric-soluble microcapsules by the same method. Based on research of process and formulation of microencapsulation, test and compare the general properties of two types of microencapsulated products, examine their ability on acid tolerance, the main conclusions are the following:1. The best process and formulation of preparation of one-walled glyceryl arachidonate microcapsules by spray drying:30% glyceryl arachidonate,15% MSF-231,54% dextrin,0.7% P0281 (lab-made emulsifier),0.3% P0299-2(lab-made emulsifier), mix and emulsify in 75℃, then homogenize twice times under 30 MPa, the stability of the emulsion made by this process has been as high as 99.89%; The best process of spray drying:180℃inlet air,95℃discharge air, half solid and half liquid, the products made in these conditions have a higher embedding rate and stable performance. The best process and formulation of preparation of double-walled glyceryl arachidonate microcapsules by spray drying:80% one-walled microcapsules, 20% HPMCP, solvent consist of ethanol and dichloromethane, and the ratio is 3:1, the concentration of wall material solution is 7%; the best process of spray drying:135℃inlet air,75℃discharge air, the release rate of oil of double-walled glyceryl arachidonate microcapsules is low, the product is dry completely.2. The structures of two types of microencapsulated products were close to spherical, the moisture content of one-walled microcapsules and double-walled microcapsules were 2.77% and 2.18%, oil rates were 23.83% and 29.86% and close to the original oil content, microencapsulation efficiencies were 96.21% and 97.36%, the initial surface oil content were 1.13% and 0.63%, the increments of surface oil content were 0.41% and 0.32% in 120 days, indicating that two types of products were dried completely, the process of microencapsulation was complete, the mixture of core material and wall material was well-proportioned, the products had a higher embedding rate and a lower percentage of surface oil and surface oil increased slowly, Important was that the original natures of one-walled microcapsules had not been destroyed by second time microcapsulated.3. The initial peroxide values of one-walled microcapsules and double-walled microcapsules were 2.57 meq/kg and 2.44 meq/kg, the increments of peroxide values were 0.41% and 0.32% in 120 days, and acid numbers were 0.61 mg KOH/g and 0.57 mg KOH/g and increased slowly, the increments were 2.75 mg KOH/g and 2.36 mg KOH/g in 250 days, but in the next 100 days storage period, acid number of one-walled microcapsules increased faster and the increment was 3.57 mg KOH/g, acid number of double-walled microcapsules increased still slowly and the increment was 0.18 mg KOH/g, low peroxide value and increased slowly indicated that two kinds of wall materials can isolate the oxygen effectively and to protect the core material; Changes of acid numbers indicated that second time microcapsulated can increase storage time of microcapsules of glyceryl arachidonate.4. After dealing with artificial gastric juice for 30 minutes, the release rate of oil of one-walled microcapsules was 18.63%, after 4 hours treatment, the release rate of oil was 92.38%, but the release rate of oil of double-walled microcapsules was 5.81% after 4 hours treatment, the different of the release rate of oil between two types microcapsulated products indicated that the second time microcapsulated can control the release of glyceryl arachidonate in the stomach effectively and reduce the deterioration in body.5. After dealing with artificial intestinal juice for 10 minutes, the release rate of oil of double-walled microcapsules was 85.95%, in 60 minutes, the release rate was 98.67%,it indicated that the wall material content of the second time microencapsulation was reasonable and HPMCP, which is a type of enteric coating wall material, can disintegrate quickly in the intestine, the second time microencapsulation has little effect on the absorption of glyceryl arachidonate in the intestine.