Study On Extraction Of Walnut Oil By Aqueous Enzymatic Method And Preparation Of The Microcapsule

This subject take the Guizhou local walnut as the object of study,Take aqueous enzymatic technology processing walnut kernel. Using the envelope method preparation of microcapsule and in performance research on the preparation of microcapsules.The results of the study are as follows:1. Based on the analysis of the components of walnut kernel and adopting water enzymatic oil extraction process. It found that single enzyme action effect is superior to compound enzymes and screened that experimental enzymes is papain. With the release of walnut oil rate as index.It is concluded that the best combination through the orthogonal experiment : The material liquid ratio is 1: 5, the p H is neutral, the temperature is 45℃,the reaction time is 4h, the dosage of enzyme is2%., Walnut oil release rate can reach 64.92% under the above conditions.2. With the embedding temperature, mixing time and Core-wall ratio as the experimental factors, With the embedding rate and the embedding efficiency as index.It is concluded that the best combination through the orthogonal experiment.the embedding temperature is 45℃, mixing time is 90 min and Core-wall ratio is 1∶12.Under these conditions, the preparation of microcapsule embedding rate was 89.93% and the encapsulation efficiency reached 87.23%.To test the basic properties of walnut oil microcapsules,it found that its appearance is white solid powder, no impurities, hand knead have sticky feeling and with faint fragrance oils. The microencapsulated oil amounted to 8.06%, the water content is 4.28%, density is 0.7346g/cm3 and recovery emulsion is white uniform solution.3. By surface morphology and particle size of microencapsulation of walnut oil analysised, it found that walnut oil microcapsules have cylindrical shape, the structure of the diamond flake form or acicular crystal structures, etc. Their average particle size is 14.55μm, particle diameter less than 25μm accounted for 74.83%. They has a wide distribution of particle diameter.4. Through the microcapsule resistance to acid and metal ions detection, it found thatmicrocapsule has high tolerance to organic acid and reducing substances. For the organic acid whose pH is below 3.0, its stability will be destroyed in the solution and it will happen coagulation.Stability of the microcapsule resistance to the most of metal ions is better,Its magnesium ions resistance stability is better than iron and calcium ions. it can survive without destroying the original system in the iron ion concentration is equal to or less than 0.168mg/mL,0.096mg/mL of magnesium ion concentration and 0.12 mg/mL of calcium ion concentration.5. When we do research to the walnut oil microcapsules by thermogravimetric analysis and differential thermal analysis, several changes will happen to the quality of the microcapsule, which mainly includes moisture, volatile matter, the quality of the core material and wall loss. The quality of the microcapsules will take large changes, when it comes to the temperature of 306.7℃, which reflects the microcapsule has high heat stability. And differential thermal analysis showed that the microcapsule of glass transition is the temperature of 213.5 ℃.6. The research on the oxidative stability of walnut oil indicates that the peroxide value of walnut oil which is not made into microcapsules changes from the beginning of 4.21 meq/kg rose to 50.25 meq/kg(seal saved walnut oil rose to 43.12 meq/kg) in the accelerated test of eight days.And the peroxide value of walnut oil microcapsule is 22.29 meq/kg in the eighth day, less than half of the former. Thus, oxidation rate of walnut oil microcapsules is obviously lower than walnut oil, which means a good methods to prevent walnut oil oxidized.7. Study on the microcapsule moisture adsorption characteristics, the micro capsule adsorption isotherms belong to the "I" type curve. This type of show that the microcapsules containing a large number of pores,the surface is relatively small and And the pore volμme who is easy to be close to determines the moisture adsorption. It obtained the equation of Langmuir adsorption isotherm at 15 ℃, 25 ℃ and 35 ℃ through the adsorption results. They are :m=28.55×1.70Aw/(1+1.70Aw);m=23.88×1.99Aw/(1+1.99Aw);m=20.13×2.23Aw/(1+2.23Aw)。...