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Microencapsulation (Microencapsulation) is embedding tiny solid particles, droplets, or gas, formed from a natural or synthetic polymer material having a semipermeable or tightness capsule particles. Select the appropriate materials as the wall material and stable microcapsules (Microcapsule, MC) preparation process has been the focus of one of microencapsulation researchers to explore. W-3 polyunsaturated fatty acids EPA and DHA-rich fish oil has many beneficial physiological functions of the human body. However, due to the fish oil is not soluble in water, light, heat, oxygen is extremely sensitive and other characteristics, limited the wide application of the fish oil in the food industry. Chitosan (Chitosan, CS) is a natural polycationic basic polysaccharide, gum arabic (Gum acacia, GA) is a natural vegetable gum, the source of the two materials are quite extensive and food safety. Therefore, CS / GA as wall material, the use of complex coacervation prepared CS / GA fish oil MC has important practical significance. The molecular weight (Molecular Weight, Mw) 1100kDa off acetyl degree (Degree ofdeacetylation, DD) is 88% of the CS as the raw materials, the use of alkyd degradation method to obtain two MW CS samples. Using the Ubbelohde viscosimeter Determination three CS Mw respectively 1080kDa, 450kDa, 230kDa, corresponding to DD average, respectively: 87.8%, 88.1%, 87.6%. Description CS degradation process, no obvious change in the DD value of CS. To ensure the uniformity of different Mw of CS DD. Degradation obtained both the CS samples FTIR spectrum peaks that do not drift, without the generation of new peaks, the sugar chain structure and the amino peaks visible, indicating that the chemical structure of the different molecular weights obtained by the degradation CS is stable. Control variables, to conduct a study on the behavior of complex coacervation factors. The experiments show that: the CS / GA 'the quality of the ratio of the concentration of the wall material, the pH, ionic strength, etc. will affect the cohesion of the two polymers to yield and equilibrium phase transmittance. For three of Mw CS, get a better cohesion yield conditions are: GA: the mass ratio of CS 6-8, the wall material and a concentration of 3-6%, pH3.5-5, low ionic strength . In the temperature range of 20-60 ℃ condensation yield with the temperature slightly elevated, but condensed production rate of more than 85%, indicating that temperature (20-60 ℃) on the complex coacervation reaction little effect. Ensuring the completion of the condensation reaction time is 30 min. The FTIR spectrum of the condensation product of: the CS sample-NH2,-CH-NH2 absorption peak disappeared, indicating that the CS molecule amino GA molecules electrostatic interactions, the formation of the condensation product in the IR spectra of condensates. To guarantee access to the high condensation yield experimental conditions to determine the wet CS / GA fish oil preparation process of the MC, and the wet MC part of the physical and chemical indicators were tested. The experimental results show that: the Mw of CS complex coacervation of GA and CS encysted effect greater impact. Which the CS of Mw1080kDa is prone to caking phenomenon occurs with GA difficult encysted; MC irregular shape CS of Mw450kDa of and GA formed sac prone adhesions. The CS can Mw230kDa formed with GA the regular spherical MC endocapsular almost no adhesion occurs. The experimental results show that: Mw230kDa the CS suitable as a GA complex coacervation the embedded fish oil wall material. The experimental material Mw230kDa the CS complex cohesion preparation of wet fish oil MC GA. High optical microscope observation that the wall material concentration in the CS / GA 5% CS: GA, the ratio is 1:7, the core material to wall ratio of 1:2, a pH of 4.5, the reaction temperature was 20 ° C, the complex coacervation reaction time was 30min under the conditions of the preparation of wet fish oil MC morphology regular, spherical and uniformly distributed, without adhesion, and complex coacervation visible Perspective formed MC larger quantities. Therefore determine laboratory prepared wet CS / GA fish oil MC preparation conditions. Adoption determining laboratory prepared wet CS / GA fish oil MC process, the obtained wet CS / GA fish oil MC of average particle diameter of 16.3μm, the embedding rate of the fish oil and wall material utilization were 75.33% and 81.01 %. The laboratory preparation of adoption determining wet CS / GA fish oil the MC process, wet CS / GA fish oil MC was prepared, after freeze-drying, to form a dry state CS / GA fish oil MC. The observed SEM photographs can be seen: dry CS / GA fish oil MC basic spherical surface of the porous structure, part of the MC appears broken. Can return to the form of freeze-dried before dry MC after rehydration. By measuring the dry state CS / GA fish oil MC sample surface oil content, and total oil content, and moisture content, the calculation and analysis of the average yield of the MC, the embedding rate and the fuel load of 72.63%, 67.53%, 31.59%, respectively. The dry state CS / GA Fish oil MC preparation process, the POV of fish oil increases, to add an antioxidant TBHQ (250mg/kg fish oils) can effectively inhibit the oxidation. CS / GA fish oil MC system, such as dry state CS / GA MC drying fish oil and dry CS / GA fish oil MC protection of fish oils, the role remains to be studied.
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