| This study selected Peru squid as raw material,the squid protein peptide was prepared by the optimum compound enzymatic hydrolysis process,and combined with previous research conclusion for protein peptide chelate iron,squid with sodium alginate-chitosan as the embedding wall material,the preparation of squid protein peptide chelate iron microcapsules,then process optimization to obtain chitosan,sodium alginate composite wall embedding ferrous chelating peptide microcapsules,and structure characterization of the microcapsules in the human gut,in vitro release kinetics research and application research on microcapsules strengthening powder.The main research conclusions are as follows:(1)According to the reference preparation by two different ways of embedding of sodium alginate-chitosan-sodium alginate(ACA)microcapsules with chitosan-chitosan-sodium alginate(CCA)microcapsule,with microcapsule embedding rate and the load rate of iron as the evaluation index,and through optical microscope and scanning electron microscope(SEM)to analyze the two kinds of preparation methods of microcapsule.The results showed that the Fe embedding rate of ACA microcapsules was higher than that of CCA microcapsules,while the Fe carrying rate of the two kinds of microcapsules was not significantly different.In addition,ACA microcapsules were observed with clear edges and clear boundaries between particles.After comprehensive analysis,the preparation method of iron chelate embedded squid protein peptide with sodium alginate-chitosan-sodium alginate was selected.The optimal conditions were obtained through single factor experiment and response surface optimization design experiment: the mass concentration of sodium alginate was 21.24mg/m L,the mass concentration of chitosan was 13.76mg/m L,the reaction system p H was 5.27,the composite wall material ratio was 2:1,the core wall ratio was 1:2,and the actual microencapsulation rate was 75.06%.The predicted value and the experimental value were in good fit.The microcapsule structure characterization was further investigated.The microcapsule particles obtained under the optimal embedding process were mostly of closed ring structure substance,with an average particle size of 23.74±2.71?m and a certain positive charge.The ferrochelate reacts with the positively charged wall material,and the secondary structure of the core material changes after embedding,indicating that the core material may be embedded in the wall material.After embedding,the secondary structure of microcapsules changed from ordered to disordered,which also indicated the corresponding change of conformation and function.It provides technological support for the further utilization of microcapsules.(2)Further by building simulation model,in the human gut microcapsules ferrous ion release rate as the measuring index,the comparative analysis of ferrous chelating peptide microcapsules with ferrous chelating peptide in simulated gastrointestinal digestion ferrous ion release the results before and after,and then according to the kinetics of in vitro simulation equation of ferrous chelating peptide release regularity of microcapsules in body simulation environment,at the same time using scanning electron microscope observation of ferrous chelating peptide surface structure of the microcapsules in the late before the gastrointestinal digestion.The results showed that the microcapsules released less ferrous ions in the stomach,and compared with the ferrous chelate peptide,they could reduce the stimulation of the stomach caused by excessive concentration of ferrous ions.The release rules of microcapsules in simulated human gastric and intestinal fluid all follow the zero-order kinetic fitting equation,which indicates that the release system of microcapsules in simulated human gastric and intestinal fluid is a constant speed and stable increase process.Scanning electron microscopy(SEM)showed that the digestive ability of simulated gastric juice to the microcapsule wall was limited,and it could not cause the collapse of the capsule wall in a short time.Under the effect of artificial intestinal fluid,the microcapsule shell dissolved gradually,and the inner core material fully diffused.Therefore,microencapsulation showed a good controlled release performance for ferrous chelate peptide.(3)Squid iron chelate peptide microcapsule was used as iron source to strengthen cow milk powder.The effects of storage stability tests were analyzed from the aspects of sensory quality,physicochemical properties and oxidation stability before and after microcapsule strengthening.The results showed that the sensory quality of milk powder before and after enhancement had the same degree of change with the storage time,which could rule out the effect of microcapsule iron enhancement on the sensory properties of milk powder.According to the experimental study on the physical and chemical properties of milk powder before and after strengthening,it was concluded that the internal friction property and scattering property of milk powder were not affected by the microencapsulated iron strengthening agent system.The change of moisture content of milk powder before and after enhancement during storage indicated that the adsorption between microencapsulated iron fortifier powder and water molecules was close to the interaction between milk powder and water molecules.The determination of impurity degree also effectively excluded the possibility of superfluous impurity produced by the enhancement of milk powder with ferrous chelate peptide microcapsules.To strengthen microcapsule powder oxidation stability analysis available: during the whole period of storage,powder before and after strengthening the lipid composition of oxidation degree change little,and have the same change trend,explain ferrous chelating peptide microcapsules in the powder system is stable,and strengthen the values drop before powder,visible microcapsule iron fortification did not affect the oxidation stability of the powder. |
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