Preparation Of Cold Water Soluble High Amylose Esterified Starch And Its Emulsion Properties

High amylose maize starch(HAMS)has unique crystalline structure,thermal properties and excellent mechanical properties,which make it have broad application prospects in the fields of low-glycemic foods,active ingredient embedding substrates and degradable materials.HAMS granules have been used in construction of Pickering emulsions to become a research hotspot in food chemistry,but its defects such as strong hydrophilicity and poor solubility in cold water seriously hinder its processing and application.Therefore,based on the molecular structure characteristics of HAMS,this paper attempts to modify HAMS by esterification in an ethanol solvothermal process.At the same time,auxiliary methods such as solid-phase mechanical grinding and ethanol swelling were used to increase the cold water solubility of HAMS to obtain a cold water soluble high amylose esterified maize starch(M-HAMS).In addition,the preparation of high internal phase Pickering emulsions(HIPPEs)and multiple Pickering emulsions constructed by M-HAMS were also studied.The main contents are as follows:(1)Preparation of esterified LA-HAMS by reaction of lauric acid(LA)with HAMS:HAMS was modified by esterification with a combination of ethanol solvothermal and mechanical grinding,and the emulsifying ability of esterified starch(LA-HAMS)was studied.The results showed that the crystal structure of HAMS changed from B to B+V type after esterification,the water contact angle increased from 44.5° to 79°,and the hydrophobicity was improved.When the oil phase volume fraction(?)was 30 vol% and the concentration of LA-HAMS granules was 5.5 wt%,the absolute value of zeta-potential of the prepared Pickering emulsion was 69.5 m V,the emulsion has good stability.(2)Preparation of cold water soluble M-HAMS granules and its emulsion properties:The cold water solubility of HAMS was enhanced by mechanical grinding and ethanol swelling process,and the ethanol solvothermal preparation conditions were optimized to obtain M-HAMS granules with excellent performance.The research showed that M-HAMS granules swelled completely into dense molecular chains in the emulsion,and this three-dimensional network structure improved the stability of emulsions.The oxidative stability of the emulsion is also enhanced with the increase of M-HAMS concentration and ?.When the p H value of the emulsion is 5 ? 9 or Na Cl in the emulsion is 50 ? 200 mmol/L,there is no significant effect on the rheology of emulsion with the changes of anions and cations in the system,and the prepared emulsion has good oxidative stability.(3)Study on the construction of stable HIPPEs with M-HAMS granules: Maize oil as the oil phase,stable HIPPEs was constructed with M-HAMS granules through the control of the preparation process.Through the analysis of the morphology,particle size,zeta potential and rheology of the emulsion,it can be seen that the gel-like HIPPEs can be successfully prepared with 2.0 ? 5.0 wt% M-HAMS granules and ? = 75 vol%.3.0 wt%M-HAMS granules can stabilize HIPPEs with an ? to 90 vol%.HIPPEs droplets exhibit a highly tightly packed shape.With the increase of M-HAMS concentration and ?,the emulsion viscosity increased,the storage modulus increased,and the system structure was stable.In addition,HIPPEs also exhibited lower temperature dependence and good thixotropy.(4)Preparation of W/O/W Pickering Emulsion: Preparation of multiple stable emulsion is greatly influenced by its preparation process.In this paper,the addition process of M-HAMS granules,the existence environment of LA and the stabilization mechanism of W/O/W Pickering emulsions were studied.The results showed that the emulsion prepared directly by M-HAMS granules has uneven size of emulsion droplets at low granlues concentration and prone to aggregation.When the granules concentration is increased,the multiple emulsion is unstable.M-HAMS granules were uniformly dispersed in the oil phase,and the stable W/O/W Pickering emulsions was prepared by using the surfactant effect formed by LA dissolved in a weak alkaline water phase.