| Puerarin is a kind of flavonoids,which has the function of relieving heat and thirst,and is applied in the treatment of cardiovascular diseases and cerebrovascular diseases.However,the poor solubility of puerarin not only reduces its bioavailability but also limits its application in food,so it is of great significance to develop a new delivery system to protect and maintain its activity.The emulsion system is an excellent carrier to package,protect and deliver nutrients.The systems loaded with pueraria have been reported,including microemulsions,nanoemulsions and phospholipid complexes.However,due to the complex preparation process of these carriers and the need for a large number of synthetic surfactants,it does not meet the requirements of healthy,safe and efficient production.High internal phase Pickering emulsion(HIPEs)is one of the most promising load systems due to its excellent stability and protection of nutrients.Currently,food-grade emulsifiers for stable HIPEs are mainly plant proteins,polysaccharides and animal proteins from egg and milk sources,and there are relatively few studies on meat proteins.Therefore,it is necessary to find a simple,low-cost,efficient,safe and stable delivery system to improve the bioavailability of puerarin.In this study,myofibrillar particles were used as emulsifiers to prepare stable HIPEs by a simple,low-cost and efficient method,and the maximum oil-phase volume fraction,stability,microstructure and universality of the emulsion were studied.Secondly,the digestion characteristics and antioxidant stability of HIPEs in different oil phase were studied.Finally,the emulsion was used as a carrier to load puerarin,puerarin and tany-carotene,and the ways to improve the bioaccessibility of puerarin were explored.The main research contents and conclusions were as follows:1.Myofibrillar proteins was extracted by one-step centrifugal method,and then dissolved in NaCl solution with different pH(pH 3.0,5.0,7.0,9.0,and 11.0)by simple one-step homogenization to prepare myofibrillar protein particles.The morphology of myofibrillar protein particles,the changes of Zeta potential,surface hydrophobicity content and particle size for the particles were investigated.The results showed that the micromorphology of protein particles were different in different pH environments.When the pH range of 3.0-7.0 a fibrous gathered formed,and when the pH range of 9.0-11.0 in the granular formed.It was because that when the pHs range of 3.0-7.0,the hydrophobic interaction between myofibrillar protein particles is the main driving force for the fibrous structure.When the pH value ranges from 9.0 to 11.0,electrostatic repulsion is the main reason for the formation of irregular granular aggregation of myofibrillar particles.2.Myofibrillar particles with different pH values were used as stabilizers and olive oil as the oil phase to prepare HIPEs.The appearances,morphology,storage stability,heating stability,freeze-thaw stability were investigated.The emulsifying effect of the stabilizer on different oil phases(corn oil,soybean oil,sunflower oil and n-hexane)was analyzed.The results showed that the HIPEs stabilized by myofibrillar protein particles could keep stable for more than 60 days and had good thermal stability and freeze-thaw stability.The microstructure observation showed that the droplets were closely connected with each other and had strong 3-D network structure which maintaining the stability of the emulsion.Moreover,myofibrin granules can form stable HIPEs with all oil phases,which is an excellent HIPEs stabilizer.3.HIPEs with olive oil,corn oil and soybean oil were prepared with myofibrillar protein particles as stabilizer.The appearance,rheological properties,antioxidant properties and digestive properties of these emulsions were further investigated.The results showed that compared with HIPEs of corn oil and HIPEs of soybean oil,HIPEs prepared by olive oil had the best viscoelasticity.In addition,olive oil and HIPEs prepared by olive oil showed good antioxidant stability,because olive oil contains more types and proportions of trace beneficial components such as polyphenol tocopherol.As for corn oil and soybean oil,compared with the control group,myofibrin granules stabilized HIPEs with better antioxidant properties,indicating that HIPEs can delay the lipid oxidation of corn oil and soybean oil to a certain extent.During the process of digestion,the degree of oil hydrolysis of HIPEs was lower than that of the control group.These results indicate that HIPEs system has the property of slowing down lipid hydrolysis.4.HIPEs prepared by meat particles and olive oil were used as the carrier for pueraein,β-carotena,mixture of puerarin and β-carotene.To explore strategies for improve the bioaccessibility of puerarin in vitro simulated digestion.(1)Loading the puerarin with HIPEs stabilized by myofibrillar protein particles;(2)Using HIPEs co-loading puerarin and β-carotene.The results showed that both strategies could improve the bioaccessibility of puerarin.When puerarin was simply dissolved in olive oil,its bioaccessibility was only 8.78%,while when it was located in HIPEs;the bioaccessibility of puerarin was increased to 62.69%.Moreover,the second strategy was significantly better than the first strategy,and the bioaccessibility of puerarin was improved to 85.17% after co-embedding.This result has certain reference value for developing functional food. |
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