| With the popularity of concept of "Healthy China" deep into the hearts of people,functional food and nutrient supplements have become an indispensable part of the daily diet,and the efficient delivery of bioactive molecules is the key to ensuring the normal functioning of human body and improving immunity.As a natural polymer material,protein can be applied to the delivery system of liposoluble bioactive molecules,which not only can provide nutrition to the human body,but also can effectively improve the solubility,stability and bioavailability of active molecules.In this study,natural rice protein was used as raw material,and nanocarriers were prepared by trypsin digestion.Besides,the liposoluble bioactive molecule lutein was used as the embedding object and the food colloid delivery system of lutein was successfully constructed.In addition,protein-based lutein nanoparticles were optimized and we explored the formation mechanism and pathways of the nanoparticles.Based on the interaction between rice protein hydrolysates and lutein,sodium carboxymethyl cellulose(CMC)was added for structural modification and regulation.The main findings are as follows:1.Three kinds of rice protein hydrolysates with different degrees of hydrolysis were prepared from natural rice protein,and the effects of hydrolysis degree on their structural and functional properties and antioxidant properties in vitro were investigated.Taking the natural rice protein as a control,the results showed that the secondary structure of the rice protein hydrolysates were more flexible and stretched,the solubility and emulsifying properties were greatly improved and the enzymatic hydrolysates had a more porous structure.Moderate hydrolysis can increase the stability but excessive hydrolysis may result in the destruction of the structure of rice protein.Compared with rice protein,the enzymatic hydrolysis process greatly enhances its antioxidant activity in vitro.The change of surface hydrophobicity and sulfhydryl content means that the enzymatic hydrolysates were more easily combined with bioactive molecules by non-covalent interaction.2.Three kinds of rice protein hydrolysates with different degrees of hydrolysis were used as nano-delivery carriers and protein-based lutein-loaded nanoparticles were prepared by anti-solvent method.The final optimized carrier concentration was 5 mg/mL and the lutein concentration was 1.25 mg/mL.Under the optimized conditions,the encapsulation efficiency of lutein nanoparticles(Lut-LRPH,Lut-MRPH and Lut-HRPH)entrained by low,medium and high hydrolysis degree of rice protein were 94.07%,89.77% and 90.52%,the loading capacity is 23.52%,22.44% and 22.63%,respectively.The microstructure of nanoparticles was observed by transmission electron microscopy(TEM),and the formation mechanism of nanoparticles was described by the interaction of lutein and rice protein hydrolysates.The experimental results confirmed that the rice protein hydrolysates can be used as carriers to develop lutein-loaded nanoparticles with simple process and green safe materials,which will provide valuable information for the future delivery of nutrient fortified foods,supplements and drugs.3.The results showed that the CMC modification of nanoparticles(Lut-R-C)can effectively protect the lutein and resist the interference of external environment,the stability and in vitro release and inhibiting tumor cell proliferation and promoting cell absorption has a unique advantage.Based on the previous research,the CMC was added to modify and regulate the protein-based lutein-loaded nanoparticles(Lut-R).It was found that the CMC-modified nanoparticles(Lut-R-C)can effectively protect lutein and resist external environmental interference,and it had unique advantages in stability,in vitro release,inhibition of tumor cell proliferation,and promotion of cellular uptake. |
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