Effect And Mechanism Of Curcumin Nanoparticles On AGEs Generation In Casein-Lactose System During Thermal Treatment

Curcumin(Cur)is a very small molecular weight of fat soluble natural polyphenols,it has anti-inflammatory,antioxidant,anti-tumor,anti-atherosclerosis and other effects,in food,medicine,cosmetics and other fields have a wide range of applications.However,Cur is a kind of hydrophobic active substance,and the problems of poor water solubility,poor stability and low bioavailability seriously limit its application.In this study,Zein-fucoidan nanoparticles loaded with Cur(CZFNPs)were prepared by nanotechnology,which improved the solubility and stability of Cur.The effect and potential mechanism of Cur nanoparticles on the generation of Advanced glycation end-products(AGEs),which are associated with non-enzymatic glycation reactions,during the heat treatment of casein-lactose system were investigated.The specific research contents are as follows:Firstly,CZFNPs were prepared by reverse solvent precipitation method with Cur as core material,Zein and algae polysaccharide as wall material.The physical and chemical parameters of CZFNPs,such as microscopic morphology,average particle size,Zeta potential,chemical composition,stability and oxidation resistance,were characterized by transmission electron microscope,Malvern zeta potential laser particle size analyzer,UV-vis spectrophotometer and Fourier transform infrared spectrometer.The results showed that the surface of CZFNPs was smooth and spherical,the average particle size was about 162.7±1.90 nm,the embedding rate was 80.87%±2.25%,and the CZFNPS had good water solubility and dispersibility.The results of UV-VIS absorption spectrum and Fourier transform infrared spectrum confirmed that the Cur was successfully embedded in the nanoparticles,and the cur,Zein and the algae polysaccharides were combined through intermolecular hydrogen bonding,electrostatic interaction and hydrophobic interaction.In addition,after 60℃ and 48 h heat treatment,the release rate of CZFNPs reached 90.4%,the degradation rate of CZFNPs was 66.6%,and the degradation rate of CZFNPs reached 83.3%.Moreover,the scavenging rates of DPPH radical and ABTS radical in CZFNPS were significantly higher than those in the Cur group.The results showed that CZFNPs improved the thermal stability and oxidation resistance of Cur under heating conditions.Secondly,casein-lactose system was used to explore the effect and mechanism of CZFNPs on the generation of AGEs during heat treatment.The results showed that CZFNPs concentration of 16 μg/m L could significantly reduce the production of AGEs in the system.After CZFNPs was added into casein-lactose system,the contents of fructosamine,glyoxal and3-deoxyglucosalaldehyde decreased,while the contents of 5-hydroxymethylfurfural increased.Meanwhile,the results of gel electrophoresis of sodium dodecyl sulfate-polyacrylamide(SDS-PAGE)showed that CZFNPs could inhibit the hydrolysis of casein during heat treatment to a certain extent.Therefore,CZFNPs may inhibit the occurrence of non-enzymatic glycosylation in the casein-lactose system by inhibiting the formation of intermediates and inhibiting the hydrolysis or aggregation of casein,thus reducing the generation of AGEs.Finally,the effects of CZFNPs on the structure and properties of casein before and after heating were analyzed by means of fluorescence spectrophotometer,Fourier transform mid-infrared spectrometer,scanning electron microscope,differential scanning calorimeter,etc.,so as to further explore the mechanism of CZFNPs affecting the generation of AGEs in casein-lactose system during heat treatment.The results showed that the fluorescence of casein(CN)was quenched obviously when CZFNPs and free Cur were added into CN solution and heat treated.FTIR spectra showed that CZFNPs could reduce the effect of heat treatment on the secondary structure of CN,and this effect was closely related to both the shell(Zein-fucoidan nanoparticles,ZFNPs)and the core material(loaded Cur molecules).In addition,when CZFNPs and ZFNPs were mixed with CN,casein clusters or micelles were slightly less concentrated than those of free Cur,that is,the system was more stable after heating in the mixed solution of CZFNPs and ZFNPs.The DSC curve shows that the presence of ZFNPs does not change the thermal stability of CN during heating.However,CZFNPs and Cur reduced the denaturing temperatures of CN by 2.1℃ and 1.4℃,respectively,suggesting that CZFNPs,ZFNPs and Cur simply mixed with CN in solution,rather than binding with CN via covalent bonds.In conclusion,this study shows that CZFNPs can not only increase the water solubility and stability of the Cur,but also contribute to improving the antioxidant activity of the Cur during heat treatment,so that CZFNPs can effectively inhibit the formation of early and middle products of non-enzymatic glycosylation reaction in casein-lactose system,and finally inhibit the generation of AGEs.In addition,CZFNPs can also protect the secondary,tertiary and quaternary structure of casein through non-covalent bonding such as hydrogen bond and hydrophobic interaction,weaken the hydrolysis and crosslinking aggregation of casein during heat treatment,and increase the stability of casein,which may help to alleviate the degree of CN participating in non-enzymatic glycosylation reaction.The results of this study provide theoretical support for the research and development of novel AGEs inhibitors,and also have certain reference value for the application of nano delivery system in functional food and beverage.