| Fucoxanthin(FX)has various biological activities,such as antioxidant,anti-obesity and anti-inflammatory,and prevention or treatment of chronic diseases.However,its insolubility in water,poor stability and low bioavailability limit its application as a nutritional supplement in the food industry.Considering that the protein delivery system has good water dispersion and biocompatibility,as well as carotenoid absorption of dietary lipids.Therefore,this study aimed to construct an innovative fatty acid-protein delivery vehicle,while improving the stability of processing digestion and intestinal absorption efficiency of FX.In this study,we investigated the effect of fatty acid introduction into the delivery system on improving the intestinal absorption of FX,and preliminarily explored the mechanism of the delivery system to promote the intestinal absorption of FX through the lipid transporter delivery pathway.The main findings are as follows:Study on the encapsulation of FX by modified zein and their thermal processing stability.The dry maillard reaction was used to modify the structure of zein with glucose and improve its hydrophilicity.The results showed that the grafting degree of modified zein(MZ)showed an increasing and then decreasing trend with increasing reaction time(12 h-84 h),reaching the highest value(50.84%)at the reaction time of 48 h.Compared with the natural zein,the isoelectric point and water contact angle of MZ both showed different degrees of decrease.The p H-driven method was used to construct the MZ-FX aqueous dispersion system,and the particle size of the complexes ranged from 200.0 nm to 250.0 nm,the polymer dispersity index(PDI)was < 0.3,and the absolute value of the zeta-potential was > 30.0 m V,and the system was homogeneous and stable.The encapsulation efficiency of FX by MZ with different grafting degrees was > 80.0%,and the encapsulation efficiency of FX by MZ with 50.84% grafting degree was as high as 96.50%.The thermal stability experiments showed that the encapsulation effect of MZ significantly improved the thermal stability of FX,and the retention of FX under simulated pasteurized and steaming processed conditions was 91.21% and 85.84%,respectively.Characterization of MZ-FAs-FX micelles and their improvement on the gastrointestinal digestive stability of FX.Combined with the results of previous studies results of our research group,the FAs with good absorption-promoting effects on FX were selected: myristic acid(MA),palmitic acid(PA)and stearic acid(SA).MZ-FAs micelles were prepared by p H-driven method.The optimal conditions were protein concentration of 3.00 mg/m L,p H of 11.0-p H 7.0(p H cycling),MZ/FA mass ratio of 40∶1.The obtained size of MZ-FAs-FX micelles ranged from200.0 nm ～ 230.0 nm,PDI ranged from 0.1 to 0.4,and the absolute values of zeta-potential >30.0 m V,with uniform particle size distribution.Transmission electron microscopy showed that the surfaces of MZ-FAs-FX were smooth and had a typical "core-shell" structure.Infrared spectrum analysis showed that MZ-FAs micelles successfully encapsulated FX in the hydrophobic core,and the encapsulation efficiency reached over 98.00%.The simulated gastrointestinal digestion results showed that the introduction of FA significantly increased the micellization rate of FX from 43.00% to more than 60.00% compared with the MZ delivery system without FA.Effects of different MZ-FAs micelles on FX absorption and lipid transporters-mediated trans-intestinal epithelial pathway study.Single gavage experiments in mice showed that MA,PA and SA significantly increased intestinal fatty acid binding protein(i FABP),ATP-binding cassette member 1(ABCA1),Cluster Determinant 36(CD36),and Scavenger Receptor class B type 1(SR-B1),and the effects were PA > MA > SA,while Arachidonic acid(AA)had no significant effect on these lipid transporters and even inhibited the Niemann-Pick C1-Like1(NPC1L1)in cells.When the above four fatty acids were introduced into the MZ delivery system,respectively,oral MZ-SA-FX micelle promoted the expression of lipid transporters more compared with the MZ-FX group.And the expressions of i FABP,ABCA1,CD36 and SR-B1 were respectively increased by 86.39%,107.92%,100.32% and 309.22% compared with the MZ-FX group;followed by MZ-PA-FX micelle,the expression of these lipid transporters was increased by 24.75%,27.26%,25.02% and 94.53%,respectively,compared to that in the MZ-FX group.Oral administration of MZ-MA-FX micelle only upregulated the expression level of SR-B1 by 27.55% compared to the MZ-FX group.In contrast,MZ-AA-FX micelle had no significant effect on these lipid transporters,and even showed a down-regulation effect.Meanwhile,single-dose oral administration of MZ-MA-FX micelle,MZ-PA-FX micelle and MZ-SA-FX micelle could increase the total response values of FX metabolites in mouse serum,while MZ-AA-FX micelle decreased the total response values,and similar results were obtained in liver and eye tissues.The above results suggest that fatty acids can regulate the intestinal absorption of FX through the lipid transporter delivery pathway,and the efficient nutritional delivery of FX can be achieved by constructing MZ-FAs delivery vehicles. |
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