| Edible oils mainly consist of triglyceride and unsaponifiable substances,and unsaponifiable substances contain large amounts of beneficial phytochemicals,including,tocopherols(common phytochemical)and sesamol(special phytochemical),which have strong various health benefits.Meanwhile,the transportation,digestion and absorption of liposoluble substances in human body is a complex process,which often leads to the limitation in some models(in vitro antioxidation activity and cell antioxidation activity model)for the evaluation of phytochemicals.Commonly used solution is to obtain a complete biological model.C.elegans,an intact organism,is an ideal model for studying lipid accumulation and in vivo antioxidant activity.However,the application of Caenorhabditis elegans(C.elegans)in the evaluation of lipid nutrition is limited by its water-soluble culture.Emulsion embedding is usually used to solve this problem,moreover,the stability of the emulsion will affect its subsequent functional study.Therefore,tocopherols and sesamol were embedded in protein emulsion and delivered into C.elegans.Their stability was evaluated firstly,then the effect of fatty acid composition on the lipid-lowering and in vivo antioxidant activities of tocopherol and sesamol were investigated.The main content are as follows:Firstly,oil-water emulsion was prepared based on protein emulsion embedding technology,and a delivery method for fat-soluble components based on C.elegans was established.The bioaccumulation of curcumin(a standard component for model built)in C.elegans was studied by semi-quantitative analysis using the fluorescence characteristics of curcumin under FITC channel.The results showed that when the oil saturation was similar,and the curcumin bioaccumulation: palm oil > coconut oil ? medium long carbon chain triglyceride(MCT);when the oil carbon chain length was similar,the curcumin bioaccumulation: soybean oil > flaxseed oil > olive oil.The fatty acid composition affected the lipid-lowering effect of curcumin.Compared with the control group,the lipid accumulation of the treatment groups was decreased by 33.70% and 47.19%,respectively.C.elegans can absorb and utilize curcumin,which can be used as a new model to study the biological activity of liposoluble components.Secondly,O/W emulsions with average particle size of 200~300nm were prepared by high pressure homogenization,and DPPH scavenging experiment in vitro was used to determine the appropriate amount of the addition.The effects of oil composition on the physical and chemical stability of emulsions during storage were investigated for the following biological activity investigation.The results showed that there were no significant changes in particle size,PDI and Zeta potential of the emulsion during storage(p<0.05).The distribution of lipid droplets was uneven and flocculated in the level of microstructure at the end of incubation.The composition of oil and fat had a significant effect on the oxidation stability of O/W emulsion.The higher the degree of unsaturation of oil,the higher the content of lipid oxidation products in the emulsion were detected.Tocopherol and sesamol can significantly reduce the degree of lipid oxidation of the emulsion(p<0.05),hydrogen peroxide products and thiobarbituric acid(TBARS)were decreased by 23.8% and 57.7%,respectively(linseed oil group,day 7).The stability of the prepared emulsion was good,and could be used for further research of the biological activity.Finally,the effects of different emulsions on the in vivo antioxidant activity and lipid lowering effect of fat-soluble component(tocopherols and sesamol)were investigated using C.elegans model.The changes of growth condition and swallowing of C.elegans were also recorded.Feeding emulsion can change the fatty acid composition of C.elegans.Tocopherol and sesamol can reduce the relative total lipid content of C.elegans,and the effect might be related to the composition of lipid in C.elegans,the relative total lipid content in soybean and palm oil group were lowered by 56.12% and 36.81%.However,the emulsion with different lipid composition had no significant effect on the movement,growth and swallowing frequency of C.elegans(p>0.05).The fatty acid composition of emulsions influenced the antioxidant activity of the phytochemicals,and the tocopherols and sesamol in the linseed oil,soybean oil and palm oil groups had better antioxidant activity.Compared with control group,the levels of MDA in the linseed oil-sesamol group were decreased by 17.55%,and the capacity of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GSH-px)were increased by 83.42%,97.51% and 78.53% respectively.To sum up,in this paper,a model for fat-soluble component was established to evaluate the lipid composition of C.elegans,and the effect of lipid composition on the in vivo antioxidant activity and lipid-lowering effect of the phytochemicals was evaluated using C.elegans considering its potential application as a functional food. |
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