Effects Of Oleogel Structuring Mechanisms On The Stability And Digestive Properties In Acer-truncatum-seed-oil Oleogels

Acer truncatum seed oil（ATSO）,as a new resource food in China,is rich in 4%to 6%of nervonic acid(NA,C24:1^Δ15).ATSO is a special nutritional oil and has great potential in the prevention and treatment of neurodegenerative diseases,such as Alzheimer’s Disease,so it has been sought after by consumers in recent years.However,ATSO has more than 90%of the unsaturated fatty acids which leads to the instability of ATSO.And the bioavailability of NA,the special nutraceutical fatty acid,is so necessary for ATSO nutritional properties.It is well known that oleogels can modulate the texture and digestive properties of liquid oils through the selection of oleogelators and their structuring mechanisms,and endow liquid oils with the ability to deliver a variety of nutrients.Therefore,this research constructed ATSO oleogels based on three kinds of oleogelators,and investigated their structure and properties.On this basis,the physical stability and in vitro digestion characteristics of ATSO oleogels were explored.Resveratrol（RES）was added to oleogels to explore its effect on the structure and properties of three kinds of oleogels.In addition,it was also studied the physical stability and in vitro digestion characteristics of three resveratrol-oleogel systems.Among them,the bioavailability of NA and RES was to evaluate whether construction of oleogels were suitable as a way to achieve the synergistic release of fatty acids and bioactive compounds.Finally,it would provide a theory and technical support for the realization of the design of personalized nutritional functional food.The main research contents and results were shown as follows:（1）Construction and properties of ATSO oleogels with different structure mechanismsATSO oleogels with three kinds of structure mechanisms were prepared based on oleogelators as followed:gelatin+xanthan gum,glycerol monolaurate andβ-sitosterol+lecithin.The gelation concentration was selected by the critical gelation concentration and oil binding capacity.And the relationship of oleogelators and oleogels was investigated by Fourier transform infrared spectroscopy（FTIR）,X-ray diffractometer（XRD）,polarized light microscope（PLM）,texture analyzer and thermo-rheometer.And the corresponding oleogels were recorded as GX8,GML8 and SL8 respectively.The results of the tests and analysis showed that the three groups of oleogelators had different structuring mechanisms.GX8 had a dense polymer network and showed a semi-crystalline state.GML8 was the oleogel constructed by crystalline particles and formedβcrystal andβ’crystal with a braid-like arrangement.SL8was the kind of oleogel which was assembled by self-assembled fibers and formedβcrystal,showing a fiber tubular arrangement.The main intermolecular driving force for the assembly of the three oleogels was hydrogen bonds.The hardness and mechanical strength showed the same trend:GX8>GML8>SL8.The rheological scanning results indicated that the structures of the three kinds of oleogels was not damaged at 37℃.In addition,GX8 had higher thermal stability and better thixotropic recovery because of its dense polymer network.（2）Effects of oleogel structuring mechanisms on the stability and digestive properties of ATSO oleogelsThe effect of different oleogel systems on protective effect of ATSO was explored by measuring the peroxide value（POV）and the level of thiobarbituric acid reactants（TBARS）.At the same time,the in vitro digestion model was established.And the total fatty acid release curve and release degree of the oleogels were monitored by p H endpoint mode.Moreover,the particle size during the digestion process was observed with a confocal laser scanning microscope（CLSM）and a laser particle sizer.GC-MS was used to quantitate all kinds of free fatty acids.It would be meaningful established the relationship between the oleogel structure and their digestive properties,and evaluated whether these three oleogels were suitable as a system for promoting NA release.The results represented all three kinds of ATSO oleogels had higher oxidative stability than the control group.However,compared with the GX8（polymer based oleogel）,the crystalline particle based oleogel（GML8）and the self-assembled fiber based oleogel（SL8）had better oxidation stability.The three kinds of oleogels could reduce irritation during gastric digestion.After intestinal digestion,the degree of total fatty acid（FFA）released in the order of GML8,GX8,SL8 and ATSO.All three kinds of oleogel systems increased the release of NA from ATSO,and GX8 had the most obvious promoting effect.The choice of structuring mechanisms is crucial to the lipolysis of oleogels.And gelation is a good way to promote the release of target fatty acids in liquid oil.（3）Influence of oleogel structuring mechanisms on the functional properties of ATSO oleogels containing resveratrolATSO oleogels with resveratrol were prepared,and then the microstructure and macroscopic properties of the oleogel were explored.Moreover,the oxidative stability of oleogel systems and the thermal stability of resveratrol were evaluated.Meanwhile,the bioavailability of NA and RES was determined by in vitro digestion experiments.It was hypothesized that oleogels could achieve a nutritional synergistic effect through rational design.Three kinds of ATSO oleogels with resveratrol（GX8-RES,GML8-RES and SL8-RES）were successfully constructed based on three groups of oleogelators.It was found that the addition of resveratrol did not significantly change the microstructure and macroscopic properties of ATSO oleogels.At the end of the storage period,the structure of oleogels could improve the oxidative stability of ATSO.Compared with GX8,GML8,and SL8,POV of GX8-RES,GML8-RES and SL8-RES were decreased by 19.39%,57.34%and 65.35%,respectively,and TBARS values were also significantly reduced.It was found that oleogel structures provided physical barrier to reduce RES decomposition during storage.Although all three ATSO oleogels promoted the release of NA,GX8-RES and GML8-RES could significantly improve the bioavailability of resveratrol.And GML8 was the most suitable as a system for the delivery system to enhance the nutritional synergistic effect of nervonic acid and resveratrol.In conclusion,personalized nutritious foods that meet needs could be created through the rational design of oleogels.The above results further explained the connection between the structuring mechanism and the function of oleogel,indicating that the oleogel could be precisely designed by studying the structuring mechanisms,so as to create oleogels that meet the dual needs of function and nutrition.Moreover,this research provided theoretical guidance and technical support for the design of double-effect food with functional and nutritional function based on oleogels.