Construction, Characterization And In Vitro Digestion Properties Of Gelatin-polyphenol-polysaccharide Ternary Complex Oil Gel

Oleogels can be used to increase the range of applications by adding lower mass fraction of gel molecules to realize the solid state of liquid oil,and it can also be used as a transport system for fat soluble substances.Studies on the interactions between proteins and polyphenols and proteins and polysaccharides have been reported,but the preparation and characterization of gelatin-polyphenol-polysaccharide ternary complex and its application in the preparation of oleogels,improvement of lipid stability and loading of fat-soluble substances need to be further explored.This study explore the gelatin-polyphenols-polysaccharide crosslinking regularity of ternary complexes and the preparation conditions,and complex oil-water interface properties and gel three-dimensional network structure characteristics of embedding chain triglycerides in the liquid,preparation and characterization of oil gel,and then discusses the gelatin-polyphenols-polysaccharide ternary oil gel in the stability of different digestion phase.Finally,the characteristics of bioactive substances under ternary oleogel loading were discussed,and the digestion stability of liposoluble substances under oleogel loading was evaluated by the bioaccessibility of rutin and resveratrol.The specific results are as follows.(1)Explore the cross-linking conditions and action rules of plant polyphenols and gelatin with amount of 0%-0.6% polyphenols,cross linking pH of 3-10 and gelatin concentration of1 %,and investigate the effects of four kinds of polyphenols(anthocyanins,tea polyphenols,gallic acid and proanthocyanidins)on the particle size,potential,turbidity and secondary structure of gelatin-polyphenols.The properties and network structure of the binary crosslinked complex were studied.The micronetwork structure and cold gel stability of the prepared polyphenol-gelatin(P-G)were better when 0.075% anthocyanins,tea polyphenols,gallic acid and procyanidins were added,and the gelatin-polyphenolic gel was the most stable at pH 8,and the sample structure was compact and complete after lyophilization.Optimized gelatin-polyphenols CD(circular dichroism spectra),UV(ultraviolet spectrum)and FTIR(Fourier transform infrared spectrum)results showed that tea polyphenols-gelatin and anthocyaninsgelatin crosslinking solution samples shows a more orderly secondary structure,and higher content of β-turn than separate gelatin protein structure.Under the condition of pH=8,0.075%tea polyphenols and anthocyanins can significantly improve the network structure of gelatin,increase the stability of gelatin,and enhance the stability of secondary structure of gelatin.(2)The gelatin(1%)-polyphenols(0.075%)-polysaccharides(0.25%)ternary complex gel was further cross-linked with polysaccharides(sodium alginate,flaxseed gum and fucoidin)and the above optimized gelatin-polyphenols(tea polyphenols/anthocyanins)binaries,and the oil gel was prepared by emulsion template method.Characterization analysis showed that the three contact angles of the ternary complexes were greater than 90°,significantly higher than that of gelatin(60°),gelatin-polyphenols and gelatin-polyphenol-alginate sodium,and the structural properties of the ternary complexes were significantly enhanced(hardness decreased,viscosity increased).Medium chain triglyceride(MCT)emulsion was prepared by using gelatin-polyphenol-polysaccharide(fucoidin and flaxseed gum)ternary compound gel.The characteristics of nuclear oil gel of ternary compound emulsion were investigated under the condition of 4:6 oil to water ratio.The results of particle size distribution,potential,SEM and CLSM confirmed that polyphenols and polysaccharides changed the structure and interfacial properties of gelatin,and the ternary complexes of gelatin-polyphenol-polysaccharide could significantly reduce the particle size of emulsion,reduce the aggregation of oil droplets,increase the stability of oleogel products and improve their texture characteristics.The oxidation products of anthocyanin oil gels at 70 ℃ were significantly lower than those of tea polyphenols.(3)The digestion stability of no-load emulsion and oleogel was compared and analyzed,and the effects of fat-soluble polyphenols resveratrol and rutin on gelatin-polyphenolpolysaccharide ternary emulsion and oleogel were investigated.It was found that polyphenols could delay the digestion process of oleogels,polysaccharides were important components to maintain the shape and stability of oleogels,and the digestion stability of gelatin-polyphenolpolysaccharide ternary oleogels was better than gelatin-polyphenols or gelatin-polyphenols.The digestive stability of anthocyanin series oil gels and their emulsions was significantly better than that of tea polyphenols.The results of loading rutin and resveratrol with fat soluble substances showed that the loading material could increase the emulsion particle size,improve the rheological properties,and increase the oil holding capacity of the oleogel.The loading rate,gastrointestinal stability and bioaccessibility of the gelatin-anthocyanidin-fucoidin composite to the fat-soluble polyphenols were higher than those of the gelatin-anthocyanidin-flaxseed gum composite.The ternary oil gel prepared by gelatin-anthocyanin-diatomaceous polysaccharide has excellent digestive stability and protective effect on bioactive substances.