Preparation,Emulsifying Ability And Application Of Octenyl Succinate Gum Arabic In Custard Sauce

Octenyl succinate gum arabic is made by esterification reaction between gum arabic and octenyl succinic anhydride.It is a component with high emulsifying ability.Which has been extensive application in the field of food and pharmaceuticals industries in foreign countries.In this thesis,gum arabic from the Acacia seyal tree species was used as the hydroxy donor to prepare octenyl succinate gum Arabic.And its structural and functional properties were analyzed.The emulsifying ability under different environmental stress conditions(temperature,ionic concentration,p H)and in vitro digestive properties of octenyl succinate arabic gum were compared to commonly used emulsifiers in food processing.Octenyl succinate arabic gum exhibited good emulsifying properties and can decrease the digestion rate of lipid in the emulsion.Finally,octenyl succinate gum arabic was applied inpreparation of custard sauce which used as an ingredient to replace the expensive emulsifier in the original custard sauce without affecting the quality of the sauce and improving its baking resistance.This study would provide important information for the application of octenyl succinate arabic gum in low-cost and high-temperature resistant custard sauce development.The main conclusions of this article are as follows:(1)Preparation and characterization of octenyl succinate gum arabicOctenyl succinate gum arabic was prepared based on acacia seyal gum arabic and octenyl succinic anhydride as raw materials by a wet method by.The degree of substitution of the sample was 0.020,and the degree of acid anhydride grafting was1.602%.The structure of prepared sample showed that the substitution reaction between octenyl succinic anhydride and gum arabic successfully occurred by FT-IR analysis and X-ray diffraction.The anhydride structure was successfully linked with gum arabic molecules through ester bonds without change of original molecular crystal state,still arrange as amorphous status,during the esterification reaction via X-rays diffraction analysis.The HLB value of octenyl succinate gum arabic is 12.99calculated by Davies formula,which is suitable for oil-in-water emulsions formation.After the esterification modification,the hydrophobic group was successfully grafted into GA molecules without changing its molecular structure,while the hydrophilic and lipophilic properties of GA were improved.The changing in interfacial tension of octenyl succinate arabic gum was similar to that of whey protein and octenyl succinate sodium starch.The tension value decreased with the increase of time indicating that OSA-GA possess interfacial emulsification properties and can reduce the free energy of oil-water interface.(2)Study on the influence of environmental stress factors on the stability of emulsionThe amphiphilic properties and emulsifying ability of gum arabic was significantly enhanced via estification with hydrophobic octenyl succinic anhydride.By comparing with O/W emulsions stabilized by whey protein and sodium starch octenyl succinate,it is found that the emulsification activity index of octenyl succinate arabinate is the highest while its emulsification stability is slightly lower than whey protein.The concentration of whey protein,octenyl succinate gum arabic,and octenyl succinate sodium starch stabilized emulsion was 1.25±0.02 mg/m~2,2.58±0.15 mg/m~2and 4.96±0.57 mg/m~2respectively.The surface coverage of oil droplets in whey protein and octenyl succinate arabic gum was smaller which showed a larger oil-water interface and stronger emulsification ability considering their particle size.Compared with unmodified gum arabic,the modified gum arabic displayed a significantly higher emulsifying ability and could stabilize(20 wt%oil)emulsions at low concentrations.The particle size of the emulsion was smaller than 1?m;the zeta potential value was close to-30 m V,which is between whey protein emulsion and sodium starch octenyl succinate emulsion.The octenyl succinate gum arabic ester exhibited good tolerance against different p H,salt ionic concentration,and heating temperature without significant stratificaiton.All emulsions showed shear thinning behavior which is characteristic of Newtonian fluids(3)Study on the properties of emulsions under simulated in vitro digestionIn vitro digestion studies of emulsions showed that whey protein and octenyl succinate acacia could effectively inhibit the accumulation of oil droplets in emulsion during oral digestion.In the digestion stage of the stomach,stratification occurred in the whey protein and starch sodium octenyl succinate stabilized emulsions.In the digestion stage of the small intestine,the release rate of fatty acid in whey protein stabilized emulsion was the fastest.The final lipid digestibility of octenyl succinate gum arabic and octenyl succinate sodium starch stabilized emulsions were both approximately 53%which effectively retarded the digestion of lipids in emulsions.(4)Study on the application of octenyl succinate gum arabic in Custard sauce preparationOctenly succinate arabic gum was replaced of original emulsifiers,namely whey protein and octenyl succinate starch sodium,and applized in custard the sauce.The properties of the new custard sauce were investigated and indicated a good freeze-thaw stability.The hardness value of new custard sauce was greater than that of original recipe sauce and without dehydration during storage.These results suggested that octenyl succinate arabic gum can be used as an emulsifier component in custard sauce.Sensory evaluation including color and other aspects showed that the custard sauce prepared by combination of octenyl succinate gum arabic and whey protein as emulsifiers possessed the highest score and the best performance.