Preparation Of Sodium Caseinate Compound Cellulose-Glyceride Emulsion And Its Gelation On Yogurt

Glyceride(Diglyceride,DAG)is a kind of multifunctional oil prepared from edible oil,which has the functions of losing weight,lowering blood lipid and resisting arteriosclerosis.Because of its easy oxidation in air,low melting point,poor fluidity and poor storage performance,more and more researchers have solved the problem by preparing nanoemulsions.In this study,milk fat DAG was prepared from milk fat by enzymatic hydrolysis,and the preparation process of DAG nanoemulsion from sodium caseinate composite nanocellulose(SC-NCC)was optimized.The comparison of four different types of water-in-oil DAG emulsions were prepared from sodium caseinate(SC),nanocellulose(NCC),bran(OB)and casein composite bran(SC-OB).Explored the stability differences between them and prepared yoghurt as a fat substitute,which provided a reference for the preparation and product application of nanoemulsions.1.Optimization of preparation process of sodium caseinate composite nano cellulose diglyceride nanoemulsionSodium casein-glyceride nanoemulsion was prepared by high pressure homogenization method.The optimum preparation conditions of sodium caseinate composite nanocellulose-glyceride nanoemulsion were as follows:1.5% NCC content,1:1 core-wall ratio,5% SC content and 100 MPa homogenization pressure based on single factor experiment and response surface analysis.2.Properties and characterization of sodium caseinate composite nanocellulose diglyceride nanoemulsion The types,rheological properties,particle size,centrifugal stability,infrared spectrum and digestibility of five kinds of DAG nanoemulsion from sodium caseinate composite nanocellulose were studied.And four other groups of nanoemulsions were used as control.The results show that the nano-emulsions prepared are all oil-in-water type,SC-NCC nano-emulsion was pseudoplastic fluid,and the rest was Newtonian fluid.The emulsion potentials were all more than 30 m V and the particle size was 100-240 nm.Salt ion and PH have great influence on nano emulsion.The infrared spectra of five kinds of nano-emulsions showed that the addition of nano-cellulose and bran did not produce chemical reaction with casein,but only physical adsorption and entanglement between macromolecules.The simulated gastrointestinal digestion results show that the release rate of free fatty acid in nano-emulsion added with NCC was the fastest,and nano-emulsion with small particle size was easier to digest and absorb.SC-NCC nanoemulsion has obvious shell-core structure and good coating effect.Fluorescence spectrum analysis showed that sodium caseinate,nanocellulose and milk fat diglyceride were combined by non-covalent bond.3.The effect of sodium caseinate composite nanocellulose diglyceride nanoemulsion on yogurt gel Rheological analysis was carried out on yogurt products added with SC-NCC nanoemulsion.Acidity,water holding capacity,texture and sensory evaluation of yogurt samples were determined.The results showed that with the increase of DAG emulsion dosage,the viscosity of yogurt changed,and the acidity had no obvious difference.The water holding capacity increased first and then decreased.The sensory score of the sample with the dosage of 2g was higher than that of other groups.