Preliminary Study On The Preparation And Application Of Ultrasonic-assisted Whey Protein-sodium Alginate Fat Simulant

The problem of obesity caused by excessive intake of fat has affected hu man health,and in recent years,people have been looking for suitable fat subs titutes to reduce the presence of fat in food.In this paper,whey protein(WPI)and sodium alginate(SA)were used as raw materials to explore a new prepa ration method of fat replacer,and the influencing factors were explored.In this paper,the composite system was prepared by changing different conditions(wh ey protein concentration,temperature,whey protein-alginate ratio,etc.).The met hylene blue spectrophotometry,turbidity,particle size and other methods were u sed to evaluate the influence of different factors and determine the stable regio n of the composite system.Then the effect of high-intensity ultrasonic treatmen t on the stability of the composite system was studied,and its properties as a fat replacer were investigated.Mainly include:emulsifying,surface hydrophobicit y,potential,ultraviolet spectrum and so on.The sonicated composite system was added to skim milk and compared with non-defatted pure milk to explore the effects on the sensory and texture of the milk.The specific research results a re as fo lows:(1)During the preparation of whey protein-sodium alginate composite syst em,the turbidity of the composite system increased continuously with the incre ase of temperature,whey protein concentration,and whey protein-sodium algina te ratio;the turbidity of the composite system was higher near the isoelectric p oint of whey protein,and with the increase of pH,the turbidity decreased and remained stable.Particle size and methylene blue spectrophotometry showed th at when the whey protein concentration was 5 mg/mL,whey protein-sodium al ginate ratio was 4:1,60?,pH 7,the system had the smallest particle size,the most uniform distribution,and the most stable binding of protein and polysac charide.(2)By studying the effects of different ultrasonic time and power intensity on the composite system,it is concluded that certain conditions of ultrasoniccan promote the interaction of protein polysaccharides,increase the emulsificati on,surface hydrophobicity and potential of the system,and make the systemmore stable.The above indicators then decrease as the ultrasound time increasesand the ultrasound power increases.In addition,the turbidity and particle size of the system decrease first and then increase with the increase of ultrasonic p ower.The turning point is 45%ultrasonic power and 15 min ultrasonic time.(3)Fat replacer with different ultrasound conditions and different replacem ent rates have different effects on the texture and sensory properties of skim milk.As the ultrasonic intensity(ultrasonic power,ultrasonic time)increases,the elasticity and viscosity of skim milk gradually increase.It is worth noting that the increase in fat replacement rate can also improve the elasticity and hardne ss of skim milk.These conditions have significantly improved the elasticity and viscosity of skim milk,but have little effect on the hardness of skimmed mil k.At the same time,combined with the sensory evaluation of the color,smell,mouthfeel and tissue state of skim milk,the optimal fat replacement rate of f at mimics was finally determined to be 30%.