The Preparation And Application Of Whey Protein Based Fat Replacer

This study was under the the financial support of National Twelfth Five-Year Grant(2013BAD18B07). With whey protein concentrate WPC80used as raw material, thisresearch adopted thermal modification to produce polymerized whey protein (PWP) andpolymerized whey protein with encapsulated fish oil (PWPFO). Applying the two fatreplacers respectively to low-fat yogurt and low-fat milk in order to observe theircharacteristics and how they affect the structure, apparent viscosity, rheological propertiesand sensory evaluation of low fat dairy products. The specific research conclusions are asfollows:(1) The optimal condition for whey protein gel is: whey protein concentration is10%,the pH value is8.5, and heated for30min at85℃, which promote whey protein gel in highcohesiveness, high viscosity, good elasticity state. The polymerized whey protein presentspseudoplastic within the shear rate of0~0.30s-1; The apparent viscosity shows a significantincreasing from the first day, but remain relatively stable from7thday to10thday; Inaddition to the adhesiveness significantly increased since first day and reached peak in the8thday, other texture indicators such as firmness, cohesiveness, elasticity have nosignificant changes (P＞0.05); There is84.8%of the particle size distribution on the rangeof1106±158nm, which is similar to fat particles which was in size of1μm in fermentedmilk.(2) Taking emulsification as reference, the homogenization at10Mpa and the heatingcondition of85℃for30min provide polymerized whey protein a good emulsification onfish oil, which shows stability within48h. The PWPFO has higher apparent viscosity,higher firmness, better adhesiveness (P <0.05) than PWP, and stored at4℃for3~10days,the cohesiveness of the PWPFO is slightly lower than the PWP, but the elasticity is almostthe same；In terms of rheological properties, the PWPFO has about10times apparentviscosity than the PWP, whose stress curve is approximately linear. The maximum shearstress of PWPFO is only as1%of the maximum shear stress of PWP.(3) PWP4is ultimately determined suitable for low fat in yogurt as fat replacers ataddition ratio of12%, which can prevent fat floating, reduce the fishy smell releasing, andpromote acceptability and strong palatability. When the PWP used as fat substitute in a replacement rate of75%, low-fat milk has viscosity, rheological curves and sensory scoresimilar to full fat milk.