| Summary: | 碩士 === 國立海洋大學 === 食品科學系碩士在職專班 === 90 === Whey protein concentrate (WPC) is one of the most available proteins for food processing. Its poor solubility, however has restricted its utilization. Hence, this research was designed by adding a serious of polyols, namely sorbitol, glycerol, propylene glycol and 2-propanol to understand their effects on improving the solubility of WPC suspension. The model can further provide information regarding to the role of different polyols as the solubility modifiers and their possible mechanisms to modify the gelling behaviors of whey proteins.
The addition propylene glycol or 2-propanol on WPC suspension can induce gel formation even at room temperature which can be prevented by controlling the addition rate.
The effect of increasing gel strength on WPC heat-set gel was depend on the decreasing denatured temperature and gel point of WPC suspension caused by adding hydrophobic-rich propylene glycol. For example, the deformation of WPC heat-set gel added with propylene glycol, which has similar molecular weight to glycerol, was increased. Even more, the deformation value was the biggest when 2-propanol was added in this system. At the same addition ratios, the breaking force of the heat-set gel added with propylene glycol was higher than adding glycerol and close to sorbitol.
Polyols containing multiple hydroxyl groups, such as sorbitol, will increase denatured temperature and gel point. The hardness was induced more by adding sorbitol than glycerol in WPC gel as a result of increased hydrogen bonding in the system.
In inclusion, the model showed that the addition effects of hydrophobic-rich polyols were opposite to hydroxyl-rich polyols. The former is not only a heat-destabilizing agent for WPC suspension which will decrease denatured temperature and gel point of WPC suspension but also a deformation-inducing agent which will increase breaking force and gel strength of heat-set WPC gel. However, the other is not only a heat-protection agent which will increase denatured temperature and gel point of WPC suspension but also a deformation-reducing agent of heat-set WPC gel. The gel strength of heat-set WPC gel increased as a result of especially increased hardness although the deformation will reduce in the system.
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