EFFECT OF HIGH-PRESSURE HOMOGENIZATION ON THE FUNCTIONAL PROPERTY OF PEANUT PROTEIN

The effect of high-pressure homogenization (HPH) at 0.1 (control), 40 or 80 MPa on the denatured peanut protein were investigated. Solubility, emulsifying property, foaming property, differential scanning calorimetry (DSC) characteristic, water-holding capacity (WHC) and scanning electron microscope (SEM) analysis of the peanut protein isolates (PPIs) from the peanut flour after various HPH treatments were analyzed. Increased solubility of the denatured peanut protein by HPH treatment depended on the pH value. In the range of pH 4-7, the HPH-treated peanut protein exhibited a higher solubility than the non-HPH-treated protein, but the HPH treatment did not affect significantly the solubility in the range of pH 8-10. HPH treatment improved the emulsifying activity index (EAI) and foaming capacity (FC) but reduced the emulsifying stability index and foaming stability. In addition, HPH treatment markedly improved the WHC but slightly affected the DSC parameter. Based on the observation of SEM, many irregular fine crackles in the peanut protein after HPH treatment appeared, which showed that the treatment resulted in the change in the surface microstructure of the protein. These results indicated that the HPH treatment led to the modification of the microstructure of peanut protein and, thus, improved its functional properties such as EAI, FC and WHC.