Effect of pH Value on Gel Properties of Peanut Protein Extracted Using Water

The peanut protein was extracted using water, and the effect of pH on the heat-induced gel properties, such as gel hardness, water-holding capacity, dynamic rheological properties and gel force, and the structural properties, such as, surface hydrophobicity, free sulfydryl and fluorescence spectrum.The results showed that peanut protein gel had the greatest gel strength, water-holding capacity and storage modulus at pH 3. Under the conditions of neutral and alkaline, the highest strength, water holding capacity and storage modulus of the peanut protein gel were obtained at pH 8. The results of the solubility of peanut protein gel showed that hydrophobic interaction played the most important role in the formation of gel, and followed by the disulfide bond. From the structure properties of peanut protein, the highest surface hydrophobicity and free sulfydryl content of peanut protein were obtained at pH 3, and the intrinsic fluorescence spectrum has obviously bathochromic shift. While, under the conditions of neutral and alkaline, the strongest surface hydrophobicity and the highest content of free sulfydryl were obtained at pH 8.