Effect of Protein Heat Treatment on Properties of Mung Bean Protein-High Acyl-Gellan Emulsion Gel

In this study, mung bean protein was heat-treated at 40, 55, 70, 85 and 100 ℃ for 15, 30, 45, 60 and 120 min, respectively. Mung bean protein-high acyl gellan gum emulsion gel was prepared and its hardness, water holding capacity, color, solubility, protein secondary structure and gel microstructure were studied analyzed to explore the influence of mung bean protein thermal denaturation on the properties of emulsion gel. Studies showed that with the increasing of heat treatment temperature and the extension of heat treatment time, the gel hardness and water holding capacity firstly increased and then decreased, and reached the maximum values at 85 ℃ and 30 min, which were 1403.91±12.05 N and 99.715%±0.022%, respectively. Heat treatment significantly reduced the gel brightness L^* (P<0.05) and increased the redness value a^*. The gel solubility results showed that hydrophobic bond and hydrogen bond were the important intermolecular forces to form the gel. With the increasing of heat treatment temperature and the extension of heat treatment time, the bonds forming the gel firstly increased and then decreased, and reached the maximum at 85 ℃ and 30 min. The hydrophobic bond and hydrogen bond concentrations were 10.87±0.02 mg/g and 4.03±0.02 mg/g, respectively. The relative content of gel secondary structure showed that the secondary structure of gel was significantly changed after heat treatment (P<0.05). The picture of the microstructure of the gel proved that the gel with high water holding capacity and hardness had a denser network structure. In summary, the heat treatment conditions of 85 ℃ and 30 min had the best effect on improving the gel properties. This research could be the theoretical basis for improving the performance of mung bean protein-high acyl gellan gum emulsion gel and further development.