Investigation of functional properties of protein co-precipitates extracted from pomegranate and grape seeds

The protein co-precipitate is an economical method to produce high-protein foods with appropriate functional properties.Grape and pomegranate seeds are useful sources of protein as food waste. The efficient utilization of waste to produce high-value food products reduces the costs waste disposal in the food industry. In this study,the functional properties of grape and pomegranate seeds protein co-precipitated were investigated at 40, 55 and 75% ammonium sulfate. Finally, 55% saturation of ammonium sulfate was selected according to the results of electrophoresis. The functional properties of produced proteins including emulsion activity, emulsion stability, oil and water holding capacity, solubility and viscosity of the samples were investigated. The results showed that the highest solubility of supernatant protein and pellet protein was obtained at pH = 6 and pH = 12, and the emulsion activity of supernatant and pellet were 4.95- 13.37 m2/g and 8.84-16.83 m2/g, respectively.Also, the emulsion stability of the supernatant proteins was 15.60- 23.59 min, and the emulsion stability of the pellet grape-pomegranate co-precipitated proteins was 17.74- 39.91 min. The results showed that the proteins in the pellet had higher water holding capacity (1.68 g) than the supernatant proteins (0.24 g).