Characterization of decolorized Chlorella pyrenoidosa protein foaming solution and its application in foam coffee

Chlorella pyrenoidosa protein (CPP) possesses superior emulsification and foaming capabilities, enabling its solution to replace milk as a foaming agent in coffee products. However, its application, is constrained by the obvious pigmentation and suboptimal foam stability. To achieve this goal, ethanol decolorization and saponin (Tea saponin (Ts), Gypenoside (Gyp)) complexation were employed to prepare decolorized Chlorella pyrenoidosa protein (DCPP) foaming solution. The interfacial properties, rheological properties, and foam properties were characterized. Initially, compared with the CPP solution, the DCPP solution exhibited a lower surface tension, an 80.52% increase in contact angle, and its emulsifying activity index (EAI) was increased by 26.58%. After ethanol decolorization and Ts or Gyp addition, foaming capacity of CPP increased by 491.31% and its foam stability enhanced by 136.80%. Furthermore, DCPP-Ts achieved the highest sensory acceptability in application of coffee. This study could provide technical support for developing plant-based coffee foaming agents in the food industry.