Abstract:In order to explore the conditions for foam separation of Cladophora protein，the recovery rate and enrichment ratio were used as indicators. Based on the single factor experiment，the response surface method was used to optimize the four factors of pH value，solid-to-liquid ratio，temperature，and liquid loading. The optimum conditions for the foam separation process of Cladophora protein were obtained as follows:solid-toliquid ratio of 5∶1 （g/L），liquid loading of 250 mL，temperature of 35 ℃，and pH of 4.9. Under these conditions，the recovery rate of Cladophora protein was 87.74%，and the enrichment ratio was 1.46. The maximum water holding capacity and oil holding capacity of the isolated Cladophora protein were 3.32 g/g and 9.27 g/g at 20 ℃ and 50 ℃，respectively. The emulsifying property and emulsion stability of Cladophora protein increased first and then decreased，and the best mass fraction was 1.0%. The foaming property and foam stability increased first and then decreased，and the best mass fraction was 0.8%. Fourier transform infrared and ultraviolet spectra showed that the Cladophora protein had characteristic absorption peaks at 230 nm and 280 nm，and the secondary structure β-turn accounted for the largest proportion of 33.48%. The total amount of amino acids in the protein was 422.453 mg/g，and the content of glutamic acid was the highest，accounting for 15.03%. The essential amino acids accounted for 31.35%，and hydrophobic amino acids accounted for 38.98%.