Protein isolates were prepared from cold-pressed pumpkin seed cakes using alkaline solubilization and acid precipitation. Response surface methodology was used to optimize extraction conditions to obtain maximum extraction efifciency. The optimum conditions for protein extraction were found to be extraction at 50℃for 22.5 min with a solid-to-solvent ratio of 1:12 (g/mL). Under these conditions, the average recovery of total solids was 23.92%and the protein isolates contained 86.48%protein (wet basis;9.31%water content). Analysis of physiochemical and functional properties showed that the crude protein extract had excellent processing properties. Especially, it was found that its water-holding and oil-binding capacities were higher than those of soybean protein isolate and varied very signiifcantly with concentration and heating time. The emulsifying capacity of the crude protein extract increased with increasing concentration, whereas its emulsion stability dramatically decreased at a concentration of 5%. The two parameters indicated highly signiifcant variations with protein concentration and exhibited a general upward trend with increasing protein concentration. This extract revealed an increasing trend in foaming capacity but almost no changes in foam stability with increasing concentration.%以冷榨南瓜子饼粕为原料，采用碱溶酸沉法提取其中的蛋白质，分析pH值、料液比、提取温度、提取时间等单因素对提取率的影响，用响应曲面法优化工艺条件，得到冷榨南瓜子油饼蛋白质提取最佳工艺：料液比1：12(g/mL)、提取温度50℃、提取时间22.5min。在此工艺条件下，饼中蛋白质粉的平均提取率为23.92%，蛋白质质量分数86.48%(湿基，蛋白粉水分质量分数为9.31%)。对提取出的蛋白粉进行各种理化及功能性分析，结果表明：提取的冷榨南瓜子蛋白粉具有良好的加工性能，特别是持水能力和持油能力，均高于大豆分离蛋白。且随着蛋白溶液浓度和加热时间的变化，其持水及持油力的变化极显著；乳化性随着蛋白质溶液浓度的升高而升高，而乳化稳定性在蛋白质质量分数5%时出现明显下降，两者数值均随蛋白质溶液质量分数的变化有极显著差异，但整体也随蛋白质质量分数的升高而升高；起泡性随蛋白质质量分数升高而增大，泡沫稳定性几乎不随蛋白质质量分数变化。
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