Pumpkin seed meal prepared by hydraulic cold pressing and subcritical low temperature cyclic defat-ting was used as raw material.Alkali extraction and acid precipitation compound ultrafiltration circulating solvent method were used to prepare pumpkin seed protein isolate.The functional properties of pumpkin seed protein isolate and its differences with commercially available soybean protein isolate were investigated to provide references for the processing and utilization of pumpkin seed isolate protein.The results indicated that the pumpkin seed fraction pro-teins were dominated by glutenin and globulin,accounting for(44.27±1.85)％and(39.73±1.40)％,respec-tively,followed by albumin(15.16±3.83)％and alcohol soluble protein(0.84±0.35)％.The optimum extrac-tion conditions for pumpkin seed protein isolate were:pH of 10,material-to-liquid ratio of 1:40,temperature of 50 ℃,and time of 1.5 h.Compared with the traditional alkali extraction and acid precipitation method,the alkali extraction and acid precipitation compound ultrafiltration method(two solvent cycles)had no significant effect on the extraction rate and purity of pumpkin seed protein isolate,the amount of alkali was reduced by about 63％,the amount of acid was reduced by about 68％,and the amount of NaCl wastewater generated was reduced by about 82％,simplified follow-up processing,was a greener extraction process.SDS-PAGE indicated that the subunits of pumpkin seed protein isolate were mainly distributed around 19 and 35 ku,significantly different from the distribution of large substrates of soybean protein isolate;the water holding capacity of pumpkin seed protein isolate was signifi-cantly lower than that of soybean protein isolate,and the emulsification,foaming and foaming stability were slightly lower than those of soybean protein isolate,while the oil holding capacity and gel ability were much higher than those of soybean protein isolate,and the hardness and gelability properties of the gels were 5.4 and 10.2 times higher than those of the soybean protein isolate gels,respectively,indicating that pumpkin seed protein isolate has potential ap-plications in the construction of plant-based gel structures.
关键词
南瓜籽分离蛋白/循环溶剂/大豆分离蛋白/功能性质/凝胶性
Key words
pumpkin seed protein isolate/circulating solvent/soybean protein isolate/functional properties/gel a-bility
维普
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