对灰树花多糖提取副产物中的蛋白进行了分离、酶解多肽和部分功能性质研究。采用5.0 ku膜超滤分离灰树花多糖醇沉上清液中的蛋白，测定其氨基酸组成和营养评价；蛋白经酶解和二次超滤得多肽，分析比较了分离蛋白和酶解多肽的溶解性、起泡性和抗氧化等功能性质。结果显示：超滤能够有效地实现蛋白质的分离纯化，分离后的蛋白纯度可达70.24%，得率7.26%，必需氨基酸/总氨基酸（EAA/TAA）为40.5%，必需氨基酸/非必须氨基酸（EAA/NEAA）为68.0 %，是一种优质食用蛋白。分离蛋白经三种蛋白酶酶解后均能显著增强溶解性和抗氧化性，其中木瓜蛋白酶的水解度最高（DH为8.94 %），其酶解多肽抗氧化效果也较好，对DPPH?、ABTS+、羟基自由基的最高清除率分别达到65.78%、98.95%、66.14%，而分离蛋白仅为44.01%、72.74%、50.88%。

Proteins in the by-products of Grifola frondosa polysaccharides extraction were isolated and their functional properties were studied. Proteins in the supernatant obtained after ethanol precipitation of Grifola frondosa polysaccharide extract were isolated by ultrafiltration membrane with a molecular weight cut-off of 5.0 ku. Polypeptides were obtained by enzymolysis and secondary ultrafiltration of the isolated protein. Functional properties of the polypeptides and proteins, including solubility, foaming capacity, and antioxidant activities,were analyzed and compared. The results indicated that ultrafiltration could effectively isolate and purify the protein, with a purity of 70.24% and a yield of 7.26%. The isolated protein was found to be a high-quality edible protein, with essential amino acids/total amino acids (EAA/TAA) and nonessential amino acids/total amino acids (EAA/NEAA) values of 40.5% and 68.0%, respectively. The solubility and antioxidant activities of the isolated protein were significantly increased after enzymolysis by each enzyme tested. Of these enzymes, papain yielded the highest degree of hydrolysis (DH = 8.94%). The polypeptide showed relatively good antioxidant activities, with scavenging rates for hydroxyl radical (?OH), 2,2-diphenyl-1-picrylhydrazyl (DPPH?), and [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS)? + free radical, of 66.14%, 65.78%, and 98.95%, respectively, while those of the isolated protein were 50.88%, 44.01%, and 72.74%, respectively.

国家科技支撑计划项目（2013BAD16B07）；浙江省自然科学基金项目（LY13200011）