杏鲍菇分离蛋白和清蛋白的理化性质及功能分析

Physicochemical and Functional Properties of Pleurotus eryngii Protein Isolate and Albumin

以杏鲍菇为原料,分别利用碱溶酸沉法提取杏鲍菇分离蛋白(Pleurotus eryngii protein isolate,PEPI)、Osborne法分离主要蛋白组分,并研究其理化性质和功能分析。结果表明,杏鲍菇的蛋白质量分数为17.57%(以干质量计),以杏鲍菇清蛋白(Pleurotus eryngii albumin,PEA)为主,占总分离蛋白组分的81.12%。PEPI和PEA中均含18种氨基酸,且必需氨基酸含量分别占总氨基酸含量的40.80%和40.51%。与PEPI相比,PEA的表面疏水性(265.25)显著高于PEPI(164.27)(P<0.05),而总巯基、二硫键含量较低,分别为61.53μmol/g和10.39μmol/g;热变性温度(100.98℃)低于PEPI(108.27℃),且PEA持水性(1.64 m L/g)、持油性(5.59 m L/g)显著低于PEPI(3.58、8.36 m L/g)(P<0.05)。PEPI和PEA的溶解性、起泡性、泡沫稳定性、乳化性及乳化稳定性随p H值的变化趋势均相似,在等电点时均为最低。傅里叶变换红外光谱显示PEPI和PEA的二级结构主要是β-折叠和β-转角,扫描电镜观察PEPI呈蜂巢结构。相比PEA,PEPI具有更好的理化性质和功能特性。

Protein isolate(PEPI)was extracted from Pleurotus eryngii by alkali dissolution followed by acid precipitation and the major protein components were isolated by the Osborne method.Their physicochemical and functional properties were studied.Results showed that the protein content of P.eryngii was 17.57%(dry mass),and the mainly protein fraction was albumin(PEA),accounting for 81.12%of the total protein isolate.Both PEPI and PEA contained 18 amino acids with essential amino acids accounting for 40.80%and 40.51%of the total,respectively.The surface hydrophobicity of PEA(265.25)was significantly higher compared to that of PEPI(164.27)(P<0.05),while the contents of total sulfhydryl group and disulfide bonds were lower,which were 61.53 and 10.39μmol/g,respectively.The thermal denaturation temperature of PEA(100.98℃)was lower than that of PEPI(108.27℃)and water holding capacity(1.64 mL/g)and oil holding capacity(5.59 mL/g)were significantly lower than those of PEPI(3.58 and 8.36 mL/g)(P<0.05).The solubility,foaming capacity,foam stability,emulsifying property and emulsion stability of PEPI and PEA showed similar trend with pH,and were the lowest at pI.Fourier transform infrared spectroscopy(FTIR)showed that the secondary structures of PEPI and PEA consisted mainly ofβ-sheet andβ-turn.Scanning electron microscopy showed that PEPI possessed a honeycomb structure.Compared to PEA,PEPI exhibited better functional properties.