番茄皮渣蛋白质提取及其性质表征

Extraction and characterization of protein from tomato peel waste

从番茄皮渣中提取蛋白质并对蛋白质进行了分析和性质表征。以番茄酱加工所得的番茄皮渣为原料,脱脂后在常温(25℃)下用pH 9.0的Na OH溶液按料液比1:20(g:m L)的比例提取0.5 h,蛋白质提取率达到约70%。所得蛋白质碱提液经过1 000 Da超滤膜超滤至完全脱除盐分同时,脱除了74.3%的色素。凯氏定氮分析显示,所提取样品中蛋白质含量为46%,元素分析(C、H、N、S)结果表明,样品中除蛋白质外存在碳水化合物,红外光谱结果也显示糖类物质的存在的可能性,因此推测所得蛋白质为糖蛋白。相比大豆分离蛋白,番茄皮渣蛋白质具有更好的起泡性和相当的乳化性,但其泡沫稳定性和乳化稳定性稍弱于大豆分离蛋白。

Tomato pulp protein was extracted and characterized. Tomato pulp is the waste of tomato source processing after defatting,and was extracted by p H 9. 0 Na OH at 25℃; the solid-to-liquid ratio was 1：20（ g：m L）,and yield was around 70%. Protein extract was then ultra-filtrated by a 1 000 Da membrane to remove salts,and meanwhile 74. 3% of the pigments were permeated. The protein content determined by Kjeldahl method was about 46%.Elemental analysis（ C,H,N,S） indicated the possibility of carbohydrates and it was further confirmed by FTIR（Fourier Transform infrared spectroscopy）. Therefore,the protein could be a glycoprotein. In comparison to soybean protein isolate,the tomato pulp protein showed better foaming ability and equivalent emulsion ability,but its foam stability and emulsion stability was weaker.