番茄皮渣蛋白质提取及其性质表征

摘要

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NaOH溶液按料液比1:20 (g:mL)的比例提取0.5h,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 pH 9.0 NaOH at 25℃;the solid-to-liquid ratio was 1∶20 (g∶ mL),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.