大蒜加工废水中蛋白质的分离及其理化性质

Separation and Physicochemical Properties of Protein in Garlic Processing Wastewater

以大蒜加工过程中产生的废水为原料,采用膜过滤与酸沉相结合的方式制备大蒜废水蛋白,并对其分子质量分布、氨基酸组成、等电点及其它理化性质进行研究。结果表明:大蒜废水蛋白的分子质量主要在30 ku以上,采用分子质量为30 ku的滤膜可获得纯度72.11%的大蒜废水蛋白,其分子质量为31.9 ku和48.4 ku,由16种氨基酸组成,其中含有7种必需氨基酸,且甲硫氨酸是该蛋白的第1限制性氨基酸。大蒜废水蛋白的等电点为3.86。DSC分析确定大蒜废水蛋白的变性温度为73.2℃,热焓变ΔH为11.87 J/g。在适宜pH条件下,大蒜废水蛋白具有良好的溶解性、乳化性、乳化稳定性、起泡性和泡沫稳定性。

The extraction of protein from garlic processing wastewater by the membrane filtration and acid precipitation was optimized and the molecular weight,amino acid composition,isoelectric point and other physicochemical properties of the protein were also investigated.The results showed that the molecular weight of protein in garlic processing wastewater was mainly above 30 ku,so the purity of 72.11% protein was obtained from garlic wastewater by using 30 ku membrane.The molecular weight of the obtained protein was 31.9 ku and 48.4 ku,which contained seven essential amino acids.Methionine was the first limiting amino acid of the protein.The isoelectric point of the protein was approximately3.86.DSC analysis confirmed that denaturation temperature of the protein was 73.2 ℃,and denaturation enthalpy ΔH was11.87 J/g.At the appropriate pH,it had good solubility,emulsifying capacity,emulsion stability,foam capacity and foam stability.