亚麻籽蛋白特性及营养价值分析

Physicochemical and Functional Properties and Nutritional Value of Flaxseed Protein

以脱壳亚麻仁为原料,除油后使用碱溶酸沉法提取蛋白质,并对其物理特性与营养价值进行分析。结果表明,该方法所得提取物中蛋白质质量分数高达98.86%,十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示位于21 kDa和33 kDa处的谱带最为强烈,高效液相色谱-串联质谱分析结果显示该混合蛋白含有11种已报道的亚麻籽源蛋白成分,其等电点约4.0,随着碱性增强溶解度不断升高。氨基酸组成分析检测到17种氨基酸,其中含有多种必需氨基酸;同质量蛋白的持油量是持水量的5倍多,同时具有较高的乳化活性,但乳化稳定性稍差。蛋白二级结构稳定性一般,但热稳定性良好,可适用于工业热加工处理。从亚麻籽蛋白集中分布区域——亚麻仁中提取蛋白质,为亚麻籽分区域高效利用提供了新见解,并通过对提取物的一级结构解析和在线酶解证实了其潜在的营养价值,同时各表征结果为实现亚麻籽蛋白的高附加值利用提供了有力的理论支撑。

Although cold-pressed flaxseed meal is rich in protein,it is mainly used as animal feed or discarded,resulting in a serious waste of resource.In this study,protein was extracted from flaxseed meal by alkali dissolution followed by acid precipitation,and its physical properties and nutritional value were evaluated.The results demonstrated that the protein content of the extract was as high as 98.86%.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)analysis showed the darkest bands at 21 and 33 kDa.A total of 11 flaxseed proteins reported in the literature were identified in the protein by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS),and the isoelectric point(pI)of the protein was located around at pH 4.0.A total of 17 amino acids including many essential ones were detected in the protein using an automatic amino acid analyzer.The oil-binding capacity of the protein was more than five times as large as its water-holding capacity.Moreover,the protein exhibited high emulsification activity,but its emulsion stability was slightly poor.The stability of the secondary structure was moderate,but it had good thermal stability.