通过改良的Osboren法对脱脂椰子粉进行分级提取,得到清蛋白、球蛋白、醇溶蛋白和谷蛋白,并对4种椰子蛋白进行氨基酸组成分析和SDS-PAGE电泳分析。在单因素实验基础上,利用正交实验对4种椰子蛋白提取条件进行优化。结果表明,4种椰子蛋白最佳提取工艺条件为:在液料比10∶1、提取时间4 h、提取温度50℃条件下,清蛋白提取率为49. 05%,纯度为57. 1%;在液料比10∶1、提取时间4 h、提取温度50℃条件下,球蛋白提取率为46. 65%,纯度为70. 8%;在液料比10∶1、提取时间5 h、提取温度55℃、乙醇体积分数75%条件下,醇溶蛋白提取率为18. 01%,纯度为32. 7%;在液料比10∶1、提取时间4 h、提取温度50℃、碱溶p H 10. 0条件下,谷蛋白提取率为26. 78%,纯度为70. 4%。椰子清蛋白、球蛋白和谷蛋白中谷氨酸、精氨酸和天冬氨酸的含量明显高于其他氨基酸。除了清蛋白有2条谱带相对分子质量较大,其他3种椰子蛋白相对分子质量都相对较小,整体来说椰子蛋白是一种较为优质的蛋白质。
The defatted coconut powder was fractionated and extracted by modified Osboren method to obtain albumin,globulin,alcohol soluble protein and gluten,and their amino acid compositions and SDS-PAGE electrophoresis were analyzed.Based on single factor experiment,the preparation conditions of the four kinds of coconut proteins were optimized by orthogonal experiment.The results showed that the optimal preparation conditions of the four kinds of coconut proteins were obtained as follows:(1)ratio of liquid to material 10∶1,extraction time 4 h and extraction temperature 50℃for albumin,reaching 49.05%of extraction rate and 57.1%of purity;(2)ratio of liquid to material 10∶1,extraction time 4 h and extraction temperature 50℃for globulin,reaching 46.65%of extraction rate and 70.8%of purity;(3)ratio of liquid to material 10∶1,extraction time 5 h,extraction temperature 55℃and volume fraction of ethanol 75%for alcohol soluble protein,reaching 18.01%of extraction rate and 32.7%of purity;(4)ratio of liquid to material 10∶1,extraction time 4 h,extraction temperature 50℃and alkali-soluble pH 10.0 for gluten,reaching 26.78%of extraction rate and 70.4%of purity.The contents of glutamic acid,arginine and aspartic acid in albumin,globulin and gluten were significantly higher than that of other amino acids.Electrophoretic analysis showed that there were two bands with relatively large molecular weights in albumin,and the other three coconut proteins had relatively small molecular weights.Overall,coconut protein was a relatively high quality protein.
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