酸碱法分离斑节对虾蛋白的营养特性研究

本研究分别以斑节对虾全虾和虾肉为原料,采用酸碱法(Isoelectric solubilization/precipitation)提取蛋白,探讨了极端酸碱pH溶解-沉淀条件对分离蛋白的提取得率、基本营养成分及营养品质的影响。结果表明:在料液比1:9(g/mL)、pH 2.0、pH 3.0以及pH 11.0、pH 12.0条件下溶解,pH 5.5条件下沉淀,全虾的蛋白提取得率在75.67%~82.72%,虾肉的蛋白提取得率在68.33%~80.5%,且均在pH 2.0和12.0时有最大蛋白提取率。斑节对虾分离蛋白中干基粗蛋白含量在82%以上,灰分含量在1.3%左右,且酸性溶解条件提取的分离蛋白中粗蛋白和灰分含量显著(p0.05)高于碱性溶解条件。对虾分离蛋白中必需氨基酸量、半必需氨基酸量、总氨基酸量和风味鲜度均高于原料对照,但虾味氨基酸量低于对照;所得分离蛋白的必需氨基酸配比符合FAO/WHO/UNU的理想模式。对虾分离蛋白中K、Mg、Cu、Zn和Mn五种元素的含量均显著(p0.05)低于原料虾和虾肉,碱性溶解条件下分离蛋白中矿质元素含量低于酸性溶解条件(p0.05)。酸碱法制备斑节对虾分离蛋白具有蛋白得率高、营养品质佳的特点,可用于生产优良的食品和饲料。

Isolation and Nutrient Composition of Protein Isolates from Penaeus monodon using Isoelectric Solubilization/Precipitation

In this study, effect of pH conditions in the extraction process on protein yield, changes of nutritional components and nutritional value of protein isolates from whole and muscle of tiger shrimp (Penaeus Monodon) using isoelectric solubilization/precipitation (ISP) was investigated. Protein isolates were obtained from tiger shrimp at a ratio of 1:9 with cold distilled water, dissolved at pH 2.0, 3.0 and pH 11.0, 12.0, subsequently precipitated at pH 5.5. Protein yields from whole and muscle of tiger shrimp were 75.67%~82.72% and 68.33%~80.5%, respectively. The highest protein extraction was observed at pH 2.0 and 12.0. Crude protein content in protein isolates extracted from both materials was more than 71% (dry weight), and the acidic treatments yielded significantly (p<0.05) higher contents of crude protein and ash in the recovered proteins than the basic treatments. The protein isolates from both pH treatments had increased contents of essential, semi essential and total amino acids as well as flavor amino acids but lowered content of shrimp-flavor amino acids than those of the starting materials. And their essential amino acids content met the FAO/WHO/UNU requirements. Both basic and acidic treatments gave rise to the removal of Cu, Mg, K, Zn and Mn, and the basic treatments yielded protein with significantly (p<0.05) higher amount of minerals than the acidic treatments. Therefore, protein isolates prepared from whole and muscle of tiger shrimp via ISP were high in protein yield and nutritional?value and may be used for the development of human food and animal feeds.