Sikorski Z E, Naczk M
Crit Rev Food Sci Nutr. 1981;14(3):201-30. doi: 10.1080/10408398109527305.
Fish protein concentrates are mixtures of cross-linked and aggregated molecules of different muscle proteins. The final conformation of the components of the mixtures is formed as a result of procedures applied to convert the raw materials into a product of desirable and stable sensory properties, containing less than 0.1% of lipids. To achieve this end usually extraction with hot organic solvents, mainly isopropyl alcohol and 1,2-dichloroethene, followed by air drying are employed. These conditions bring about denaturation of many of the proteins followed by aggregation of the molecules due to the interaction of reactive functional groups in extended polypeptide chains. In the final product a large proportion of hydrophobic groups is exposed to the solvent and the proteins exhibit an extremely low water affinity. Such concentrates, although valuable as protein supplements, have only limited suitability as active components of various processed foods, as they have poor technological value. They are insoluble or have a very low water dispersibility and swelling ability, do not form gels after heating, or have any significant fat-emulsifying capacity. Changing the dissociation or number of ionic groups of the molecules prior to extraction, e.g., by acidifying or acylating, can partially reduce the denaturing effect of heat and organic solvents and thus improve the functional properties of the product. An upgrading of the quality of concentrates produced by hot extraction can be achieved by partial enzymatic or chemical deaggregation, hydrolysis followed by the plastein reaction, or formation of suitable derivatives. The best results have been obtained by partial hydrolysis of acylated proteins or precipitation of the aggregated products using sodium hexametaphosphate. The functional properties of such products are comparable to those of vegetable protein isolates used as meat extenders. Various proteins of high technological value can be also obtained by enzymatic hydrolysis of the raw material, followed by separation of the lipids without organic solvent extraction. Such products, however, have a distinct odor and flavor and must be stabilized because of residual lipids.
鱼蛋白浓缩物是不同肌肉蛋白的交联和聚集分子的混合物。混合物成分的最终构象是通过将原材料转化为具有理想且稳定感官特性、脂质含量低于0.1%的产品所采用的程序形成的。为达到此目的，通常采用热有机溶剂（主要是异丙醇和1,2 - 二氯乙烯）萃取，随后进行风干。这些条件会导致许多蛋白质变性，随后由于延伸多肽链中反应性官能团的相互作用，分子发生聚集。在最终产品中，很大一部分疏水基团暴露于溶剂中，蛋白质表现出极低的水亲和力。这种浓缩物虽然作为蛋白质补充剂很有价值，但作为各种加工食品的活性成分适用性有限，因为它们的工艺价值较低。它们不溶或水分散性和膨胀能力极低，加热后不形成凝胶，也没有任何显著的脂肪乳化能力。在萃取前改变分子的解离或离子基团数量，例如通过酸化或酰化，可以部分降低热和有机溶剂的变性作用，从而改善产品的功能特性。通过部分酶解或化学解聚、水解后进行类蛋白反应或形成合适的衍生物，可以提高热萃取生产的浓缩物的质量。通过酰化蛋白质的部分水解或使用六偏磷酸钠沉淀聚集产物可获得最佳效果。此类产品的功能特性与用作肉类增量剂的植物蛋白分离物相当。通过对原材料进行酶解，随后在不使用有机溶剂萃取的情况下分离脂质，也可以获得各种具有高技术价值的蛋白质。然而，此类产品有明显的气味和风味，并且由于残留脂质必须进行稳定化处理。
