Amino acid composition and anti-anaemia action of hydrolyzed offal protein from Harengula Zunasi Bleeker

A hydrolyzed offal protein (HOP) from Harengula Zunasi offal was produced according to the poly-enzymatic method. Its amino acid composition and in vivo anti-anaemia action were investigated. Chemical analysis showed that the hydrolyzed offal protein contained 16.0% protein, 4.21% fat, 76.28% moisture and 3.39% ash. Compared with the amino acid profiles recommended by FAO/WHO, the protein quality of the hydrolyzed offal protein was fairly high, due to its high contents of essential amino acids, including isoleucine, leucine, lysine, methionine, cystine, and threonine, valine, that covered 91–100% of those suggested by FAO/WHO. Particularly, the high amount of lysine in the hydrolyzed offal protein may provide good protein supplementation for vegetable foods, in which lysine is commonly a limiting amino acid. Animal experiments revealed that the hydrolyzed offal protein inhibited mice anaemia caused by an injection of cyclophosphamide. The hydrolyzed offal protein could significantly inhibit the decreases in red blood cells, hematocrit, hemoglobin and platelets, but not white blood cells of the mice caused by cyclophosphamide. Presumably, its anti-anaemia action might be due to prevention of the functional groups of protein (including amido, mercapto, hydroxyl group and carboxyl groups in mouse body) undergoing the reaction of alkylation with cyclophosphamide. In addition, the anti-anaemia action of the hydrolyzed offal protein might also be due to nutritional functions of minerals (calcium, phosphorus and iron). The results of the present study provide some technical information and suggestions for the seafood industry for more effective utilization of fish offal.