Properties of recovered solids from stick-water treated by centrifugation and pH shift

Processing of sardine fishmeal generates pollution and waste with potentially useful protein. Sardine stick-water (SW) from fishmeal operation was submitted to a complementary centrifugation step followed by pH adjustment (acidic + alkaline) to recover solids for their compositional, functional and nutritional properties evaluation. Insoluble fractions (from acidic treatment (IF1) and alkaline treatment (IF2)) had a chemical composition of 76 ± 4 and 16.9 ± 3.1% protein, 12 ± 6.2 and 2.9 ± 1.9% fat, 7.9 ± 2 and 75.4 ± 2.6% ash, respectively. IF1 and IF2 were good sources of Ca++, Mg++, P3−, K+ and essential amino acids. IF2 was whiter than IF1 but less colour stable over time. Solubility of proteins from IF1 and IF2 was higher than that of commercially used materials such as egg albumin and sodium caseinate. IF1 chemical, nutritional and functional characteristics suggest its potential use as food/feed compositional ingredient.