Effect of sodium alginate on functional properties of extruded feed for fish for human consumption. Journal of Animal Science Advances.

Agglutinating compounds are commonly used to improve the physical quality of aquafeeds. An evaluation was done of the effect of the agglutinating compound sodium alginate on the functional properties of aquaculture fish feed produced by extrusion. Meals containing one of four sodium alginate concentrations (0, 0.5, 1.5 and 2%) were extruded in a simple-screw extruder at 120 C, 20% moisture content and a 1:1 compression ratio, extruding each treatment in duplicate. Expansion index values ranged from 1.11 to 1.12 with no differences (P > 0.05) between the diets containing sodium alginate. In contrast, the different sodium alginate levels had positive (P < 0.05) effects on water absorption index values (2.24 to 2.79 g/g), water solubility index values (10 to 12.94%), sinking velocity (6 to 8.56 cm/s) and hardness (1.98 to 3.31 N). Maximum hardness (3.31 N) was produced in the 2% sodium alginate diet. The highest sodium alginate level tested (2%) had the most appropriate physical and functio