EFFECT OF BEAN FLOUR CONCENTRATION (Phaseolus vulgaris L.), MOISTURE CONTENT AND EXTRUSION TEMPERATURE ON THE FUNCTIONAL PROPERTIES OF AQUAFEEDS

The effect of bean (Phaseolus vulgaris L.) flour content, moisture content and extrusion temperature on the functional properties of fish feed was evaluated. Diets with fish meal and different bean flour concentrations (15, 30 and 45%) and control diet were developed. The results show that the bean flour present in the diets has an effect (p < 0.05) on expansion index (El), bulk density (BD), water absorption index (WAI), water solubility index (WSI) and sinking velocity (SV). Extrusion moisture decreased (p < 0.05), El, WSI and the color parameters L* and b*, but increased (p < 0.05), BD, SV, WAI, and the color parameter a*. The results also showed that an increase on extrusion temperature decreased (p < 0.05), El, BD, WSI, SV, color and increased (p < 0.05), WAI. The highest (p < 0.05) El was found in the extruded diet containing 15% of bean flour, 18% extrusion moisture and extruded at 120 degrees C, compared to other diets. The lowest (p < 0.05) SV was determined in the extruded diets with less than 30% bean flour and an extrusion moisture of 18%. The optimum extrusion conditions were found with diets containing 15% of bean flour and extruded with 18% moisture at 120 degrees C.