Characterization of fish protein concentrate from underutilised red-toothed triggerfish <i>Odonus niger</i> (Ruppell, 1836)

Odonus niger, despite being nutritionally comparable to many commercially important species, continues to remain underutilised in the food sector. Owing to its high content of quality protein, it represents a promising raw material for developing fish protein concentrate (FPC). FPC prepared using a combination method (alkaline sodium bicarbonate washing followed by acetic acid precipitation) was characterised for yield, bulk density (UTBD and TBD), water holding capacity (WHC), oil absorption capacity (OAC), water activity (aw), colour (L*, a*, b*), proximate composition, and amino acid profile. The developed FPC exhibited a proximate composition meeting the requirements mentioned in IS:9808 standards for FPC, containing 89±0.20% crude protein, 9.54±0.10% moisture, 0.36±0.04% crude fat, and 0.31±0.03% ash. A total of 21 amino acids were identified, with essential amino acids including lysine (12.79%), leucine (15.07%) and methionine (13.29%) constituting the major fraction of the total amino acid profile The FPC demonstrated good physicochemical quality with a yield of 13.56±0.38%, UTBD and TBD of 0.65±0.03 and 0.75±0.01 g ml-1, respectively, OAC of 0.79±0.03 g g-1, WHC of 7.96±0.63 ml g-1, aw of 0.40±0.02 and L*, a*, b* values of 76.88±0.36, 3.33±0.53, and 24.43±0.78, respectively. The results demonstrated that the characteristics of the developed FPC were. in agreement with those reported in earlier studies. Therefore converting O. niger into a stable protein preparation represents an effective approach for its optimal utilisation, with potential incorporation into suitable value added food products. Keywords: Amino acid profile, Bulk density, Functional properties, proximate composition, Water activity