(P04-006-25) Protein Quality of Salmon Protein Hydrolysates Using the Digestible Indispensable Amino Acid Score (DIAAS) Method

Objectives: This study aimed to determine the protein quality of salmon protein hydrolysates using the digestible indispensable amino acid score (DIAAS) method described by FAO and test the hypothesis that they can supplement lower-quality proteins and provide adequate meals in indispensable amino acids (AA).

Methods: One source of salmon protein hydrolysate concentrate (SPHC) and two sources of salmon protein hydrolysate isolate (SPHI1 and SPHI2) were included in one experimental diet each. Growing pigs were used to estimate the ileal digestibility of AA. A protein-free diet was used to determine endogenous losses of AA and allow for digestibility calculations. The DIAAS values were calculated for two age groups: children from 6 months to 3 years and individuals older than 3 years (i.e., older children, adolescents, and adults). The protein quality was classified based on determined DIAAS: below 75 indicated no claim can be made regarding the protein quality; between 75 and 99 was considered “good,” and 100 or more was considered “excellent.”

Results: Digestibility values for protein and indispensable AA were close to or greater than 90% for all sources of salmon protein hydrolysates. For both age groups, SPHC had greater (P < 0.05) DIAAS values compared with the two sources of SPHI, and SPHI2 had greater (P < 0.05) DIAAS values than SPHI1. For children from 6 months to 3 years, leucine was the first limiting AA for SPHC (DIAAS = 92), and tryptophan was the first limiting AA for SPHI1 (DIAAS = 55) and SPHI2 (DIAAS = 74). For individuals older than 3 years, there was no limiting AA for SPHC (DIAAS ≥ 100), but leucine was the first limiting AA for SPHI1 (DIAAS = 69) and SPHI2 (DIAAS = 80).

Conclusions: Digestibility values for protein and indispensable AA were considered high for all sources of salmon protein hydrolysates, suggesting that these nutrients were easily absorbed and available for utilization by the body. SPHC has excellent protein quality and can compensate for lower quality foods in mixed meals, but SPHI2 should be used in mixed meals for individuals older than 3 years only if another food that is high in leucine is also consumed

Funding Sources: Financial support for this study was provided by Biomega^®, Bergen, Norway.