Herring roe protein has a high digestible indispensable amino acid score (DIAAS) using a dynamic in vitro...

It is hypothesized that the digestible indispensable amino acid score (DIAAS) can be determined based on dynamic in vitro gastrointestinal digestion experiments as replacement for invasive animal studies. We determined the in vitro DIAAS for immature herring eggs (roe) proteins in comparison with reference proteins. The true ileal digestibility of protein and indispensable amino acids (IAA) was measured under human conditions simulated in a gastrointestinal model (tiny-TIM). The in vitro true ileal digestibility of ovalbumin, cooked and raw chicken egg white, and casein was similar to that found in humans (r(2) = 0.96), providing a casual observation to support the validity of tiny-TIM. The digestibility of the immature herring egg proteins was 71% to 92%. The highest IAA digestibility was found for immature whole herring egg protein (55%-80%) in comparison to immature herring egg membrane and immature de-membraned herring protein (50%-70%). The DIAAS as recommended by FAO for children and adults, but measured in vitro, were 91% for immature whole herring egg protein (lysine first limiting), 71% for immature herring egg membrane protein (histidine first limiting), and 88% for immature herring egg de-membraned protein (sulfur AA first limiting). True ileal protein and amino acid digestibility can be determined in a dynamic gastrointestinal model, such as tiny-TIM, which can be used for estimating the DIAAS. Immature herring egg proteins, a previously underutilized resource, were determined to be an important and valuable source of IAA for human consumption.