Beyond Protein Content: Testing Whether Alternative Proteins Are Digestible
A protein ingredient is only as valuable as the nutrition it delivers. As InnoProtein moves into the next phase of research, the focus shifts from cultivation to understanding how these proteins really perform inside the human body.
To explore this, research partners at Tecnalia conducted a series of laboratory trials examining the in vitro digestibility of four alternative protein sources developed within the InnoProtein project: microalgae, bacteria, fungi, and insects. These laboratory trials simulate the conditions of actual human digestion, offering an early indication of how well each protein source could perform in real food systems.
Simulating Human Digestion in the Lab
Using the standardized INFOGEST protocol, InnoProtein researchers recreated the three key stages of human digestion (oral, gastric, and intestinal) using enzymes and fluids that mimic those found in the human body[1].
The key measurement was the degree of hydrolysis, which tracks how much of the protein breaks down into smaller components, such as peptides and amino acids, as it moves through each digestive phase.
After intestinal digestion, researchers also measured how many of those amino acids ended up dissolved and available, giving an indication of how much the body could realistically absorb.
What Initial Results are Showing
All four protein sources showed moderate digestibility overall, which is a meaningful finding at this stage of development. As expected, very little breakdown occurred during the simulated gastric phase for all proteins.
The more significant differences emerged during intestinal digestion, where factors such as protein solubility and the composition of each extract influenced the accessibility of proteins to digestive enzymes. Of the four sources, insect protein showed the highest digestibility overall, while microalgae showed the lowest, though no statistically significant differences were detected between them.
To assess protein quality more precisely, researchers also calculated the DIAAS (Digestible Indispensable Amino Acid Score) for each extract, the metric recommended by the FAO and WHO for evaluating how well the body can use the essential amino acids in a given protein[2].
Each extract showed a distinct profile, with different essential amino acids acting as the limiting factor depending on the source. This kind of detail is particularly useful when thinking about how these proteins might be combined or formulated in future food products.
What Comes Next
This study represents the first part of a broader digestibility assessment. More testing is planned to evaluate whether the amino acids released during digestion can be absorbed into the bloodstream as well.
The ultimate goal is not just to produce alternative proteins sustainably, but to prove they can genuinely nourish the people and animals that consume them.
References
[1] Brodkorb, A., Egger, L., Alminger, M., Alvito, P., Assunção, R., Ballance, S., Bohn, T., Bourlieu-Lacanal, C., Boutrou, R., Carrière, F., Clemente, A., Corredig, M., Dupont, D., Dufour, C., Edwards, C., Golding, M., Karakaya, S., Kirkhus, B., Le Feunteun, S., Lesmes, U., … Recio, I. (2019). INFOGEST static in vitro simulation of gastrointestinal food digestion. Nature protocols, 14(4), 991–1014. https://doi.org/10.1038/s41596-018-0119-1
[2] FAO (2013). Dietary protein quality evaluation in human nutrition. FAO Food and Nutrition
Paper 92.
