Study of the in vitro digestibility of oilseed protein concentrates compared to isolates for food applications

The research has primarily focused on isolates (>90 % protein) when studying oilseed protein products, but there is a growing interest in concentrates (65-90 % protein) due to their industrial viability and lower environmental impact. This study aimed to compare the in vitro digestibility of rapeseed and sunflower protein concentrates with isolates. Simulated digestion was conducted, and the resulting samples were analyzed using a size-exclusion chromatography approach. This approach can reliably quantify assimilable peptide fractions without interference from the complex matrix of these products. Surprisingly, similar digestibility values (around 40 %) were found for both oilseed protein concentrates and isolates. The study also compared the digestibility of total protein isolates versus albumin isolates from rapeseed and sunflower. The results highlighted the significant gastrointestinal resistance of the albumin fraction, which is the most important factor affecting the digestibility of these products. These digestibility results emphasize the strong potential of concentrates in food applications.