Report on EFSA project OC/EFSA/GMO/2017/01 “In vitro protein digestibility” (Allergestion)
The primary objective of the assessment of novel proteins is to evaluate whether they are safe to consume, including potential allergenicity. As part of a suite of assessments, the in vitro digestion of protein has been seen as a useful exercise. Thus, in line with the guidance offered by the EFSA GMO Panel we are using an early phase and a late phase gastric simulation as well as a simulation of the infant gastric compartment, all followed by intestinal phases. These digestion scenarios were used with a panel of 10 proteins from plant and animal origin that were proteins with distinct allergenic potential. The results from the SDS‐PAGE and densitometry show significant and mainly expected differences between the different digestion scenarios. The milk proteins were fully digested in the intestinal phase but the BLG was largely resistant to pepsin. In contrast, the egg proteins showed significant persistence except under late phase conditions. For the plant proteins, KTI and ConA were largely resistant to all conditions whereas LIP and AP were only resistant to infant conditions. Similarly, Ara h 1 showed some resistance to infant gastric conditions. The LC‐MS analysis of peptides was able to highlight a number of clusters where differences were seen between the digestion scenarios and these could in some cases be mapped onto the primary sequence and where relevant compared with known allergenic epitopes. Under the different digestion scenarios, we were able to show significant differences in the persistence of peptides larger than 9 amino acids and significant overlap of abundant peptides from early phase intestinal digestion and known epitopes for a number of proteins. Although, linking these differences to immunological responses (epitope mapping) still seems to be quite challenging, there are clear differences between scenarios and strong potential for improved risk assessment.