One shot-proteomic profiling, allergenicity assessment and varietal discrimination of lentils seeds by discovery high resolution tandem mass spectrometry

Lentils (Lens culinaris) represent important food staple replacing meat products in human diet with various applications of foods and feeds due to the high protein content. This work reported on the comparative proteomic profiling of four lentils commercial varieties Crimson, Eston, Laird and Black, providing novel knowledge on the differential expression of specific protein accessions with specific focus placed on the major protein families also investigating their allergenicity risk. The electrophoretic profile of lentil extracts confirmed that most of the proteomic profile was conserved across the investigated varieties, with only few differences highlighted for convicillin, vicilin and legumin subunits. A more in-depth analysis was carried out by one-shot discovery proteomics and provided the unequivocal identification and label-free quantification of 365 protein entries ranked into the main protein families. Statistically significant differences were disclosed for most of these protein groups and/or subgroups, cupins being the major contributors to the protein profile for all lentil samples. Noteworthy, the 7 S/11 S ratio describing seed nutritional quality highlighted clear differences among the four varieties with highest values reported for Eston and Laird samples. However, such higher nutritional quality was offset by a higher risk of allergenicity for sensitized individuals; indeed, the in-silico allergenicity prediction reported that most of the identified proteins presented either strong or weak evidence of immunogenicity with highest abundance in the Eston and Laird lentil samples. In perspective, the differential expression of specific protein accessions suggested the possibility to identify protein markers for varietal discrimination: a preliminary multivariate statistical analysis was accomplished to this aim.