Comparative Proteomics and in Silico Allergenicity of Fresh and Powdered Skipjack Tuna and Nile Tilapia

Fish is an important food source but can contain allergens which cause mild to life-threatening symptoms. The aim of this study was to compare the identified proteins in fresh and powdered fish in skipjack tuna and Nile tilapia using proteomic approach. The biological functions of the proteins were identified using the UniProt database. Potential allergens were identified based on the sequence similarity to known allergens using the Allermatch program. The major functions of the identified proteins in both the fresh and powder forms of skipjack tuna and Nile tilapia were related to metabolic processes and the cytoskeleton. Eleven proteins in skipjack tuna and seven proteins in Nile tilapia, in fresh and powdered forms, were identified as novel potential allergens using the Allermatch program. Fructose-bisphosphate aldolase, enolase, parvalbumin, glyceraldehyde-3-phosphate dehydrogenase, and tropomyosin were found in abundance as potential allergens in both fishes. For both fishes, more isoforms of tropomyosin were found in powered fish than in fresh fish. Alpha- and beta-enolase, glyceraldehyde-3-phosphate dehydrogenase, alpha-, beta- and 2-parvalbumin, and tropomyosin alpha-1 chain could be developed as peptide markers for fish adulteration in both skipjack tuna and Nile tilapia. Interestingly, the peptides from eight potential allergens in fish were most similar to peptides from chicken powder and egg yolk powder. Here, proteomic analysis was used to study protein expression in skipjack tuna and Nile tilapia (both fresh and powdered). In addition, use of the untargeted proteomics approach could aid in the discovery of potential allergens and lead to the design of peptide markers to enhance food safety.