Multispecies Identification of Oilseed- and Meat-Specific Proteins and Heat-Stable Peptide Markers in Food Products.

Consumer demand for both plant products and meat products enriched with plant raw materials is constantly increasing. Therefore, new versatile and reliable methods are needed to find and combat fraudulent practices in processed foods. The objective of this study was to identify oilseed species-specific peptide markers and meat-specific markers that were resistant to processing, for multispecies authentication of different meat and vegan food products using the proteomic LC-MS/MS method. To assess the limit of detection (LOD) for hemp proteins, cooked meatballs consisting of three meat species and hemp cake at a final concentration of up to 7.4% were examined. Hemp addition at a low concentration of below 1% was detected. The LOD for edestin subunits and albumin was 0.9% (w/w), whereas for 7S vicilin-like protein it was 4.2% (w/w). Specific heat-stable peptides unique to hemp seeds, flaxseed, nigella, pumpkin, sesame, and sunflower seeds, as well as guinea fowl, rabbit, pork, and chicken meat, were detected in different meat and vegan foods. Most of the oilseed-specific peptides were identified as processing-resistant markers belonging to 11S globulin subunits, namely conlinin, edestin, helianthinin, pumpkin vicilin-like or late embryogenesis proteins, and sesame legumin-like as well as 2S albumins and oleosin isoforms or selected enzymic proteins.

Identification of species-specific peptide markers in cold-pressed oils.

In recent years, cold-pressed vegetable oils have become very popular on the global market. Therefore, new versatile methods with high sensitivity and specificity are needed to find and combat fraudulent practices. The objective of this study was to identify oilseed species-specific peptide markers, using proteomic techniques, for authentication of 10 cold-pressed oils. In total, over 380 proteins and 1050 peptides were detected in the samples. Among those peptides, 92 were found to be species-specific and unique to coconut, evening primrose, flax, hemp, milk thistle, nigella, pumpkin, rapeseed, sesame, and sunflower oilseed species. Most of the specific peptides were released from major seed storage proteins (11 globulins, 2S albumins), and oleosins. Additionally, the presence of allergenic proteins in the cold-pressed oils, including pumpkin Cuc ma 5, sunflower Hel a 3, and six sesame allergens (Ses i 1, Ses i 2, Ses i 3, Ses i 4, Ses i 6, and Ses i 7) was confirmed in this study. This study provides novel information on specific peptides that will help to monitor and verify the declared composition of cold-pressed oil as well as the presence of food allergens. This study can be useful in the era of widely used unlawful practices.