Proteomic investigation of protein profile changes and amino acid residue level modification in cooked lamb meat: the effect of boiling

Hydrothermal treatment (heating in water) is a common method of general food processing and preparation. For red meat-based foods, boiling is common, however, how the molecular level effects of this treatment correlate to the overall food properties is not yet well understood. The effect of differing boiling times on lamb meat and the resultant cooking water were here examined through proteomic evaluation. The longer boiling time was found to result in increased protein aggregation involving particularly proteins such as glyceraldehyde-3-phosphate dehydrogenase, as well as truncation in proteins such as in alpha-actinin-2. Heat-induced protein backbone cleavage was observed adjacent to aspartic acid and asparagine residues. Amino acid residue side-chain modifications resulting from the heating, including oxidation of phenylalanine and formation of carboxyethyllysine, were characterized in the cooked samples. Actin and myoglobin bands from the cooked meat per se remained visible on SDS-PAGE even after significant cooking time. These proteins were also found to be the major source of observed heat-induced modifications. This study provides new insights into molecular-level modifications occurring in lamb meat proteins during boiling and a protein chemistry basis for better understanding the effect of this common treatment on the nutritional and functional properties of red meat-based foods.