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 effects 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 α-actinin-2.
Heat-induced protein backbone cleavage was observed adjacent to aspartic
acid and asparagine residues. Side-chain modifications of amino acid
residues 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 sodium dodecyl sulfate–polyacrylamide gel electrophoresis,
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.