Processed Meat Protein and Heat-Stable Peptide Marker Identification Workflow Using Microwave-Assisted Tryptic Digestion

Abstract

SummaryNew approaches to rapid examination of proteins and peptides in complex food matrices are of great interest to the community of food scientists. The aim of the study is to examine the infl uence of microwave irradiation on the acceleration of enzymatic cleavage and enzymatic digestion of denatured proteins in cooked meat of fi ve species (catt le, horse, pig, chicken and turkey) and processed meat products (coarsely minced, smoked, cooked and semi-dried sausages). Severe protein aggregation occurred not only in heated meat under harsh treatment at 190 °C but also in processed meat products. All the protein aggregates were thoroughly hydrolyzed aft er 1 h of trypsin treatment with short exposure times of 40 and 20 s to microwave irradiation at 138 and 303 W. There were much more missed cleavage sites observed in all microwave-assisted digestions. Despite the incompleteness of microwave-assisted digestion, six unique peptide markers were detected, which allowed unambiguous identifi cation of processed meat derived from the examined species. Although the microwave-assisted tryptic digestion can serve as a tool for rapid and high-throughput protein identifi cation, great caution and pre-evaluation of individual samples is recommended in protein quantitation.

Peptides as probes for food authentication

“…Peptide fingerprint coupled with statistical analysis (such as OPLS‐DA) has been successfully used to differentiate beef, horse, pork, chicken, and turkey both in raw and cooked meat mixtures . In processed products, protein aggregation can lead to a limited extraction and digestion efficiency, thus, microwave treatment can be used to assist the tryptic digestion, enhancing sample solubilization . However, some reproducibility issues make it inadequate for quantitative purposes.…”