Carboxypeptidases for food processing: structural characteristics, expression optimization, and advances in applications

Carboxypeptidases, a class of exopeptidases that specifically cleave C-terminal amino acid residues from peptide chains, are extensively utilized for food component modification and quality enhancement. This review focuses on the three-dimensional structural characteristics and active-site catalytic mechanisms of serine carboxypeptidases, metallocarboxypeptidases, and cysteine carboxypeptidases and describes the construction and optimization strategies for heterologous expression systems, with particular emphasis on Escherichia coli ( E. coli ), Bacillus subtilis , and Pichia pastoris . Furthermore, the use and current research status of carboxypeptidases in food processing are comprehensively explored, including the debittering of protein hydrolysates, the targeted preparation of high-Fischer-ratio (high-F-ratio) oligopeptides, the quality enhancement of fermented foods, and the green biological detoxification of ochratoxin A (OTA). Further research can focus on enhancing the substrate specificity and catalytic efficiency of carboxypeptidases through molecular modification. This review aims to provide a theoretical foundation for the broader application of carboxypeptidases in green food manufacturing and quality improvement.