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.