Lactiplantibacillus plantarum enhances the texture of fermented milk by facilitating protein gelatinization through the action of a novel coagulation-promoting protease.

Enzymatic modification can effectively improve the gel properties of protein-based food matrices. However, how bacterial proteases influence milk gels has been rarely reported. In the current study, the proteases isolated from two strains of Lactiplantibacillus plantarum , namely YM13–8.1 and YN22–3.1, demonstrated significant improvement in the textural properties of acid-induced gels characterized by increased hardness and a more compact, dense and fine-pored structure. The inclusion of milk-coagulating proteases resulted in a significant augmentation of hydrophobic interactions and disulfide bonds within the protein gels. Furthermore, both proteases exhibited rennet-like characteristics through κ-casein hydrolysis, with key hydrolysis sites identified as Tyr25-Ile26, Ala65-Ala66 and Lys112-Asn113. By utilizing MALDI-TOF-MS, whole genome sequencing and RT-qPCR analysis, we successfully identified the gene responsible for encoding the proteases as prtA , which has not been previously characterized. In conclusion, our findings demonstrate that the newly characterized protease prtA exerts a positive influence on milk gelling. [Display omitted] • A novel coagulation-promoting protease was found from Lactiplantibacillus plantarum. • The protease enhanced the textural characteristics of acid-induced gels. • The protease exhibited specific hydrolysis sites within κ-casein. • The protease was identified as prtA through LC-MS/MS and whole genome sequencing. [ABSTRACT FROM AUTHOR]