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The ultrasound-induced impacts on the peptide characteristics and taste of unsmoked bacon have been evaluated through the use of peptidomics and bioinformatics approaches. Furthermore, the effect of such ultrasound-induced changes on the main endogenous proteases responsible for peptide generation was also investigated. In fact, the activity of main endogenous proteases was significantly increased after ultrasonic treatment during the processing of unsmoked bacon, and contributed to an increased number and an enhanced LFQ intensity of peptides. Besides, such increased amount of peptides and LFQ intensity with up to 500 W ultrasonic treatment were beneficial for the taste improvement of the final products as shown by taste prediction analysis. Nevertheless, an excessive ultrasonic power like 750 W hindered protein hydrolysis and further exerted a negative effect on peptide generation. Therefore, ultrasound under controlled conditions could be considered as a promising way to improve the taste of unsmoked bacon., This work was financially supported by the earmarked fund for China Agriculture Research System (CARS-35) and the Kekedala City of the 4th Division Science and Technology Plan (2022GY03).

This study evaluated the food safety and proximate composition of shrimp head (SH). Potentially toxic elements in SH were below European Union legislation limits. SH had a high content of tasting amino acids (sweet and umami amino acids was 57%) and a high content of functional amino acids (essential amino acids was 37%). Moreover, the changes of flavor and key umami molecules in SH were studied by sensory evaluation, electronic tongue, electronic nose, automated amino acid analyzer, and high performance liquid chromatography (HPLC). The results showed that the significant difference of flavor in SH happened during autolysis. SH with autolysis had the best umami taste at 6 h, which may result from the synergistic work of free amino acids and nucleotide related compounds. Additionally, the performance of endogenous proteases in SH was investigated to efficiently analyze autolysis. The optimum pH and temperature of endogenous proteases in SH were 7.5 and 50 °C, respectively. The autolysis of SH depends on two endogenous proteases (~50 kDa and ~75 kDa). These results suggest that the formation of flavor in SH during autolysis can be controlled, which could provide guidance for SH recycle. SH could consider as one of the food materials for producing condiments.

Regulated proteolysis is a pivotal regulatory mechanism in all living organisms from bacteria to mammalian cells and viruses. The ability to design proteases to sense, transmit, or trigger a signal opens up the possibility of construction of sophisticated proteolysis-regulated signaling networks. Cleavage of the polypeptide chain can either activate or inactivate the selected protein or process, often with a fast response. Most designs are based on sequence-selective proteases that can be implemented for transcriptional, translational, and ultimately post-translational control, aiming to engineer complex circuits that can dynamically control cellular functions and enable novel biotechnological and biomedical applications.

Extensive proteolysis and formation of flavor substances occur during the processing of dry-salted fish due to the action of endogenous proteases. This study analyzed the evolution of the endogenous proteases and the relationship between endogenous protease levels and protein degradation during processing. Cathepsin B and L activity increased significantly during the last two stages, while cathepsin H activity decreased non-significantly (residual activity was 92.27%) compared to initial activity levels in fresh fish. Dipeptidyl peptidase (DPP I, IV) activity decreased overall. The activity of three aminopeptidases (arginine aminopeptidase; alanyl aminopeptidase; leucyl aminopeptidase) initially decreased (P