Study on activation strategy and effect of protease activity during the post-processing stage of dry-cured meat based on electrical stimulation

Electrical stimulation (ES) is commonly used during the slaughter and tenderizing of meat. However, it is often lacking during the post-processing stage as a method for regulating endogenous protease. Therefore, it is valuable to explore an effective method for peptide production under sodium salt conditions, which can shorten the ripening time of dry-cured ham and develop products with active peptides. This study demonstrated ES could enhance salt diffusion, reduce pH, and improve color under 3% NaCl conditions. Existing studies verify a tendency for cathepsin activity to fall all the way down or rise briefly and then fall during processing, none of the studies considered the precise use of ES. In this paper, the ES was precisely designed, the experimental samples were set into 6 groups, and the current intensity and action time were set at 0 A&0 s, 0.2 A&60 s, 0.6 A&30 s, 0.6 A&60 s, 0.6 A&90 s and 1.0 A&60 s when cured with NaCl (w/w). ES significantly increased cathepsin B and L activity during processing, which increased 172%-600% and 77%-372% times respectively, accelerating proteolysis. Analysis of the electronic tongue and free amino acids (FAAs) showed that ES effectively increased the final content of free amino acids by up to 95.51%; reduced bitter and bitter-related amino acids and enhanced freshness. Furthermore, the study showed correlations with most of the free amino acids such as glutamate, histidine and arginine, which are associated with freshness, sourness and bitterness, and cathepsin activity consistent with the correlation between cathepsin B, L and sourness, freshness and astringency in the E-tongue. The experimental data showed the effect of ES on the regulation of enzyme activity in the post-stimulation processing stage and its potential utilization value.