This study explored the effect of electrical stimulation (ES) and Pediococcus pentosaceus LL-07 (P. pentosaceus LL-07) and Staphylococcus simulans QB7 (S. simulans QB7) on the quality and microbial community of loin ham during the ripening. After the ES and starter culture treatments, the Aw and pH were decreased. Surface hydrophobicity, myogenic fiber fragmentation index (MFI), TCA-soluble peptide, amino nitrogen and free amino acids (FAAs) were also significantly higher than the control group (CK) (P < 0.05). This increase was more significant in the E-S group (electrical stimulation followed by inoculation with P. pentosaceus LL-07 and S. simulans QB7) than the rest of the experimental group (E、S、S-E group). Furthermore, the CK and E-S groups were subjected to a bacterial community comparison experiment. The microbial diversity of these two groups was increased. Pediococcus spp. and Staphylococcus spp. became the dominant bacteria in E-S groups during the ripening. Correlation analyses show a strong correlation between protein hydrolysis, microorganisms and FAAs. In conclusion, the combination of ES and starter culture could promote protein hydrolysis, the accumulation of FAAS, and improves the bacterial community of loin ham.

Dry-cured meat products are considerably popular around the world due to unique flavor. Proteolysis is one of the enzymatic reactions from which flavor substances are derived， which is affected by endogenous proteases. The purpose aimed to reveal the potential relationship between endogenous proteases and key flavor substances in dry-cured pork coppa in this paper. The dynamic changes of endogenous proteases activity， free amino acids， and volatiles during dry-cured pork coppa processing were characterized. The results showed that 5 kinds of free amino acids， Glu， Lys， Val， Ala， and Leu， were identified as significant contributors to taste. Meanwhile， key volatiles， such as hexanal， nonanal， octanal， benzaldehyde， 3-methyl butanoic acid， 2-methyl propanoic acid， and ethyl octanoate， greatly contributed to the flavor characteristics of dry-cured pork coppa. Further partial correlation analysis was performed to better elucidate the relationship among parameters. The results revealed that close relationship between endogenous proteases and key substances. RAP not only significantly affected the accumulation of key active-amino acids， but also affected the accumulation of ethyl octanoate， 2，3-pentanedione， and 2，3-octanedione by regulating the accumulation of octanoic acid and Leu. In addition， cathepsin B and D， DPP Ⅱ， DPP Ⅳ and RAP notably affected accumulation of hexanal.

NaCl is the main curing agent in dry-cured meat products, and a large amount of NaCl addition leads to high salt content of final products. Salt content and composition are important factors affecting the activity of endogenous proteases, which in turn could affect proteolysis as well as the quality of dry-cured meat products. With the increasing emphasis on the relationship between diet and health, reducing sodium content without sacrificing quality and safety of products is a great challenge for dry-cured meat industry. In this review, the change of endogenous proteases activity during processing, the potential relationship between sodium reduction strategy, endogenous proteases activity, and quality were summarized and discussed. The results showed that sodium replacement strategy and mediated-curing had a complementary advantage in influencing endogenous proteases activity. In addition, mediated-curing had the potential to salvage the negative effects of sodium substitution by affecting endogenous proteases. Based on the results, a sodium reduction strategy that sodium replacement in conjunction with mediated-curing based on endogenous proteases was proposed for the future perspective.

This study focused on investigating the impacts of Staphylococcus simulans QB7 (S. simulans QB7) on the generation of antioxidant and anti-inflammatory peptides in dry-fermented sausages and the associated mechanisms by in silico. S. simulans QB7 remarkably increased (P < 0.05) the peptide concentration, antioxidant, and anti-inflammatory capacity of peptide extracts. There were 29 peptide sequences with potential activities of antioxidation and anti-inflammation according to BIOPEP-UWM prediction. Molecular docking results indicated that peptide GPGPWG can bind to Kelch-like ECH-associated protein 1 (Keap1) with highest interaction energy, while peptide ANPILEAFG showed highest interaction energy towards p65, I kappa B kinase 2 (IKK-β), c-Jun N-terminal kinases (JNK), and p38 kinases (p38) due to form salt bridge, h-bond, and pi-alkyl. These results suggested that S. simulans QB7 promoted antioxidant and anti-inflammatory peptide generation within dry-fermented sausages.

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.

The unique processing technology of dry-cured meat products leads to strong proteolysis, which produces numerous peptides. The purpose of this investigation was the systematic isolation, purification, and identification of potentially cardioprotective bioactive peptides from dry-cured pork coppa during processing. According to the results of anti-platelet-activating factor acetyl hydrolase activity and radical scavenging ability in vitro, the inhibitory effect of M1F2 in purified fractions on cardiovascular inflammation was higher than that of M2F2. The peptide of M1F2 was identified by nano-liquid chromatography-tandem mass spectrometry. A total of 30 peptides were identified. Based on bioinformatics methods, including in silico analysis and molecular docking, LTDKPFL, VEAPPAKVP, KVPVPAPK, IPVPKK, and PIKRSP were identified as the most promising potential platelet-activating factor acetyl hydrolase inhibitory peptides. Overall, bioactive peptides produced during dry-cured pork coppa processing demonstrate positive effects on human health.

This study focused on how different concentrations of tea branch liquid smoke (TLS) in the curing solution impacted the physicochemical properties and antioxidant properties of pork tenderloin. Five experimental (1.25 mL/kg, 2.5 mL/kg, 5 mL/kg, 10 mL/kg, 20 mL/kg) and blank groups set up over 4 days, and it was found that the physicochemical indexes, antioxidant capacity, thermal stability and protein network structure of the cured meat using 5 mL/kg of liquid smoke were excellent than the other groups used (P < 0.05). However, concentrations at 20 mL/kg accelerated protein oxidation. Low frequency nuclear magnetic resonance (LFNHR) revealed that TLS also improved the water holding capacity of the cured meat by increasing the percentage of bound water. Additionally, the correlation analysis demonstrated that the inoxidizability of myofibrillar protein was significantly related to cooking loss and water distribution, which were adjusted by changing the usage of liquid smoke.

Dry-cured meat products are popular worldwide because of their distinct flavor. However, the high sodium chloride levels of these products have raised public health concerns. Accordingly, to meet the needs of consumers, it is necessary to develop low-salt dry-cured meat products with high quality and safety. In this review, we discuss the effects of salt on dry-cured meat products, current research on salt reduction, and the advantages and disadvantages of salt reduction strategies. In addition, we also summarize salt reduction methods for meat products using exogenous mediation strategies, discuss salt reduction mechanisms used for mediated curing, and present future research directions for mediated salting strategies.