Effect of sodium, potassium, calcium and magnesium chloride salts on porcine muscle proteases

Perspective of sodium reduction based on endogenous proteases via the strategy of sodium replacement in conjunction with mediated-curing

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.

Zinc-protoporphyrin formation in nitrite-free Parma Ham and its relationship with intrinsic parameters and red color profile of processed hams

A total of 134 fresh hams, assayed for Ferrochelatase (FeCH) activity and ultimate pH (pH48), were processed in compliance with the procedures established for PDO Parma ham and finally, analyzed for salt, moisture, Zinc Protoporphyrin IX (ZnPP), heme, iron and zinc contents, and proteolysis index (PI). The variation in ZnPP content was related to the intrinsic parameters of fresh and matured hams by a Partial Least Square Regression model. The most favorable factors on the formation of ZnPP were total iron content (representative of the initial hemoprotein content), and FeCH activity, demonstrating the main role played by these raw matter-specific predictors in the long matured dry-cured hams. To a lesser extent, zinc content and pH48 were involved with a positive and negative role, respectively. Salt content and PI of matured hams showed an inhibitory and a favorable influence, respectively, toward the ZnPP formation. Principal Component Analysis showed the associations between the sensory red color profile and the physicochemical traits of matured hams. The red color intensity increased in agreement with the red-violet and red-pink hues scores. The formation of a high amount of ZnPP was associated with the increased perception of the red-violet shade, with a lower lightness (L*) and Hue angle (h°). Moisture increase contributed to the shift in color perception to red-pink, while marked progress in PI strengthened the perception of the red-brown shade. ZnPP and final heme favored the red color of matured hams, although a high concentration of these pigments increased in particular the red-violet perception.

Identification and Quantitation of Bioactive and Taste-Related Dipeptides in Low-Salt Dry-Cured Ham

The reduction of salt in meat products influences the natural mechanisms of proteolysis occurring in their processing, and could affect the final characteristics of the product in terms of texture and flavor due to its effect on the activity of enzymes. In the present study, the quantitation of dipeptides PA, GA, VG, EE, ES, DA, and DG in low-salt Spanish dry-cured ham was carried out using a triple quadrupole mass spectrometry instrument. The developed methodology demonstrated the advantages of hydrophilic interaction liquid chromatography in the removal of salt as a clean-up/separation step before ionization. This resulted in a value of 44.88 μg/g dry-cured ham for GA dipeptide, and values ranging from 2 to 8 μg/g dry-cured ham for VG, EE, ES, DA, and DG dipeptides. PA showed the lowest concentration with a value of 0.18 μg/g dry-cured ham. These outcomes prove the remarkable activity of muscular dipeptidyl peptidases during dry-curing as well as confirming the presence of these dipeptides which are related to certain taste attributes (e.g., ‘bitter’ or ‘umami’). Such dipeptides have also been confirmed as anti-inflammatory and potential cardiovascular protectors using in vitro assays, with the advantage of dipeptides small size increases their chance to resist both gastrointestinal digestion and intestinal/bloodstream transport without being degraded or modified.

Effect of NaCl Partial Replacement by Chloride Salts on Physicochemical Characteristics, Volatile Compounds and Sensorial Properties of Dry-Cured Deer Cecina

The present study aimed to evaluate the effect of NaCl replacement in the physicochemical quality and volatile and sensorial profile of dry-cured deer cecina. Two salt mixtures were used as NaCl substitute: mixture I (30% NaCl-70% KCl) and mixture II (30% NaCl-50% KCl-15% CaCl₂-5% MgCl₂). Regarding the physicochemical parameters, only ash content, pH and L* values were affected by NaCl replacement. However, lipid oxidation was affected by NaCl replacement. The greatest thiobarbituric acid reactive substances (TBARS) values were observed in the control batch (3.28 mg MDA/kg). The partial replacement of NaCl by salt mixtures affected (p < 0.001) Ca, K, Mg, and Na content. The total amounts of free fatty acids and free amino acids were not affected (p > 0.05) by NaCl replacement. Concerning the volatile compounds, control samples presented the highest concentrations of furans (p < 0.01), while samples produced with mixture II had the lowest (p < 0.001) amounts of esters and acids. Our results indicated that all sensory attributes of the attribute map were affected (generalized procrustes analysis (GPA) explained 100% of the total variability among treatments). Considering the results obtained from the sensorial analysis, only mixture II reduced the overall acceptance and preference of consumers. Control attained significantly (p < 0.05) greater scores of acceptance and preference than mixture II despite the higher TBARS content.

Effects of partial replacement of NaCl with KCl on bacterial communities and physicochemical characteristics of typical Chinese bacon

This work aimed to determine the effects of partial substitution of NaCl with 0% (control), 30%, 50%, and 70% of KCl on the bacterial communities, proteolysis and lipid oxidation of Chinese bacon during processing. The proportion of genus Lactobacillus increased from 22.45% (fresh meat) to 72.78%, 81.64%, 76.53% and 85.63% at the end of processing for 0%, 30%, 50% and 70% KCl replacement samples, respectively. During the processing, Lactobacillus gradually became the dominant one, and higher the KCl ratio, more rapid was the process. After salting, the TBARS of control was markedly higher (P < 0.05) than that of the others, while a similar lipid oxidation level (P > 0.05) was observed at the end of processing for different groups. After salting, there was no difference in total free amino acids (TFAA) content among four treatments (P > 0.05), whereas KCl replacement samples shared significantly higher (P < 0.05) values than control at the end of processing. Redundancy analysis and Pearson correlation showed positive correlation between Lactobacillus versus TBARS and TFAA. Partial replacement of NaCl with KCl could, directly or subsequently by promoting the growth of Lactobacillus, influence proteolysis and lipid oxidation over the manufacturing process.

Insights into the evolution of myosin light chain isoforms and its effect on sensory defects of dry-cured ham

To better understand the contribution of myosin light chain (MLC) isoforms to sensory defects in Jinhua ham, dipeptidyl peptidase (DPP) activities, peptide fragments, cleavage sites and the potential of DPP to develop sensory defects of dry-cured ham were evaluated and discussed in normal and defective hams. Higher residual activities of DPP I were found in defective ham compared with normal ham; approximate 3-fold peptide fragments were identified in defective ham than in normal ham. These regions of positions 11-35 and 116-141 in MLC 1, 13-53 and 139-156 in MLC 2, and 18-50 in MLC 3 contributed to the intense generation of peptide fragments in defective ham. PLS-DA further revealed DPP I showing intense response to degrade peptides. Cleavage sites including Glu-128, Tyr-132 and Glu-133 were responsible for the intense release of dipeptides in defective ham. These cleavages could play key role in discriminating taste attributes between defective and normal hams.

Substituting sodium by various metal ions affects the cathepsins activity and proteolysis in dry-cured pork butts

Salt contents and compositions are crucial parameters to enzyme activity and might even affect the proteolysis and quality of dry-cured meat. However, the metal ions significantly vary with geographic origin, which would be a determinant in the dry-cured meat manufacture. Therefore, the main salt compositions of KCl, CaCl₂, MgCl₂ and ZnCl₂ were therefore used to partially substitute NaCl while additionally assessing and regulating their function during the dry-cured pork butts processing. Physiochemical properties, cathepsins activity, proteolysis and sensory evaluation were investigated. The results indicated that partial substitution of sodium prevented the dehydration, and accelerated the pH reduction. CaCl₂ and MgCl₂ partial substitution moreover exerted some promoting effect on cathepsin activity whereas ZnCl₂ was a subtle inhibitor. The proteolysis index of CaCl₂ and MgCl₂ substitution were superior to the rest. The metal ions partial substitution reduced saltness, while the presence of KCl and MgCl₂ enhanced bitterness. Further correlation analysis was performed to better understand the interactions between those parameters.

Hydrolysis and oxidation of protein and lipids in dry-salted grass carp (Ctenopharyngodon idella) as affected by partial substitution of NaCl with KCl and amino acids

To obtain healthier meat products with reduced Na content, the salt substitute containing l-histidine and l-lysine was compared with NaCl in the hydrolysis and oxidation of protein and lipids of dry-salted fish during processing. Compared with NaCl-treated fish (S-F), salt substitute treated fish (SS-F) had a lower Na content, higher moisture content and lower hardness. Sensory analysis showed that salt substitute didn't affect the acceptability of salted fish. The free fatty acids of SS-F treated fish had a slight tendency toward lipolysis at the end of processing. Additionally, the conjugated diene value, lipoxygenase activity and malondialdehyde value were lower in the ventral and dorsal muscles for the SS-F treatment. Meanwhile, the protein carbonyls and thiol groups were significantly decreased as cathepsin B and L activities and FAA content were increased in the ventral and dorsal muscles for the SS-F treatment. l-Histidine and l-lysine accelerated the hydrolysis (inhibit the oxidation) of protein and lipids in dry-salted grass carp, illustrating that l-histidine and l-lysine will be a positive approach to develop healthier meat products.

A peptidomic approach of meat protein degradation in a low-sodium fermented sausage model using autochthonous starter cultures

Fermented sausage technology is currently compromised in decreasing the addition of NaCl. Use of starter cultures with peptidogenic potential could be a valuable strategy that can mask or hide off flavors produced by the use of NaCl substituents. In the present work, the peptidogenic potential of four lactic acid bacteria species was evaluated in a low-sodium beaker sausage (BS) model. Using a peptidomic approach, a total of 86 low molecular weight (LMW) peptides were accurately identified, mostly derived from myofibrillar proteins, especially actin, which generated 53 peptides. The BS inoculated with L. curvatus CRL705 generated 56 LMW peptides, followed by Enterococcus (E.) mundtii CRL35 with 43 peptides. In addition, BS inoculated with Lactobacillus (L.) plantarum and with L. sakei produced higher amino acid amounts over time as compared to the rest of BS models, highlighting the importance of both, time and sample effect on the overall free amino acid generation. The presence of each LAB strain in BS models generated a unique profile of small peptides and amino acids that could serve as a distinctive biochemical trait to differentiate specific fermented products. According to these results, E. mundtii and L. sakei, which are compatible between them, are proposed as the most efficiently adapted to low-sodium conditions. The use of selected strains during the processing of low-sodium fermented sausages could have a positive effect on the production of small peptides and free amino acids.

Dipeptidyl peptidase IV inhibitory peptides generated in Spanish dry-cured ham

Dipeptidyl peptidase IV (DPP-IV) inhibitors are promising new therapies for type 2 diabetes. The aim of this study was to assay DPP-IV inhibitory peptides that can be present in a water soluble extract of Spanish dry-cured ham. Such an extract was fractionated by size-exclusion chromatography and the in vitro DPP-IV inhibitory activity determined in each collected fraction. Then, several peptides previously identified in dry-cured ham extracts or known to be products of DPP IV action were synthesised and assayed for DPP-IV inhibition. Peptides KA and AAATP showed the strongest DPP-IV inhibitory activity, with IC50 values of 6.27 mM and 6.47 mM, respectively. Dipeptides AA, GP, PL, and carnosine, as well as peptides AAAAG, ALGGA, and LVSGM were also DPP-IV inhibitors, although at a lower degree. These findings suggest the potential of Spanish dry-cured ham as a natural precursor of DPP-IV inhibitory peptides. These biopeptides could also be used as ingredients for functional foods or pharmaceutical products against type 2 diabetes.

Biochemical and sensory changes in dry-cured ham salted with partial replacements of NaCl by other chloride salts

The reduction of the content of sodium chloride in dry-cured ham was studied in to prevent the problems related to high sodium intake (i.e. the hypertension). One of the possibilities to reduce the sodium content is the partial replacement of sodium chloride by mixtures of potassium, magnesium and calcium chloride salts. The effect of two salting formulations (formulation II: 50% NaCl-50% KCl and formulation III: 55% NaCl, 25% KCl, 15 CaCl(2) and 5 MgCl(2)) on the protease activity through the dry-curing process and on the sensory characteristics of the final product was evaluated and compared to those of control hams (formulation I, 100% NaCl). Sensory attributes were all affected in the hams containing CaCl(2) and MgCl(2) while hams containing 50% KCl and NaCl (formulation II) were better valued, except for the attribute taste probably due to the potassium contribution to bitter taste.

Healthier meat products as functional foods

A promising approach to improving health care would be to produce a healthier food supply as a preventive health care strategy. The food supply could be improved by producing functional foods that have nutritional profiles that are healthier than conventional products. However, production of functional foods is not always easily accomplished since they must also taste good, be convenient and reasonably priced so that consumers will regularly purchase and use the products. Meats have great potential for delivering important nutrients such as fatty acids, minerals, dietary fiber, antioxidants and bioactive peptides into the diet. However, to produce successful products with these ingredients, technologies must be developed to increase their stability and decrease their flavor impact on muscle foods. In addition, many regulatory hurdles must be overcome for the commercial production of meats with added nutrients. These include redefinition of standard of identities and policies that allow front of the package nutritional claims. Without these regulatory changes, production of healthier meat products won't become a reality since these products would not have a competitive advantage over unfortified meats.

Nutritional composition of dry-cured ham and its role in a healthy diet

Dry-cured ham is a traditional product with a strong presence in markets in the Mediterranean area. It is very popular with European consumers and is of enormous economic importance for the meat industry in the Mediterranean area. Although the great palatability of ham largely outweighs other considerations, aspects relating to health and wellbeing are increasingly important factors in consumer decisions. The potential role of ham in a context of healthy nutrition has not been clearly elucidated, especially considering that origins and production methods of dry-cured hams can induce differences in composition. The object of this review was on the one hand to provide an analysis of the components of dry-cured ham and their role in a healthy diet, and on the other hand to suggest possible strategies for improving its nutritional composition.