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In response to the increasing consumers' mistrust in synthetic additives, the meat industry is focused on searching sources of natural antioxidants. Two different sources of natural antioxidants i) a mixture of garlic, cinnamon, cloves and rosemary essential oils and ii) a Rosa canina L. extract, were compared with a commercial antioxidant additive (Artinox®) for their ability to control protein and lipid oxidation in cooked hams after a settling period of 30 days and at the end of a chilled storage (150 days). The mixture of essential oils was the most effective against lipid oxidation while R. canina L. extracts were the most effective in controlling protein carbonylation at day 150. Accordingly, the use of these antioxidants via brine injection is a successful strategy to enhance the oxidative stability of cooked hams without modifying their physicochemical properties.

The effect of the addition of natural antioxidants from strawberry tree (Arbutus unedo L.; AU) and dog rose (Rosa canina L.; RC), in frankfurters elaborated with or without the addition of antioxidant additives (sodium ascorbate and nitrite) was studied. Six different types of experimental frankfurters were prepared depending on the addition of phenolic-rich extracts from RC and AU and the presence (P) or absence (C) of antioxidant additives. Thiobarbituric acid reactive substances (TBARS)-numbers significantly increased during chilled storage of C-frankfurters while additives and fruit phenolics inhibited lipid oxidation in P-frankfurters. The amount of protein carbonyls significantly increased in all treatments except in P-AU frankfurters. The discoloration process that occurred during the chilled storage was reduced by the addition of substances with proven antioxidant activity (P-frankfurters). Texture characteristics as hardness, springiness, cohesiveness and gumminess also suffered a significant deterioration in C-frankfurters. The use of phenolic fruit extracts in combination with traditional antioxidant additives is a successful strategy to enhance the oxidative stability of frankfurters without modifying their color and texture properties.

Nitrate and nitrite are commonly added to dry-cured ham to provide protection against pathogen microorganisms, especially Clostridium botulinum. Both nitrate and nitrite were monitored with ion chromatography in dry-cured hams salted with different NaCl formulations (NaCl partially replaced by KCl and/or CaCl2, and MgCl2). Nitrate, that is more stable than nitrite, diffuses into the ham and acts as a reservoir for nitrite generation. A correct nitrate and nitrite penetration was detected from the surface to the inner zones of the hams throughout its processing, independently of the salt formulation. Nitrate and nitrite achieved similar concentrations, around 37 and 2.2 ppm, respectively in the inner zones of the ham for the three assayed salt formulations at the end of the process, which are in compliance with European regulations.

[EN] 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. © 2011 Elsevier Ltd., This work was supported by grant AGL2004-05064-C02-01 from Ministry of Education and Science (Madrid, Spain) and FEDER. FPI/MEC scholarship to M. Armenteros is also acknowledged.

The effect of partial replacement of NaCl by KCl in the dry-curing of loins has been evaluated by biochemical and sensory analysis of the final products. Endoproteolytic enzymes like cathpesins B and B + L appeared to be more active when more KCl and less NaCl were present in the curing salt while cathepsin H remained unaffected. Proteolysis was reflected by SDS–PAGE in the higher density of the sarcoplasmic proteins bands within the range 55.0–28.0 kDa. Alanyl aminopeptidase (AAP) was unaffected while arginyl and leucyl aminopeptidases were more activated by KCl. On the other hand, methionyl aminopeptidase and dipeptidylpeptidase I and III were more inhibited as KCl increased in the curing salt blends. The sensory analysis revealed no significant differences between control loins with 100% NaCl and those with up to 50% of KCl substitution. Furthermore, loins elaborated with 50% of each salt obtained the highest scores.

This study is focused on the effect of sodium chloride alternative salts (KCl, MgCl2 and CaCl2) on porcine muscle proteases (cathepsins, dipeptidylpeptidases and aminopeptidases). In general, KCl exerted a very similar effect to NaCl for all the studied enzymes, while the effect of divalent salts (CaCl2 and MgCl2) was more pronounced. Cathepsins, dipeptidyl peptidase III, dipeptidyl peptidase IV and alanyl aminopeptidase activities were strongly inhibited by all the chloride salts especially by divalent ones. Dipeptidyl peptidase II and leucyl aminopeptidase were little affected and methionyl aminopeptidase was only inhibited by divalent salts. Dipeptidyl peptidase I was strongly activated by low concentrations of the chloride salts except NaCl. Arginyl aminopeptidase was activated by NaCl and KCl and low amounts of MgCl2, while CaCl2 showed a strong inhibitory effect. This is very important as these enzymes play important roles in dry-cured meats and their activity is, in general, regulated by sodium chloride. Thus, reductions in the sodium concentration with subsequent increases of other alternative cations may have relevant consequences on enzyme activity that should be taken into account when processing dry-cured meats.

An intense proteolysis of muscle proteins, mainly due to the action of endogenous proteolytic enzymes, has been reported to occur during the processing of dry-cured ham. This gives rise to an important generation of free amino acids and peptides of small size that contribute directly or indirectly to flavor characteristics of the final product. The nature and properties of the free amino acids generated during postmortem proteolysis have been well established. However, little is known about the identity of peptides generated during the processing of dry-cured ham. In the present paper, we describe the isolation (by ethanol precipitation followed by size exclusion and reverse phase chromatographies) and identification (by matrix-assisted laser desorption/ionization time-of-flight MS and collision-induced dissociation MS/MS) in a Spanish dry-cured ham of the following four oligopeptides: (A) TKQEYDEAGPSIVHR, (B) ITKQEYDEAGPSIVHRK, (C) DSGDGVTHNVPIYE, and (D) DSGDGVTHNVPIYEG. This is the first time that these peptide fragments have been reported in dry-cured ham at the end of processing. Sequence homology analysis revealed that the four peptides originated from muscle actin, indicating an extensive hydrolysis of this protein during dry-curing. Some of the cleavage sites corresponding to these fragments in actin were reproduced by other authors through the incubation of this myofibrillar protein in the presence of cathepsin D (EC 3.4.23.5), thus supporting a relevant action of this enzyme during the processing of dry-cured ham.