Production, dry-cured ham

Flavor is an outstanding characteristic of dry-cured ham. The odor-active compounds of this product have been recently identified, and these data have shown the great importance of both lipid and amino acid derived compounds. To obtain samples with odor characteristics similar to those of dry-cured ham, several temperatures were applied to meat samples, and a mild temperature was selected. Compounds previously identified as dry-cured ham odorants were researched by SPME-GC-MS, and the effect of several factors on them was checked. The increase of sodium chloride content caused a general increase in aldehydes, except for 3-methylbutanal. The addition of sodium nitrite caused a general decrease, specially in straight-chain aldehydes. The addition of cysteine and proline on the odorants identified was less important. Reaction time influenced the odorants, with a marked effect on pentanal and hexanal. 

Flavor is one of the most valuable characteristics of dry-cured ham (i, 2), a valuable non-cooked but ripened pork meat product from southwestern European countries, and dry-cured ham flavored products are also appreciated. The great interest of dry-cured ham flavor has lead to an extensive research on this topic. The first works on the compounds involved in dry-cured ham flavor were... 

Aldehydes are by far the most numerous compounds identified as dry-cured ham odorants, with different odors (green, rancid, toasted) and thresholds in air ranging from 0.09 to 480 ng/L (Table 1). Most of them were identified in the first works focused on dry-cured ham volatile compounds (7,2). Aldehydes are essential for meat flavor (70), but large quantities in meat and meat products have been related to lipid oxidation and deterioration (77). The effect of several quality factors has been researched and it was found that the rearing system of pigs (S) and ripening conditions (7) influence on the contribution to odor and the content of some aldehydes. 

Considering that the zero tolerance requirement brought about many problems in terms of export of San Daniele dry cured ham to the USA because of a remote chance that it may be affected by a very low contamination with L. monocytogenes (<10 CFU/g) as it is impossible to completely eliminate it during production or in the finished product, the aim of the work was to produce and validate different methods to eliminate or reduce L. monocytogenes from San Daniele Dry cured ham. The methods used included chemical solutions (1.5% sodium lactate, 1% sodium diacetate, a 1.5%/1.0% sodium lactate/diacetate mixed solution), ionized air, water and ozonised air, hydrogen peroxide solution, essential oils and microbial protective starter (Leuconostoc camosum). 

Odour and color of both treated samples were not changed by the ionized treatment. Only a minor dehydration on the surface of both treated samples was noticed. Indeed, no oxidative products were released by the ionized treatments. The number of peroxides in the treated DCH slices must be considered low, being 7.4-7.9 meq O /Kg. This value was less than or similar to the untreated samples, that is 7.7-10.3 meq OJKg. The differences might stem from the applied method and from the difficulties in extracting fat from dry cured ham slices. The peroxide products were not assessed in treated pig skin samples because their oxidation does not lead to a loss in the product quality. 

Listeria monocytogenes is a ubiquitous micro-organism and therefore may contaminate dry cured ham during the production phase. The technology used in production poses a few hurdles such as salting and dehydration, which prevent the germ from growing. 

For the production of San Daniele dry cured ham, these treatments could be defined as post-lethality processes to be applied to the finished product after debon-ing and before packaging under vacuum. The treatments showed a high level of repeatability and reproducibility. 

Comi G, Urso R, Paiani M, Ottaviani S (2005a) Dry cured ham cured and packaged in modified atmosphere or under vacuum effects of different additives and of Aw on the behavior of L. monocytogenes. Ind Alim XLIV, Marzo, 272-278 Comi G, Lovo A, Bortolussi N, Paiani M, Berton A, Bustreo G (2005b) Use of an ionizing device for air decontamination in cells used for the production of San Daniele dry cured ham. Ind Alim XLIV, Ottobre, 1-9... 

Country-cured hams are made by dry curing hams so as to be stable at ambient temperatures and are produced in a similar form in many countries (Kemp et ai, 1983 Pearson and Tauber, 1984 Romans et al, 1985). These products have a high-salt content, which lowers their a and makes them stable. During storage, the indigenous enzymes, particularly the cathepsins, play a role in flavor development (Toldra and Etherington, 1988 Lopez et al, 1992). Country-cured hams have an a , of about 0.80-0.85 and are in demand in the southern United States. 

Several recent studies have demonstrated that peptides obtained from proteins from the following sources are able to inhibit DPP-IV dairy products [126, 127, 129-131, 135, 139-141], defatted rice bran [132], tuna cooking juice [133], dry-cured ham [Vi, Amaranthus hypochondriacus [136], barley [126], canola [126], oat [126], soybean [126], wheat [126], chicken egg [126], bovine meat [126, 142],... 

For example, intense proteolyses of muscle proteins, due to the action of endogenous proteolytic enzymes, have been reported to occur during the processing of dry-cured ham. This gives rise to the formation of free amino acids and short peptides (especially from actin through the action of cathepsin D in meat and from caseines as a result of plasmin and other proteases in cheeses) that contribute directly or indirectly to the flavour characteristics of the final product. In the case of octapeptide Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala, isolated from beef broth, this reportedly showed umami taste with a threshold value of about 500 mg/1. 

Other stressing treatments employed to improve the microbial stability of some meat products merit consideration. This is the case for high hydrostatic pressure (HHP) treatment in use in several countries for the preservation of various sausage or dry-cured ham. By a proteomic investigation, it was notably shown that Lact. sakei can react differently from other bacterial species after an HHP treatment (Jofre et al. 2007). In addition, flow cytometry was successfully used to test the ability of Lact. sakei cells to survive different stresses like acidic or high temperature stresses (Bonomo et al. 2013) illustrating one of the numerous tools available for starter culture selection. 

Fermented meat products comprise a heterogeneous group of dry-cured sausages and hams. At present, the application of starter cultures is almost exclusively confined to fermented, dried sausages. 

In Spain there are many food products (wine, spirits, cheeses, virgin olive oils, cured ham, rice, dried pulses, peppers, asparagus, fruits, picked vegetables, fresh meat, cured sausages, honey, nougat, and cured meats) that are protected under a Protected Designation of Origin (PDO) or a... 

In a follow-up study by the same research group, this methodology was used to investigate the effects of different pig rearing systems on the quality of the final product of dry-cured Iberian ham. In this work, a switchable reagent ion source was used to generate H3O +,... 

In the case of meat products such as dried ham, salt plays an important role in the development of flavors as well as in the texture of the product. As a matter of fact, the pH, the concentration of NaCl and the temperature are the factors that most influence proteolysis during ham curing. An ultimate low pH (< 5.7) promotes the release of proteases, whereas a strong concentration in NaCl is an inhibitor for the activity of proteases. As a result, the decrease in NaCl in dry ham not only causes problems of health safety but also texture defects (flabby and doughy) [HAR 14]. 

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