J. Arnau

Effect of sodium chloride replacement on some characteristics of fermented sausages

The reduction of added NaCl in fermented meat products has been proposed to decrease the amount of sodium in the diet. The effect of substituting NaCl by KCl, potassium lactate (K-lactate) or glycine (0-40%) in some sensory, microbiological and physicochemical characteristics of fermented sausages was evaluated. The sensory effects of substituting NaCl by mixtures of glycine and KCl or glycine and K-lactate was also evaluated. The partial substitution of NaCl by KCl, K-lactate and glycine had little effect on microbiological stability. However, flavour and/or textural defects were detected by sensory analysis with substitution levels of 40% by KCl, 30% with K-lactate and 20% with glycine. The partial substitution (above 40%) of NaCl with different mixtures of KCl/glycine and K-lactate/glycine showed important flavour and textural defects which did not permit an increase in the level of substitution compared to those obtained with the individual components.

Potassium chloride, potassium lactate and glycine as sodium chloride substitutes in fermented sausages and in dry-cured pork loin

Salt is essential in the elaboration of dry meat products, contributing to their texture and flavour development. The effect brought about by substituting NaCl with KCl (0-60%), potassium lactate (0-100%) and glycine (0-100%) on the texture, flavour and colour characteristics of fermented sausages and dry-cured pork loins was evaluated. Texture profile analysis and a sensory analysis were performed. Important flavour defects were detected with substitutions above 40% for the three substituents in both products, and with substitutions above 30% for glycine in dry-cured loin. A loss of cohesiveness was detected by the sensory analysis in fermented sausages at substitution levels higher than 30% with potassium lactate (K-lactate) and higher than 50% with glycine. Although the instrumental analysis detected texture changes in dry-cured loin, the sensory analysis did not detect any substitution effect on texture.

Texture parameters of dry-cured ham m. biceps femoris samples dried at different levels as a function of water activity and water content.

Instrumental texture parameters of m. biceps femoris (BF) samples from six commercial dry-cured hams, dried to a different degree, were related to water activity and water content. Samples were carved into cubes and Texture Profile Analysis (compression 50%, 10 mm high samples), water activity (a(w) 25 °C) and water content analyses were performed. A negative non-linear relationship between hardness and water content and water activity was observed. From this relationship, critical X and a(w) values, below which there is a dramatic increase in hardness, can be found (around 0.55 kg H(2)O/kg dry matter and around 0.70, respectively). Cohesiveness and springiness showed a positive linear relationship with water content and water activity.

The influence of meat pH on mechanical and sensory textural properties of dry-cured ham.

The texture of dry-cured ham is one of the most important factors in consumer quality perception of the product. In this study the texture and mechanical properties of normal and Dark, Firm and Dry (DFD) dry-cured hams were studied as well as the relationship between them. DFD hams were softer, pastier, more crumbly and more adhesive than normal ones despite having lower non-protein nitrogen (p<0.05). One of the reasons for the texture characteristics of DFD hams could be the higher level of moisture observed in the Biceps femoris muscle and the high pH value. The mechanical parameters studied also showed clear differences between the two groups of hams, specially in the inner part which was less affected by the drying process. In general the correlation coefficients between sensorial and mechanical parameters were not very high (0.23-0.62). The use of a non-destructive mechanical test, compressing the ham with a spherical probe, makes it possible for DFD hams to be detected in the earlier stages of the manufacturing process and means that technological changes can be made in order to reduce the problematic texture obtained from this kind of meat.

Effects of potassium lactate and high pressure on transglutaminase restructured dry-cured hams with reduced salt content.

Ten raw hams (from 5 carcasses) were boned and salted either with salt reduction (15g/kg NaCl) or salt reduction with addition of potassium lactate (15g/kg NaCl and 39.74g/kg of a 60% K-lactate solution). Subsequently, the ham pieces were assembled together with transglutaminase, vacuum packed into water-permeable plastic bags and kept at 3°C and 85% RH until reaching above 30% weight losses. The effects of K-lactate addition and the high-pressure (HP) treatment at 600MPa on the physicochemical, instrumental colour and texture (Tensile test) and sensory characteristics of the biceps femoris (BF) muscle were evaluated. The addition of K-lactate did not have a negative effect on colour, flavour or texture of restructured dry-cured hams. The HP treatment increased significantly the pH, L(∗), a(∗) and b(∗) values and the breaking stress, and decreased the water-holding capacity and elasticity (apparent Youngs modulus) of BF muscle. The HP treatment also affected significantly the flavour (increasing saltiness, umami and sweetness) and the sensory texture attributes (increasing muscle binding, hardness, gumminess and fibrousness and decreasing adhesiveness and pastiness), as well as slice appearance (increasing brightness and iridescence and decreasing colour homogeneity).

The effect of green ham pH and NaCl concentration on cathepsin activities and the sensory characteristics of dry‐cured hams

There is a tendency to reduce the amount of NaCl in the manufacturing process of Spanish dry-cured ham. NaCl, pH and temperature determine the stability of this product. This study was concerned with the evaluation of green ham pH and sodium chloride concentration on cathepsin activities, physico-chemical parameters and sensory characteristics of dry-cured hams. Two different amounts of salt (55 and 80 g kg−1) and two different pH levels (pH at 24 h post mortem 6·2) were used. Physico-chemical composition, cathepsin activity and a number of sensory parameters were evaluated. Hams with high pH displayed lower cathepsin activity, NPN, saltiness and hardness whereas the levels of brightness, crumbliness, pastiness and adhesivity were found to be higher than in normal hams. A high level of salt produced greater cathepsin B and B+L activity and lower pastiness and adhesivity than the samples with a low NaCl level.

Physical and chemical changes in different zones of normal and PSE dry cured ham during processing

Abstract The changes of moisture, pH, NaCl, nitrate and nitrite in different zones of the ham during the process were evaluated in 15 normal and 15 PSE hams. No difference in pH was found between PSE and normal hams. When all the sampling times were analysed together, the PSE hams were found to contain more moisture and NaCl than normal hams in certain muscles. In most zones, pH increased during the process. The external zones showed a higher salt concentration at the beginning, but this trend reversed during aging owing to salt penetration from the drier external zones to the more humid inner zones. The total NaCl in the lean tissue of the hams increased after salting and remained constant after the resting phase. Nitrate diminished quickly during the resting period, especially in the external zones, whereas nitrite increased after the salting period and did not exceed 10 ppm at the end of the process. Dry cured ham is a nonhomogeneous product that undergoes a salting and dehydration process that determines the dynamics of the migration of the water, NaCl, nitrate and nitrite.

Effect of pH24, NaCl content and proteolysis index on the relationship between water content and texture parameters in biceps femoris and semimembranosus muscles in dry-cured ham

The aim of the present study was to determine the effect of pH level and NaCl content on the relationship between water content and texture parameters in semimembranosus and biceps femoris muscles in dry-cured ham. The experiment was undertaken using 18 hams, selected in a commercial slaughterhouse. Half of the hams had a pH<5.7 and the rest a pH>6.2, measured in the semimembranosus muscle at 24-h post mortem (pH(SM24)). The hams were treated with 20, 50 or 80g of NaCl per kg of ham. At the end of the aging process nine samples from semimembranosus and biceps femoris muscles were dried to different levels of water content covering the range from 22.4% to 58.5%. At the end of the drying period, a Texture Profile Analysis was used to determine textural parameters. Samples from biceps femoris muscle and samples from hams with low pH(SM24) showed a higher proteolysis index (100×non-protein nitrogen/total nitrogen) than samples from semimembranosus muscle and samples from hams with high pH(SM24), respectively. The proteolysis index decreased when the added NaCl amount increased. The proteolysis index was the parameter that best explained the modifications in the relationship between water content and the texture parameters (hardness, cohesiveness and springiness) of dry-cured ham muscles and it would be considered in order to predict the texture in dry-cured ham at different drying levels. Dry-cured hams with a lower proteolysis index were more prone to present harder texture at low water contents, which is typical of hams with crustiness problems.

Relationship between water content, NaCl content, pH and texture parameters in dry-cured muscles

The aim of the present study was to describe the effect of NaCl and pH on the relationship between water content and hardness, cohesiveness and springiness in dry-cured muscles. The experiment was undertaken using 18 hams, selected in a commercial slaughterhouse. Half of the hams had a pH<5.7 and the rest a pH>6.2, measured on the semimembranosus muscle at 24-h postmortem. The semimembranosus and biceps femoris muscles were cut from hams, cured and individually packaged in bags and were laid in trays in a room at 2±2°C for 45days. Thereafter nine samples from each muscle were shaped like a parallelepiped and dried until different levels of drying, ranging from 28.5% to 59.7% water content, were attained. The rest of the muscle was ground and packaged until its subsequent physicochemical analysis. At the end of the drying period, a Texture Profile Analysis was used to determine textural parameters. The results indicated that for a range of X (kg H(2)O/kg dry matter) between 0.8 and 1.3 the hardness remains practically unchanged while for X<0.6 the hardness increases substantially. The samples from hams with low pH(SM) had greater hardness, cohesiveness and springiness than those from hams with high pH(SM). Dry-cured muscles with lower NaCl content showed lower hardness, cohesiveness and springiness, especially in those with pH(SM)>6.2. At X values lower than 0.6 the hardness was more influenced by water content than by NaCl content or pH(SM).

Effect of curing salt and phosphate on the activity of porcine muscle proteases

The effect of curing salt on the activity of porcine muscle proteases was evaluated, within the salt concentration range found in the manufacturing process of Spanish cured ham. Salt (NaCl) acts as a strong inhibitor of proteolytic activity; sodium nitrate and potassium nitrate do not affect cathepsin D activity; cathepsin L is inhibited at levels of the salts not found in cured ham, and Ca-dependent proteolytic activity is enhanced by nitrate concentrations below 800 ppm. The appearance of phosphate precipitates in several areas of ham has led to the study of phosphate effect on enzymatic activity. Results show that phosphate is an inhibitor of proteolytic activity.