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Physicochemical changes in dry-cured hams salted with potassium, calcium and magnesium chloride as a partial replacement for sodium chloride
Meat Science 86 (2010) 331–336
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Meat Science j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / m e a t s c i
Physicochemical changes in dry-cured hams salted with potassium, calcium and magnesium chloride as a partial replacement for sodium chloride M. Aliño a, R. Grau a, F. Toldrá b, J.M. Barat a,⁎ a b
Departamento de Tecnología de Alimentos. Universidad Politécnica de Valencia, Camino de Vera s/n. 46022, Valencia, Spain Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Apartado de correos 73, 46100, Burjassot, Valencia, Spain
a r t i c l e
i n f o
Article history: Received 25 December 2009 Received in revised form 3 May 2010 Accepted 4 May 2010 Keywords: Dry-cured ham Sodium-replacement Potassium Calcium Magnesium
a b s t r a c t The reduction of added sodium chloride in dry-cured ham has been proposed to reduce dietary sodium intake in Mediterranean countries. The effect of substituting sodium chloride with potassium chloride, calcium chloride and magnesium chloride on some physicochemical characteristics of dry-cured ham during processing was evaluated. The results showed that hams salted with a mixture of sodium and potassium chloride registered higher salt concentrations and lower water contents and thus, needed less time to reach the required weight loss at the end of the process. The opposite effect was observed when calcium and magnesium chloride were added to the salt mixture. The observed differences in the texture and colour parameters were mainly due to differences in water and salt content. © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.
1. Introduction Dietary intake of sodium, from all sources, influences blood pressure (BP) levels in populations and should be limited in order to reduce the risk of coronary heart disease and both forms of stroke (WHO, 2003). However, sodium intake exceeds the nutritional recommendations in most industrialised countries; the main source of sodium in the diet being sodium chloride. Dry-cured ham is a product with truly extraordinary sensory and nutritional characteristics associated with haute gastronomy. It is one of the most traditional cured meat products in the Mediterranean area, with an enormous economic importance in its sector; for example, more than 40 million pieces are produced per year in Spain. However, its high sodium content makes dry-cured ham a nonrecommended product for hypertensive consumers. Therefore, it is a challenge for the dry-cured ham industry to lower sodium content in ham (typically 5–6%) due to concern for hypertension-suffers (Morgan, Aubert, & Brunner, 2001). Increased sodium intake is associated with increased BP, whereas increased potassium and calcium intake may slightly decrease BP (Geleijnse, Witteman, Bak, den Breeijen, & Grobbee, 1994). Moreover, magnesium intake has been inversely associated with BP (Mizushima, Cappuccio, Nichols, & Elliott, 1998; Jee et al., 2002). A possible approach to reduce the global sodium content is the partial or total replacement of NaCl with other chloride salts (KCl, CaCl2
⁎ Corresponding author. Tel.: + 34 963877365; fax: + 34 963877956. E-mail address: [email protected] (J.M. Barat).
and MgCl2) or non-chloride salts such as phosphates, or a combination of both (Sofos, 1984, 1986, 1989; Terrell, 1983). Partial sodium replacement with other cations such as potassium, calcium and magnesium has recently been proposed for Spanish dry-cured porkloins (Aliño et al., 2009; Armenteros, Aristoy, Barat, & Toldrá, 2009a,b). The results obtained were useful for the application of this salting method to the Spanish dry-cured ham process. The use of mixtures of salts with low sodium content may imply significant changes in the different steps (salting, post-salting and dry-ripening) that constitute the whole manufacturing process. The salting stage with sodium replaced salts has been characterised in previous studies using pork-loin as a model system for dry-cured ham, due to its shape, homogeneity and short processing treatment (Aliño, Grau, Baigts & Barat, 2009; Aliño, Grau, Fuentes & Barat, 2010a). After pile-salting, greater potassium penetration was observed while calcium and magnesium cations had more difficulty penetrating the muscle remaining in the brine formed during the pile-salting process. Cation composition in the brine changed considerably from the solid salt. So, the rub-salting method was proposed for dry-cured ham processing in order to control cation proportions in the mixture of chloride salts. Moreover, the presence of KCl decreased salting time whereas CaCl2 and MgCl2 had the opposite effect. Salt diffusion takes place during post-salting, enabling the salt located near the ham surface, which is gained during salting to penetrate the deeper zones, thus decreasing the water activity and ensuring the preservation of the hams when increasing the temperature in the following step (dry-ripening). Therefore, the influence of different mixtures of chloride salts with partial replacement of sodium on the physicochemical properties and the microbiota of dry-cured ham during
0309-1740/$ – see front matter © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2010.05.003
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M. Aliño et al. / Meat Science 86 (2010) 331–336
the post-salting stage were studied (Aliño, Grau, Fuentes & Barat, 2010b; Blesa et al., 2008). The results showed that the presence of other chloride salts delayed the decrease in water activity and thus increased the post-salting time needed to reach similar water activities as in the traditional process. Moreover, no significant differences in microbial counts were observed between hams salted with the different salt formulations. The results obtained in these previous studies were used to elaborate the final product. The next step (dry-maturation or ripening period) involves time– temperature combinations. The homogenized pieces are placed in natural or air-conditioned drying chambers where the relative humidity usually varies between 90% and 70% with a temperature range from 5 to 26 °C. The aim was to study the influence of partial sodium replacement with potassium, calcium and magnesium chloride salts on the physicochemical parameters of dry-cured ham at the end of the manufacturing process. 2. Materials and methods
The final weight of each ham was measured. Physicochemical analyses were carried out on each ham in five zones, obtained from the widest section of the ham, A (near the lean surface) and A′ in the Semimembranosus muscle; B, B′ (both near the femoral artery) and C (near the subcutaneous fat) in the Biceps femoris muscle. These points are shown in Fig. 1. 2.2. Colour determinations Colour measurements were taken shortly after cutting the slice in zones A, A′, B, B′ and C. Reflectance spectra were determined with a UV/VS Minolta Spectrophotometer model CM-3600d from 400 to 700 nm, at 10 nm intervals, using an integrating sphere. The colour system employed was CIE L*a*b*. D-65 illuminant was used with 10° observer angles (Cassens et al., 1995). The illuminant D-65 evaluates colour using typical bright daylight with an overcast sky and colour temperature at 6500 K. L*, a* and b* values were obtained from the mean of 6 determinations per analysed zone. 2.3. Texture profile analysis (TPA)
Twenty-one fresh hams with an average weight of 10.8 ± 0.5 kg were selected in a local slaughterhouse controlling the pH within the 5.5 to 6.0 range. All the hams were frozen in an industrial freezer at −40 °C and stored for at least 30 days at −20 °C. Then, the frozen hams were thawed in a cold chamber at 3 °C for 5 days, in a similar way to the industrial process (Bañón, Cayuela, Granados & Garrido, 1999, Motilva, Toldrá, Nadal, & Flores, 1994). Three of the hams were used as a control for the raw material. Their moisture (xw), water activity (aw), fat content (xf) and chloride (XCl), sodium (XNa), potassium (XK), calcium (XCa) and magnesium (XMg) concentrations were analysed on a dry matter basis (Table 1). The remaining 18 hams were randomly divided into three groups of 6 hams each, salted using 100% NaCl salt (batch I), a mixture of NaCl and KCl at 50% (batch II) and a mixture of 55% NaCl, 25% KCl, 15% CaCl2 and 5% MgCl2 (batch III). Salt formulations were chosen according to the results obtained in previous works on low sodium dry-cured porkloins (Aliño, Grau, Toldrá, et al., 2009; Armenteros et al., 2009a,b). The salting stage was carried out at 3 ± 1 °C and 90% relative humidity for a total of 10 days and all hams were weighed every day. Hams were salted by rubbing and kneading with the 3 combinations of salts, the quantity of salt mixture was 2% of the weight of the ham, 200 ppm of KNO3 and 100 ppm of NaNO2 were added to the mixture for each ham as curing agents. After salting, hams were post-salted at 4.5 °C and a relative humidity between 75 and 85%. At the end of the post-salting stage, the hams were taken to the last processing stage (dry-ripening) where the temperature was progressively increased from 6 to 20 °C and relative humidity reduced from 80 to 65%. The process was finished when total weight loss reached 32–34% of the initial weight, which is in the range of typical values achieved in industry (Toldrá, 2006).
Textural properties were measured by double compression using a Texture Analyzer TA.XT2 (Stable MicroSystems, UK) equipped with a flat-ended cylindrical plunger (SMS-P/75). The force (N) was recorded continuously during compression on a texture profile curve with a load cell of 250 N. Determinations were carried out on 3 cubes taken (inner, middle and outer) from one slice of each loin. Cubic samples (20 × 20× 20 mm.) were compressed axially (20% compression), with a constant cross-head speed of 1 mm/s. The holding time between both compressions was 5 s (Tabilo, Flores, Fiszman, & Toldrá, 1999). Force versus time was recorded and the following parameters were calculated: hardness (g), cohesiveness (dimensionless), springiness (dimensionless), adhesiveness and chewiness (g). 2.4. Analytical determinations The pH of the hams was measured with a portable pH-meter (Crisol, model 507). The average pH of the 21 hams was 5.8 ± 0.2. Moisture content (xw) was determined by oven drying to constant weight at 100 °C (ISO Norm R-1442, 1979). Fat content (xf) was analysed according to ISO Norm R-1443 (1973) using a FOSS Soxtec System 2055 Tecator. The water activity (aw) of each sample was determined using an Aqualab® dew point hygrometer (Decagon Devices, Inc., Washington, USA). Chloride was determined after sample homogenisation in a known amount of Milli®-Q water at 9000 rpm in an ULTRATURRAX T25 for 5 min and centrifuged at 10,000 g for 20 min at 4° to remove any fine debris present in the sample. Afterwards, the supernatant was filtered through nylon membrane filters (45 µm) and a sample of exactly 500 μl was taken and titrated in Chloride Analyzer equipment (CIBA Corning Mod. 926). The same aliquot was used to analyse the sodium, potassium, calcium and magnesium in each sample by ion chromatography using
2.1. Sampling In all the treatments, the sampling was carried out at the end of the dry-ripening stage, once hams reached 32–34% of total weight loss. Table 1 Mean values ± standard deviation of water activity (aw), water (xw) and fat (xf) contents (w/w) and chloride, sodium, potassium, calcium and magnesium concentrations on a dry matter basis (DM), in grams/gram of dry matter, X Cl, X Na, X K, X Ca and X Mg, respectively, in the raw material. aw ± SD xw ± SD (w/w) xf ± SD (w/w) XCl ± SD (DM)
0.987 ± 0.001 0.741 ± 0.008 0.03 ± 0.02 0.0028 ± 0.0002
X Na ± SD X K ± SD X Ca ± SD X Mg ± SD
(DM) (DM) (DM) (DM)
0.00130 ± 0.00003 0.0040 ± 0.0002 0.00022 ± 0.00005 0.00018 ± 0.00003
Fig. 1. Samples A, A′, B, B′ and C from the widest ham section.
M. Aliño et al. / Meat Science 86 (2010) 331–336
an ion exchange column (Metrosep C2, 250/4.0, Methrom®, Herisau, Switzerland) in PC-controlled Compact IC 761 equipment (Methrom®, Herisau, Switzerland), with the following parts: built-in double piston pump, electrically operated injection valve and a temperature-stabilized high performance conductivity detector. The mobile phase was tartaric acid–dipicolinic acid (4.0–0.75 mmol/L) at a rate of 1.0 ml/min. The separation was monitored using a conductivity detector and IC Net 2.3 software (Methrom® Ltd., Herisau, Switzerland) was used to process the data. The concentration of each cation was determined by interpolation on the corresponding calibration curve. The calibration for the assay was established using a triplicate set of standard solutions of Na+, K+, Ca2+ and Mg2+ (Fluka, Switzerland, Sigma, St. Louis, MO). The results were the means of three determinations. Salt weight fraction (xss) was calculated as the addition of the major ionic compounds (Eq. 1), being xCl, xNa, xK, xCa and xMg, the chloride, sodium, potassium, calcium and magnesium weight fractions. ss
Cl
Na
x =x +x
K
+x +x
Ca
+x
Mg
ð1Þ
Total salt, chloride, sodium, potassium, calcium and magnesium concentrations on a dry matter basis (Xss, XCl, XNa, XK, XCa and XMg respectively) were estimated from xw, xss, xCl xNa, xK, xCa and xMg, respectively, as shown in Eq. (2).
i
X =
i
x ð1−xw Þ
ð2Þ
Total salt concentration in the meat liquid phase (zss) was estimated from xw and xss as shown in Eq. (3).
ss
z =
xss x + xw
ð3Þ
ss
2.5. Statistics The effect of the salt formulation on the variables: water activity (aw), salt concentration on a dry basis (Xss), colour and texture parameters, was performed by analysis of variance, one-way ANOVA. In those cases where the effect was significant (p b 0.05) the mean values were compared using Fisher's least significant difference (LSD) procedure. Statistical processing was performed using Statgraphics® Plus 5.1 version software (Manugistics, Rockville, MD, USA).
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3. Results and discussion 3.1. Values of total salt content, water content and water activity at the end of the process The effects of the salt formulation on total salt content on a dry matter basis (Xss), on total water content (xw, w/w) and on water activity (aw) are shown in Table 2. Total salt content (Xss) was affected by salt composition. In fact, hams salted with the salt mixture containing 50% NaCl and 50% KCl (II), registered higher Xss values than the control batch (I: 100% NaCl). However, these differences were not statistically significant (p ≥ 0.05). Moreover, mean Xss values in hams salted with III, containing CaCl2 and MgCl2 (15% and 5%, respectively), were lower than in I and II. These differences were significant (p ≤ 0.05) in zones A and A′ with regard to batch I and in zones A, A′ and B′ with regard to batch II. So, it seems that the presence of divalent cations slows down salt penetration into the muscle. This is in agreement with the results obtained for dry-cured loins and in the post-salting stage of dry-cured ham (Armenteros et al., 2009b; Aliño et al., 2010b). As it can be seen, xw mean values in hams salted with II were lower than in I and III in all the analysed zones, being significantly different from the control batch (p ≤ 0.05) in the outer zones A and A′, next to the lean surface. xw mean values in III in the inner zones B′ and C were significantly higher (p ≤ 0.05) than in batches I and II. It seems that salt content and water content affected total weight losses at the end of the process (ΔMºf), being lower in hams salted with formulation III, containing CaCl2 and MgCl2 (15% and 5%, respectively) On the contrary, hams salted with formulation II, registered higher weight losses than the control batch (I) and batch III. The mean processing time needed to reach the final weight loss at the end of the process (32–34%) was 185 ± 24 days in the control batch, 165 ± 14 days in batch II and 203 ± 36 days in batch III, these differences being significantly different (p ≤ 0.05) between batches II and III. So, even if hams salted with II needed more post-salting time to reach similar aw than in the traditional process (Aliño et al., 2010b), this did not affect the whole processing time. On the contrary, it seems that an increase in the whole processing time would be needed when salting with mixture III. Regarding aw, mean values in III were significantly higher than mean values in I and II in A, A′, B′ and C. Higher aw values in III could have been expected as MgCl2 and CaCl2 decrease aw more than NaCl and KCl. In fact, the values of parameter “B”, characteristic of every electrolyte in the equation of the Pitzer–Bromley model to predict water activity in aqueous solutions, are B = 0.1129, 0.0948, 0.0574 and 0.024, for MgCl2, CaCl2, NaCl and KCl, respectively. Nevertheless, the lower salt concentration in III due to the difficulty of divalent cations penetrating the muscle induced higher water content and thus higher aw values. The opposite effect was seen in hams salted with II.
Table 2 Mean values ± standard deviation of salt content on a dry matter basis (Xss), water content (xw, w/w) and water activity (aw) in the sample points A (lean surface), A′, B, B′ and C (inner point) zones at the end of the process in the three batches I, II and III. Zone
Xss (I) Xss (II) Xss (III) xw (I) xw (II) xw (III) aw (I) aw (II) aw (III)
A
A′
B
B′
C
0.069 ± 0.009 a 0.070 ± 0.005 a 0.053 ± 0.003 b 0.54 ± 0.02b 0.51 ± 0.02a 0.53 ± 0.02ab 0.935 ± 0.004a 0.932 ± 0.003a 0.942 ± 0.004b
0.090 ± 0.008 a 0.093 ± 0.004 a 0.068 ± 0.005 b 0.59 ± 0.02b 0.56 ± 0.04a 0.59 ± 0.02ab 0.935 ± 0.004a 0.932 ± 0.004a 0.945 ± 0.004b
0.086 ± 0.024a 0.086 ± 0.011a 0.070 ± 0.006 a 0.55 ± 0.06a 0.56 ± 0.05a 0.56 ± 0.06a 0.936 ± 0.004a 0.937 ± 0.005a 0.941 ± 0.006a
0.107 ± 0.010 ab 0.112 ± 0.017 a 0.091 ± 0.005 b 0.63 ± 0.01a 0.62 ± 0.01a 0.65 ± 0.01b 0.939 ± 0.004a 0.932 ± 0.004b 0.950 ± 0.003c
0.102 ± 0.007 a 0.107 ± 0.021a 0.087 ± 0.004a 0.62 ± 0.01a 0.62 ± 0.01a 0.64 ± 0.01b 0.935 ± 0.005a 0.933 ± 0.004a 0.949 ± 0.003b
Means in a column with different letters are significantly different at p-value ≤ 0.05.
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aw mean values in II were lower than in the control batch, however, these differences were only significant (p ≤ 0.05) in B′. It must be noted that no significant differences were observed in any of the parameters in zone B. This could be due to the higher fat content (xf, w/w) of this zone compared to the rest of the zones, which would hinder salt penetration by any salt mixture, xf (A) = 0.02 ± 0.01, xf (A′) = 0.024 ± 0.01, xf (B) = 0.09 ± 0.03, xf (B′) = 0.014 ± 0.008, xf (C) = 0.013 ± 0.008. The use of salt concentration in the ham liquid phase (zss) is closely related to aw values in the ham throughout the salting and postsalting periods and to the perceived saltiness of the final product. It also enables a better understanding of the transport phenomena taking place in the meat liquid phase throughout the process. Barat, Rodríguez-Barona, Andrés and Fito (2002) found in a study of cod salting that after 15 days, the equilibrium zNaCl value and the NaCl weight fraction value in the brine (yNaCl) were the same. This observation was in agreement with other solid–liquid operations in which the equilibrium between the liquid phases present in the system is defined by the equality in concentrations (Barat, Chiralt, & Fito, 1998; Griskey, 2002). Fig. 2 shows aw values at the end of the dry-ripening period. The aw values for the ham in all the sample points were slightly lower than those corresponding to brine with the same salt proportions as the salt formulations (I, II and III). These differences were higher with lower water content compared to those that would be seen during the post-salting stage (Aliño, Grau, Baigts, & Barat, 2009). These particular differences could be explained by the water interacting with the ham protein matrix and with the peptides and amino acids in the meat liquid phase generated as a result of the intense enzymatic activity. These differences were significantly higher (p ≤ 0.05) in II than in I and III (0.031 ± 0.006, 0.033 ± 0.005 and 0.0297 ± 0.0036 units of aw, in I, II and III respectively). 3.2. Sodium, potassium and magnesium penetration in the ham profile Fig. 3 shows the sodium–potassium ratios (Na/K) of the added salts at the end of the dry-curing process in the ham profile and in the solid salt in batches II (a) and III (b). As can be seen, Na/K was constant throughout the ham profile. In fact, both sodium and potassium concentrations in the
Fig. 3. Na/K ratio in the ham and in the salt mixture throughout the ham profile, in batches II (a) and III (b).
meat liquid phase (zNa and zK) remained uniform in the 5 zones of the ham profile so that equilibrium concentration was reached at the end of the process (zNa (II)= 0.0118 ±0.0006 g Na/g liquid phase and zK (II)= 0.0204±0.0008 g K/g liquid phase; zNa (III) = 0.0110 ±0.0002 g Na/g liquid phase and zK (III) = 0.0115 ± 0.0004 g K/g liquid phase.). The Na/K ratio was lower in the ham than in the salt mixture in both salting treatments, indicating that K+ penetrated the muscle more than Na+. The same results were obtained in dry-cured loin salted with mixtures of NaCl and KCl salts in different proportions (Aliño, Grau, Toldrá, et al., 2009; Armenteros et al., 2009a). This difference was higher in hams salted with III, where the presence of Ca2+ and Mg2+ could have hindered penetration of salts and NaCl in particular. Fig. 4 shows Na/Ca (a), Na/Mg (b), K/Ca (c) and K/Mg (d) ratios of added salts at the end of the dry-curing process in the ham profile and in the salt mixture in batch III. Na/Mg and K/Mg ratio values were higher, and significantly different (p ≤ 0.05) in the inner zones than in the superficial zones, inducing a higher penetration of sodium and potassium in the inner muscles than magnesium. It seems that calcium had similar behaviour, remaining mainly in the outer zones. However, no significant differences were observed in the mean values of Na/Ca and K/Ca ratios between the zones (A, A′, B, B′ and C). Higher differences could have been expected; nevertheless, the high standard deviations (SD) obtained in calcium concentration values could have influenced the results (zCa (A) = 0.0015 ± 0.0005 zCa (A′) = 0.0012 ± 0.0007, zCa (B) = 0.0013 ± 0.0009, zCa (B′) = 0.0016 ± 0.0012 and zCa (C) = 0.0012 ± 0.0006 g Ca/g liquid phase). These high SD's could be explained by the heterogeneity of CaCl2 penetration, the amount of Ca2+ in the raw material or the small quantities added. In fact, calcium binds more strongly to the outermost layers of the muscle proteins, compacting the surface of the meat (Iyengar & Sen, 1970). Moreover, these ratios were higher in the ham than in the salt mixture. It seems that divalent cations had more difficulty penetrating the muscle. Considering that during the salting stage brine (salt solution) is generated and surrounds the ham, forming a layer on its surface, cation penetration in the ham would be affected by brine composition. Aliño, Grau, Baigts and Barat (2009) studied cation penetration throughout pork-loin pile-salting with mixtures of NaCl, KCl, CaCl2 and MgCl2 and found that higher Ca2+ and Mg2+ concentrations were observed in the brine with regard to their concentration in the solid salt due to the higher water solubility of CaCl2 and MgCl2 compared to NaCl and KCl. In addition, these divalent cations penetrated less than monovalent cations in the muscle. Further studies need to be done to determine cation concentrations outside the ham, in the brine formed during the salting stage. 3.3. Colour and texture measurements
Fig. 2. Relationship between the water activity (aw) and the salt concentration in the meat liquid phase (zss) at the end of the dry-curing process for NaCl brine (a), II brine (b) and III brine (c).
Table 3 shows the mean values of colour parameters (L*: lightness, a*: redness, b*: yellowness, C*: chroma and h*: hue) in the Semimembranosus muscle (outer zone: A and A′) and in the Biceps femoris muscle (inner zone: B, B′ and C) of the ham profile. No significant differences
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Table 4 Mean values ± standard deviation of texture parameters: hardness (g), chewiness (g), springiness, cohesiveness and adhesiveness in the Semimembranosus muscle (outer zone: A) and in the Biceps femoris muscle (inner zone: C) of the ham profile. Salt Zone Hardness (g) I II III I II III
A A A C C C
1349 ± 519a 1407 ± 455a 1035 ± 265a 90 ± 26a 243 ± 91b 84 ± 21a
Chewiness (g)
Springiness
Cohesiveness Adhesiveness
816 ± 349a 897 ± 341a 550 ± 98a 34 ± 1 a 124 ± 61b 37 ± 7a
0.79 ± 0.06a 0.78 ± 0.08a 0.73 ± 0.07a 0.7 ± 0.2a 0.8 ± 0.4a 0.68 ± 0.06a
0.76 ± 0.03a 0.79 ± 0.06a 0.69 ± 0.14a 0.59 ± 0.09a 0.63 ± 0.05a 0.64 ± 0.03a
− 6 ± 3a −6±4 a −6±4 a − 29 ± 19 a − 26 ± 19 a − 27 ± 11 a
Means in a column with different letters are significantly different at p-value ≤ 0.05.
Fig. 4. Na/Ca (a), Na/Mg (b), K/Ca (c) and K/Mg (d) ratios in the ham and in the salt mixture, throughout the ham profile, in batch III.
were observed between salt formulations in zones A, A′ and B for any of the parameters. Hams salted with II registered lower values of b* and C* in zone B′, and lower values of L* in B′ and in C (p ≤ 0.05). This could be explained by the lower water content of these hams. Only considering the differences between zones, those located in the Biceps femoris (B, B′ and C) registered higher values of L* than those in the Semimembranosus muscle, these differences being significant with regard to zone A in batch I (p ≤ 0.05), and L* mean values in A and A′ were significantly different than the mean value in C (p ≤ 0.05), in batch III. These results are in accordance with those obtained by Pérez-Álvarez et al. (1998); Sayas-Barberá, Pérez-Álvarez, Fernández-López and Aranda-Catalá (1998). Differences in L* have been associated with differences in water content, pH, additives, muscle structure, intramuscular fat and with water holding capacity (Elias & Carrascosa, 2000; Kauffman, Joo, Schultz, Warner, & Faustman, 1991; Sayas-Barberá et al., 1998). Table 4 shows the mean values for hardness (g), chewiness (g), springiness, cohesiveness and adhesiveness in the Semimembranosus Table 3 Mean values ± standard deviation of colour parameters L*: lightness, a*: redness, b*: yellowness, C*: chroma and h*: hue, in the Semimembranosus muscle (outer zone: A and A′) and in the Biceps femoris muscle (B, B′ and C) of the ham profile. Salt I II III I II III I II III I II III I II III
Zone A A A A′ A′ A′ B B B B′ B′ B′ C C C
L*
a* a
33 ± 2 35a ± 2 34a ± 4 38a ± 4 36a ± 6 34a ± 3 38a ± 5 38a ± 6 37a ± 3 39.4a ± 0.7 35b ± 3 38ab ± 3 41.5a ± 0.5 37b ± 3 41ab ± 4
b* a
8.0 ± 0.8 7a ± 2 8a ± 2 8a ± 1 8.0a ± 0.9 8.6a ± 1.3 8.5a ± 0.6 9a ± 2 8a ± 1 8.5a ± 0.5 8.1a ± 0.5 8a ± 1 7.4a ± 0.8 8a ± 1 7a ± 2
C* a
4.7 ± 1.6 3.3a ± 1.5 3.9a ± 0.5 6.7a ± 1.5 6a ± 2 6a ± 1 6.5a ± 0.8 6a ± 1 6.5a ± 0.4 7.5a ± 1.5 5.3b ± 1.5 7ab ± 1 8a ± 2 5.8a ± 1.4 7.4a ± 0.3
9.3 ± 1.4 8a ± 2 9a ± 2 11a ± 1 10a ± 1 10.5a ± 1.5 10.8a ± 0.6 11a ± 2 10.6a ± 0.8 11a ± 1 10b ± 1 10.6ab ± 0.6 11a ± 2 10a ± 2 10.3a ± 1.5
4. Conclusions Hams salted with a mixture of sodium and potassium chloride had higher salt content, lower water activity and water content at the end of the process and thus, needed less time to reach the target weight loss. The opposite effect was observed when calcium and magnesium chloride were added to the salt mixture. In fact, a higher potassium penetration was observed while calcium and magnesium had more difficulty penetrating the muscle. No significant differences in colour and texture parameters between salt formulations were observed in the Semimembranosus muscle. Moreover, the observed differences in the Biceps femoris were principally due to the differences in water and salt contents of the dry-cured hams. It seems that hams salted with III would need higher salt concentrations inside the ham so as to prevent quality defects such as pastiness. Acknowledgements
h* a
muscle (outer zone: A) and in the Biceps femoris muscle (inner zone: C) of the ham profile. No significant differences were observed between salt formulations in any of the parameters in the Semimembranosus muscle. Regarding inner zone C, hardness and chewiness showed substantially reduced values, in comparison to the outer zone A, due to its higher moisture and salt contents. Hams salted with II registered higher values of hardness and chewiness (p ≤ 0.05) in the Biceps femoris, probably due to their lower water and higher salt concentrations. In fact, hardness increases with salt content (Andrés, Cava, Ventanas, Thovar, & Ruiz, 2004; Ruiz-Ramírez, Arnau, Serra, & Gou, 2005). Even if hams salted with III had lower values for hardness, no significant differences were observed with regard to the control batch. However, there is a risk of increased pastiness in biceps femoris in batch III with lower salt concentrations due to the increase in proteolytic activity (Rico, Toldrá, & Flores, 1991; Toldrá, Rico, & Flores, 1992). A possible solution would be to increase the amount of salt added to the ham in batch III so as to ensure higher salt concentrations inside the ham, which would inhibit cathepsin activities (Rico et al., 1991).
a
30 ± 7 25a ± 9 26a ± 2 39a ± 9 36a ± 8 35a ± 5 37a ± 5 35a ± 7 38a ± 4 41a ± 6 32a ± 8 41a ± 7 45ab ± 9 35a ± 5 47b ± 7
Means of a zone (A, A′, B, B′ and C) in a column with different letters are significantly different at p-value ≤ 0.05.
We would like to thank the Spanish Government (Ministerio de Ciencia y Tecnología) and the European Union (FEDER program) for the financial support of the project (AGL2004-05064-C02). Author Marta Aliño thanks the Spanish Government (Ministerio de Educación y Ciencia) for a FPU grant (AP2005-438). References Aliño, M., Grau, R., Baigts, D., & Barat, J. M. (2009). Influence of sodium replacement on pork loin salting kinetic. Journal of Food Engineering, 95(4), 551−557. Aliño, M., Grau, R., Fuentes, A., & Barat, J. M. (2010). Characterization of pile salting with sodium replaced mixtures of salts in dry-cured loin manufacturing. Journal of Food Engineering, 97(3), 434−439. Aliño, M., Grau, R., Fuentes, A., & Barat, J. M. (2010). Influence of low-sodium mixtures of salts on the post-salting stage of dry-cured ham process. Journal of Food Engineering, 92(2), 198−205.
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Aliño, M., Grau, R., Toldrá, F., Blesa, E., Pagán, M. J., & Barat, J. M. (2009). Influence of sodium replacement on physicochemical properties of dry-cured loin. Meat Science, 83, 423−430. Andrés, A., Cava, R., Ventanas, J., Thovar, V., & Ruiz, J. (2004). Sensory characteristics of Iberian ham: Influence of salt content and processing conditions. Meat Science, 68, 45−51. Armenteros, M., Aristoy, M. C., Barat, J. M., & Toldrá, F. (2009). Biochemical changes in dry-cured loins salted with partial replacements of NaCl by KCl. Food Chemistry, 117, 627−633. Armenteros, M., Aristoy, M. C., Barat, J. M., & Toldrá, F. (2009). Biochemical and sensory properties of dry-cured loins as affected by partial replacement of sodium by potassium, calcium and magnesium. Journal of Agricultural and Food Chemistry, 57, 9699−9705. Bañón, S., Cayuela, J. M., Granados, M. V., & Garrido, M. D. (1999). Pre-cure freezing affects proteolysis in dry-cured hams. Meat Science, 51, 11−16. Barat, J. M., Chiralt, A., & Fito, P. (1998). Equilibrium in cellular food osmotic solution systems as related to structure. Journal of Food Science, 63(4), 836−840. Barat, J. M., Rodríguez-Barona, S., Andrés, A., & Fito, P. (2002). Influence of increasing brine concentration in the cod salting process. Journal of Food Science, 65(7), 1922−1925. Blesa, E., Aliño, M., Barat, J. M., Grau, R., Toldrá, F., & Pagán, M. J. (2008). Microbiology and physico-chemical changes of dry-cured ham during the post-salting stage as affected by partial replacement of NaCl by other salts. Meat Science, 78, 135−142. Cassens, R. G., Demeyer, D., Eikelenboom, G., Honikel, K. O., Johansson, G., Nielsen, T., et al. (1995). Recommendation of reference method for assessment of meat color. Proceedings of 41st International Congress of Meat Science and Technology (pp. 410−411). San Antonio, TX. Elias, M., & Carrascosa, A. V. (2000). Microbiological and physicochemical aspects of vacuum-packed Iberian ham. Fleischwirtschaft International, 2, 36−41. Geleijnse, J. M., Witteman, J. C., Bak, A. A., den Breeijen, J. H., & Grobbee, D. E. (1994). Reduction in blood pressure with a low sodium, high potassium, high magnesium salt in older subjects with mild to moderate hypertension. British Medical Journal, 309, 436−440. Griskey, R. G. (2002). Transport phenomena and unit operations. A combined approach. New York: John Wiley & Sons, Inc. Pub. ISO Norm R-1442, International Standards Organisation (1979). Determination of moisture. ISO Norm R-1443, International Standards Organisation (1973). Determination of lipids. Iyengar, J. R., & Sen, D. P. (1970). The equilibrium relative humidity relationship of salted fish (Barbus carnaticus and Rastelliger canagurta): The effect of calcium and magnesium as impurities in common salt used for curing. Journal of Food Science and Technology, 9, 17−19. Jee, S. H., Miller, E. R. I. I. I., Guallar, E., Singh, V. K., Appel, L. J., & Klag, M. J. (2002). The effect of magnesium supplementation on blood pressure: A meta-analysis of randomized clinical trials. American Journal of Hypertension, 15, 691−696. Kauffman, R., Joo, S. T., Schultz, C., Warner, R., & Faustman, C. (1991). Measuring water holding capacity in post-rigor muscle. 47th Annual Reciprocal Meat Conference (pp. 70−72). : AMSA.
Mizushima, S., Cappuccio, F. P., Nichols, R., & Elliott, P. (1998). Dietary magnesium intake and blood pressure: A qualitative overview of the observational studies. Journal of Human Hypertension, 12, 447−453. Morgan, T., Aubert, J. F., & Brunner, H. (2001). Interaction between sodium intake, angiotensin II and blood pressure as a cause of cardiac hypertrophy. American Journal of Hypertension, 14, 914−920. Motilva, M. -J., Toldrá, F., Nadal, M. -I., & Flores, J. (1994). Effect of pre-freezing hams on the lipolysis during the dry-curing process. Journal of Food Science, 59, 303−305. Pérez-Álvarez, J. A., Sayas-Barberá, M. E., Fernández-López, J., Gago-Gago, M. A., PagánMoreno, M. J., & Aranda-Catalá, V. (1998). Spanish dry-cured ham aging process: Colour characteristics. In A. Diestre, & J. M. Montfort (Eds.), Proceedings 44th International Congress of Meat Science and Technology (pp. 984−985). Barcelona, Spain: Estrategias Alimentarias, S.L. Eurocarne. Rico, E., Toldrá, F., & Flores, J. (1991). Effect of dry-curing process parameters on pork muscle cathepsins B, H and L activities. Zeitscrift für Lebensmittel Untersuchung und Forschung, 193, 541−544. Ruiz-Ramírez, J., Arnau, J., Serra, X., & Gou, P. (2005). Relationship between water content, NaCl content, pH and texture parameters in dry-cured muscles. Meat Science, 70, 579−587. Sayas-Barberá, M. E., Pérez-Álvarez, J. A., Fernández-López, J., & Aranda-Catalá, V. (1998). Traditional and fast salting effect on physicochemical and ultrastructural properties of Spanish dry-cured ham. In A. Diestre, & J. M. Montfort (Eds.), Proceedings 44th International Congress of Meat Science and Technology (pp. 972−973). Barcelona, Spain: Estrategias Alimentarias, S.L. Eurocarne. Sofos, J. N. (1984). Antimicrobial effects of sodium and other ions in foods: A review. Journal of Food Safety, 6, 45−78. Sofos, J. N. (1986). Use of phosphates in low-sodium meat products. Food Technology, 40, 52 (54–58, 60, 62, 64, 66, 68–69). Sofos, J. N. (1989). Phosphates in meat products. In S. Thorne (Ed.), Developments in food preservation—5 (pp. 207−252). New York: Elsevier Applied Science. Tabilo, G., Flores, M., Fiszman, S. M., & Toldrá, F. (1999). Postmortem meat quality and sex affect textural properties and protein breakdown of dry-cured ham. Meat Science, 51, 255−260. Terrell, R. N. (1983). Reducing the sodium content of processed meats. Food Technology, 37, 66−71. Toldrá, F., Rico, E., & Flores, J. (1992). Activities of pork muscle proteases in model cured meat systems. Biochimie, 74, 291−296. Toldrá, F. (2006). Dry-cured ham. In Y. H. Hui, E. Castell-Perez, L. M. Cunha, I. GuerreroLegarreta, H. H. Liang, Y. M. Lo, D. L. Marshall, W. K. Nip, F. Shahidi, F. Sherkat, R. J. Winger, & K. L. Yam (Eds.), Handbook of food science, technology. WHO/FAO (World Health Organization/Food and Agriculture Organization) (2003). Diet, nutrition and the prevention of chronic diseases. WHO Technical Report Series 916. Geneva: World Health Organization.
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Meat Science j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / m e a t s c i
Physicochemical changes in dry-cured hams salted with potassium, calcium and magnesium chloride as a partial replacement for sodium chloride M. Aliño a, R. Grau a, F. Toldrá b, J.M. Barat a,⁎ a b
Departamento de Tecnología de Alimentos. Universidad Politécnica de Valencia, Camino de Vera s/n. 46022, Valencia, Spain Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Apartado de correos 73, 46100, Burjassot, Valencia, Spain
a r t i c l e
i n f o
Article history: Received 25 December 2009 Received in revised form 3 May 2010 Accepted 4 May 2010 Keywords: Dry-cured ham Sodium-replacement Potassium Calcium Magnesium
a b s t r a c t The reduction of added sodium chloride in dry-cured ham has been proposed to reduce dietary sodium intake in Mediterranean countries. The effect of substituting sodium chloride with potassium chloride, calcium chloride and magnesium chloride on some physicochemical characteristics of dry-cured ham during processing was evaluated. The results showed that hams salted with a mixture of sodium and potassium chloride registered higher salt concentrations and lower water contents and thus, needed less time to reach the required weight loss at the end of the process. The opposite effect was observed when calcium and magnesium chloride were added to the salt mixture. The observed differences in the texture and colour parameters were mainly due to differences in water and salt content. © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.
1. Introduction Dietary intake of sodium, from all sources, influences blood pressure (BP) levels in populations and should be limited in order to reduce the risk of coronary heart disease and both forms of stroke (WHO, 2003). However, sodium intake exceeds the nutritional recommendations in most industrialised countries; the main source of sodium in the diet being sodium chloride. Dry-cured ham is a product with truly extraordinary sensory and nutritional characteristics associated with haute gastronomy. It is one of the most traditional cured meat products in the Mediterranean area, with an enormous economic importance in its sector; for example, more than 40 million pieces are produced per year in Spain. However, its high sodium content makes dry-cured ham a nonrecommended product for hypertensive consumers. Therefore, it is a challenge for the dry-cured ham industry to lower sodium content in ham (typically 5–6%) due to concern for hypertension-suffers (Morgan, Aubert, & Brunner, 2001). Increased sodium intake is associated with increased BP, whereas increased potassium and calcium intake may slightly decrease BP (Geleijnse, Witteman, Bak, den Breeijen, & Grobbee, 1994). Moreover, magnesium intake has been inversely associated with BP (Mizushima, Cappuccio, Nichols, & Elliott, 1998; Jee et al., 2002). A possible approach to reduce the global sodium content is the partial or total replacement of NaCl with other chloride salts (KCl, CaCl2
⁎ Corresponding author. Tel.: + 34 963877365; fax: + 34 963877956. E-mail address: [email protected] (J.M. Barat).
and MgCl2) or non-chloride salts such as phosphates, or a combination of both (Sofos, 1984, 1986, 1989; Terrell, 1983). Partial sodium replacement with other cations such as potassium, calcium and magnesium has recently been proposed for Spanish dry-cured porkloins (Aliño et al., 2009; Armenteros, Aristoy, Barat, & Toldrá, 2009a,b). The results obtained were useful for the application of this salting method to the Spanish dry-cured ham process. The use of mixtures of salts with low sodium content may imply significant changes in the different steps (salting, post-salting and dry-ripening) that constitute the whole manufacturing process. The salting stage with sodium replaced salts has been characterised in previous studies using pork-loin as a model system for dry-cured ham, due to its shape, homogeneity and short processing treatment (Aliño, Grau, Baigts & Barat, 2009; Aliño, Grau, Fuentes & Barat, 2010a). After pile-salting, greater potassium penetration was observed while calcium and magnesium cations had more difficulty penetrating the muscle remaining in the brine formed during the pile-salting process. Cation composition in the brine changed considerably from the solid salt. So, the rub-salting method was proposed for dry-cured ham processing in order to control cation proportions in the mixture of chloride salts. Moreover, the presence of KCl decreased salting time whereas CaCl2 and MgCl2 had the opposite effect. Salt diffusion takes place during post-salting, enabling the salt located near the ham surface, which is gained during salting to penetrate the deeper zones, thus decreasing the water activity and ensuring the preservation of the hams when increasing the temperature in the following step (dry-ripening). Therefore, the influence of different mixtures of chloride salts with partial replacement of sodium on the physicochemical properties and the microbiota of dry-cured ham during
0309-1740/$ – see front matter © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2010.05.003
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the post-salting stage were studied (Aliño, Grau, Fuentes & Barat, 2010b; Blesa et al., 2008). The results showed that the presence of other chloride salts delayed the decrease in water activity and thus increased the post-salting time needed to reach similar water activities as in the traditional process. Moreover, no significant differences in microbial counts were observed between hams salted with the different salt formulations. The results obtained in these previous studies were used to elaborate the final product. The next step (dry-maturation or ripening period) involves time– temperature combinations. The homogenized pieces are placed in natural or air-conditioned drying chambers where the relative humidity usually varies between 90% and 70% with a temperature range from 5 to 26 °C. The aim was to study the influence of partial sodium replacement with potassium, calcium and magnesium chloride salts on the physicochemical parameters of dry-cured ham at the end of the manufacturing process. 2. Materials and methods
The final weight of each ham was measured. Physicochemical analyses were carried out on each ham in five zones, obtained from the widest section of the ham, A (near the lean surface) and A′ in the Semimembranosus muscle; B, B′ (both near the femoral artery) and C (near the subcutaneous fat) in the Biceps femoris muscle. These points are shown in Fig. 1. 2.2. Colour determinations Colour measurements were taken shortly after cutting the slice in zones A, A′, B, B′ and C. Reflectance spectra were determined with a UV/VS Minolta Spectrophotometer model CM-3600d from 400 to 700 nm, at 10 nm intervals, using an integrating sphere. The colour system employed was CIE L*a*b*. D-65 illuminant was used with 10° observer angles (Cassens et al., 1995). The illuminant D-65 evaluates colour using typical bright daylight with an overcast sky and colour temperature at 6500 K. L*, a* and b* values were obtained from the mean of 6 determinations per analysed zone. 2.3. Texture profile analysis (TPA)
Twenty-one fresh hams with an average weight of 10.8 ± 0.5 kg were selected in a local slaughterhouse controlling the pH within the 5.5 to 6.0 range. All the hams were frozen in an industrial freezer at −40 °C and stored for at least 30 days at −20 °C. Then, the frozen hams were thawed in a cold chamber at 3 °C for 5 days, in a similar way to the industrial process (Bañón, Cayuela, Granados & Garrido, 1999, Motilva, Toldrá, Nadal, & Flores, 1994). Three of the hams were used as a control for the raw material. Their moisture (xw), water activity (aw), fat content (xf) and chloride (XCl), sodium (XNa), potassium (XK), calcium (XCa) and magnesium (XMg) concentrations were analysed on a dry matter basis (Table 1). The remaining 18 hams were randomly divided into three groups of 6 hams each, salted using 100% NaCl salt (batch I), a mixture of NaCl and KCl at 50% (batch II) and a mixture of 55% NaCl, 25% KCl, 15% CaCl2 and 5% MgCl2 (batch III). Salt formulations were chosen according to the results obtained in previous works on low sodium dry-cured porkloins (Aliño, Grau, Toldrá, et al., 2009; Armenteros et al., 2009a,b). The salting stage was carried out at 3 ± 1 °C and 90% relative humidity for a total of 10 days and all hams were weighed every day. Hams were salted by rubbing and kneading with the 3 combinations of salts, the quantity of salt mixture was 2% of the weight of the ham, 200 ppm of KNO3 and 100 ppm of NaNO2 were added to the mixture for each ham as curing agents. After salting, hams were post-salted at 4.5 °C and a relative humidity between 75 and 85%. At the end of the post-salting stage, the hams were taken to the last processing stage (dry-ripening) where the temperature was progressively increased from 6 to 20 °C and relative humidity reduced from 80 to 65%. The process was finished when total weight loss reached 32–34% of the initial weight, which is in the range of typical values achieved in industry (Toldrá, 2006).
Textural properties were measured by double compression using a Texture Analyzer TA.XT2 (Stable MicroSystems, UK) equipped with a flat-ended cylindrical plunger (SMS-P/75). The force (N) was recorded continuously during compression on a texture profile curve with a load cell of 250 N. Determinations were carried out on 3 cubes taken (inner, middle and outer) from one slice of each loin. Cubic samples (20 × 20× 20 mm.) were compressed axially (20% compression), with a constant cross-head speed of 1 mm/s. The holding time between both compressions was 5 s (Tabilo, Flores, Fiszman, & Toldrá, 1999). Force versus time was recorded and the following parameters were calculated: hardness (g), cohesiveness (dimensionless), springiness (dimensionless), adhesiveness and chewiness (g). 2.4. Analytical determinations The pH of the hams was measured with a portable pH-meter (Crisol, model 507). The average pH of the 21 hams was 5.8 ± 0.2. Moisture content (xw) was determined by oven drying to constant weight at 100 °C (ISO Norm R-1442, 1979). Fat content (xf) was analysed according to ISO Norm R-1443 (1973) using a FOSS Soxtec System 2055 Tecator. The water activity (aw) of each sample was determined using an Aqualab® dew point hygrometer (Decagon Devices, Inc., Washington, USA). Chloride was determined after sample homogenisation in a known amount of Milli®-Q water at 9000 rpm in an ULTRATURRAX T25 for 5 min and centrifuged at 10,000 g for 20 min at 4° to remove any fine debris present in the sample. Afterwards, the supernatant was filtered through nylon membrane filters (45 µm) and a sample of exactly 500 μl was taken and titrated in Chloride Analyzer equipment (CIBA Corning Mod. 926). The same aliquot was used to analyse the sodium, potassium, calcium and magnesium in each sample by ion chromatography using
2.1. Sampling In all the treatments, the sampling was carried out at the end of the dry-ripening stage, once hams reached 32–34% of total weight loss. Table 1 Mean values ± standard deviation of water activity (aw), water (xw) and fat (xf) contents (w/w) and chloride, sodium, potassium, calcium and magnesium concentrations on a dry matter basis (DM), in grams/gram of dry matter, X Cl, X Na, X K, X Ca and X Mg, respectively, in the raw material. aw ± SD xw ± SD (w/w) xf ± SD (w/w) XCl ± SD (DM)
0.987 ± 0.001 0.741 ± 0.008 0.03 ± 0.02 0.0028 ± 0.0002
X Na ± SD X K ± SD X Ca ± SD X Mg ± SD
(DM) (DM) (DM) (DM)
0.00130 ± 0.00003 0.0040 ± 0.0002 0.00022 ± 0.00005 0.00018 ± 0.00003
Fig. 1. Samples A, A′, B, B′ and C from the widest ham section.
M. Aliño et al. / Meat Science 86 (2010) 331–336
an ion exchange column (Metrosep C2, 250/4.0, Methrom®, Herisau, Switzerland) in PC-controlled Compact IC 761 equipment (Methrom®, Herisau, Switzerland), with the following parts: built-in double piston pump, electrically operated injection valve and a temperature-stabilized high performance conductivity detector. The mobile phase was tartaric acid–dipicolinic acid (4.0–0.75 mmol/L) at a rate of 1.0 ml/min. The separation was monitored using a conductivity detector and IC Net 2.3 software (Methrom® Ltd., Herisau, Switzerland) was used to process the data. The concentration of each cation was determined by interpolation on the corresponding calibration curve. The calibration for the assay was established using a triplicate set of standard solutions of Na+, K+, Ca2+ and Mg2+ (Fluka, Switzerland, Sigma, St. Louis, MO). The results were the means of three determinations. Salt weight fraction (xss) was calculated as the addition of the major ionic compounds (Eq. 1), being xCl, xNa, xK, xCa and xMg, the chloride, sodium, potassium, calcium and magnesium weight fractions. ss
Cl
Na
x =x +x
K
+x +x
Ca
+x
Mg
ð1Þ
Total salt, chloride, sodium, potassium, calcium and magnesium concentrations on a dry matter basis (Xss, XCl, XNa, XK, XCa and XMg respectively) were estimated from xw, xss, xCl xNa, xK, xCa and xMg, respectively, as shown in Eq. (2).
i
X =
i
x ð1−xw Þ
ð2Þ
Total salt concentration in the meat liquid phase (zss) was estimated from xw and xss as shown in Eq. (3).
ss
z =
xss x + xw
ð3Þ
ss
2.5. Statistics The effect of the salt formulation on the variables: water activity (aw), salt concentration on a dry basis (Xss), colour and texture parameters, was performed by analysis of variance, one-way ANOVA. In those cases where the effect was significant (p b 0.05) the mean values were compared using Fisher's least significant difference (LSD) procedure. Statistical processing was performed using Statgraphics® Plus 5.1 version software (Manugistics, Rockville, MD, USA).
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3. Results and discussion 3.1. Values of total salt content, water content and water activity at the end of the process The effects of the salt formulation on total salt content on a dry matter basis (Xss), on total water content (xw, w/w) and on water activity (aw) are shown in Table 2. Total salt content (Xss) was affected by salt composition. In fact, hams salted with the salt mixture containing 50% NaCl and 50% KCl (II), registered higher Xss values than the control batch (I: 100% NaCl). However, these differences were not statistically significant (p ≥ 0.05). Moreover, mean Xss values in hams salted with III, containing CaCl2 and MgCl2 (15% and 5%, respectively), were lower than in I and II. These differences were significant (p ≤ 0.05) in zones A and A′ with regard to batch I and in zones A, A′ and B′ with regard to batch II. So, it seems that the presence of divalent cations slows down salt penetration into the muscle. This is in agreement with the results obtained for dry-cured loins and in the post-salting stage of dry-cured ham (Armenteros et al., 2009b; Aliño et al., 2010b). As it can be seen, xw mean values in hams salted with II were lower than in I and III in all the analysed zones, being significantly different from the control batch (p ≤ 0.05) in the outer zones A and A′, next to the lean surface. xw mean values in III in the inner zones B′ and C were significantly higher (p ≤ 0.05) than in batches I and II. It seems that salt content and water content affected total weight losses at the end of the process (ΔMºf), being lower in hams salted with formulation III, containing CaCl2 and MgCl2 (15% and 5%, respectively) On the contrary, hams salted with formulation II, registered higher weight losses than the control batch (I) and batch III. The mean processing time needed to reach the final weight loss at the end of the process (32–34%) was 185 ± 24 days in the control batch, 165 ± 14 days in batch II and 203 ± 36 days in batch III, these differences being significantly different (p ≤ 0.05) between batches II and III. So, even if hams salted with II needed more post-salting time to reach similar aw than in the traditional process (Aliño et al., 2010b), this did not affect the whole processing time. On the contrary, it seems that an increase in the whole processing time would be needed when salting with mixture III. Regarding aw, mean values in III were significantly higher than mean values in I and II in A, A′, B′ and C. Higher aw values in III could have been expected as MgCl2 and CaCl2 decrease aw more than NaCl and KCl. In fact, the values of parameter “B”, characteristic of every electrolyte in the equation of the Pitzer–Bromley model to predict water activity in aqueous solutions, are B = 0.1129, 0.0948, 0.0574 and 0.024, for MgCl2, CaCl2, NaCl and KCl, respectively. Nevertheless, the lower salt concentration in III due to the difficulty of divalent cations penetrating the muscle induced higher water content and thus higher aw values. The opposite effect was seen in hams salted with II.
Table 2 Mean values ± standard deviation of salt content on a dry matter basis (Xss), water content (xw, w/w) and water activity (aw) in the sample points A (lean surface), A′, B, B′ and C (inner point) zones at the end of the process in the three batches I, II and III. Zone
Xss (I) Xss (II) Xss (III) xw (I) xw (II) xw (III) aw (I) aw (II) aw (III)
A
A′
B
B′
C
0.069 ± 0.009 a 0.070 ± 0.005 a 0.053 ± 0.003 b 0.54 ± 0.02b 0.51 ± 0.02a 0.53 ± 0.02ab 0.935 ± 0.004a 0.932 ± 0.003a 0.942 ± 0.004b
0.090 ± 0.008 a 0.093 ± 0.004 a 0.068 ± 0.005 b 0.59 ± 0.02b 0.56 ± 0.04a 0.59 ± 0.02ab 0.935 ± 0.004a 0.932 ± 0.004a 0.945 ± 0.004b
0.086 ± 0.024a 0.086 ± 0.011a 0.070 ± 0.006 a 0.55 ± 0.06a 0.56 ± 0.05a 0.56 ± 0.06a 0.936 ± 0.004a 0.937 ± 0.005a 0.941 ± 0.006a
0.107 ± 0.010 ab 0.112 ± 0.017 a 0.091 ± 0.005 b 0.63 ± 0.01a 0.62 ± 0.01a 0.65 ± 0.01b 0.939 ± 0.004a 0.932 ± 0.004b 0.950 ± 0.003c
0.102 ± 0.007 a 0.107 ± 0.021a 0.087 ± 0.004a 0.62 ± 0.01a 0.62 ± 0.01a 0.64 ± 0.01b 0.935 ± 0.005a 0.933 ± 0.004a 0.949 ± 0.003b
Means in a column with different letters are significantly different at p-value ≤ 0.05.
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aw mean values in II were lower than in the control batch, however, these differences were only significant (p ≤ 0.05) in B′. It must be noted that no significant differences were observed in any of the parameters in zone B. This could be due to the higher fat content (xf, w/w) of this zone compared to the rest of the zones, which would hinder salt penetration by any salt mixture, xf (A) = 0.02 ± 0.01, xf (A′) = 0.024 ± 0.01, xf (B) = 0.09 ± 0.03, xf (B′) = 0.014 ± 0.008, xf (C) = 0.013 ± 0.008. The use of salt concentration in the ham liquid phase (zss) is closely related to aw values in the ham throughout the salting and postsalting periods and to the perceived saltiness of the final product. It also enables a better understanding of the transport phenomena taking place in the meat liquid phase throughout the process. Barat, Rodríguez-Barona, Andrés and Fito (2002) found in a study of cod salting that after 15 days, the equilibrium zNaCl value and the NaCl weight fraction value in the brine (yNaCl) were the same. This observation was in agreement with other solid–liquid operations in which the equilibrium between the liquid phases present in the system is defined by the equality in concentrations (Barat, Chiralt, & Fito, 1998; Griskey, 2002). Fig. 2 shows aw values at the end of the dry-ripening period. The aw values for the ham in all the sample points were slightly lower than those corresponding to brine with the same salt proportions as the salt formulations (I, II and III). These differences were higher with lower water content compared to those that would be seen during the post-salting stage (Aliño, Grau, Baigts, & Barat, 2009). These particular differences could be explained by the water interacting with the ham protein matrix and with the peptides and amino acids in the meat liquid phase generated as a result of the intense enzymatic activity. These differences were significantly higher (p ≤ 0.05) in II than in I and III (0.031 ± 0.006, 0.033 ± 0.005 and 0.0297 ± 0.0036 units of aw, in I, II and III respectively). 3.2. Sodium, potassium and magnesium penetration in the ham profile Fig. 3 shows the sodium–potassium ratios (Na/K) of the added salts at the end of the dry-curing process in the ham profile and in the solid salt in batches II (a) and III (b). As can be seen, Na/K was constant throughout the ham profile. In fact, both sodium and potassium concentrations in the
Fig. 3. Na/K ratio in the ham and in the salt mixture throughout the ham profile, in batches II (a) and III (b).
meat liquid phase (zNa and zK) remained uniform in the 5 zones of the ham profile so that equilibrium concentration was reached at the end of the process (zNa (II)= 0.0118 ±0.0006 g Na/g liquid phase and zK (II)= 0.0204±0.0008 g K/g liquid phase; zNa (III) = 0.0110 ±0.0002 g Na/g liquid phase and zK (III) = 0.0115 ± 0.0004 g K/g liquid phase.). The Na/K ratio was lower in the ham than in the salt mixture in both salting treatments, indicating that K+ penetrated the muscle more than Na+. The same results were obtained in dry-cured loin salted with mixtures of NaCl and KCl salts in different proportions (Aliño, Grau, Toldrá, et al., 2009; Armenteros et al., 2009a). This difference was higher in hams salted with III, where the presence of Ca2+ and Mg2+ could have hindered penetration of salts and NaCl in particular. Fig. 4 shows Na/Ca (a), Na/Mg (b), K/Ca (c) and K/Mg (d) ratios of added salts at the end of the dry-curing process in the ham profile and in the salt mixture in batch III. Na/Mg and K/Mg ratio values were higher, and significantly different (p ≤ 0.05) in the inner zones than in the superficial zones, inducing a higher penetration of sodium and potassium in the inner muscles than magnesium. It seems that calcium had similar behaviour, remaining mainly in the outer zones. However, no significant differences were observed in the mean values of Na/Ca and K/Ca ratios between the zones (A, A′, B, B′ and C). Higher differences could have been expected; nevertheless, the high standard deviations (SD) obtained in calcium concentration values could have influenced the results (zCa (A) = 0.0015 ± 0.0005 zCa (A′) = 0.0012 ± 0.0007, zCa (B) = 0.0013 ± 0.0009, zCa (B′) = 0.0016 ± 0.0012 and zCa (C) = 0.0012 ± 0.0006 g Ca/g liquid phase). These high SD's could be explained by the heterogeneity of CaCl2 penetration, the amount of Ca2+ in the raw material or the small quantities added. In fact, calcium binds more strongly to the outermost layers of the muscle proteins, compacting the surface of the meat (Iyengar & Sen, 1970). Moreover, these ratios were higher in the ham than in the salt mixture. It seems that divalent cations had more difficulty penetrating the muscle. Considering that during the salting stage brine (salt solution) is generated and surrounds the ham, forming a layer on its surface, cation penetration in the ham would be affected by brine composition. Aliño, Grau, Baigts and Barat (2009) studied cation penetration throughout pork-loin pile-salting with mixtures of NaCl, KCl, CaCl2 and MgCl2 and found that higher Ca2+ and Mg2+ concentrations were observed in the brine with regard to their concentration in the solid salt due to the higher water solubility of CaCl2 and MgCl2 compared to NaCl and KCl. In addition, these divalent cations penetrated less than monovalent cations in the muscle. Further studies need to be done to determine cation concentrations outside the ham, in the brine formed during the salting stage. 3.3. Colour and texture measurements
Fig. 2. Relationship between the water activity (aw) and the salt concentration in the meat liquid phase (zss) at the end of the dry-curing process for NaCl brine (a), II brine (b) and III brine (c).
Table 3 shows the mean values of colour parameters (L*: lightness, a*: redness, b*: yellowness, C*: chroma and h*: hue) in the Semimembranosus muscle (outer zone: A and A′) and in the Biceps femoris muscle (inner zone: B, B′ and C) of the ham profile. No significant differences
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Table 4 Mean values ± standard deviation of texture parameters: hardness (g), chewiness (g), springiness, cohesiveness and adhesiveness in the Semimembranosus muscle (outer zone: A) and in the Biceps femoris muscle (inner zone: C) of the ham profile. Salt Zone Hardness (g) I II III I II III
A A A C C C
1349 ± 519a 1407 ± 455a 1035 ± 265a 90 ± 26a 243 ± 91b 84 ± 21a
Chewiness (g)
Springiness
Cohesiveness Adhesiveness
816 ± 349a 897 ± 341a 550 ± 98a 34 ± 1 a 124 ± 61b 37 ± 7a
0.79 ± 0.06a 0.78 ± 0.08a 0.73 ± 0.07a 0.7 ± 0.2a 0.8 ± 0.4a 0.68 ± 0.06a
0.76 ± 0.03a 0.79 ± 0.06a 0.69 ± 0.14a 0.59 ± 0.09a 0.63 ± 0.05a 0.64 ± 0.03a
− 6 ± 3a −6±4 a −6±4 a − 29 ± 19 a − 26 ± 19 a − 27 ± 11 a
Means in a column with different letters are significantly different at p-value ≤ 0.05.
Fig. 4. Na/Ca (a), Na/Mg (b), K/Ca (c) and K/Mg (d) ratios in the ham and in the salt mixture, throughout the ham profile, in batch III.
were observed between salt formulations in zones A, A′ and B for any of the parameters. Hams salted with II registered lower values of b* and C* in zone B′, and lower values of L* in B′ and in C (p ≤ 0.05). This could be explained by the lower water content of these hams. Only considering the differences between zones, those located in the Biceps femoris (B, B′ and C) registered higher values of L* than those in the Semimembranosus muscle, these differences being significant with regard to zone A in batch I (p ≤ 0.05), and L* mean values in A and A′ were significantly different than the mean value in C (p ≤ 0.05), in batch III. These results are in accordance with those obtained by Pérez-Álvarez et al. (1998); Sayas-Barberá, Pérez-Álvarez, Fernández-López and Aranda-Catalá (1998). Differences in L* have been associated with differences in water content, pH, additives, muscle structure, intramuscular fat and with water holding capacity (Elias & Carrascosa, 2000; Kauffman, Joo, Schultz, Warner, & Faustman, 1991; Sayas-Barberá et al., 1998). Table 4 shows the mean values for hardness (g), chewiness (g), springiness, cohesiveness and adhesiveness in the Semimembranosus Table 3 Mean values ± standard deviation of colour parameters L*: lightness, a*: redness, b*: yellowness, C*: chroma and h*: hue, in the Semimembranosus muscle (outer zone: A and A′) and in the Biceps femoris muscle (B, B′ and C) of the ham profile. Salt I II III I II III I II III I II III I II III
Zone A A A A′ A′ A′ B B B B′ B′ B′ C C C
L*
a* a
33 ± 2 35a ± 2 34a ± 4 38a ± 4 36a ± 6 34a ± 3 38a ± 5 38a ± 6 37a ± 3 39.4a ± 0.7 35b ± 3 38ab ± 3 41.5a ± 0.5 37b ± 3 41ab ± 4
b* a
8.0 ± 0.8 7a ± 2 8a ± 2 8a ± 1 8.0a ± 0.9 8.6a ± 1.3 8.5a ± 0.6 9a ± 2 8a ± 1 8.5a ± 0.5 8.1a ± 0.5 8a ± 1 7.4a ± 0.8 8a ± 1 7a ± 2
C* a
4.7 ± 1.6 3.3a ± 1.5 3.9a ± 0.5 6.7a ± 1.5 6a ± 2 6a ± 1 6.5a ± 0.8 6a ± 1 6.5a ± 0.4 7.5a ± 1.5 5.3b ± 1.5 7ab ± 1 8a ± 2 5.8a ± 1.4 7.4a ± 0.3
9.3 ± 1.4 8a ± 2 9a ± 2 11a ± 1 10a ± 1 10.5a ± 1.5 10.8a ± 0.6 11a ± 2 10.6a ± 0.8 11a ± 1 10b ± 1 10.6ab ± 0.6 11a ± 2 10a ± 2 10.3a ± 1.5
4. Conclusions Hams salted with a mixture of sodium and potassium chloride had higher salt content, lower water activity and water content at the end of the process and thus, needed less time to reach the target weight loss. The opposite effect was observed when calcium and magnesium chloride were added to the salt mixture. In fact, a higher potassium penetration was observed while calcium and magnesium had more difficulty penetrating the muscle. No significant differences in colour and texture parameters between salt formulations were observed in the Semimembranosus muscle. Moreover, the observed differences in the Biceps femoris were principally due to the differences in water and salt contents of the dry-cured hams. It seems that hams salted with III would need higher salt concentrations inside the ham so as to prevent quality defects such as pastiness. Acknowledgements
h* a
muscle (outer zone: A) and in the Biceps femoris muscle (inner zone: C) of the ham profile. No significant differences were observed between salt formulations in any of the parameters in the Semimembranosus muscle. Regarding inner zone C, hardness and chewiness showed substantially reduced values, in comparison to the outer zone A, due to its higher moisture and salt contents. Hams salted with II registered higher values of hardness and chewiness (p ≤ 0.05) in the Biceps femoris, probably due to their lower water and higher salt concentrations. In fact, hardness increases with salt content (Andrés, Cava, Ventanas, Thovar, & Ruiz, 2004; Ruiz-Ramírez, Arnau, Serra, & Gou, 2005). Even if hams salted with III had lower values for hardness, no significant differences were observed with regard to the control batch. However, there is a risk of increased pastiness in biceps femoris in batch III with lower salt concentrations due to the increase in proteolytic activity (Rico, Toldrá, & Flores, 1991; Toldrá, Rico, & Flores, 1992). A possible solution would be to increase the amount of salt added to the ham in batch III so as to ensure higher salt concentrations inside the ham, which would inhibit cathepsin activities (Rico et al., 1991).
a
30 ± 7 25a ± 9 26a ± 2 39a ± 9 36a ± 8 35a ± 5 37a ± 5 35a ± 7 38a ± 4 41a ± 6 32a ± 8 41a ± 7 45ab ± 9 35a ± 5 47b ± 7
Means of a zone (A, A′, B, B′ and C) in a column with different letters are significantly different at p-value ≤ 0.05.
We would like to thank the Spanish Government (Ministerio de Ciencia y Tecnología) and the European Union (FEDER program) for the financial support of the project (AGL2004-05064-C02). Author Marta Aliño thanks the Spanish Government (Ministerio de Educación y Ciencia) for a FPU grant (AP2005-438). References Aliño, M., Grau, R., Baigts, D., & Barat, J. M. (2009). Influence of sodium replacement on pork loin salting kinetic. Journal of Food Engineering, 95(4), 551−557. Aliño, M., Grau, R., Fuentes, A., & Barat, J. M. (2010). Characterization of pile salting with sodium replaced mixtures of salts in dry-cured loin manufacturing. Journal of Food Engineering, 97(3), 434−439. Aliño, M., Grau, R., Fuentes, A., & Barat, J. M. (2010). Influence of low-sodium mixtures of salts on the post-salting stage of dry-cured ham process. Journal of Food Engineering, 92(2), 198−205.
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Aliño, M., Grau, R., Toldrá, F., Blesa, E., Pagán, M. J., & Barat, J. M. (2009). Influence of sodium replacement on physicochemical properties of dry-cured loin. Meat Science, 83, 423−430. Andrés, A., Cava, R., Ventanas, J., Thovar, V., & Ruiz, J. (2004). Sensory characteristics of Iberian ham: Influence of salt content and processing conditions. Meat Science, 68, 45−51. Armenteros, M., Aristoy, M. C., Barat, J. M., & Toldrá, F. (2009). Biochemical changes in dry-cured loins salted with partial replacements of NaCl by KCl. Food Chemistry, 117, 627−633. Armenteros, M., Aristoy, M. C., Barat, J. M., & Toldrá, F. (2009). Biochemical and sensory properties of dry-cured loins as affected by partial replacement of sodium by potassium, calcium and magnesium. Journal of Agricultural and Food Chemistry, 57, 9699−9705. Bañón, S., Cayuela, J. M., Granados, M. V., & Garrido, M. D. (1999). Pre-cure freezing affects proteolysis in dry-cured hams. Meat Science, 51, 11−16. Barat, J. M., Chiralt, A., & Fito, P. (1998). Equilibrium in cellular food osmotic solution systems as related to structure. Journal of Food Science, 63(4), 836−840. Barat, J. M., Rodríguez-Barona, S., Andrés, A., & Fito, P. (2002). Influence of increasing brine concentration in the cod salting process. Journal of Food Science, 65(7), 1922−1925. Blesa, E., Aliño, M., Barat, J. M., Grau, R., Toldrá, F., & Pagán, M. J. (2008). Microbiology and physico-chemical changes of dry-cured ham during the post-salting stage as affected by partial replacement of NaCl by other salts. Meat Science, 78, 135−142. Cassens, R. G., Demeyer, D., Eikelenboom, G., Honikel, K. O., Johansson, G., Nielsen, T., et al. (1995). Recommendation of reference method for assessment of meat color. Proceedings of 41st International Congress of Meat Science and Technology (pp. 410−411). San Antonio, TX. Elias, M., & Carrascosa, A. V. (2000). Microbiological and physicochemical aspects of vacuum-packed Iberian ham. Fleischwirtschaft International, 2, 36−41. Geleijnse, J. M., Witteman, J. C., Bak, A. A., den Breeijen, J. H., & Grobbee, D. E. (1994). Reduction in blood pressure with a low sodium, high potassium, high magnesium salt in older subjects with mild to moderate hypertension. British Medical Journal, 309, 436−440. Griskey, R. G. (2002). Transport phenomena and unit operations. A combined approach. New York: John Wiley & Sons, Inc. Pub. ISO Norm R-1442, International Standards Organisation (1979). Determination of moisture. ISO Norm R-1443, International Standards Organisation (1973). Determination of lipids. Iyengar, J. R., & Sen, D. P. (1970). The equilibrium relative humidity relationship of salted fish (Barbus carnaticus and Rastelliger canagurta): The effect of calcium and magnesium as impurities in common salt used for curing. Journal of Food Science and Technology, 9, 17−19. Jee, S. H., Miller, E. R. I. I. I., Guallar, E., Singh, V. K., Appel, L. J., & Klag, M. J. (2002). The effect of magnesium supplementation on blood pressure: A meta-analysis of randomized clinical trials. American Journal of Hypertension, 15, 691−696. Kauffman, R., Joo, S. T., Schultz, C., Warner, R., & Faustman, C. (1991). Measuring water holding capacity in post-rigor muscle. 47th Annual Reciprocal Meat Conference (pp. 70−72). : AMSA.
Mizushima, S., Cappuccio, F. P., Nichols, R., & Elliott, P. (1998). Dietary magnesium intake and blood pressure: A qualitative overview of the observational studies. Journal of Human Hypertension, 12, 447−453. Morgan, T., Aubert, J. F., & Brunner, H. (2001). Interaction between sodium intake, angiotensin II and blood pressure as a cause of cardiac hypertrophy. American Journal of Hypertension, 14, 914−920. Motilva, M. -J., Toldrá, F., Nadal, M. -I., & Flores, J. (1994). Effect of pre-freezing hams on the lipolysis during the dry-curing process. Journal of Food Science, 59, 303−305. Pérez-Álvarez, J. A., Sayas-Barberá, M. E., Fernández-López, J., Gago-Gago, M. A., PagánMoreno, M. J., & Aranda-Catalá, V. (1998). Spanish dry-cured ham aging process: Colour characteristics. In A. Diestre, & J. M. Montfort (Eds.), Proceedings 44th International Congress of Meat Science and Technology (pp. 984−985). Barcelona, Spain: Estrategias Alimentarias, S.L. Eurocarne. Rico, E., Toldrá, F., & Flores, J. (1991). Effect of dry-curing process parameters on pork muscle cathepsins B, H and L activities. Zeitscrift für Lebensmittel Untersuchung und Forschung, 193, 541−544. Ruiz-Ramírez, J., Arnau, J., Serra, X., & Gou, P. (2005). Relationship between water content, NaCl content, pH and texture parameters in dry-cured muscles. Meat Science, 70, 579−587. Sayas-Barberá, M. E., Pérez-Álvarez, J. A., Fernández-López, J., & Aranda-Catalá, V. (1998). Traditional and fast salting effect on physicochemical and ultrastructural properties of Spanish dry-cured ham. In A. Diestre, & J. M. Montfort (Eds.), Proceedings 44th International Congress of Meat Science and Technology (pp. 972−973). Barcelona, Spain: Estrategias Alimentarias, S.L. Eurocarne. Sofos, J. N. (1984). Antimicrobial effects of sodium and other ions in foods: A review. Journal of Food Safety, 6, 45−78. Sofos, J. N. (1986). Use of phosphates in low-sodium meat products. Food Technology, 40, 52 (54–58, 60, 62, 64, 66, 68–69). Sofos, J. N. (1989). Phosphates in meat products. In S. Thorne (Ed.), Developments in food preservation—5 (pp. 207−252). New York: Elsevier Applied Science. Tabilo, G., Flores, M., Fiszman, S. M., & Toldrá, F. (1999). Postmortem meat quality and sex affect textural properties and protein breakdown of dry-cured ham. Meat Science, 51, 255−260. Terrell, R. N. (1983). Reducing the sodium content of processed meats. Food Technology, 37, 66−71. Toldrá, F., Rico, E., & Flores, J. (1992). Activities of pork muscle proteases in model cured meat systems. Biochimie, 74, 291−296. Toldrá, F. (2006). Dry-cured ham. In Y. H. Hui, E. Castell-Perez, L. M. Cunha, I. GuerreroLegarreta, H. H. Liang, Y. M. Lo, D. L. Marshall, W. K. Nip, F. Shahidi, F. Sherkat, R. J. Winger, & K. L. Yam (Eds.), Handbook of food science, technology. WHO/FAO (World Health Organization/Food and Agriculture Organization) (2003). Diet, nutrition and the prevention of chronic diseases. WHO Technical Report Series 916. Geneva: World Health Organization.