The influence of three salting treatments (treatment II: 50% NaCl-50% KCl; III: 45% NaCl-25% KCl-20% CaCl2-10% MgCl2; IV: 30% NaCl-50% KCl-15% CaCl2-5% MgCl2) on the formation of volatile compounds throughout the process was studied and compared to those of a control “lacón” (treatment I: 100% NaCl). There was an intense formation of volatile compounds throughout the processing, particularly during the dry-ripening stage. The most abundant chemical family in all the formulations, in the final product was hydrocarbons followed by aldehydes. The total volatile compound release was more intense in the control “lacóns” (1164 AU×106·g–1dry matter) than in “lacóns” from formulations II, III and IV (817–891 AU×106·g−1dry matter). The “lacóns” from formulation I showed the highest amounts of aldehydes. The “lacóns” from formulations I and II presented the highest amounts of hydrocarbons. The main conclusion is that the replacement of NaCl produces changes in the volatile profile and could be affect the aroma of “lacón”.
Dry-cured “lacón” is a traditional cured meat product made in the north-west of Spain from the fore leg of the pig which is cut at the shoulder blade-humerus joint, following very similar manufacturing processes to those used in the production of dry-cured ham as described by Purriños
Salt is an essential ingredient in dry-cured “lacón” due to its contribution to the water-holding capacity, prevention of microbial growth, and reduction in water activity which facilitate the solubilization of certain proteins and confer a typical salty taste (Lorenzo
In recent years different studies have begun to show that meat consumption is being more and more influenced by health and nutritional considerations. The mean daily sodium intake of the European population ranges from about 3 to 5 g (8 to 11 g NaCl) (EFSA,
Due to the increased knowledge about the links between sodium intake and coronary heart diseases, consumers’ demand for low-salt meat products with the same quality as conventional ones has increased. To this regards, the partial substitution of NaCl by a mixture of salts (potassium, calcium, and magnesium salts) appears to be the best alternative to reduce the sodium content in dry-cured “lacón” (Lorenzo
The aim of this work was to determine the influence of partial NaCl replacement by a mixture of KCl, CaCl2 and MgCl2 on the generation and release of volatile compounds to the headspace of dry-cured “lacón” for their possible contribution to the flavor of this product.
Fifty-two fresh “lacón” pieces with an average weight of 4.61±0.47 kg each were obtained from a local slaughterhouse in the area of Ourense (Spain). Four of the raw pieces were sampled and analyzed in order to characterize the raw material. The remaining forty-eight “lacón”raw pieces were submitted to the traditional “lacón” processing (Purriños
Moisture, fat and protein contents were determined according to the Association of Official Analytical Chemists (
The quantification of mineral elements (Na, K, Ca and Mg) was performed by inductively coupled plasma-optical emission spectroscopy (ICP-OES), according to the procedure described by Lorenzo
The extraction of the volatile compounds was performed using solid-phase micro-extraction (SPME). A SPME device (Supelco, Bellefonte, PA, USA) containing a fused-silica fiber (10 mm length) coated with a 50/30 µm thickness of DVB/CAR/PDMS (divinylbenzene/carboxen/polydimethylsiloxane) was used for HS-SPME extraction.
The muscle samples were ground with a commercial grinder, a 1 g portion was weighed into a 24 mL vial and the vial was screw-capped with a laminated Teflon rubber disk. The fiber was inserted into the sample vial through the septum and then exposed to the headspace. The extractions were carried out in an oven to ensure a homogeneous temperature for sample and headspace. The fiber was conditioned prior to analysis by heating it in a gas chromatograph injection port at 270 °C for 60 min, following the manufacturer specifications. Extraction was performed at 35 °C for 30 min. Before extraction, the samples were equilibrated for 15 min at the temperature used for extraction. Once sampling was finished, the fiber was drawn into a needle and transferred to the injection port of the gas chromatograph–mass spectrometer (GC–MS) system.
A gas chromatograph 6890N (Agilent Technologies Spain, S.L., Madrid, Spain) equipped with a mass detector 5973N (Agilent Technologies Spain, S.L., Madrid, Spain) was used with a DB-624 capillary column (J&W scientific: 30 m, 0.25 mm id, 1.4 µm film thickness). The SPME fiber was desorbed and maintained in the injection port at 260 °C for 8 min. The sample was injected in the splitless mode. Helium was used as carrier gas with a linear velocity of 40 cm·s−1. The temperature programme was isothermal for 10 min at 40 °C, raised to 200 °C at a rate of 5 °C·min−1, and then raised to 250 °C at a rate of 20 °C·min−1, and held for 5 min: total run time 49.5 min. Injector and detector temperatures were both set at 260 °C. The mass spectra was obtained using a mass selective detector working in electronic impact at 70 eV, with a multiplier voltage of 1953 V and collecting data at a rate of 6.34 scans·s−1 over the range m/z 40-300.
The compounds were identified comparing their mass spectra with those contained in the NIST05 (National Institute of Standards and Technology, Gaithersburg) library, and/or by comparing their mass spectra and retention time with standards (Supelco, Bellefonte, PA, USA), and/or by calculation of retention index relative to a series of standard alkanes (C5–C14) (for calculating linear retention index, Supelco 44585-U, Bellefonte, PA, USA) and matching them with data reported in the literature. The results are expressed as AU (area units)×106·g−1 of dry matter.
All statistical analyses were performed using the IBM SPSS Statistics 19 software (IBM, Corp,
The results of chemical composition and pH values at the end of dry-cured “lacón” submitted to four different salting treatments are shown in
Chemical composition and pH values of dry-cured lacón at the end of processing (mean ± standard deviation of four replicates)
Salt formulations | SEM | Sign. | ||||
---|---|---|---|---|---|---|
|
||||||
|
|
|
|
|||
Moisture (%) | 55.28±3.83 |
53.21±2.92 |
58.87±0.87 |
61.66±0.28 |
1.12 |
|
Protein (% of dry matter) | 33.28±2.77 | 36.76±4.07 | 31.03±2.91 | 32.09±3.66 | 0.94 | n.s. |
Fat (% of dry matter) | 9.82±2.52 | 7.65±2.55 | 6.19±1.57 | 7.50±2.85 | 0.63 | n.s. |
pH | 5.96±0.08 |
6.08±0.09 |
5.83±0.05 |
5.92±0.05 |
0.03 | ** |
Salt formulations: treatment I: control, 100% NaCl; treatment II: 50% NaCl and 50% KCl; treatment III: 45% NaCl, 25% KCl, 20% CaCl2 and 10% MgCl2; treatment IV: 30% NaCl, 50% KCl, 15% CaCl2 and 5% MgCl2
Mean values in the same row (corresponding to the same parameter) not followed by a common letter differ significantly (
Sign.: Significance; n.s.: not significant;
(
*** (
Regarding pH values, the NaCl replacement by other salts induced significant (
Mineral composition (ppm) of dry-cured lacón at the end of processing (mean ± standard deviation of four replicates)
ppm | Salt formulations | SEM | Sign. | |||
---|---|---|---|---|---|---|
|
||||||
|
|
|
|
|||
Na | 2446.60±108.46 |
1483.91±118.55 |
738.21±20.34 |
586.35±109.39 |
189.50 |
|
K | 565.11±22.22 |
1915.42±78.12 |
876.08±80.46 |
1668.94±99.21 |
127.61 |
|
Ca | 9.35±1.27 |
9.31±0.59 |
42.87±10.48 |
33.73±11.08 |
4.19 |
|
Mg | 35.04±5.35 |
31.89±3.35 |
42.73±2.14 |
36.97±3.70 |
1.64 |
|
Salt formulations: treatment I: control, 100% NaCl; treatment II: 50% NaCl and 50% KCl; treatment III: 45% NaCl, 25% KCl, 20% CaCl2 and 10% MgCl2; treatment IV: 30% NaCl, 50% KCl, 15% CaCl2 and 5% MgCl2
Mean values in the same row (corresponding to the same parameter) not followed by a common letter differ significantly (
Sign.: significance: n.s.: not significant;
(
(
The SPME technique is not normally used for absolute quantifications, but when exactly the same extraction methodology is applied, this technique allows for comparing relative amounts among samples. A total of 31 volatile compounds were detected in the headspace of “lacón” at the end of the dry-ripening process. The compounds were grouped by chemicals and their linear retention index (
Volatile compounds (AU×106·g−1dry matter) in the headspace of dry-cured “lacón” salted with different salt formulations at the end of processing. Data are the average values of four replicates
Salt formulations | SEM | Sign. | ||||||
---|---|---|---|---|---|---|---|---|
|
||||||||
LRI | R |
|
|
|
|
|||
Acetic acid | 720 |
|
2.47 | 1.81 | 1.88 | 1.31 | 0.37 | ns |
Butanoic acid | 883 |
|
15.58 |
20.92 |
22.53 |
5.16 |
2.94 |
|
Nonanoic acid | 1370 |
|
0.57 |
0.00 |
0.67 |
0.00 |
0.10 |
|
|
|
|
|
|
|
|
||
1-Pentanol | 834 |
|
21.35 |
5.59 |
14.83 |
23.77 |
2.71 |
|
1-Hexanol | 925 |
|
7.27 |
0.00 |
20.89 |
16.63 |
2.59 |
|
1-Octen-3-ol | 1095 |
|
24.32 |
16.61 |
32.84 |
41.94 |
3.36 |
|
Benzyl alcohol | 1107 |
|
15.84 | 12.55 | 13.29 | 11.66 | 0.85 | ns |
|
|
|
|
|
|
|
||
Pentanal | 736 |
|
15.64 |
0.00 |
13.84 |
12.05 |
2.34 |
|
Hexanal | 823 |
|
608.55 |
40.97 |
297.10 |
274.90 |
59.87 |
|
Heptanal | 933 |
|
8.32 |
6.46 |
12.31 |
16.20 |
1.29 |
|
Decanal | 1347 |
|
3.92 |
2.60 |
0.00 |
0.00 |
0.53 |
|
|
|
|
|
|
|
|
||
Ethanol, 2-(2-butoxyethoxy)-, acetate | 1419 |
|
1.69 |
1.27 |
0.00 |
0.00 |
0.25 |
|
1,2,3-Propanetriol, diacetate | 1514 |
|
1.10 |
0.87 |
0.00 |
0.00 |
0.17 |
|
|
|
|
|
|
|
|
||
Pentane, 2,3,4-trimethyl- | 660 |
|
3.81 | 5.01 | 2.66 | 2.07 | 0.51 | ns |
Heptane | 700 |
|
2.71 | 2.26 | 2.40 | 0.63 | 0.39 | ns |
Pentane, 2,3,3-trimethyl- | 706 |
|
12.23 |
9.38 |
3.24 |
3.99 |
1.25 |
|
Octane | 800 |
|
14.1 | 27.82 | 14.79 | 16.56 | 2.45 | ns |
Heptane, 3-methylene- | 807 |
|
2.63 |
3.42 |
0.00 |
0.00 |
0.52 |
|
Hexane, 3-ethyl- | 860 |
|
1.30 |
1.82 |
0.00 |
1.93 |
0.32 | ns |
Heptane, 2,2,4-trimethyl- | 904 |
|
7.29 |
7.37 |
0.00 |
0.00 |
1.20 |
|
Heptane, 2,5,5-trimethyl- | 924 |
|
5.42 |
6.73 |
0.00 |
0.00 |
0.89 |
|
Heptane, 2,2,4,6,6-pentamethyl- | 998 |
|
569.66 |
627.46 |
376.47 |
428.29 |
37.99 |
|
3-Ethyl-3-methylheptane | 1003 |
|
1.73 |
2.14 |
1.64 |
0.00 |
0.27 |
|
Decane, 2,6,7-trimethyl- | 1134 |
|
48.14 |
30.57 |
37.37 |
0.00 |
7.54 |
|
Dodecane | 1200 |
|
3.97 | 3.51 | 2.68 | 2.45 | 0.28 | ns |
Undecane, 5-methyl- | 1207 |
|
5.63 |
4.77 |
4.01 |
3.00 |
0.40 |
|
Decane, 5-methyl-6-methylene- | 1265 |
|
3.16 | 3.95 | 3.08 | 1.98 | 0.46 | ns |
Tridecane | 1300 |
|
1.39 | 1.42 | 2.04 | 1.83 | 0.13 | ns |
|
|
|
|
|
|
|
||
2-Butanone, 3-hydroxy- | 765 |
|
15.87 |
7.76 |
4.02 |
11.86 |
1.52 |
|
2-Heptanone | 940 |
|
3.73 |
2.73 |
5.61 |
3.49 |
0.33 |
|
|
|
|
|
|
|
|
||
Furan, 2-pentyl- | 1009 |
|
4.06 | 3.80 | 6.05 | 5.80 | 0.53 | ns |
|
|
|
|
|
|
|
Salt formulations:
Sign.: significance; ns: not significant;
Means in the same row not followed by a common superscript letter differ significantly (
S.E.M.: Standard error of the mean; AU: area units resulting of counting the total ion chromatogram (TIC) for each compound; LRI: linear retention index calculated for DB-624 capillary column (J&W scientific: 30 m×0.25 mm id, 1.4 µm film thickness) installed on a gas chromatograph equipped with a mass selective detector; R: Reliability of identification; LRI: volatiles identified by comparing their LRI with those reported in the literature (Lorenzo and Fonseca,
The changes in the most relevant volatile compounds during “lacón” processing are shown in
Evolution of volatile compounds throughtout dry-cured “lacón” processing using different salting formulations. Error bars indicate the standard error for each treatment. Different letters indicate significant differences among formulations (
As mentioned above, hydrocarbons were the most abundant chemical group at the end of the ripening process in dry-cured “lacón”. They represent 55, 49 and 51% of the total volatile compounds in “lacóns” from formulations I, III and IV, respectively, and 85% of the total volatile compounds in “lacóns” from formulation II. In this study, heptane, 2,2,4,6,6-pentamethyl, was the most abundant hydrocarbon in all the batches (representing about 90% of total hydrocarbons), followed by decane, 2,6,7-trimethyl and octane. These results agree with Bermúdez
An increase in the total amount of hydrocarbons was observed during the process, from initial values of 72 AU×106·g−1 DM in fresh meat to 650, 698, 432 and 459 AU×106 ·g−1 DM at the end of the dry-ripening of samples from formulations I, II, III and IV, respectively (
In the present study, aldehydes represented about 35–50% of the total volatile compounds in the “lacóns” from batches I, III and IV and 5.9% of the total volatile compounds in “lacóns” from batch III. Regarding the aldehydes, hexanal, derived from the
The amount of aldehydes increased from initial values of 6.45 AU×106·g−1 DM in the raw pieces to 626, 318 and 299 AU×106·g−1 DM at the end of dry-ripening of “lacóns” submitted to formulations I, III and IV, respectively. These results were previously reported by Armenteros
On the other hand, hexanal showed differences (
Armenteros
Alcohols were the third chemical family after the ripening period, they represented between 4 and 10% of the total volatile compounds, and four different alcohols were identified: 1-pentanol, 1-hexanol, 1-octen-3-ol and benzyl alcohol. These compounds have also been detected in other dry-cured meat products (Bermúdez
The formation and release of alcohols was affected from the beginning by the processing time, as well as by the formulation. In fresh meat alcohols were not detected, and they increased during cold stages. After the post-salting stage the values of alcohols were 131.2, 64.4, 37.9 and 43.4 AU×106·g−1 DM in “lacóns” from formulation I, II, III and IV, respectively. Then, total alcohols of the samples from formulations I and II gradually declined to the end of the process, while in samples submitted to formulations III and IV increased to the end of the process (
The samples submitted to formulation IV presented the higher values of 1-octen-3-ol, 1-pentanol and 1-hexanol than the samples from formulations I and II. The intermediate values were observed in samples from formulation III. Our results are in agreement with Armenteros
Only three acids were detected through the manufacture process of dry-cured “lacón”. Butanoic acid was the most abundant at the end of the process representing about 80–90% of total acids. These findings are in agreement with the study of Bermúdez
In this study, two ketones were detected in the headspace of “lacón”. The most abundant ketone was 2-butanone, 3-hydroxy representing about 70–75% of total ketones. In contrast, Bermúdez
Only furan, 2-pentyl, was detected after the dry-ripening process (values between 3.8 and 6.1 AU× 106·g−1 DM) and it did not show differences among treatments. Furan, 2-pentyl, has been found in other dry-cured meat products manufactured from whole pieces (Bermúdez
Finally, esters were only detected in samples from formulations I and II, but their amounts were very low (2.79 and 1.85 AU×106·g−1 DM in the “lacóns” submitted to formulations I and II, respectively), and they represented less than 0.02% of the total volatile compounds. Esters have low olfaction threshold values. However, taking into account that the samples have very low values of these compounds, it can be considered that they do not contribute to the aroma of “lacón”.
In addition, in a previous study (Lorenzo
The formation of the volatile compounds significantly increased during the dry-curing process, particularly during the dry-ripening stage. The replacement of NaCl by other salts influenced the formation of the majority of volatile compounds. At the end of processing, the control samples (salted with 100% of NaCl) showed the highest values of total volatile compounds. This fact is mainly due to higher values of hexanal and total aldehydes in this batch than in the other ones. Therefore, NaCl acts as a pro-oxidizing and solubilizing agent, increasing the relative levels of volatile compounds from lipid oxidation, among others. The results obtained in this study indicate that partial NaCl replacement by other chloride salts has an impact on the formation of volatile compounds in dry-cured “lacón”. Finally, the odor intensity was directly related to the amount of total volatile compounds.
The authors are grateful to The Xunta de Galicia (The Regional Government) (Project FEADER 2012/45) for financial support. Special thanks go to GISVA, S.A. (Arteixo, A Coruña) for the lacón samples supplied for this research.