Biogenic amine content during the manufacture of dry-cured lacón, a Spanish traditional meat product: Effect of some additives

The content of nine biogenic amines (agmatine, tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine) was determined throughout the manufacture of dry-cured lacón, a traditional dry-salted and ripened meat product made in the north-west of Spain from the fore leg of the pig following a similar process to that of dry-cured ham. The effect of the use of additives (glucose, sodium nitrite, sodium nitrate, sodium ascorbate and sodium citrate) on the biogenic amine content during manufacture was also studied. Tryptamine and spermine were the main biogenic amines in fresh meat, while tryptamine and cadaverine were the most abundant at the end of the manufacturing process. During ripening the total amine content increased significantly (P<0.05) in the batches made both without and with additives. The use of additives significantly (P<0.05) increased the total amine content and the content of tryptamine, tyramine and histamine. The total biogenic amine content at the end of the manufacturing process was low as expected for a product in which there is little active microbial metabolism during manufacture.     

Influence of the salting time on volatile compounds during the manufacture of dry-cured pork shoulder "lacón"

The effect of the length of salting time on volatile compounds throughout the manufacture of dry-cured "lacón" was studied using a purge-and-trap extraction and GC/MS analysis. For this study, six treatments of "lacón" were salted with different amounts of salt (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)). The total area of volatile compounds increased significantly (P<0.001) as the length of salting time increased. Significant differences were found for the total area of all aldehydes for each salting time at the end of process. Hexanal presented the most relative abundance, showing highest content in HS treatments while LS treatments showed the lowest one at the end of salting, post-salting and drying-ripening stage. The influence of salting time on the content of 3-Octen-2-one was significant on salting stage (P<0.001) and drying-ripening stage (P<0.01). The salting time affected (P<0.001) the relative abundance of esters at the end of salting and at the end of drying-ripening stage. The salting time affected significantly (P<0.001) on alcohols content at the end of drying-ripening process. However, no significant effect of salt level (P>0.05) was detected on total hydrocarbons and total furans at the end of process.     

Lipolysis, proteolysis and sensory characteristics of a Spanish fermented dry-cured meat product (salchichón) with oregano essential oil used as surface mold inhibitor

The superficial antifungal activity of oregano essential oil (OEO) in Spanish fermented dry-cured sausages ("salchichón"), and its effects on lipolysis, proteolysis and sensory characteristics were evaluated. The surface application of OEO reduced mold contamination on the surface, without significantly affecting the drying process. To evaluate the intensity of lipolysis during the ripening process, the profile and content of free fatty acids were determined. The addition of OEO led to a higher amount of unsaturated fatty acids, but lipolysis was not greatly affected. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which was used to qualitatively assess the proteolytic changes in the sarcoplasmic and myofibrillar proteins during the process, pointed to very similar patterns in all the sausages. OEO did not significantly affect the sensory properties, but increased hardness, resulting in a better texture. Therefore, a shorter ripening time may be necessary for sausages treated with OEO.     

Changes in the volatile fraction during ripening of Mahón cheese

Mahón cheeses, manufactured in the Island of Minorca (Spain), were produced and ripened under controlled conditions. Cheeses were sampled and analyzed at different stages of ripening. Twenty-one major aroma components were identified. It was observed that, during ripening until the most commercially valuable product was obtained, (60–90 days) only 16 compounds varied significantly with time: butanoic, isovaleric, hexanoic, octanoic and decanoic fatty acids (p<0.001), together with heptanoic acid (p<0.005), 2-methyl pentanone, 2-methyl heptanone, 2-methyl nonanone, methyl ketones (p<0.001), ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl tetradecanoate, ethyl hexadecanoate and ethyl esters (p<0.001). These changes could be described by means of zero order kinetics. Through a PCA analysis it was found that three factors explained ca. 87% of the total variance. According to the first two components the variables were grouped by their chemical characteristics (fatty acids, methyl ketones, ethyl esters) and the cases by their ripening time (0/18 days, 35 days, 53/67/82 days).     

Study of Enterobacteriaceae during the manufacture and ripening of San Simón cheese

The aim of this work was to study the evolution of the population of Enterobacteriaceae in one of the traditional Spanish cheeses, San Simón cheese, during the manufacture and ripening processes and its interrelation with the changes in some physico–chemical parameters.The evolution of the Enterobacteriaceae counts (VRBGA medium) and coliform counts (VRBA medium) was studied from samples of milk, curd and inner and surface zones of the cheese at different stages of ripening from five batches of traditionally manufactured artisan cheese. The counts obtained were very similar in both media and in general one log unit higher in the inner portion of the cheeses than on the surface.TheEnterobacteriaceae counts in milk were 10²–10³cfu g⁻¹and the counts increased during the first week of ripening reaching 10⁶–10⁷cfu g⁻¹in the inner portion of the cheese. From this time onwards, the counts slowly decreased to the end of ripening without disappearing completely.The most abundant species in the milk were Klebsiella oxytoca (36% of the isolated strains), Enterobacter cloacae (24%) and Klebsiella pneumoniae (20%). Escherichia coli, constituted the dominant species from the inner portion of the cheeses at the end of ripening (56% of the isolated strains), followed by Hafnia alvei (44%). However, in the samples of the surface portion of the cheese the dominant species at the end of ripening were K. oxytoca (40%), H. alvei (35%) and E. cloacae (20%).     

Microbiological and biochemical changes during ripening of salchichón,a Spanish dry cured sausage

Development of the microflora and changes in the lipid and protein fractions during the ripening of salchichón, a kind of Spanish dry cured sausage, were studied. A commercial mixture of Pediococcus pentosaceus andMicrococcus varians was used as starter culture. Total aerobic bacteria, lactic acid bacteria, Micrococcaeae, Staphylococcus aureus, Entero-bacteriaceae , sulphite reducer Clostridium , yeasts and moulds were determined. The sarcoplasmic and myofibrillar solubility, denaturation and proteolysis index, parameters related to fat stability and the free fatty acid composition were analysed throughout the curing process: after mincing, after the fermentation stage, after the 2nd week of drying and in the final product (4th week of drying). The major changes in the characteristics of salchichón took place during the fermentation stage. This was due to proteolysis and lipolysis phenomena derived from high counts of lactic acid bacteria and Micrococcaeae in this stage. These changes were shown in the increase of the total free amino acid content, the peroxide index and the carbonyl compound content, and in the decrease of the protein solubility and the percentage of polyunsaturated free fatty acids, thus achieving the organoleptic characteristics of the final product.     

Study of the biochemical changes during ripening of Ahumado de Áliva cheese: a Spanish traditional variety

The changes in chemical composition, main physico-chemical parameters, classical nitrogen fractions, caseins and their degradation products, and some fat characteristics were studied during the ripening of ten batches of Ahumado de Áliva cheese, a traditional variety made in the north of Spain. The values of the different compositional and physico-chemical parameters at the end of the ripening did not differ significantly from those found in other cows' milk cheeses elaborated by similar technology. The low pH values are outstanding. The presence of residual lactose at the end of ripening is also relevant. Total soluble nitrogen and non-protein nitrogen increased very little during ripening. The evolution of the values of the different nitrogen fractions show that this cheese undergoes very little proteolysis and that the rennet is the main proteolytic agent. Using PAGE, it was possible to show that, throughout ripening, only 22% of α_s-casein and 9% of β-casein were degraded. The TBA value indicated that the fat of Ahumado de Áliva cheese does not undergo noticeable autooxidation during ripening. The acidity index of the fat also indicated that this cheese underwent little lipolysis during ripening.     

Characterisation of the microflora of attiéké, a fermented cassava product, during traditional small-scale preparation

Attiéké is a fermented cassava product consumed mainly in Cote d'Ivoire. The aim of this study was to characterise the attiéké fermentation by examining products from 15 small-scale production sites at various stages of its preparation. For the preparation of attiéké, fresh cassava is grated to a pulp and inoculated with 10% of a spontaneous traditional inoculum. The inocula contained aerobic mesophiles at mean numbers of 8.2 x 10(7) cfu/g and lactic and acetic acids at mean concentrations of 0.2% and 0.1%, respectively. The mean pH was 5.0. Lactic acid bacteria were the dominant microorganisms in cassava pulp throughout fermentation with the mean numbers being 1.2 x 10(9) cfu/g after 15 h. The identification to the species level of microorganisms from one representative attiéké production of good quality showed that, at the start of fermentation, Leuconostoc mesenteroides subsp. mesenteroides was present in the highest numbers, accounting for 20% of all lactic acid bacteria. As the fermentation proceeded, this species was replaced by homofermentative lactic acid bacteria, Lactobacillus salivarius and Lactobacillus delbrueckii subsp. delbrueckii, present at 20% and 16%, respectively, and obligate heterofermentatives, Lactobacillus fermentum and Lactobacillus confusus at 12% and 10%, respectively, of total lactic acid bacteria in the flora at the end of fermentation. High numbers of acid-sensitive microorganisms, Bacillus circulans, Bacillus lentus, Enterobacter sakazakii, Enterobacter cloacae and Klebsiella pneumoniae subsp. pneumoniae, were transferred to the pulp in the inocula, but acidification to a mean pH of 4.4 with mean lactic and acetic acid concentrations of 0.59% and 0.2%, respectively, prevented their growth and reduced their numbers to less than 10(2) cfu/g at the end of fermentation. The mean numbers of Candida tropicalis, the main yeast present, remained relatively constant at about 10(5) cfu/g throughout attiéké production. The mean numbers of aerobic mesophiles decreased to below 10(2) cfu/g as a result of the steaming process. The finished attiéké had a mean pH of 4.4 and mean lactic and acetic acid concentrations of 0.6% and 0.1%, respectively.     

PRKAG3 and CAST genetic polymorphisms and quality traits of dry-cured hams - I. Associations in Spanish dry-cured ham Jamón Serrano

The functional single polymorphisms identified in the calpastatin (CAST) gene have been related to the rate of meat tenderization and the protein turnover after slaughter, and the Ile199Val polymorphism identified in the coding region of the protein kinase AMP-activated (PRKAG3) gene has been proven to affect ultimate pH in muscle. The aim of the present study was to show the effects of these genetic polymorphisms on the quality traits of Spanish dry-cured ham Jamón Serrano. A tissue sample from 665 crossbreed pigs were genotyped for PRKAG3 Ile199Val, CAST Arg249Lys and CAST Ser638Arg polymorphisms, and a subsample of 120 dry cured hams was selected to perform physico-chemical, rheological, instrumental colour and sensory analyses. Associations between the polymorphisms and several quality traits of dry-cured ham, mainly related to flavour and texture, were found. The genotypes PRKAG3 Ile/Ile, CAST249 Arg/Arg and CAST638 Arg/Arg, and the haplotype CAST 249Arg-638Arg were the most favourable for Jamón Serrano production.     

Influence of salt content and processing time on sensory characteristics of cooked "lacón"

The influence of salt content and processing time on the sensory properties of cooked "lacón" were determined. "Lacón" is a traditional dry-cured and ripened meat product made in the north-west of Spain from the fore leg of the pig, following a similar process to that of dry-cured ham. Six batches of "lacón" were salted with different amounts of salt (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)) and ripened during two times (56 and 84 days of dry-ripening). Cured odour in all batches studied, red colour and rancid odour in MS and HS batches, flavour intensity in MS batch and fat yellowness, rancid flavour and hardness in the HS batch were significantly different with respect to the time of processing. Appearance, odour, flavour and texture were not significantly affected by the salt content (P>0.05). However, the saltiness score showed significant differences with respect to the salt levels in all studied batches (56 and 84 days of process). The principal component analysis showed that physicochemical traits were the most important ones concerning the quality of dry-cured "lacón" and offered a good separation of the mean samples according to the dry ripening days and salt level.     

Biochemical changes in Picón Bejes-Tresviso cheese,a Spanish blue-veined variety,during ripening

The changes in the gross chemical composition, physico-chemical parameters, nitrogen fractions, caseins and their degradation products, and some fat characteristics were studied during the ripening process of 10 batches of Picón Bejes-Tresviso cheese, a traditional blue-veined variety made in the north of Spain. The values of the different compositional and physico-chemical parameters at the end of ripening did not differ very much from those found in other Spanish and European blue-veined cheeses. The total soluble nitrogen and the non-protein nitrogen increased by factors of 5.4 and 8, respectively, at the end of ripening compared to the values found in cheese curd after salting. The final values of all the nitrogen fractions showed that Picón Bejes-Tresviso cheese undergoes extensive and in depth proteolysis. The intense degradation of the caseins during ripening was confirmed when the caseins and their degradation products were quantified using PAGE techniques. The autooxidation of the fat does not seem very important during the ripening of this cheese. Nevertheless, lipolysis was very intense; the acidity index of the fat values (free fatty acid contents) increased by a factor of about 20 during ripening.     

Changes in physico-chemical, microbiological, textural and sensory attributes during ripening of dry-cured foal salchichón

The changes in the physico-chemical, microbiological, textural and sensory attributes of foal salchichón were followed during ripening. Foal salchichón samples were taken at 0 days (mix before stuffing), and after 7, 14, 21, 28, 35, 42 and 49 days of ripening. The final a_w was 0.82, whereas pH values stayed around their initial values. TBAR'S values increased significantly (P < 0.001) during processing, from 0.44 to 2.26 mg/kg of sausage. Ripening time also affected the lightness (L*), redness (a*) and yellowness (b*) (P < 0.001). Hardness, gumminess and chewiness increased (P < 0.001) from 0.96, 0.6 and 0.47 to 46.92 kg/cm², 21.34 kg/cm² and 15.14 kg, respectively during processing, whereas cohesiveness and springiness values decreased during ripening. Lactic acid bacteria increased slowly in number and a large increase of Micrococcaceae was noticed. Regarding sensorial characteristics, foal salchichón samples showed high values for intensity of flavour (7.22 ± 0.44), hardness (7.33 ± 0.71) and dryness (6.67 ± 0.71) and low scores for acid taste (1.67 ± 0.71) and saltiness (3.11 ± 0.6).     

Role of an autochthonous starter culture and the protease EPg222 on the sensory and safety properties of a traditional Iberian dry-fermented sausage "salchichón"

The effect of the addition of an autochthonous starter culture and the protease EPg222 on the physico-chemical and sensory characteristics of dry-fermented sausage ‘‘salchichon” was investigated. Sausages were prepared with purified EPg222 and Pediococcus acidilactici MS200 and Staphylococcus vitulus RS34 as starter culture (P200S34), separately and together, ripened for 90 days, and compared with a control batch. Dry-fermented sausages ripened with EPg222 and starter culture showed higher amounts of AN and volatile compounds derived from amino acid catabolism than the control, especially in samples in which was added the association of enzyme and starter culture (P200S34 + EPg222). There were clear differences shown by the texture analysis, with the P200S34 + EPg222 batch being less hard. Especially important was the result found in biogenic amines, since the association P200S34 + EPg222 reduced their accumulation compared to the EPg222 batch. The use of EPg222 may be of great interest to improve the sensory characteristics of dry-fermented sausages, but its association with the selected starter culture with low decarboxylase activity is necessary to guarantee healthiness and homogeneity.     

Development of a solid phase microextraction protocol for the GC–MS determination of volatile off-flavour compounds from citral degradation in oil-in-water emulsions

The conditions for headspace solid phase microextraction (HS-SPME) analysis of volatile off-flavour compounds in citral emulsion were determined. Type of SPME phase (65 μm PDMS/DVB, 100 μm PDMS and 75 μm CAR/PDMS), adsorption temperature and salt concentration were significant factors affecting total peak area in the gas chromatogram and optimised in one factor experiments. Then, adsorption temperature (30–50 °C), adsorption time (20–40 min), and salt concentration (0–6 M) were studied to develop HS-SPME condition for obtaining the highest extraction efficiency. PDMS/DVB in 65 μm was the optimum fiber because of high adsorption efficiency and good reproducibility. The optimal condition was adsorption at 50 °C for 40 min and 6 M salt added to sample. Good Linearity, high recovery, good reproducibility and low limit of detection (LOD) for all off-odour compounds according to the optimised SPME conditions indicated that the SPME procedure was applicable for the analysis of the degraded citral products in headspace volatile of emulsion.     

Effect of modified atmosphere packaging on the microbiological and sensory quality on a dry cured beef product: "Cecina de león"

The aim of this study was to investigate the shelf-life of commercial “Cecina de León” (CL) packaged in vacuum (VP) and in CO₂/N₂ atmospheres (20/80% CO₂/N₂ and 80/20% CO₂/N₂). Packaged product was stored at 6 °C, measuring microbiological, physico-chemical and sensory parameters during 210 days. The values obtained for mesophilic aerobic, anaerobic and psychrotrophic counts did not vary in both the vacuum and the gas packaged samples after 210 days of storage. Enterobacteria and enterococci were always below the detection limit, and in the gas-packaged CL, pseudomonad numbers were significantly inhibited. No changes were observed in the counts of the typical microflora of CL (Lactic Acid Bacteria, yeasts and moulds and Micrococcaceae) up to 210 days and no differences (p > 0.05) were found between the counts in the VP and in the gas-packaged samples. A pronounced initial fading was observed in redness (a^∗) within the first 15 days in the VP samples and within the second month in the gas-packaged samples attributed to the presence of white film on surface of CL portions. No differences were observed (p > 0.05) in texture parameters evaluated between packaging methods during storage, and the values found are within the range for CL not packaged. The sensory properties of CL stored in 20/80% CO₂/N₂ were slightly less acceptable than the samples packed under vacuum and under 80/20% CO₂/N₂ at 210 days of storage. It is concluded that no clear advantage of the gas packaging was observed compared to the VP of “Cecina de León”.     

Characterisation by SPME–GC–MS of the volatile profile of a Spanish soft cheese P.D.O. Torta del Casar during ripening

The volatile profile of the Spanish soft cheese of the Protected Designation of Origin (PDO) Torta del Casar, made from raw ewes’ milk, was studied in four different stages of ripening (1, 30, 60 and 90 days) by the method of SPME–GC–MS. A total of 46 compounds were detected: 13 acids, 9 esters, 4 ketones, 7 alcohols, 3 aldehydes, 7 aromatic compounds and 3 compounds which could not be classified into those groups. Carboxylic acids were the most abundant group isolated; their levels significantly increased during ripening and comprised 61.5% of the total aroma extract at the end of ripening. At day 90, acids of microbial origin were the most abundant, followed by acids derived from amino acids while acids from lipolysis of triglycerides were the least abundant. Esters were the next most important group and their amount also increased significantly during maturation, as did ketones, while alcohols content slightly decreased at the end of the ripening. At day 90, the compounds at highest levels were acetic acid, 3-methylbutanoic acid, butanoic acid propyl ester and 2-butan-one; so these compounds, due to their high levels and their low threshold value could play an important role in the final aromatic profile of this cheese.     

Physico-chemical and microbiological profiles of "salchichón" (Spanish dry-fermented sausage) enriched with orange fiber

Spanish dry-fermented sausages with three concentrations (0, 1 and 2%) of orange fiber (juice industry by-product) were prepared and studied. Fermentation and dry-curing processes were followed by physico-chemical (pH and water activity), chemical (moisture, lactic acid and residual nitrite level) and microbiological (aerobic mesophilic bacteria, lactic acid bacteria, Enterobacteriaceae, Micrococcaceae and molds and yeasts counts) analysis. Sensory analyses were conducted on the finished products. Only residual nitrite level and counts of micrococcus were affected by fiber addition during fermentation. pH, water activity, residual nitrite level and counts of Micrococcaceae were affected by fiber addition during dry-curing. Orange fiber decreases residual nitrite levels and favours micrococcus growth. Both effects have a positive impact on sausage safety and quality. The reduction in residual nitrite level decreases the risk of nitrosamine formation. For all sensorial attributes evaluated sausages containing 1% fiber showed similar scores to controls.     

Castration and slaughter age effects on panel assessment and aroma compounds of the "mestiço" goat meat

Cooked meat from castrated male and intact "mesti?o" goats slaughtered at 175, 220, 265 and 310 days of age, were analysed by panellists and GC-MS. Slaughter age had a (P<0.05) effect on organoleptic qualities of goat meat. Scores for sensorial attributes were not different (P<0.05) for intact and castrated goats. A total of 87 compounds were identified and a further 21 were partially characterized by GC-MS. Hydrocarbons were presented in the highest relative amounts and all aroma isolates were dominated by products of lipid degradation. Total relative abundance of volatiles was identified at higher levels in the cooked meat from castrated goats than from entires. Meat from goats slaughtered at first age (175 days) was preferred by panellists and was found to have the lowest number of volatiles and total relative abundance.     

The effect of α-tocopherol and butylated hydroxyanisole on the colour properties and lipid oxidation of kavurma, a cooked meat product

Kavurma is a cooked meat product and is consumed sliced. The amount of animal fat in kavurma (30-40%) is higher than in other meat products; therefore, lipid oxidation and colour defects are a major problem during storage and in the market place. To preserve the quality characteristics of kavurma in markets antioxidants must be added and the product must be packaged and stored at low temperature. In this study, the effects of α-tocopherol and butylated hydroxyanisole (BHA) levels on lipid oxidation and colour deterioration of sliced and vacuum-packaged kavurma were investigated. Kavurma was made from beef meat and melted beef fat in 5 groups: No-added antioxidant, 50mg/kg BHA, 100mg/kg BHA, 50mg/kg α-tocopherol and 100mg/kg α-tocopherol. The kavurma produced was sliced (3-4-cm thick) and vacuum packed and stored at 4°C for 300 days, and thiobarbituric acid reactive substance, pH, moisture, lightness, redness and yellowness values of sliced product were determined during storage. The use of antioxidants in kavurma production caused a significant (P<0.01) decrease in the thiobarbituric acid reactive substances (TBARS) values. The lipid oxidative stability effect of the antioxidants was in following order: 100mg/kg BHA>100mg/kg α-tocopherol>50mg/kg BHA=50mg/kg α-tocopherol>no-added antioxidant group. Also, TBARS values did not differ significantly (P>0.05) between 0 and 300 days in the 100mg/kg BHA and 100mg/kg α-tocopherol groups. In addition, the no-added antioxidant group had lower lightness and yellowness values than all the antioxidant groups. Sliced and vacuum-packaged kavurma with added antioxidant showed greater colour and lipid oxidative stability during storage than kavurma to which no antioxidant was added.