Search

Peptidyl post-translational modifications (PTMs) could influence the final quality of processed meat. In this study, the peptide oxidative phenomena in Spanish dry-cured ham (Biceps femoris muscle) was evaluated at different ripening times (9, 12, 15, 18 and 24 months of processing) evidencing interactions amongst the lipid and protein oxidation, major peptidyl PTMs and the release of free amino acids (FAAs). Results showed that 12 months of processing enabled the most abundant protein-bound carbonyls, while TBARS value was significantly favored (p < 0.001) by ripening. However, FAAs were still intensively generated during overall ripening. Peptidomics and chemometrics further revealed that proteolysis mostly hampered the oxidized peptides rather than the deamidated ones during ripening. Myosin light chain (MYL1 and MYL3) showed high oxidative susceptibility owing to peptidyl methionine and proline oxidation as well as acetaldehyde adduct formation on lysine or histidine residues., Grant AGL2017-89381-R and FEDER funds from the Spanish Ministry of Economy, Industry and Competitiveness, and Ramón y Cajal postdoctoral contract by L.M. are acknowledged. C.L. appreciated the financial support from China Scholarship Council (CSC) through the State Scholarship Fund for Overseas Study (No. 201806760050). The peptidomic analysis was performed in the proteomics facility of SCSIE University of Valencia. This proteomics laboratory is a member of Proteored, PRB3 and is supported by grant PT17/0019, of the PE I + D + i 2013-2016, funded by ISCIII and ERDF

Peptides and free amino acids are naturally generated in dry-cured ham as a consequence of proteolysis phenomenon exerted by muscle peptidases. The generation of bioactive peptides in different types of dry-cured ham produced in Spain, Italy and China is reviewed in this manuscript. Major muscle proteins are extensively hydrolysed firstly by endogenous endo-peptidases followed by the successive action of exo-peptidases, mainly, tri- and di-peptidylpeptidases, aminopeptidases and carboxypeptidases. Such proteolysis is very intense and consists of the generation of large amounts of free amino acids and a good number of peptides with different sequences and lengths, some of them exerting relevant bioactivities like angiotensin converting enzyme inhibitory activity, antioxidant activity, di-peptidylpeptidase IV inhibitory activity among other and in vivo antihypertensive, hypoglycemic or anti-inflammatory activity. This manuscript reviews the recent findings showing that dry-cured ham constitutes a good source of natural bioactive peptides that have potential benefit for human health., The research leading to these results received funding from Grant AGL2017-89831-R from the Spanish Ministry of Economy, Industry and Competitivity and FEDER funds The Ramón y Cajal postdoctoral contract to LM is also acknowledged.

This study evaluates the effect of dietary selenium (Se) supplementation source (organic, Se-enriched yeast; SY vs. inorganic, sodium selenite; SS), dose (0.2: L vs. 0.4: H mg/kg) and the combination of Se and vitamin E (VITE + SS) for 26 days on drip loss, TBARS, colour changes, myofibrillar protein pattern and proteolysis in pork. The lowest water losses were observed in the SY-H group when compared to the others. SY-H and VITE + SS groups presented lower myofibrillar protein hydrolysis/oxidation. VITE + SS supplementation also resulted in higher PRO, TRP and PHE content at days 2 and 7, whereas the SY group showed increased GLY and CAR and tended to have higher TAU and ANS at day 2. The myofibrillar fragmentation index was not modified by the dietary treatment; however, at day 8, it tended to be higher in groups supplemented with SeY and VITE + SS. The results of the present study might indicate a possible relation between muscle proteolysis and water loss., This research was supported by projects CDTI IDI-20111017 and S2013/ABI-2913-MEDGAN-CAM.

Angiotensin I-converting enzyme (ACE) inhibitory peptides have been searched in thornback ray (Raja clavata) muscle hydrolysed with Bacillus subtilis A26 proteases until a hydrolysis degree of 18.35%. The hydrolysate showed an IC50 of 0.83 mg mL−1. To identify peptides responsible for this activity, the extract was eluted through size-exclusion chromatography and fractions collected. The highest ACE inhibitory activity was found for fractions F2 and F3 which had IC50 of 0.42 and 0.51 mg mL−1, respectively. These fractions were analysed by nano-liquid chromatography coupled to tandem mass spectrometry (nLC-MS/MS). A total of 131 and 108 peptide sequences mainly derived from actin, myosin heavy chain and procollagen alpha 1 chain proteins were identified in fractions F2 and F3, respectively. FQPSF and LKYPI showed the best results with an IC50 of 12.56 and 27.07 μM, respectively. These results prove the potential of thornback ray muscle hydrolysate as a source of ACE inhibitory peptides., This work was funded by a grant from the Ministry of Higher Education and Scientific Research of Tunisia and grant Prometeo/2012/001 from Conselleria d´Educació Cultura i Sport of Generalitat Valenciana, both are acknowledged. JAEDOC- CSIC postdoctoral contract cofounded by ESF to L.M. is also acknowledged

Angiotensin converting enzyme (ACE) inhibitory peptides have been extensively studied as an alternative to synthetic drugs for the treatment of hypertension. Recent studies have shown that dry-cured ham is an important source of naturally generated bioactive peptides, especially showing ACE inhibitory activity. However, due to their excessive degradation by digestive and brush-border enzymes, it is not clear whether these peptides resist intestinal absorption and reach the blood stream where they may exert their antihypertensive effect. Therefore, dry-cured ham extracts and specific pure peptides naturally generated during the dry-curing process, showing ACE inhibitory activity, have been studied for their stability during transepithelial transport in a Caco-2 cell monolayer. The ACE inhibitory activity of transport samples was assayed, showing the highest values in apical samples at 15 min of incubation. In concentrated basal solutions, ACE inhibition values increased during transport for purified peptides, reaching values close to 70% for AAPLAP and KPVAAP at 60 min of cellular transport. Fragments generated by cellular activity were detected by using tandem mass spectrometry techniques, showing that AAATP, AAPLAP, and KPVAAP were hydrolysed during the transport, although KPVAAP was also absorbed intact. This study highlights the potential of intact dry-cured ham peptides as well as their fragments to be absorbed across the intestinal epithelium and reach the blood stream to exert an antihypertensive action., The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under Grant Agreement 312090 (BACCHUS). This publication reflects only the author views and the Community is not liable for any use made of the information contained therein. Grant AGL2013-47169-R from MINECO and FEDER funds and the FPI Scholarship BES-2011-046096 from MINECO (Spain) to M.G. are fully acknowledged. The JAEDOC-CSIC postdoctoral contract to L.M. co-funded by the European Social Fund and BOF (Special Research Fund of Ghent University) for their financial support (Project 01B04212) are also acknowledged.

Recent advances in proteomics have become an indispensable tool for a fast, precise and sensitive analysis of proteins in complex biological samples at both, qualitative and quantitative level. In this study, a label-free quantitative proteomic methodology has been optimised for the relative quantitation of proteins extracted from raw pork meat. So, after the separation of proteins by one-dimensional gel electrophoresis and trypsin digestion, their identification and quantitation have been done using nanoliquid chromatography coupled to a quadrupole/time-of-flight (Q/ToF) mass spectrometer. Relative quantitation has been based on the measurement of mass spectral peak intensities, which have been described that are correlated with protein abundances. The results obtained regarding linearity, robustness, repeatability and accuracy show that this procedure could be used as a fast, simple, and reliable method to quantify changes in protein abundance in meat samples., The research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under Grant Agreement 312090 (BACCHUS). This publication reflects only the author views and the Community is not liable for any use made of the information contained therein. JAEDOC-CSIC postdoctoral contract to L.M. is also acknowledged. FPI Scholarship BES-2011-046096 and grant AGL2010-16305 from MINECO (Spain) and FEDER funds are also acknowledged.

Coenzyme Q10 (CoQ10) or ubiquinone (2,3-dimethoxy-5-methyl-6-multiprenyl-1,4-benzoquinone) is an endogenous hydroxybenzoquinone liposoluble compound which plays important physiological roles that makes it to be considered as a bioactive compound that may be used for clinical practices and as food supplement. The purpose of this work was to analyse CoQ10 in three muscles with different oxidative patterns and determine its variability in different animal species (pork, beef, lamb and rabbit). The content of CoQ10 ranged from 4.3 to 30.9μg/g meat with the highest content in those muscles with oxidative pattern. So, more specific data on type of meat cut and proportion of muscles must be given for this nutrient when reporting its content in food composition databases., Grant PROMETEO/2012/001 from Conselleria d'Educació, Formació i Ocupació of Generalitat Valenciana (Spain) is fully acknowledged.

The complex proteolysis in Spanish dry-cured ham processing generates large amounts of small peptides and free amino acids which are responsible for the characteristic texture and flavour of this traditional product. The aim of this work was to study the degradation of the giant protein titin throughout the dry-curing process (2, 3.5, 5, 6.5, and 9 months) through the use of proteomic tools. A total of 320 peptides have been identified by nanoliquid chromatography coupled to tandem mass spectrometry, being some of them identified only at 9 months of processing. In order to confirm the absence of these peptides at other times of processing, MALDI-TOF MS was also employed as a fast and easier technique. Only four peptides, KDEAAKPKGPIKGVAKK, KKLRPGSGGEK, KNTDKWSECAR and ISIDEGKVL, were exclusively identified at 9 months of curing by using both methodologies so that these peptides could be used as potential biomarkers of dry-cured ham processing time., FPI Scholarship BES-2011-046096 from MINECO (Spain) to M.G. and grant AGL2010-16305 from MINECO and FEDER funds are fully acknowledged. JAEDOC-CSIC postdoctoral contract to L.M. is also acknowledged. The proteomic analysis was carried out in the SCSIE_University of Valencia Proteomics Unit, a member of ISCIII ProteoRed Proteomics Platform.

Pork meat is generally recognised as a food with relevant nutritional properties because of its content in high biological value proteins, group B vitamins, minerals especially heme iron, trace elements and other bioactive compounds. But pork meat also contributes to the intake of fat, saturated fatty acids, cholesterol, and other substances that, in inappropriate amounts, may result in negative physiologically effects. However, there are relevant factors affecting the content of many of these substances and somehow such variability should be taken into consideration. So, genetics, age and even type of muscle have a relevant influence on the amount of fat and the contents in heme iron. Also the composition in fatty acids of triacylglycerols is very sensitive to the contents of cereals in the feed; for instance, polyunsaturated fatty acids may range from 10% to 22% in pork meat. The content of other nutrients, like vitamins E and A, are also depending on the type of feed. Some bioactive substances like coenzyme Q10, taurine, glutamine, creatine, creatinine, carnosine and anserine show a large dependence on the type of muscle. This manuscript describes the main factors affecting the composition of pork meat nutrients and how these changes may affect the general food composition databases. (C) 2012 Elsevier Ltd. All rights reserved., Grant AGL2010-16305 from the Spanish Ministry of Science and Innovation (Madrid, Spain) and FEDER Funds and collaboration of Vaquero Foundation for R+D on Pork Meat (Madrid, Spain) are acknowledged. Grant PROMETEO/2012/001 from Generalitat Valenciana (Spain) is also acknowldeged. Work prepared within the Unidad Asociada IAD (UPV)-IATA (CSIC) framework.

This study is focused on the characterization of the proteolysis occurred during the processing of Pastırma, a traditional Turkish dry-cured meat product, which is responsible for its final characteristics. Thus, the evaluation of naturally generated free amino acids and peptides present at 0, 2, 5, 10, and 21 days of processing and the bioactivity of peptide fractions have been approached. Peptides were examined by MALDI-TOF and results showed differences in the amount of generated peptides at different times of processing, and a total of 29 peptides were newly generated at Day 21 in comparison with Day 2 during processing. The water soluble fraction of Pastırma at the end of the curing period (Day 21) was also analyzed by size-exclusion chromatography and some of the collected fractions demonstrated strong ACE-inhibitory and antioxidant activities. In fact, Pastırma showed an ACE inhibitory activity higher than 86% from 220 to 270 mL corresponding to molecular masses between 900 and 1500 Da, and also a DPPH radical-scavenging activity above 60% at 250 to 300 mL corresponding to molecular masses between 700 and 2000 Da. Thus, Pastırma represents a good source of natural ACE-inhibitory and antioxidant peptides which might be due to the proteolysis occurred by endogenous enzymes and the contribution of the çemen paste used in production., Grant AGL2014-57367-R from MINECO (Spain) and FEDER funds and JAEDOC-CSIC postdoctoral contract of L.M. cofunded by European Social Funds are acknowledged. The research fellowship grant provided by Erasmus + KA1 Student Mobility Programme for Higher Education for the author Ebru Deniz is also gratefully acknowledged.

The effects of amino acid composition and peptide molecular mass on ACE-inhibitory and antioxidant activities of protein fragments obtained from tomato waste fermented using Bacillus subtilis were evaluated. The addition of B. subtilis increased the relative amounts of aromatic and positively-charged amino acids which have been described to influence the biological activities of peptide fragments. IC50 values of hydrolysates for ACE-inhibitory and 2, 2′-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities were found to be 1.5 and 8.2 mg/mL, respectively. Size-exclusion chromatography (SEC) pattern of the hydrolysate indicated the breakdown of parent proteins to smaller peptides with molecular weights mainly below 1400 Da. MALDI-TOF mass spectrometry analysis revealed that the highest ACE-inhibitory activity was due to peptides showing molecular mass range 500–800 Da, while the most active antioxidant peptides were found to be mainly at the two different peptide weight ranges 500–800 Da and 1200–1500 Da., This study was funded by Grant of Ministry of Science, Research and Technology of Iran and Emerging Research Group Grant from Generalitat Valenciana in Spain (GV/2015/138). Also, a JAEDOC-CSIC postdoctoral contract was cofunded by the European Social Fund to Dr. Mora.

6 pages.-- Review article., [EN] Potassium and sodium salts of nitrite (E 249 and E 250) and nitrate (E 251 and E 252) are authorised for use under certain levels in several foodstuffs such as non-heat-treated, cured and dried meat products, other cured meat products, canned meat products and bacon. The key point in the use of nitrate and nitrite as preservatives is to find a balance between ensuring the microbiological safety of the ham and keeping as low as possible the level of nitrosamines in the final product. Nitrites and nitrates are authorised as additives for dry-cured ham in the Directive 2006/52/EC of 5 July 2006 that modifies previous Council Directive 95/2/EC on food additives other than colours and sweeteners. The effect of nitrate and its reduction to nitrite in controlling the lipid oxidation process during the ham ripening is very important for the development of the characteristic cured flavour. The main benefits and drawbacks of the use of nitrites and nitrates in dry-cured ham and how these levels may affect its flavour are discussed in this manuscript., [ES] Las sales sódica y potásica del nitrito (E249 y E250) y del nitrato (E251 y E252) están autorizados para su uso en los productos cárnicos, secos, curados y no tratados por el calor, otros productos cárnicos curados, productos cárnicos enlatados y bacon. El punto esencial en el uso de nitrato y nitrito como conservantes consiste en encontrar un balance entre el aseguramiento de la seguridad microbiológica del jamón y mantener el nivel de nitrosaminas tan bajo como sea posible. Los nitratos y nitritos están autorizados como aditivos en el jamón curado según la Directiva Europea 2006/52/EC de 5 de Julio de 2006 que modificaba la previa Directiva Europea 95/2/EC de aditivos alimentarios distintos a los colorantes y edulcorantes. El efecto del nitrato y su reducción a nitrito para controlar la oxidación de los lípidos durante la maduración del jamón es muy importante para el desarrollo del característico flavor a curado. Se presentan en este manuscrito los principales beneficios y problemas del uso de los nitratos y nitritos en el jamón curado así como sus efectos en el sabor., Grant AGL2007-65379-C02-01/ALI from the Spanish Ministry of Science and Innovation and FEDER funds is fully acknowledged.

This study is focused on the effect of sodium chloride alternative salts (KCl, MgCl2 and CaCl2) on porcine muscle proteases (cathepsins, dipeptidylpeptidases and aminopeptidases). In general, KCl exerted a very similar effect to NaCl for all the studied enzymes, while the effect of divalent salts (CaCl2 and MgCl2) was more pronounced. Cathepsins, dipeptidyl peptidase III, dipeptidyl peptidase IV and alanyl aminopeptidase activities were strongly inhibited by all the chloride salts especially by divalent ones. Dipeptidyl peptidase II and leucyl aminopeptidase were little affected and methionyl aminopeptidase was only inhibited by divalent salts. Dipeptidyl peptidase I was strongly activated by low concentrations of the chloride salts except NaCl. Arginyl aminopeptidase was activated by NaCl and KCl and low amounts of MgCl2, while CaCl2 showed a strong inhibitory effect. This is very important as these enzymes play important roles in dry-cured meats and their activity is, in general, regulated by sodium chloride. Thus, reductions in the sodium concentration with subsequent increases of other alternative cations may have relevant consequences on enzyme activity that should be taken into account when processing dry-cured meats.

Large amounts of different peptides are naturally generated in dry-cured meats as a consequence of the intense proteolysis mechanisms which take place during their processing. In fact, meat proteins are extensively hydrolysed by muscle endo-peptidases (mainly calpains and cathepsins) followed by exo-peptidases (mainly, tri- and di-peptidyl peptidases, dipeptidases, aminopeptidases and carboxypeptidases). The result is a large amount of released free amino acids and a pool of numerous peptides with different sequences and lengths, some of them with interesting sequences for bioactivity. This manuscript is presenting the proteomic identification of small peptides resulting from the hydrolysis of four target proteins (glyceraldehyde-3-phosphate dehydrogenase, beta-enolase, myozenin-1 and troponin T) and discusses the enzymatic routes for their generation during the dry-curing process. The results indicate that the hydrolysis of peptides follows similar exo-peptidase mechanisms. In the case of dry-fermented sausages, most of the observed hydrolysis is the result of the combined action of muscle and microbial exo-peptidases except for the hydrolysis of di- and tri-peptides, mostly due to microbial di- and tri-peptidases, and the release of amino acids at the C-terminal that appears to be mostly due to muscle carboxypeptidases., The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under Grant Agreement 312090 (BACCHUS). This publication reflects only the author views and the community is not liable for any use made of the information contained therein. JAEDOC-CSIC postdoctoral contract cofunded by European Social Fund to L.M. and FPI Scholarship to M. G. are also acknowledged.

Proteolysis is a complex and dynamic process which takes place throughout the whole dry-cured processing due to the action of endogenous muscle peptidases, and results in the generation of a high number of small peptides and free amino acids responsible for the final quality of dry-cured ham. In this study, a total of sixty-eight peptides derived from the ubiquitin-60S ribosomal protein have been identified in dry-cured ham at 2, 3.5, 5, 6.5, and 9 months of processing using various chromatographic separations and a quadrupole/time-of-flight mass spectrometer in tandem. Some of the identified peptides have been detected during the whole process, whereas a total of fourteen of them were exclusively identified at 9 months of curing. The presence of any of these peptides could be a good indicative that dry-cured ham pieces have reached a minimum curing process of 9 months. The study of the generated peptides has contributed both to a better knowledge of proteolysis evolution and the endogenous enzymes participating, and to determine their potential to be used as quality markers to monitor the processing time., Grant PROMETEO/2012/001 from Conselleria d'Educació, Formació i Ocupació of Generalitat Valenciana (Spain) is fully acknowledged. FPI Scholarship BES-2011-046096 from MINECO (Spain) to M.G. and JAEDOC-CSIC postdoctoral contract to L.M. are also acknowledged. Mass spectrometry analysis was performed in the SCSIE_University of Valencia Proteomics Unit, a member of ISCIII ProteoRed Proteomics Platform.

All rights reserved. In this study, a peptidomic approach has been used in the identification of naturally generated peptides during a dry-curing process, showing methionine (Met) oxidation in their sequence. A total of 656 peptides derived from major myofibrillar proteins in Protected Designation of Origin (PDO) Teruel dry-cured ham have been identified by nanoliquid chromatography coupled to tandem mass spectrometry (nLC-MS/MS), including 120 peptides showing methionine oxidation. The percentage of oxidised peptides in the studied proteins ranged from 6% to 35%, being peptides derived from nebulin, titin, myosin heavy chains, and troponin I proteins, those showing the highest number of oxidised methionine. The identification of the peptide sequence incorporating the oxidised amino acid provides valuable information of neighbouring amino acids, degree of hydrolysis of the sample, and characteristics of the peptide, which might be very useful for a future better understanding of the oxidation mechanisms occurring in dry-curing processing., Grant AGL2013-47169-R from MINECO (Spain) and FEDER funds and FPI Scholarship BES-2011-046096 from MINECO (Spain) to M.G. are fully acknowledged. JAEDOC-CSIC postdoctoral contract and support from European Social Funds to L.M. are also acknowledged.

Peptidomics is a necessary alternative in the analysis of naturally generated peptides in dry-fermented processing. The intense proteolysis occurred during the processing of dry-fermented sausages is due to the action of endopeptidases and exopeptidases from both, endogenous muscle origin and lactic acid bacteria (LAB) added in the starter. Sodium caseinate is frequently used as an additive in this type of products because of its emulsifying properties, and consequently influences the protein profile available during the proteolysis. In this study, a mass spectrometry approach has been used to determine the impact of added sodium caseinate in the final peptide profile as well as to analyse its possible influence in the presence of certain previously described casein-derived bioactive peptides.

The simultaneous brine thawing/salting operation has been proposed as an effective alternative for the accelerated processing of frozen cured hams. The aim of the present study was to study the effect of this new technology on the lipolytic and proteolytic enzymes responsible for the generation of flavour precursors during the salting and post-salting stages of the manufacturing of Spanish dry-cured ham. The effect of the frozen and thawed process produced a higher proteolytic and lipolytic activity than in the fresh traditional salted hams (FPS) that was detected by a higher concentration in free amino acids and free fatty acids. On the other hand, the brine thawed/salted treatments, at atmospheric pressure (BTS) and with vacuum impregnation (BTS-TP), produced an acceleration of the myofibrillar degradation that occurred in the BTS and BTS-TP hams in comparison to FPS. However, the lipolysis was affected by the frozen treatment but not by the brine thawed treatments, as few differences in free fatty acids and lipase activity were detected among the frozen and brine thawed hams at the end of post-salting stage.

A prolyl aminopeptidase (PAP) (EC 3.4.11.5) was isolated from the cell extract of Debaryomyces hansenii CECT12487. The enzyme was purified by selective fractionation with protamine and ammonium sulfate, followed by two chromatography steps, which included gel filtration and anion-exchange chromatography. The PAP was purified 248-fold, with a recovery yield of 1.4%. The enzyme was active in a broad pH range (from 5 to 9.5), with pH and temperature optima at 7.5 and 45°C. The molecular mass was estimated to be around 370 kDa. The presence of inhibitors of serine and aspartic proteases, bestatin, puromycin, reducing agents, chelating agents, and different cations did not have any effect on the enzyme activity. Only iodoacetate, p -chloromercuribenzoic acid, and Hg 2+ , which are inhibitors of cysteine proteases, markedly reduced the enzyme activity. The K m for proline-7-amido-4-methylcoumarin was 40 μM. The enzyme exclusively hydrolyzed N-terminal-proline-containing substrates. This is the first report on the identification and purification of this type of aminopeptidase in yeast, which may contribute to the scarce knowledge about D. hansenii proteases and their possible roles in meat fermentation.

The processing of dry-cured ham results in an intense proteolysis that leads to the generation of peptides of different sizes and composition, which have been shown to be biologically active. In this study, a total of ninety-three peptides mainly derived from actin, β-enolase, myosin heavy chain, and creatine kinase proteins have been identified from a size-exclusion chromatography (SEC) fraction that resulted as antioxidant by using matrix-assisted laser desorption/ionisation time-of-flight (MALDI-ToF) and nESI-ion trap mass spectrometry. Several of the identified peptides have been synthesised and their antioxidant activity tested in vitro by using DPPH radical-scavenging assay and reducing power analysis. The peptide with sequence SNAAC showed the best results with an IC50 of 75.2μM in DPPH radical-scavenging assay and 205μM in ferric-reducing antioxidant power analysis, very good when comparing with the positive control 2,6-di-tert-butyl-4-methyl phenol (BHT) that showed an IC50 of 358.5μM and 90.3μM, respectively, in the different assays. These results suggest that Spanish dry-cured ham represents an important source of powerful antioxidant peptides which due to their natural characteristics may represent a highly valuable alternative in human health., HEFCE infrastructure funding is acknowledged for MS equipment to PDF. LM and PDF are grateful to the EU-FP7 Marie Curie IEF scheme (FOOSAF project) for the financial resources. FPI Scholarship from Spanish Ministry of Science and Innovation to E.E. and grant AGL2010-16305 from Spanish Ministry of Economy and Competitiveness and FEDER funds are fully acknowledged.

Aims: The effect of the common curing conditions used during the manufacture of dry fermented sausage on the proteolytic activity of Lactobacillus casei CRL705 against meat proteins was investigated. Methods and Results: Hydrolysis of pork muscle sarcoplasmic and myofibrillar proteins was evaluated by SDS-PAGE and reverse phase-HPLC analysis. Ascorbic acid exerted a stimulatory effect on both sarcoplasmic and myofibrillar protein breakdown by Lact. casei CRL705 with the release of hydrophilic peptides and free amino acids, while NaCl and NaNO2 mainly stimulated myofibrillar degradation. Conclusions: Even when processing temperature (25°C) did not positively affect bacterial protein hydrolysis, the presence of curing salts accounted for a remarkable increase in the non-volatile components that constitute taste-active compounds that strongly influence the final flavour of the product. Significance and Impact of the Study: To predict the suitability of Lact. casei CRL705 and its proteolytic enzymes as a starter culture for the dry processing of dry fermented sausages. Fil: Fadda, Silvina G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Aristoy, M. C.. Consejo Superior de Investigaciones Científicas. Instituto de Agroquímica y Tecnología de Alimentos; España Fil: Oliver, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Toldrá, F.. Consejo Superior de Investigaciones Científicas. Instituto de Agroquímica y Tecnología de Alimentos; España

Strains of Lactobacillus plantarum originally isolated from sausages were screened for proteinase and aminopeptidase activities toward synthetic substrates; on the basis of that screening, L. plantarum CRL 681 was selected for further assays on muscle proteins. The activities of whole cells, cell extracts (CE), and a combination of both on sarcoplasmic and myofibrillar protein extracts were determined by protein, peptide, and free-amino-acid analyses. Proteinase from whole cells initiated the hydrolysis of sarcoplasmic proteins. The addition of CE intensified the proteolysis. Whole cells generated hydrophilic peptides from both sarcoplasmic and myofibrillar proteins. Other peptides of a hydrophobic nature resulted from the combination of whole cells and CE. The action of both enzymatic sources on myofibrillar proteins caused maximal increases in lysine, arginine, and leucine, while the action of those on sarcoplasmic proteins mainly released alanine. In general, pronounced hydrolysis of muscle proteins required enzyme activities from whole cells in addition to those supplied by CE.

Lactobacillus curvatus CECT 904 and Lactobacillus sake CECT 4808 were selected on the basis of their proteolytic activities against synthetic substrates. Further, the effects of whole cells, cell extracts, and a combination of both enzymatic sources on muscle sarcoplasmic proteins were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography analyses. Strains of both species displayed proteinase activities on five sarcoplasmic proteins. The inoculation of whole cells caused a degradation of peptides, whereas the addition of cell extracts resulted in the generation of both hydrophilic and hydrophobic peptides. This phenomenon was remarkably more pronounced when L. curvatus was involved. Whole cells also consumed a great amount of free amino acids, while the addition of intracellular enzymes contributed to their generation. L. sake accounted for a greater release of free amino acids. In general, cell viability and also proteolytic events were promoted when cell suspensions were provided with cell extracts as an extra source of enzymes.

[EN] Sodium intake exceeds the nutritional recommendations in most industrialized countries becoming one concern for public health. This elimination or reduction is not simple due to its role in final food sensory, quality and safety. The aim of this work is to review the possibilities of magnesium ion, due to its healthy properties, to become a partial substitute of sodium in the production of fish and meat products, and a particular case for Spanish dry-cured ham and loin. Magnesium diffusion into different muscle based foods such as ham or loin, and its effect in the most important characteristics of the final product (microbiology, physico-chemical and sensory properties) has been analyzed. Results show that magnesium has more difficulty to penetrate inside the muscle and slightly modifies the water-holding capacity of proteins, their solubility and the enzymatic activity. Salty taste, bitterness and off-flavor are the most affected characteristics. However, these effects could be compensated by using longer post-salting periods and by employing masking agents. It is possible to reduce the sodium content in fish and meat products using magnesium as one of the ingredients, allowing to obtain new products with similar physicochemical characteristics and safety conditions., Grant AGL2007-65379-C02-01 & 02 and AGL2010-16305 from Ministry of Science and Innovation (Spain) and FEDER funds are acknowledged.

[EN] While muscle foods are the more commonly consumed portion of an animal, meat by-products such as the entrails and internal organs are also widely consumed. Considered high-priced delicacies or waste material to be tossed away, the use and value of offal-edible and inedible meat by-products depend entirely on the culture and country in question. The skin, blood, bones, meat trimmings, fatty tissues, horns, hoofs, feet, skull, and internal organs of harvested animals comprise a wide variety of products including human or pet food or processed materials in animal feed, fertilizer, or fuel. Industry is using science and innovation to add value to animal by-products far beyond its usual profitability. Regardless of the final product's destination, it is still necessary to employ the most up-to-date and effective tools to analyze these products for nutritional properties, to search for key active molecules in nutrition like bioactive peptides, food safety (antimicrobial peptides), medicine, cosmetics or other fields, to develop new technological applications and to continue innovation towards advanced value-addition of meat by-products. © 2012 Elsevier Ltd., Grant from Vaquero Foundation for R + D on Pork Meat (Madrid, Spain), grant AGL2010-16305 from the Spanish Ministry of Science and Innovation and FEDER funds are acknowledged. Work was prepared within the Unidad Asociada IAD (UPV)-IATA (CSIC) framework.

[EN] Simultaneous brine thawing/salting process was applied as an alternative to traditional pile salting process using 51 frozen Iberian hams. The effect of this type of salting process on endogenous enzyme activity and sensory quality of Iberian dry-cured hams was analysed. The frozen hams were simultaneously thawed and salted with saturated brine, with and without vacuum pulses, and were compared to hams thawed under refrigeration and traditionally salted. The peptidase and lipase activities were measured at the end of salting and post-salting stages. The activity of cathepsin B+L was reduced in the two brine salted batches while few differences among batches were observed for the other peptidases. Several lipase activities were significantly reduced in the two brine salted batches. The brine thawed processing affected the free fatty acid content at the different stages although the differences were more appreciated at the beginning of the process and no differences were observed at the end. The long ripening time makes these differences negligible and the consumer did not appreciate any differences between the sensory quality of Iberian brine/thawed hams and traditional Iberian thawed pile salted hams. (C) 2011 Elsevier Ltd. All rights reserved., Financial support from PETRI by the Ministry of Science and Innovation (PTR-1995-0754-OP-03) is fully acknowledged. Work was carried out under the Unidad Asociada IIAD (UPV) - IATA (CSIC) framework. The authors are grateful to M. Lozano and MI. Nadal for technical assistance.

HPLC methods based on hydrophilic interaction chromatography (HILIC) have been recently applied to the analysis of biochemical compounds, related to the quality, in meat and poultry as well as meat products like cooked ham and dry-cured ham. This type of chromatography has also been successfully used for the analysis of antibiotic residues in meat and poultry. HILIC chromatography has an increasing relevance for the analysis of polar compounds in foods due to its good retention without need for derivatisation. In general, HILIC-based methods have shown good performance for the analysis of polar biochemical compounds like dipeptides, creatine and creatinine, nucleotides and nucleosides, sphingolipids and residues, mainly antibiotics, in rather complex matrices such as muscles. Thus, this manuscript presents a review of recent applications of HILIC methods for the analysis of quality-related biochemical compounds and residues in meat, poultry and processed meats. © 2010 Springer Science+Business Media, LLC., Grant AGL2007-65379-C02-01 from Ministry of Science and Innovation (Spain) and FEDER funds are fully acknowledged. FPU Scholarship from Ministerio de Ciencia y Educacion (Spain) to L. M. and scholarship from Consejo Nacional de Ciencia y Tecnologia (CONACyT) and Colegio de Postgraduados (Mexico) to A. S. H-C. are fully acknowledged. This work was performed under the Associated Unit IAD (UPV)-IATA (CSIC).

This work describes the correlation found along 10 days between potentiometric measurements obtained by using an electronic tongue and the variation in certain physicochemical, microbial and biochemical parameters measured on a whole piece of pork loin stored under refrigeration. The electronic tongue consists of a set of six electrodes made of Au, Ag, Cu, Pb, Zn and C, and a reference electrode. Through the use of various multivariate analysis techniques, such as: PCA and two types of artificial neural networks (i.e. multilayer perceptron (MLP) and fuzzy ARTMAP) it was found that it is possible to determine the time elapsed in relation to the degradation of the loin by using simple potentiometric measurements. Additionally, in the same pork sample used to measure redox potentials with the electronic tongue, the following parameters were also determined; pH, microbial count, concentrations of inosine 5'-monophosphate (IMP), inosine (Ino) and hypoxanthine (Hx). Through the use of PLS analysis, it was found a rather good correlation between pH and the potentiometric data. Also a remarkable correlation was observed between the measures carried out with the electronic tongue and the so-called K-index that simultaneously measures the variation in the adenosine triphosphate (ATP) degradation products. These results suggest that this simple, or a similar electronic tongue, could be useful for the undemanding qualitative or semi-quantitative evaluation of freshness in meat samples in a wide range of situations. © 2010 Elsevier Ltd. All rights reserved., We would like to thanks the Spanish Government for support (Project CTQ2006-15456-C04-01/BQU and AGL2007-65379-C02-01 and 02/ALI). This work has been partially carried out under Associated Unit framework between IIAD (UPV) and IATA (CSIC).