Dry-cured Ham Research Articles

Near-Infrared Spectroscopy Procedure for Online Determination of Sodium and Potassium Content in Low-Salt Cured Hams.

This paper reports the development of a near-infrared spectroscopy (NIRS) calibration procedure for the determination of sodium and potassium content in cured ham samples. Sliced samples of hams treated with different salts in different percentages were included in the study. Calibration models developed using partial least squares regression were cross-validated and predictive models were tested using the samples of cured ham with low sodium content. The results showed that the developed NIRS procedure is capable of directly measuring the potassium content of packaged dry-cured ham slices with low sodium content with a fitting accuracy of 91.44%, and that it can indirectly determine the sodium content by applying a correction factor to the values obtained for potassium. The prediction error between the calculated and actual sodium values determined using inductively coupled plasma atomic emission spectrophotometry (ICP-AES) was 0.004%, and this confirms that the NIRS procedure is a viable option for the determination of sodium and potassium content in this type of sample.

Efficacy of Liquid Smoke to Mitigate Infestations of the Storage Mite, Tyrophagus putrescentiae, in a Model Semi-Moist Pet Food.

The storage mite Tyrophagus putrescentiae infests a wide range of food products including pet food. Control of this mite depends on chemical methods such as fumigation and spraying with insecticides. Methyl bromide was used as a fumigant for high-value stored products, especially to control mite infestation in dry-cured hams and cheeses, but it is now banned for most uses in many countries because of its atmospheric ozone-depleting effects. Effective alternatives to methyl bromide are needed to develop integrated pest management programs for this pest. Liquid smoke is a naturally derived flavoring and preservative with known antimicrobial properties. The objective of this study was to investigate the efficacy of liquid smoke preparations, with varying phenol and carbonyl concentrations and pH, on the survivability and orientation behavior of T. putrescentiae in a model semi-moist pet food. The mite survivability assays using liquid smoke-treated and untreated semi-moist pet food samples indicated that there was no difference among treatments (p > 0.05) for mite infestation and survival. Two-choice behavioral assays using semi-moist pet food cubes dipped in varying concentrations (0%, 0.3%, 1%, 5%, 10%, 25%, 50%, or 100% v/v) of liquid smoke preparations found that some of the liquid smoke preparations containing medium to high carbonyl content repelled the mites. In conclusion, liquid smoke did not kill or inhibit the mite population growth in semi-moist pet food. However, some liquid smoke fractions containing medium to high carbonyl content were repellent to mites and may retard mite infestation in stored semi-moist foods.

Effect of storage temperature and high-pressure processing on the preservation of sliced Duroc vacuum-packed dry-cured ham

This study assesses the physicochemical and microbiological stability of Duroc ham slices over a long-term storage (8 months) under various conditions. Thus, three treatments were designed: T4ºC; refrigerated (4ºC ± 1) and non-pressurised vacuum packages; T20ºC; vacuum and not pressurised packages stored at 20ºC ± 2 and high hydrostatic pressure (HHP) + T20ºC; vacuum packages pressurized (600 MPa for 8 min) and stored at 20ºC ± 2. Storage at 20 °C led to higher decrease in lightness over time and lower γ-tocopherol and polyunsaturated fatty acid values from 3 months onwards. But, storage at 20ºC did not increase lipid oxidation or microbiological counts -except for mesophiles at 8 months of storage-, so visual appearance could be the limiting factor of the shelf life. The HHP treatment led to lipid oxidation and γ-tocopherol degradation.

Effect of Yeast-Derived Peptides on Skeletal Muscle Function and Exercise-Induced Fatigue in C2C12 Myotube Cells and ICR Mice.

In our previous study, the antioxidant peptides (XHY69AP, AP-D, YPLP, and AGPL) were obtained from potential probiotic yeast (Yamadazyma triangularis XHY69), which was selected by our lab from dry-cured ham. This work aimed to explore the effects of yeast-derived peptides on skeletal muscle function and muscle fatigue. Results showed that yeast-derived peptides up-regulated slow-twitch fiber expression and down-regulated fast-twitch fiber expression in C2C12 cells (p < 0.05). The peptides improved mitochondrial membrane potential, adenosine triphosphate generation, and expression of cytochrome-relative genes, thus promoting mitochondrial function. Among these peptides, YPLP up-regulated the relative gene expression of the AMP-activated protein kinase (AMPK) pathway and activated AMPK by phosphorylation. Moreover, YPLP could prolong treadmill time, increase muscle and liver glycogen contents, reduce lactic acid and urea nitrogen contents, and alleviate muscle tissue injury in ICR exercise mice. These results demonstrate that yeast-derived peptides could change the muscle fiber composition, improve muscle function, and relieve muscle fatigue.

PH sensitive cold-set hydrogels based on fibrinogen hydrolysates/carrageenan: Insights of rheology, coacervation, microstructure and antioxidant ability

In order to investigate the effect of pH treatments on the coacervation mechanism of fibrinogen hydrolysates and carrageenan complex, the cold-set hydrogels of carrageenan and fibrinogen hydrolysates derived from the hydrolysis of chymotrypsin, alcalase and flavourzyme were prepared under different pH; mechanical strength, rheological properties, gelling structure, morphological observation, and chemical action force were investigated, and the antioxidant capacity of the hydrogels was further evaluated in meat preservation model. The results indicated that the hydrogels of carrageenan and fibrinogen hydrolysates derived from the hydrolysis of alcalase (AHs) showed the largest gel strength and the best viscoelasticity at pH 7.0 compared with other pH and hydrolase treatments. FTIR spectrum revealed that AHs showed more β-sheet and β-turn at pH 7.0 among all treatments. The interaction forces of these hydrogels showed various under different pH and hydrolase treatments, and the network of AHs hydrogels at pH 7.0 was mainly stabilized by electrostatic interaction and hydrophobic interaction. SEM and AFM demonstrated that the more regular three-dimensional network with smaller pore sizes was formed in AHs at pH 7.0 compared with pH 5.0 and pH 9.0. The AHs showed the largest scavenging ability for DPPH radicals (72.4%) at pH 7.0 in vitro, and the coated meat samples with AHs significantly increased the preservation times of fresh pork and dry-cured ham during the storage by inhibiting the increase of TBARS, TVB-N, and metmyoglobin. The finding of this work is expected to broaden the application of fibrinogen hydrolysate hydrogels into the field of food industry.

NIRS (Near Infrared Spectroscopy) classification of sliced Duroc dry-cured ham under various packaging systems and storage temperature and time

The potential of Near Infrared Spectroscopy (NIRS) was assessed for storage temperature discrimination (4 °C ± 2 vs. 20 °C ± 2) and for the prediction of the length of time that sliced Duroc dry-cured ham was in storage, considering the following packaging types; vacuum (n = 133) and modified atmosphere (MAP) (n = 133), without opening the package. The models, obtained by means of Partial least squares-discriminant analysis, indicated successful classification of the product according to storage temperature after validation (accuracy values of 100.00% in vacuum and between 92.00 and 100% in MAP). Furthermore, good accuracy was obtained for the assignments into storage times, with values comprised between 92.31% and 100.00% for samples under vacuum and between 91.00% and 97.00% for those under MAP, in both cases after validation. Thus, NIRS technology could help to support the preservation temperature traceability and the stocks of sliced dry-cured hams.

Bioactive Peptides in Meat and Meat Products

A number of bioactive peptides with health benefits have been reported to be generated in meat through the proteolysis phenomena taking place during postmortem aging or further processing. Bioactive peptides consist of short sequences, less than 20 amino acid residues, that are inactive while in the parent protein. These sequences may be activated when they are released from the parent protein by peptidases. Such peptides are released through the hydrolysis of major muscle proteins by muscle endopeptidases, like calpains and cathepsins, and resulting protein fragments and polypeptides are further hydrolyzed by muscle exopeptidases, mainly, tri- and di-peptidylpeptidases, aminopeptidases, and carboxypeptidases. As a result, a variety of peptides with different sequences and lengths and large amounts of free amino acids are generated. The highest amounts of bioactive peptides, and their major health benefits, have been reported in dry-cured ham as a result of the intense proteolysis experienced during the long processing time under mild conditions that favor the action of muscle peptidases. The generated peptides must be bioaccesible and bioavailable to exert their physiological benefit.This means that they must be resistant to gastrointestinal digestion and be absorbed through the intestinal barrier. Some bioactive peptides may be generated through hydrolysis during gastrointestinal digestion. This review is focused on the generation of bioactive peptides in meat and processed meats, on the most relevant bioactivities exerted by such peptides(such as inhibition of angiotensin I–converting enzyme and dipeptidyl peptidase IV as well as antioxidant and anti-inflammatory activity), and on their reported benefits to consumers’health.

Flavour Characteristics of Fermented Meat Products in China: A Review

Fermentation of meat products refers to a series of physical, biological or chemical changes in raw meat that occurs under the actions of enzymes or via microbial fermentation and results in the formation of meat products with special flavours, colours and textures that have a long history in China. These products have a unique fermented flavour, bright colour and longer shelf life than ordinary meat products, and some have proteins that are more easily absorbed by the body due to the fermentation of beneficial bacteria. Flavour development in meat products is a dynamic process. During the processing and storage of fermented meat products, the breakdown of proteins and fats is accelerated due to the addition of different fermenting agents. Moreover, the physicochemical reactions that occur within the meat products and the actions of microorganisms during the fermentation process result in the production of flavour compounds, which will determine the final flavour characteristics of the fermented meat product. This paper reviews the flavour characteristics of Chinese dry-cured hams, sausages, bacon, cured fish and sour meat and analyses the flavour substance composition of various products. Due to the differences in the raw materials, processes, auxiliary materials and fermentation processes of various types of fermented meat products in China (ham, sausage, bacon, etc.), the flavour substances contained in the various types of fermented meat products in China are different from each other. However, most fermented meat products in China are cured and fermented, and therefore, they share similarities in terms of their flavour substance composition. The flavour substances in fermented meat products mainly include alcohols, ketones, aldehydes, acids, phenols and aromatic hydrocarbons. The study of such flavour characteristics is of great significance in fermented meat product quality, and provides certain theoretical references for the study of domestic fermented meat products.

Quality and safety aspects of traditionally air-dried and nitrite-free meat product with reduced salt level

This paper studies the effect of reduced sodium chloride amounts (3%, 5% and 7%) on the quality aspects and safety elements of traditionally salted ham without any nitrates and nitrites added, dried and ripened under natural air-drying conditions. The physicochemical and textural properties, the degree of proteolysis, the microbiological characteristics and sensory profile of dry-cured ham were analysed at different production stages. A salting degree above 3% in the manufacture of this traditional dried product had a key role in the development of the desired microbiological and sensory characteristics in the absence of nitrites. Salting of the pork hams with 5% and 7% sodium chloride for 45 days at a temperature of 2±2 °С ensured a salt concentration and water activity that would guarantee the product safety with regard to the microbiological risks during the subsequent drying and ripening under natural air-drying conditions. The Elena ham samples salted with 5% sodium chloride and ripened for a period of 12 months in natural air-drying chambers were characterized as having the most balanced flavor.

Generation of kokumi γ-glutamyl short peptides in Spanish dry-cured ham during its processing

The typical dry-cured ham flavor is rich in umami and brothy perceptions, for which short peptides may contribute. Particularly, γ-glutamyl peptides could be the responsible of these previously reported attributes, as they exert a synergistic interaction with other basic tastes and modify the intensity of salty, sweet, and umami tastes. The content of peptides has been reported to evolve along the processing, but no kokumi γ-glutamyl peptides have been identified in Spanish dry-cured hams yet. In this research, nine γ-glutamyl dipeptides (γ-EA, γ-EC, γ-EE, γ-EF, γ-EL, γ-EM, γ-EV, γ-EW, and γ-EY) and two γ-glutamyl tripeptides (GSH and γ-EVG) have been quantitated at 6, 12, 18 and 24 months of traditional processing of Spanish dry-cured ham by performing a Q Exactive Orbitrap-based tandem mass spectrometry. The results show an increase of γ-EA, γ-EE, γ-EF, γ-EL, γ-EM and γ-EVG, obtaining maximums at 24 months of curing ranging from 0.14 (γ-EVG) to 18.86 (γ-EL) μg/g dry-cured ham. Otherwise, γ-EV, γ-EW and γ-EY accumulated until the 18th month of storage to 15.10, 0.54 and 3.17 μg/g dry-cured ham, respectively; whereas γ-EC and GSH amounts decreased starting from 0.0676 and 4.41 μg/g dry-cured ham, respectively at earlier stages. The concentration dynamics of these compounds may be linked with proteolytic and oxidative reactions during processing. In addition, due to their synergistic effect on kokumi activity, this could constitute insights of the brothy perceptions of dry-cured ham, and these peptides probably contribute to the sensory differences existing in long processed Spanish dry-cured hams.

Iberian dry-cured ham sliced: Influence of vacuum packaging on volatile profile during chill-storage

Packed sliced ham has become one of the most relevant new sales format, but its influence on the volatile profile of Iberian ham has not been widely studied. Hence, in this work, the influence of storage time of Iberian dry-cured ham vacuum packaging on the volatile profile and therefore, on its quality, was evaluated. For that, 12 samples of three white label Iberian dry-cured ham pieces from three supermarkets were analysed by headspace sorptive extraction-gas chromatography-mass spectrometry, using 2 polydimethylsiloxano Twisters®. The results showed differences between the volatile profile of vacuum packed samples with different packaging times and those which were not, mainly in alcohols and ketones. Furthermore, important changes were observed after only one week of packaging. The most of the volatile compounds affected during the storage time in vacuum packaging were related to negative sensory notes, being able to influence the quality of this product.

Effects of low salt on lipid oxidation and hydrolysis, fatty acids composition and volatiles flavor compounds of dry-cured ham during ripening

In order to study the effect of low salt on lipid oxidation and volatile flavor of dry-cured ham, a formula containing 18% potassium lactate, 12% lysine and 70% NaCl was used as an alternative salt for curing ham. The control group using 100% NaCl as pickled formulation dry-cured ham.The results showed that low salt significantly increased peroxide value (POV) and thiobarbituric acid value (TBARS) (P < 0.05). Acid lipase, neutral lipase, and phospholipase enzyme activity, as well as the amount of free fatty acids (FFAs), were all considerably higher in the low salt group than in the full salt group (P < 0.05). The volatile flavor compounds of dry-cured ham were determined by GC-MS, and 14 differential metabolites were screened out by using OPLS-DA analysis based on P < 0.05 and VIP >1. The enrichment analysis showed that low salt mainly affected low molecules fatty acids (palmitic acid, stearic acid, linoleic acid and myristic acid). Meanwhile, low salt treatment also influenced biosynthesis of unsaturated fatty acids, linoleic acid metabolism, fatty acid biosynthesis, fatty acid elongation and fatty acid degradation. This study demonstrates that low salt promotes the formation of ham flavor quality by affecting lipid oxidation and hydrolysis.

Assessment of antioxidant bioactive properties of iberian dry-cured ham fat-derived essences using the yeast Saccharomyces cerevisiae as experimental model

A new essence derived from Iberian dry-cured ham trimmed fat, with high content of mono- and poly-unsaturated fatty acids, and with antioxidant properties may act as protective agent counteracting the cellular effects of an oxidative insult. We used Saccharomyces cerevisiae, as in vivo experimental model to determine antioxidant properties of essences T30, T60 and T80. Antioxidant capacity was measured as recovery of yeast growth parameters and survivorship, as proxy of systemic cellular response to oxidative stress, when compared to unstressed or stressed cells treated with known antioxidants (vitamin C and resveratrol). At lower dose (1 μl), treated yeasts recovered growth rate (rT30 = 0.252 ± 0.016, rT60 = 0.224 ± 0.054, rT80 = 0.244 ± 0.032 h−1) and increased the number of relative survivors (RST30 = 1.494 ± 0.686, RST60 = 1.384 ± 0.405, RST80 = 1.720 ± 0.650) when compared to oxidative stressed yeasts (r = 0.093 ± 0.029 h−1, RS = 1.000 ± 0.000). The developed essences (T30, T60 and T80) counteract oxidative damage, with no-statistical significantly differences between essences, in a dose-dependent manner. In conclusion, the developed essences could be used as a functional food ingredient to relief oxidative stress, either raising from the onset of various chronic diseases or from external conditions (improving skin conditions), although they need to be validated in clinical studies.

Determination of ATP-related compounds by HPLC to study the effect of cell-free supernatants of Lactiplantibacillus plantarum on the shelf life of sliced dry-cured ham

This research aimed to study the evolution of ATP-related compounds in dry-cured ham and to assess their suitability as chemical markers of food contamination. A rapid high-performance liquid chromatography (HPLC) method was developed for the analysis of five ATP-related compounds namely, ATP, ADP, AMP, hypoxanthine, and Ino in sliced dry-cured ham. Moreover, a positive correlation between ATP content and microbial load was found in ham during storage. In addition, the method developed herein was employed to quantify ATP-related compounds in sliced dry-cured ham wrapped in a novel antibacterial packaging film containing the cell-free supernatant (CFS) of a probiotic Lactiplantibacillus plantarum strain. The contents of ATP-related compounds in ham samples wrapped in the antibacterial packaging film were lower than in control samples during the 7 days of storage (181 vs 269 mg/kg on day 2; 247 vs 286 mg/kg on day 5; 272 vs 297 mg/kg on day 7). Thus, the evaluated CFS could be considered in packaging material applications for the preservation of sliced ham. This study presents an effective method to assess the quality of sliced ham, which might also contribute to the adoption of active packaging in the food industry.

Antilisterial activity of cinnamon essential oil, pomegranate extract, or strawberry tree extract against Listeria monocytogenes in slices of dry-cured ham and pork loin.

Owing to concerns about the antimicrobial resistance of agents that can prevent the growth of Listeria monocytogenes in meat, researchers have investigated natural preservatives with antilisterial effects. However, in vivo application of essential oils and plant extracts usually results in reduced antimicrobial activity in meat products when compared to in vitro studies. This study aimed to evaluate the in vivo antimicrobial activity of cinnamon essential oil, pomegranate, and strawberry tree extracts in slices of dry-cured ham and pork loin against L. monocytogenes. Fragments of sterile dry-cured ham were inoculated with 100 μL cinnamon oil 0.5%, pomegranate, or strawberry crude extract. After 10 min, 100 μL of L. monocytogenes serotype 4b (104 colony-forming unit [CFU]/mL) was inoculated, and samples were incubated at 7 °C for 7 d to simulate the processing and storage temperature conditions of dry-cured meat products. L. monocytogenes was detected and quantified. Only strawberry extract presented significant differences (P < 0.05) from the control; thus, it was selected for the assay with 2% and 4% salt-treated pork loin. The strawberry tree extract significantly (P < 0.05) reduced the growth of L. monocytogenes in dry-cured ham. However, it could not reduce L. monocytogenes growth in pork loin, regardless of the salt concentration. This is the first report on the antimicrobial effect of strawberry tree leaf extract against L. monocytogenes in dry-cured ham.

Deciphering Staphylococcus xylosus and Staphylococcus equorum mode of action against Penicillium nordicum in a dry-cured ham model system

Penicillium nordicum is one of the major producers of ochratoxin A (OTA) in dry-cured ham. Staphylococcus xylosus Sx8 and Staphylococcus equorum Se31 have been previously proposed as biocontrol agents (BCAs) to prevent the OTA contamination, although their antifungal mode of action has not been established yet. Thus, the aim of this work was to elucidate their mode of action against P. nordicum in a dry-cured ham model system. For this, the effect of live cells, dead cells, and cell-free broth; the nutritional utilisation pattern, niche overlap index (NOI), interactions by dual-culture assays, antifungal effect of volatile compounds, OTA detoxification, and effect on fungal proteome were determined. No fungal growth was observed after 14 days of co-culture with live cells of each staphylococcus at 15 or 20 °C. However, such inhibition was not observed with either dead cells or extracellular extracts. The number of carbon sources utilised by P. nordicum was higher than those used by both cocci at 20 °C, whilst the opposite occurred at 15 °C. According to NOI, nutritional dominance depends on temperature, at 20 °C P. nordicum dominated the niche, but at 15 °C the mould is dominated by the BCAs. The volatile pattern generated by each coccus did not show antifungal effect, and both staphylococci failed to degrade or adsorb OTA. However, in the interaction assay, S. xylosus and S. equorum were able to decrease the fungal growth and its OTA production. In addition, proteomic analyses showed changes in the abundance of proteins related to the cell wall integrity (CWI), carbohydrate metabolism and the biosynthesis of secondary metabolites such as OTA. In conclusion, overall, the antagonistic effects of the two studied cocci against P. nordicum are greater at 15 °C than at 20 °C, being linked to competition for space and nutrients, triggering alterations in CWI pathway, OTA biosynthesis, and carbohydrate metabolism.

Efficacy of a carboxymethylcellulose (CMC)-based edible film with propylene glycol to control ham mite populations that infest dry cured ham

Dry-cured hams are susceptible to ham mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), infestations during the aging process. Methyl bromide (MB) fumigation has been used to control mites from infesting hams. However, MB is an ozone depleting substance that is both expensive and scarce, so alternative control methods must be discovered. The objective of this research was to determine the efficacy of using an edible film to control or reduce mite growth and reproduction on dry-cured hams. The edible films consist of water, 1% of carboxymethylcellulose (CMC), and propylene glycol (PG), which was included at five concentrations: 0%, 5%, 10%, 15%, and 20%. The resulting films’ ability to reduce mite infestation was tested against two control groups: exposed ham cubes (negative control) and ham cubes wrapped in polyester nets (positive control) containing 40% PG, 1% carrageenan, and 1% propylene glycol alginate. Two weeks after inoculation with 20 mites, all film treatments had fewer (P < 0.05) mites than the negative control (262-mites). Film treatments with 0% (24-mites), 5% (26-mites), and 10% PG (17 mites) were effective at slowing mite reproduction, but not to the extent of the positive control (0-mites), 15% (6-mites), and 20% (1-mite) PG films as evidenced by a linear decrease in mite counts (F1 = 19.22, P < 0.0001) as PG concentration increased. Water Vapor Transmission (WVT) and Oxygen Permeability (OP) results indicated that all films exhibited substantial breathability with values ranging from 805 g m−2 day−1 to 899 g m−2 day−1 for WVT and 355 cc m−2 day−1 to 3413 cc m−2 day−1 for OP. Sensory analysis results indicated that the film treatments did not alter the sensory properties of the treated hams when compared to the untreated control. Further studies will include application of films to whole hams during aging and improved manufacturing techniques for films.

Comparative Quantitation of Kokumi γ-Glutamyl Peptides in Spanish Dry-Cured Ham under Salt-Reduced Production.

Salting is a crucial step during the production of dry-cured ham and it is not well known whether it has an impact on the generation of taste-active peptides. The present study focused on the quantitation of kokumi γ-glutamyl peptides in low-salted Spanish dry-cured hams with 12 months of processing. By using mass spectrometry, peptides were quantitated from samples obtained after ethanolic deproteinization-based and non-ethanolic deproteinization-based extraction methods. Peptides γ-EA, γ-EE, and γ-EL registered mean values of 0.31, 2.75, and 11.35 µg/g of dry-cured ham, respectively, with no differences observed between both extraction protocols. However, γ-EF, γ-EM, γ-EV, γ-EW, γ-EY, and γ-EVG presented significantly (p < 0.05) higher concentrations in the ethanolic deproteinized samples showing values of 5.58, 4.13, 13.90, 0.77, 3.71, and 0.11 µg/g of dry-cured ham, respectively. These outcomes reflect the importance of protocols for the extraction of peptides to achieve the most feasible results. In addition, potential precursors for the formation of γ-glutamyl peptides are generated during dry-curing under salt restriction. The kokumi activity of these γ-glutamyl peptides could enhance the sensory attributes countering the taste deficiencies caused by the salt restriction.

Application of a non-invasive tool and identification of genetic markers in swine to enhance ham quality: a preliminary study.

A genome-wide association study (GWAS) was performed as a preliminary step to identify regions potentially related to ham quality traits. In this research, genomic information was obtained from 238 commercial hybrid pigs utilising the GeneSeek® Genomic Profiler genome-wide porcine genotyping array. Carcasses were tested for hot weight, the thickness of backfat and loin, and lean meat percentage. The corresponding fresh hams were assayed for weight and ultimate pH; the activities of Cathepsin B and Ferrochelatase of Semimembranosus muscle were determined through fluorimetric methods. The lean meat percentage of fresh ham (LMPH), salt absorbed after first (SALT1) and overall salting stages (SALT) were estimated online by the Ham Inspector™ apparatus. Hams were processed in compliance with the procedures established for Protected Designation of Origin Parma ham, and ham weight losses were measured at the main processing stages. Hot carcass weights showed a significant negative correlation with their lean meat percentage and LMPH, while LMPH was correlated positively with carcass lean meat, SALT1, SALT, and weight losses. The GWAS detected genome-wide association for 12 single nucleotide polymorphisms with Ferrochelatase activity. The results obtained in this preliminary study were achieved by combining innovative and non-destructive technologies for screening hams under processing, measures of enzymatic muscle properties relevant to dry-cured ham quality, and genomic information obtained through a GWAS. Additional studies carried out in a larger number of pigs have been planned to investigate the effect of gene variants of Ferrochelatase activity in the dry-cured ham's quality with main reference to colour development and to confirm the GWAS results obtained in this study.

Insights into free fatty acid profiles and oxidation on the development of characteristic volatile compounds in dry-cured ham from Dahe black and hybrid pigs

The aims of this study were to investigate the roles of free fatty acid (FFA) profiles and oxidation in the formation of characteristic volatile compounds in ham produced from Dahe black (DW) and hybrid breed (Yorkshire × Landrace × DW, YLDW; and Duroc × Landrace × Yorkshire, DLY) pigs using two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF-MS). Among the three types of hams studied, DW ham exhibited the highest total contents of FFAs (11,088.91 μg/kg), volatile flavor compounds (3750.867 μg/kg), aldehydes and alcohols. A total of 38 FFAs and 80 volatile compounds were identified in the three hams. According to odor activity values, 18 odorant-active compounds, including isovaleraldehyde, heptanal, 2-methylbutyraldehyde, decanal, hexanal, n-octanal, nonanal, 1-octen-3-ol, methional and eucalyptol, which mainly comprised aldehydes and alcohols, were selected for the discriminatory analysis between hams produced from DW, YLDW and DLY pigs. Furthermore, correlation analysis demonstrated that the oxidative decomposition of polyunsaturated fatty acids (i.e., trans-9-octadecenoic, cis-9,12-linoleic, γ-linolenic, α-linolenic, and arachidonic acid) is essential for the formation of volatile characteristics of ham. These results indicated that FFAs and volatile profiles of ham were breed dependent, and that the formation of volatile profiles in ham is closely related to lipid oxidation.