Ham Processing Research Articles

Exploring the Internal Environmental Changes of Muscle Cells and Apoptotic Phase of Mitochondria in Dry-Cured Loin Using Electrical Stimulation: Promoting the Precise Regulation of Loin Ham Quality.

Traditional dry-curing methods have a long cycle time and low efficiency, resulting in the inconsistent quality of dry-cured ham. By applying electrical stimulation (ES) technology in the dry-curing process, it was found that ES affected mitochondrial apoptosis by modulating the intracellular environment of muscle cells, which, in turn, enhanced the quality of dry-cured pork loin. Specifically, ES accelerated glycogen and ATP depletion, which led to a rapid decline in pH. Meanwhile, compared to the control group (CK), the activities of Na+-K+-ATPase and Ca2+-ATPase in the ES group (ES) increased by 160% and 124%, respectively, leading to the generation of H+ gradient and Ca2+ overload in mitochondria, which in turn triggered mitochondrial apoptosis and increased the apoptosis rate by 259%. In addition, Western blot analysis showed that ES promoted the Desmin and Troponin-T degradation levels. This study highlights the advantages of ES in dry-cured ham processing, which is expected to be a precise regulation technology.

Monitoring of the Dry-Curing Process in Iberian Ham Through the Evaluation of Fat Volatile Organic Compounds by Gas Chromatography-Ion Mobility Spectrometry and Non-Destructive Sampling.

The current quality control of the dry-curing process in Iberian ham is performed with an olfactory evaluation by ham experts. The present study proposes to monitor the dry-curing process of Iberian ham using an objective analytical methodology that involves non-destructive sampling of the subcutaneous fat of the hams and a volatile profile analysis using gas chromatography-ion mobility spectrometry. Thirty-eight 100% Iberian acorn-fed hams were examined in total, with eighteen hams monitored during the post-salting stage and twenty during the drying-maturation stage. A total of 164 markers were detected in the samples monitored during the post-salting stage, whereas 276 were detected in the hams monitored during the drying-maturation stage. The study of the trends observed in the intensities of the markers throughout the curing process enabled the detection of potential indicators of the end of the post-salting stage. Thus, representative intensity thresholds were established for some markers (3-methylbutanal, pentanal, hexanal, (E)-octen-2-al, 2-hexen-1-ol and heptan-1-ol) to determine the optimal point to specify the end of the post-salting process for hams. These findings provide an objective tool to support the traditional sensory evaluation currently performed in the industry.

Study on the Changes and Correlation of Microorganisms and Flavor in Different Processing Stages of Mianning Ham.

(1) Background: Mianning ham is a dry-cured ham from Southwest China, known for its distinct regional characteristics and delicious taste. It is particularly favored by consumers due to its safety, as no artificial nitrites are added during processing. The microbial changes during its different processing stages significantly influence the final product's flavor. This study aims to investigate the changes in microbial communities and flavor compounds across the nine stages of Mianning ham production, from raw material preparation to salting, drying, fermentation, and maturation, using 16S and ITS sequencing, as well as solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). The goal is to explore the correlation between these changes and provide a basis for process improvement from the initial raw material preparation. (2) Results: The microbiota of Mianning ham across different processing stages mainly consisted of Proteobacteria, Firmicutes, and Ascomycota. A total of 324 volatile compounds were identified, of which 27 were key contributors to the ham's flavor. Aldehydes contributed the most to flavor, with octanal, trans-2-nonenal, and trans, trans-2,4-decadienal being the most significant contributors at various stages. Mature Mianning ham, fermented for 1-3 years, exhibited fresh grass and earthy aromas, buttery and fatty flavors, and a distinctive roasted potato note. Correlation analysis revealed that Cobetia was the primary bacterial contributor to the main flavor compounds, especially prominent in the second year of fermentation. Among fungi, Yamadazyma and Aspergillus positively influenced several key aldehyde flavor compounds throughout the processing stages, significantly contributing to the flavor profile of Mianning ham. (3) Conclusions: Correlation analysis showed that the Mianning ham that matured for two years had the richest and most characteristic flavor. The positive and consistent impact of fungi on the ham's flavor suggests that they may warrant further research and application in Mianning ham production. This provides a theoretical basis for improving the flavor quality and enhancing the market competitiveness of Mianning ham. One of the key features of Mianning ham is its substantial accumulation of hydrocarbons, which surpasses that of hams from other regions in China. A notable characteristic of Mianning ham processing is the absence of artificially added nitrites as antioxidants and color fixatives. Whether this absence is a contributing factor to the significant accumulation of hydrocarbons warrants further investigation.

Electrical Stimulation Induces Activation of Mitochondrial Apoptotic Pathway and Down-Regulates Heat Shock Proteins in Pork: An Innovative Strategy for Enhancing the Ripening Process and Quality of Dry-Cured Loin Ham.

A fundamental regulatory framework to elucidate the role of electrical stimulation (ES) in reducing long production cycles, enhancing protein utilization, and boosting product quality of dry-cured ham is essential. However, how mitochondria and enzymes in meat fibers are altered by ES during post-processing, curing, and fermentation procedures remains elusive. This study sought to explore the impact of ES on the regulation of heat shock proteins (HSP27, HSP70), apoptotic pathways, and subsequent influences on dry-cured pork loin quality. The gathered data validated the hypothesis that ES notably escalates mitochondrial oxidative stress and accelerates mitochondrial degradation along the ripening process. The proapoptotic response in ES-treated samples was increased by 120.7%, with a cellular apoptosis rate 5-fold higher than that in control samples. This mitochondrial degradation is marked by increased ratios of Bax/Bcl-2 protein along the time course, indicating that apoptosis could contribute to the dry-cured ham processing. ES was shown to further down-regulate HSP27 and HSP70, establishing a direct correlation with the activation of mitochondrial apoptosis pathways, accompanied by dry-cured ham quality improvements. The findings show that ES plays a crucial role in facilitating the ripening of dry-cured ham by inducing mitochondrial apoptosis to reduce HSP expression. This knowledge not only explains the fundamental mechanisms behind myofibril degradation in dry-cured ham production but also offers a promising approach to enhance quality and consistency.

Microbial diversity in dry-cured Iberian ham: an approach to the concept of microbial terroir

Microbial terroir has been scarcely studied in the dry-cured ham industry. The microbial population and ochratoxin A (OTA) contamination in two Spanish facilities located in a specific geographical region (Salamanca) with differences in the environmental conditions used for the ham processing were evaluated for establishing the microbial terroir. Differences between the levels of Gram-positive catalase-positive cocci (GCC+), lactic acid bacteria (LAB), yeasts and moulds were found at the processing stage (post-salting, drying and cellar) and facility levels. Such variations could be responsible for the development of different flavour profiles, which indicate their potential functionality for determining the microbial terroir in the artisan dry-cured Iberian ham industry, despite the fact that this work constitutes a preliminary study. Furthermore, it has been demonstrated that the differences in the microbial population throughout the processing of both sampled facilities could directly impact on one of the main concerns of the meat industry from the food safety point of view consisting of the accumulation of OTA, since differences in its levels were detected between both checked facilities. These findings could lead to the enforcement of the terroir concept in artisan dry-cured Iberian ham elaboration, resulting in a value enhancement that might be reflected in economic and social positive results for the territory. Nevertheless, microbial terroir in the dry-cured Iberian ham must be further explored by the increase of the number of studied facilities.

Identification of characteristic flavor compounds and small molecule metabolites during the ripening process of Nuodeng ham by GC-IMS, GC–MS combined with metabolomics

To investigate effects of metabolites and volatile compounds on the quality of Nuodeng ham, gas chromatography-mass spectrometry (GC–MS), ultra-high performance liquid chromatography-Q exactive orbitrap-mass spectrometry (UHPLC-QE-MS), and gas chromatography-ion transfer spectroscopy (GC-IMS) were used to analyze the differences of free fatty acids, small molecule metabolites and volatile compounds of Nuodeng ham at different ripening stages (the first, second and third year sample). 40 free fatty acids were detected. 757 and 300 metabolites were detected in positive and negative ion modes, respectively. 48 differential metabolites (VIP ≥ 1.5, P < 0.05) might important components affecting flavor differences of Nuodeng ham. Metabolic pathways revealed that fermenting-ripening of ham was associated with 31 metabolic pathways, among, 19 pathways were significant (Impact > 0.01, P < 0.05). 58 volatile compounds were identified, combined with PCA and PLS-DA, 15 flavor markers were screened out. These findings provide a scientific basis for further research on the flavor formation mechanism of Nuodeng ham.

UHPLC-MS/MS-based lipidomics for the evaluation of the relationship between lipid changes and Zn-protoporphyrin formation during Nuodeng ham processing

The effects of changes in lipids on the formation of Zn-protoporphyrin (ZnPP) during the processing of Nuodeng ham were analyzed using a lipidomics approach based on UHPLC-MS/MS. The Nuodeng ham samples had a strong fluorescence emission peak at 590 nm, and the fluorescence intensity increased with the processing time. Lipid profiles were mainly affected by processing time. A total of 5 lipid classes were detected, of which glycerophospholipids (GP) and glycerolipids (GL) were the most abundant lipids. Fifty differential lipid compounds were screened, which were mainly GP and GL. Correlation analysis showed that 13 differential lipid compounds were significantly positively correlated with ZnPP content, and they contained more linoleic acid and oleic acid branch chains. Meanwhile, all triglycerides (TG) were negatively correlated with heme content, and they were enriched in stearic acid and palmitic acid branch chains. These findings can deepen the understanding of the relationship between ZnPP and lipids.

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.

Exploring insecticidal properties and acetylcholinesterase inhibition by three plant essential oils against the cheese skipper Piophila casei (Diptera: Piophilidae)

Piophila casei is a highly problematic pest in the food industry, specifically ham processing. However, given the specific requirements of the food industry, there is an urgent requirement for environmentally friendly, more efficient and safer approaches to manage the P. casei. This study aimed to assess the fumigant and contact toxicity of three plant essential oils (EOs) against P. casei by examining their impact on P. casei acetylcholinesterase (AChE) activity and investigating the potential mode of action of their primary constituents using molecular docking and molecular dynamics simulations. The results indicate that Mentha canadensis EO exhibited substantial contact toxicity against P. casei, with the LC50 of 2.98 μL/cm2 after 48-h contact with second instar larvae and an IC50 of 4.99 μL/cm2 for inhibiting pupation in third instar larvae over a 5-day period. Moreover, M. canadensis and Jasminum sambac EOs demonstrated their significant fumigant toxicity, with LT50 of 7.06 and 17.55 h, respectively, at an air concentration of 0.5 mL/L. Among the three EOs, M. canadensis EO displayed the most effective inhibition of P. casei AChE activity, while the other two EOs also exhibited certain levels of activity inhibition, shedding light on the insecticidal mechanisms of EOs against P. casei. Additionally, the molecular docking and molecular dynamics simulations were employed to investigate the mechanisms of action and binding capacity of menthol and limonene, the major constituents of M. canadensis EO. The experimental validation verified the efficacy of menthol. Overall, the results demonstrate that M. canadensis EO and its components exhibit remarkable insecticidal properties and high safety profiles, rendering them suitable for insecticide deployment in pest management within the food industry.

Dynamic changes in physicochemical property, biogenic amines content and microbial diversity during the fermentation of Sanchuan ham

Sanchuan ham is appreciated in Yunnan Province, China, for its characteristic flavor and taste, while the microbial community structure and biogenic amines content remain unclear during fermentation processes. In this study, we explored the physicochemical property, biogenic amines concentration and microbial diversity of external and internal Sanchuan ham by high-throughput sequencing during the processing of Sanchuan ham. Results showed that the nitrite remained at a stable level of 0.15 mg/kg which was significantly lower than the national health standard safety level of 20 mg/kg. In addition, compared with fresh hams, the content of total free amino acids in ripe Sanchuan ham has grown 14 folds; sour and bitter were the main tastes of Sanchuan ham. Notably, the concentration of cadaverine was the highest of all biogenic amines during the entire fermentation period. At the bacterial phyla level, Firmicutes and Actinobacteria were the two main phyla, while at the genus level, Staphylococcus was a significant strain throughout the whole fermentation. Moreover, the dry stage has a great impact on the succession change of microbial community structure. Simultaneously, the change trends and composition of bacteria in the interior have slight discrepancies with those of the exterior of Sanchuan ham.

Characterization of Leuconostoc carnosum and Latilactobacillus sakei during Cooked Pork Ham Processing

Cooked ham is a popular, ready-to-eat product made of pork meat that is susceptible to microbial growth throughout its shelf life. In this study, we aimed to monitor the microbial growth and composition of nine vacuum-packed cooked ham lots using plate counting until the microbial limit of 7.4 log10 AMC/LAB CFU/g was exceeded. Eight out of nine lots exceeded the microbial limit after 20 days of storage. Lactic acid bacteria strains, particularly Leuconostoc carnosum and Latilactobacillus sakei, prevailed in vacuum-packed cooked ham. Leuconostoc carnosum 2 (Leuc 2) and Latilactobacillus sakei 4 (Sakei 4) were isolated from raw meat and the post-cooking area of the food processing facility. Carbohydrate utilization patterns of Leuc. carnosum PFGE types isolated from raw meat and the food processing environment differed from those isolated from cooked ham. These findings demonstrate how raw meat and its processing environment impact the quality and shelf life of cooked ham.

Quality Control of Jinhua Ham from the Influence between Proteases Activities and Processing Parameters: A Review

Endogenous proteases are significant for Jinhua ham quality. Protein degradation affects the chemical traits, texture and the formation of flavor substances. Protease activities are affected by different process parameters, such as processing temperature, maturation time, salt content and the drying rate. They affect ham quality, which can be controlled by process parameters. The influences of key factors on Jinhua ham quality are briefly summarized, which can provide a theoretical basis for the selection of specific parameters in dry-cured ham processing. Furthermore, some suggestions are proposed for correcting and improving the flavor and textural defects of ham, yet the effectiveness depends on the operating conditions. The determination of enzyme activity is not real-time and unsupervised at the moment. Future research will focus on the determination of the actual endogenous protease activity and the quantitative relationship between the enzyme activity and main processing parameters.

Insight into the impacts of Jinhua ham processing conditions on cathepsin B activity and conformation changes based on molecular simulation

To produce the high quality products and improve the stability of Jinhua hams, the activities of cathepsins and their correlation with processing parameters were explored. The effect of heat treatment on the structure of cathepsin B, together with potential of hydrogen and NaCl concentration, were investigated. At 45 °C, the activity of cathepsin B was maximum and it decreased rapidly at high temperature. The decrease on sulfhydryl group content indicated that the enzyme activity varied due to the breaking of disulfide bond in molecule. Infrared spectroscopy indicated that the secondary structure of cathepsin B had altered. Meanwhile, the root mean squared deviation and the root mean square fluctuation curves reflected that the cathepsin B vitality was in a decline under high temperature. In addition, in the presence of 0.6 mol ⋅ L−1 NaCl, lots of conformational changes were evidenced. Under acidic conditions (pH = 6), there were more formed hydrogen bonds, and the hydrogen bonding interactions became stronger. Simulation results contributed to providing an important theoretical basis for understanding the roles of processing parameters on the quality control of Jinhua ham.

Combined application of high-throughput sequencing and LC-MS/MS-based metabolomics to evaluate the formation of Zn-protoporphyrin in Nuodeng ham

In order to deepen the understanding of the formation mechanism of Zn-protoporphyrin (ZnPP), Nuodeng ham was used as the research object, and the effects of bacterial communities and small molecule metabolites on the formation of ZnPP during the processing of Nuodeng ham were analyzed by high-throughput sequencing and LC-MS/MS-based metabolomics. With the prolongation of processing time, the ZnPP content increased significantly, while the heme content decreased significantly. Compound curing agent significantly inhibited the formation of ZnPP and significantly decreased the heme content. The bacterial communities changed dynamically and the five bacterial genera were significantly positively correlated with ZnPP content. Forty-seven differential metabolites were obtained through screening, of which seventeen differential metabolites were significantly positively correlated with ZnPP content. Correlation analysis showed a strongly positive correlation between Staphylococcus, Delftia, Acinetobacter and these seventeen differential metabolites. These findings can provide a theoretical basis for further establishing the color control measures of Nuodeng ham.

Processing methods for human amniotic membrane as scaffold for tissue engineering with mesenchymal stromal human cells.

Tissue engineering is an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function. The aims of this work were to compare chemically and physically processed human Amniotic Membranes (hAM) and analyze the cytocompatibility and proliferation rate (PR) of two primary human mesenchymal stromal cell lines, from different sources and donor conditions seeded over these scaffolds. The evaluated hAM processes were: cold shock to obtain a frozen amniotic membrane (FEAM) with remaining dead epithelial cells, denudation of hAM with trypsin for 20/10min (DEAM20/10) or treatment with sodium dodecyl sulfate to decellularized hAM (DAM). All samples were sterilized with gamma radiation. The selection of the treated hAM to then generate composites was performed by scanning and transmission electron microscopy and characterization by X-ray diffraction, selecting DEAM10 and FEAM as scaffolds for cell seeding. Two sources of primary human stromal cells were used, both developed by our researchers, human Dental Pulp Stem Cells (hDPSC) from living donors and human Mesenchymal Stromal Cells (hMSC) from bone marrow isolated from brain dead donors. This last line of cells conveys a novel source of human cells that, to our knowledge, have not been tested as part of this type of construct. We developed four in vitro constructs without cytotoxicity signs and with different PR depending on the scaffolds and cells. hDPSC and hMSC grew over both FEAM and DEAM10, but DEAM10 allowed higher PR.

Evolution of antioxidant peptides and their proteomic homology during processing of Jinhua ham

This study aimed to clarify the evolution of antioxidant peptides and their proteomic homology during a continuous period of Jinhua ham processing. The peptide content increased during the process, reaching a value of 1.92% (weight %, based on meat weight) in ham at the end of dry-ripening, which was approximately 8-fold higher than that prior to salting. From scavenging effects on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) and hydroxyl radical (•OH) and chelating ability on Fe2+, it was suggested that peptides generated at the end of dry-ripening had the highest level of antioxidant activity. Size-exclusion chromatography indicated that the antioxidation of peptides might be related to their MWs, where more fractions with small MWs result in higher antioxidant activity. The results of endogenous protease activities showed 22.33% of the initial activities of Cathepsin B were retained, suggesting that Cathepsin B plays a key role in the formation of antioxidant peptides. Homology-based proteomics showed that peptides primarily arose from myosin (32.37%), followed by actin (16.91%), troponin T (12.08%) and others.

Evaluation of protein degradation and flavor compounds during the processing of Xuan'en ham.

Protein degradation occurs during the processing of dry-cured ham, which has important influences on the flavor and quality of products. The aim of this work was to study the degradation kinetics of myofibrillar proteins (MPs) and sarcoplasmic proteins (SPs) extracted from the biceps femoris muscle during the processing of Xuan'en ham. A relationship between protein degradation and the flavor formation was found. During the processing of Xuan'en ham, MPs and SPs were mainly degraded in the salting stage and incipient fermentation. Accompanied by protein degradation, the content of carbonyl group in SPs increased gradually, but in MPs, it first increased and then decreased. Interconversion between sulfhydryl and disulfide bonds was investigated during this processing. Oxidation, degradation, and thermal effects significantly affected the surface hydrophobicity of proteins. More than one hundred volatile compounds have been identified at each stage of ham preparation. Among them, organic acids were the predominant group, followed by hydrocarbons, aldehydes, alcohols, ketones, and esters.

Contribution of cathepsin B and L to endogenous proteolysis in the course of modern Jinhua ham processing

Although cathepsins have significant effects on protein degradation during the manufacture of Jinhua ham, the influences of cathepsin B and cathepsin L have seldom been assessed. In our research, the cathepsin B and L activities, proteolytic index (PI) values and the changes in microstructure and protein expression levels are investigated. E−64 is further selected as cathepsin inhibitor to verify the effect of cathepsin B and L on proteolysis and set up control groups. The results show a high level of enzymatic residual activity and PI values increase from 2.58% to 22.60% which implies a noticeable proteolysis. Microstructure analysis presents that the muscle fiber is sparse and the distribution is irregular over time. Based on immunohistochemistry analysis, the weak or strong red fluorescent which marks cathepsins can be observed in the ham muscle tissues, which is consistent with the active cathepsins. The increased number of sheet-like blue collagen fibrous proliferation in the interstitial space results in the reduction of enzyme staining sites. The decreased content of 38 and 36 kDa fragments indicates that cathepsins are released from lysosome dramatically, which is liable for proteins degradation and the formation of flavor. These results can highlight the important contribution of cathepsin B and L to protein degradation throughout overall processing, and have a new understanding towards the changes of endogenous protease in Jinhua ham.

UPLC-MS-MS-based lipidomics for the evaluation of changes in lipids during dry-cured mutton ham processing

Six key stages in the processing of dry-cured muton ham were selected, and changes in the main lipid metabolites as well as the major pathways involved were identified using a lipidic metabolomics approach based on UPLC-MS-MS. In total, 581 lipid metabolites from 22 subclasses were identified, including 521 significantly differential lipids (p < 0.05, VIP > 1). Glycerolipids (GL) were the most abundant lipids, followed by glycerophospholipids (GP), fatty acyls (FA), and sphingolipids (SL). PCA and OPLS-DA of metabolites showed that the quality of mutton ham changed the most during the P3 fermenting stage, including TG(18:1/18:2/18:3), PE(20:5/18:1), and TG(16:1/18:1/18:4) that were significantly downregulated, and CE(20:3), FFA(24:6), LPC(20:3/0:0), and FFA(18:4) that were significantly upregulated. Moreover, glycerophospholipid metabolism and sphingolipid metabolism were the key metabolic pathways involved in the processing of dry-cured mutton ham. Our results provide a basis for quality control and product improvement of dry-cured mutton ham.

Identification of dipeptides by MALDI-ToF mass spectrometry in long-processing Spanish dry-cured ham

The processing of dry-cured ham results in the generation of small peptides by the action of endogenous enzymes on muscle proteins. Common proteomic workflows involve previous separation techniques based on liquid chromatography which are expensive and time-consuming. In this study, a convenient proteomic approach based on MALDI-ToF is proposed for the first time for the detection of dipeptides in Spanish dry-cured ham. Dipeptides AH, AL, DD, EV, and VF were identified in hams of 18 and 24 months of dry-curing. This work provides insights on the efficiency of a new peptidomic workflow for the short peptide identification from a complex food matrix and permits to evaluate the sample in terms of the presence of taste-related and bioactive dipeptides.