Techniques for postmortem tenderisation in meat processing: effectiveness, application and possible mechanisms

Physicochemical, microstructural, and sensory attributes of frozen Buffalo loins treated with sodium tripolyphosphate and sous-vide cooking

This study investigates the effects of sous-vide cooking with varying concentrations of sodium tripolyphosphate (STPP) on the physicochemical properties (pH, cooking loss, water-holding capacity, colour properties, and shear force), lipid oxidation (thiobarbituric acid reactive substances, TBARS), secondary protein structures (Fourier transform infrared, FTIR), microstructure (scanning electron microscope, SEM), and sensory attributes (descriptive analysis) of frozen buffalo loins. Commercial buffalo loins (Black Gold) imported from India were used as samples (n = 15). They were sliced into steaks of 2 cm thickness, injected with 0 %, 0.15 %, and 0.3 % STPP, vacuum-sealed, and tumbled at 4 °C for 1 h. Subsequently, they were cooked sous-vide at 60 °C for 6 h. Results indicated that STPP significantly increased pH, reduced cooking loss, and enhanced water-holding capacity. Higher STPP concentrations increased lightness and redness while lowering shear force values. TBARS reached 2 mg MDA/kg in the 0 % STPP group by day 7, while buffalo loins with 0.15 % and 0.3 % STPP reached this level by days 21 and 28, respectively. FTIR showed similar secondary protein structure patterns in buffalo loins with 0.15 % and 0.3 % STPP, while the untreated sample had irregular patterns. SEM analysis revealed porous muscle fibres and thinner perimysium in the 0.3 % STPP samples, indicating greater tenderness. Sensory evaluation confirmed improvement in visual appeal, juiciness and aroma with 0.3 % STPP concentration.

A Novel Electromagnetic Response Measurement System for Continuous Monitoring of Meat Aging

The aging of dry meat enhances its flavor and tenderness; however, continuous internal quality monitoring throughout the aging process is challenging. We developed and validated a novel electromagnetic response measurement system for meat aging that enables continuous bioimpedance monitoring under stable, optimal temperature/humidity conditions. The system comprises a temperature-controlled dry aging fridge and a newly designed puncture-type semi-rigid coaxial probe, allowing for minimally invasive internal measurements over a broad frequency range. The probe achieved stable measurements across 10 kHz to 10 MHz, and its small diameter (1.25 mm) enabled almost non-destructive internal sensing. Beef and pork samples were monitored over 14 days via multi-channel bioimpedance measurements. After an initial stabilization period, bioimpedance steadily decreased throughout aging. This decline reflected progressive increases in tissue conductivity as cell membranes broke down and intracellular fluids leaked out. High-frequency measurements (e.g., around 10 MHz) were more sensitive to environmental disturbances. Periodic defrost cycles in the chamber caused temporary impedance dips at these frequencies, highlighting the influence of short-term temperature/humidity fluctuations. The system enables long-term continuous measurement without removing samples from the fridge, thus maintaining aging conditions during monitoring. Overall, the system enables the stable, long-term, and multi-channel electromagnetic monitoring of meat quality under optimal aging conditions-a capability not achieved in previous studies. This new method offers a minimally invasive, frequency-resolved approach for assessing meat quality evolution during aging. This advance demonstrates a new approach for tracking meat quality changes during dry aging.

Characterization of firmness in fermented sea bass (Lateolabrax japonicas) by multidimensional integration strategies: Insights from proteomic and microstructural analyses

Fermented sea bass, recognized for its firmness and chewy texture, provides a distinct sensory experience.This study investigated the texture and microstructural properties of fermented sea bass during fermentation. Proteomics analysis identified the key proteins involved in firmness development, revealing the molecular mechanisms behind these changes. Water migration and myofibril thickening were significant contributors to the increased firmness, hardness, and chewiness. Label-free proteomics revealed 881 proteins, with 426 were differentially expressed, leading to the identification of 155 key protein biomarkers linked to texture. Structural proteins such as myosin light chain and actin correlated positively with hardness, chewiness, and adhesiveness. Fermentation also increased phosphorylation, enhancing protein degradation and texture attributes. Signaling pathways such as PI3k-AkT, HIF-1, and calcium ion signaling pathways were implicated in metabolism and myosin assembly, fortifying muscle tissue firmness. This study provided critical insights into the quality control and production optimization in the fermented sea bass industry.

Towards more realistic cultivated meat by rethinking bioengineering approaches

Cultivated meat (CM) refers to edible lab-grown meat that incorporates cultivated animal cells. It has the potential to address some issues associated with real meat (RM) production, including the ethical and environmental impact of animal farming, and health concerns. Recently, various biomanufacturing methods have been developed to attempt to recreate realistic meat in the laboratory. We therefore overview recent achievements and challenges in the production of CM. We also discuss the issues that need to be addressed and suggest additional recommendations and potential criteria to help to bridge the gap between CM and RM from an engineering standpoint.

Tailoring meat products for the elderly: A comprehensive review

The population of the elderly is projected to grow significantly in most of the developed countries in the near future. This should earn this demographic the title of 'Consumer of the future'. Meat has high quality proteins and essential vitamins which are important for all demographics but more so for the elderly due to their susceptibility to sarcopenia. This review explored the landscape of meat research and product development that meets the distinctive requirements of the elderly, drawing from published refereed articles, industry reports, and unpublished grey literature. The review emphasised the importance of understanding the evolving dietary and sensory requirements associated with ageing and how they intersect with meat consumption. One notable aspect observed is the diversity within the elderly population, which underscores the necessity for tailored approaches in meat product development to cater to the varying preferences and nutritional needs of different individuals. This review also highlights the ongoing efforts in developing meat-based products that span a spectrum of consistencies, ranging from solid to liquid forms, to accommodate the diverse needs of elderly consumers. Despite these advancements, the review found a discrepancy between the pace of meat product development for the elderly and the rapid advancements in kitchen-level technologies and suggests that further research is needed to bridge this gap and align product innovation with emerging technological trends.

Phosphate and two-stage cooking: Impact on lipid oxidation and tenderness in sous-vide beef semitendinosus

The study investigated phosphate's effects on tenderness and lipid oxidation in beef cooked sous-vide. Semitendinosus beef cuts were treated with 0.15% and 0.3% sodium tripolyphosphate (STPP), and plain water (0% STPP). These cuts were then sous-vide cooked at two different temperatures, 60 °C and 70 °C, for two different durations, 3 h and 6 h. Analytical techniques including Warner-Bratzler shear force (WBSF), pH, thiobarbituric acid reactive substances (TBARS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were employed. STPP concentration did not yield a statistically significant impact on the pH and FTIR spectrum of sous-vide beef (p > 0.05). However, STPP markedly enhanced tenderness by loosening the myofibril structure (observed in SEM) and weakening myosin and actin bands (observed in SDS-PAGE). This improvement led to lower WBSF values with 0.3% STPP, particularly noticeable at 60 °C for 6 h. Additionally, 0.3% STPP delayed lipid oxidation, evidenced by lower oxidation values after 4 weeks of refrigerated storage at 4 °C. These findings highlight STPP's potential to improve tenderness and lipid oxidation stability in sous-vide beef.

Exploring the effect of part differences on metabolite molecule changes in refrigerated pork: Identifying key metabolite compounds and their conversion pathways

Effect of part differences on metabolite molecule alterations in refrigerated pork was investigated. A metabolomics methodology combined with chemometric analysis was successfully established to identify key compounds and their conversion pathways, including precursors and volatile metabolites, in the Longissimus lumborum as well as the breast and flank stored for 11 days. In total, 12 discriminative precursors were identified using the Short Time-series Expression Miner. In tandem with Random Forest and ANOVA analyses, nine volatile metabolites were identified as key compounds that could be attributed to differences in pork sections. Bidirectional orthogonal partial least squares analysis revealed a potential correlation between these key metabolites and discriminative precursors. Metabolic pathway enrichment analysis demonstrated that the primary metabolic process affected by variations in pork sections is linoleic acid metabolism, which participates in the metabolism of cysteine and glutamic acid to produce methoxy-phenyl-oxime. This study provides valuable insights into the identification of differential metabolites.

Effect of NaCl replacement by other salt mixtures on myofibrillar proteins: Underlining protein structure, gel formation, and chewing properties

The protein structure, gel changes, and chewing properties of low-sodium myofibrillar protein (MP) prepared by compound chloride salts (KCl/MgCl2, KCl/CaCl2, and KCl/MgCl2/CaCl2) and different substitution degrees (10%, 25%, and 40%) at same ionic strength (0.6 M) were investigated. The results revealed that the low-sodium MP gels containing CaCl2 manifested more liquid loss and less moisture content accompanied by obvious morphological shrinkage, while KCl/MgCl2 contributed to the gel juiciness. At high substitution degree of 40%, KCl/CaCl2 substitution rendered the gel with dense structure and highest strength, but worse water retention capacity. Using other compound chloride salts influenced the chewing efficiency, and CaCl2 substitution made the gel relatively hard to chew. The inhomogeneous structure accompanied by cluster blocks in KCl/CaCl2-substituted MP gel accelerated the overall fracture rate. During heating process, more proteins in CaCl2-substituted MP did not participate in gel formation, intervening the final gel properties. The chloride salt mixtures containing MgCl2, rather than CaCl2, avoided or alleviated the liquid loss and shrinkage of low-sodium MP gel within the substitution degree of 10%-40%, and substitution degree not exceeding 25% was more reasonable for the controlled qualities.

Application of seed mucilage as functional biopolymer in meat product processing and preservation

Meat products consumption is rising globally, but concerns about sustainability, fat content, and shelf life. Synthetic additives and preservatives used for extending the shelf life of meat often carry health and environmental drawbacks. Seed mucilage, natural polysaccharides, possesses unique functional properties like water holding, emulsifying, and film forming, offering potential alternatives in meat processing and preservation. This study explores the application of seed mucilage from diverse sources (e.g., flaxseed, psyllium, basil) in various meat and meat products processing and preservation. Mucilage's water-holding and emulsifying properties can potentially bind fat and decrease the overall lipid content in meat and meat-based products. Moreover, antimicrobial and film-forming properties of mucilage can potentially inhibit microbial growth and reduce oxidation, extending the shelf life. This review emphasizes the advantages of incorporating mucilage into processing and coating strategies for meat and seafood products.

Systematic evaluation of the meat qualities of free-range chicken (Xuan-Zhou) under different ages explored the optimal slaughter age

Meat qualities of free-range chicken (Xuan-Zhou) (XZ-FRC) are closely associated with slaughter age and directly influence the economic benefits of supplier and consumer's preference. Understanding of the relationship between meat qualities and ages will be of prime important to explore a better slaughter age of XZ-FRC. In this study, the quality traits of breast and thigh muscles from XZ-FRCs at 9 to 14 wk were analyzed to establish a relatively reliable method for selecting a better slaughter age. The results showed that the effects of slaughter ages on color (CIE L*, a* and b* values), shear force, centrifugal loss, and flavor of XZ-FRCs were significant (P < 0.05). There were greater differences in meat qualities, whatever breast or thigh muscles, between same or different ages. Eleven feature indexes used for colligation evaluation of slaughter age were selected by combining the quality characteristics and data analysis. The score of colligation evaluation for XZ-FRCs at 12 wk was higher than that at 9 and 14 wk, suggesting that the 12 wk was an optimal slaughter age. This work would provide a reference method that helps the producers of livestock and poultry to select a better slaughter age.

Ultrasound-induced modifications of beef flavor characteristics during postmortem aging

To investigate the effect of ultrasound treatment on the flavor profile of beef during postmortem aging, a comprehensive analysis of beef flavor was conducted at 0, 7, and 12 d of aging using sensory evaluation and electronic nose. Furthermore, the key volatile flavor compounds were identified using gas chromatography-mass spectrometry (GC-MS), and the odor activity value (OAV) was further evaluated. In addition, the primary pathway involved in flavor formation during beef aging after ultrasound treatment was explored. The results indicated that ultrasound enhanced the flavor profile of beef during postmortem aging by modifying the OAV of hexanal, heptanal, octanal, nonanal, decanal, (Z)-2-nonenal, dodecanal, pentanal, 1-octen-3-ol, octanoic acid, and 2-pentylfuran. Lipid oxidation was a crucial pathway through which ultrasound promoted the generation of volatile flavor compounds in beef, confirmed by the improved oxidation level of fatty acids, particularly monounsaturated ones. The study indicates that ultrasound technology can be regarded as an effective method for enhancing the beef flavor profile during postmortem aging.

Aging mechanism for improving the tenderness and taste characteristics of meat

Tenderness and taste characteristics of meat are the key determinants of the meat choices of consumers. This review summarizes the contemporary research on the molecular mechanisms by which postmortem aging of meat improves the tenderness and taste characteristics. The fundamental mechanism by which postmortem aging improves the tenderness of meat involves the operation of the calpain system due to apoptosis, resulting in proteolytic enzyme-induced degradation of cytoskeletal myofibrillar proteins. The improvement of taste characteristics by postmortem aging is mainly explained by the increase in the content of taste-related peptides, free amino acids, and nucleotides produced by increased hydrolysis activity. This review improves our understanding of the published research on tenderness and taste characteristics of meat and provides insights to improve these attributes of meat through postmortem aging.

Meat tenderization using acetaminophen (paracetamol/APAP): A review on deductive biochemical mechanisms, toxicological implications and strategies for mitigation

Meats consist of edible portions originating from domestic and wild animals. Meat's palatability and sensory accessibility largely depend on its tenderness to consumers. Although many factors influence meat tenderness, the cooking method cannot be neglected. Different chemical, mechanical, and natural means of meat tenderization have been considered healthy and safe for consumers. However, many households, food vendors, and bars in developing countries engage in the unhealthy use of acetaminophen (paracetamol/APAP) in meat tenderization due to the cost reduction it offers in the overall cooking process. Acetaminophen (paracetamol/APAP) is one of the most popular, relatively cheap, and ubiquitous over-the-counter drugs that induce serious toxicity challenges when misused. It is important to note that acetaminophen during cooking is hydrolyses into a toxic compound known as 4-aminophenol, which damages the liver and kidney and results in organ failure. Despite the reports on the increase in the use of acetaminophen for meat tenderizing in many web reports, there have not been any serious scientific publications on this subject. This study adopted classical/traditional methodology to review relevant literature retrieved from Scopus, PubMed, and ScienceDirect using relevant key terms (Acetaminophen, Toxicity, Meat tenderization, APAP, paracetamol, mechanisms) and Boolean operators (AND and OR). This paper provides in-depth information on the hazard and health implications of consuming acetaminophen tenderized meat via genetic and metabolic pathways deductions. Understanding these unsafe practices will promote awareness and mitigation strategies.

Application of Plant Proteases in Meat Tenderization: Recent Trends and Future Prospects

Papain, bromelain, and ficin are commonly used plant proteases used for meat tenderization. Other plant proteases explored for meat tenderization are actinidin, zingibain, and cucumin. The application of plant crude extracts or powders containing higher levels of compounds exerting tenderizing effects is also gaining popularity due to lower cost, improved sensory attributes of meat, and the presence of bioactive compounds exerting additional benefits in addition to tenderization, such as antioxidants and antimicrobial effects. The uncontrolled plant protease action could cause excessive tenderization (mushy texture) and poor quality due to an indiscriminate breakdown of proteins. The higher cost of separation and the purification of enzymes, unstable structure, and poor stability of these enzymes due to autolysis are some major challenges faced by the food industry. The meat industry is targeting the recycling of enzymes and improving their stability and shelf-life by immobilization, encapsulation, protein engineering, medium engineering, and stabilization during tenderization. The present review critically analyzed recent trends and the prospects of the application of plant proteases in meat tenderization.

Methods for improving meat protein digestibility in older adults

This review explores the factors that improve meat protein digestibility and applies the findings to the development of home meal replacements with improved protein digestion rates in older adults. Various methods improve the digestion rate of proteins, such as heat, ultrasound, high pressure, or pulse electric field. In addition, probiotics aid in protein digestion by improving the function of digestive organs and secreting enzymes. Plant-derived proteases, such as papain, bromelain, ficin, actinidin, or zingibain, can also improve the protein digestion rate; however, the digestion rate is dependent on the plant enzyme used and protein characteristics. Sous vide processing improves the rate and extent of protein digestibility, but the protein digestion rate decreases with increasing temperature and heating time. Ultrasound, high pressure, or pulsed electric field treatments degrade the protein structure and increase the proteolytic enzyme contact area to improve the protein digestion rate.

Insight into the mechanism of fracture properties modulated by microstructure in the myofibrillar protein and polysaccharide gel systems

The objective of this study was to investigate the mechanism of fracture properties modulated by microstructure in the myofibrillar protein (MP) and polysaccharides gel systems. Compare to the modified starch, the dietary fiber significantly improved the fracture stress and reduced the fracture strain at same concentration. The treatment with 2% dietary fiber had the highest value of fracture stress and the lowest value of fracture strain, which were 259 g and 1.12 respectively. From the skeleton structure, the Raman spectroscopy result showed that dietary fiber addition significantly reduced the intensity at 2945 cm−1, which suggested that the aggregation of hydrophobic groups was improved. The SEM showed that the treatment with 2% dietary fiber had the highest fractal dimension value of 1.7772 and the lowest lacunary value of 0.258. From the filling structure, the paraffin section showed that the polysaccharides were just simply trapped in MP gel networks and formed numerous large volumes and no-elastic of cavities. The principal component analysis suggested that the compactness of three-dimensional gel networks determined fracture stress of composite gel. The no- no-elastic of cavities formed by modified starch and dietary fiber resulted in the reduction of fracture strain. These results would promote the development of innovative nutritional meat product formulation with satisfied textural property.

Graphical Abstract

Meat quality and flavor compounds of soft-boiled chickens: Effect of Chinese yellow-feathered chicken breed and slaughter age

The objective of this research was to investigate the effects of Mahuang and Tuer chickens, 2 representatives of the native chicken breed, and the slaughter age on meat quality and flavor compounds of soft-boiled chickens (SCs) in comparison to a commercial cross boiler. A total of 432 chicks were randomly allocated into the following groups: 817 groups raised for 55 d, and Mahuang and Tuer chickens raised for 60, 65, 70, and 75 days (d). After the completion of rearing period, the chickens were slaughtered, and 5 carcasses per group were randomly selected for SC manufacturing. Meat quality was determined based on product yield, pH, color, meat tenderness, and textural and sensorial attributes. The volatile compounds of chicken breast were identified by gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that the yellow-feathered chicken breed, especially Mahuang chicken, had a higher product yield, and lower shear force and sensorial scores than the cross broiler. The pH, L* and b* values in SC breast meat were not significantly influenced by breed (P > 0.05), while greater a* was observed in SC of yellow-feathered chickens compared to cross broilers. The slaughter age had a significant effect on the pH, color, shear force, and textural properties of SC (P < 0.05). The meat tenderness of SC was significantly decreased as the age of chicken increased from 65 d to 75 d (P < 0.05). The relatively young age of yellow-feathered chickens (60 d and 65 d) was rated to have a higher overall sensory score of SC (P < 0.05). A total of 65 organic volatile compounds were identified in SC, including 18 aldehydes, 16 alcohols, 10 ketones, 9 esters, 2 acids, 3 furans, 5 pyrazines, and 2 sulfur-containing compounds. Three chicken breeds were separately clustered in the plot of principal component analysis, indicating breed-specific flavor characteristics. Collectively, the present study provides valuable information for SC processing in terms of carcass selection of yellow-feathered chicken breeds and slaughter age.

Effects of Ozone Water Combined With Ultra-High Pressure on Quality and Microorganism of Catfish Fillets (Lctalurus punctatus) During Refrigeration

This study described the quality and microbial influence on ozone water (OW) and ultra-high pressure (UHP) processing alone or in combination with refrigerated catfish fillets. The analysis parameters included total volatile base nitrogen (TVBN), thiobarbituric acid reactive substances (TBARs), chromaticity, microbial enumeration, 16S rRNA gene sequencing, electronic nose (E-nose), and sensory score. The study found that compared with the control (CK), ozone water combined with ultra-high pressure (OCU) delayed the accumulation of TVBN and TBARs. The results of sensory evaluation illustrated that OCU obtained a satisfactory overall sensory acceptability. The counting results suggested that compared to CK, OCU significantly (p < 0.05) delayed the stack of TVC, Enterobacteriaceae, Pseudomonas, lactic acid bacteria (LAB), and hydrogen sulfide-producing bacteria (HSPB) during the storage of catfish fillets. The sequencing results reflected that the dominant were Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria at the phylum level, and the dominant were Acinetobacter, Pseudomonas, Lelliottia, Serratia, Shewanella, Yersinia, and Aeromonas at the genus level. The dominant was Acinetobacter in initial storage, while Pseudomonas and Shewanella were in anaphase storage. Based on the TVC and TVBN, the shelf life of catfish fillets was extended by at least 3 days compared to the control. In short, the combination of ozone water and ultra-high-pressure processing is a favorable strategy to control microbial quality and delay lipid oxidation during catfish storage.

Evaluation of ultrasound-assisted L-histidine marination on beef M. semitendinosus: Insight into meat quality and actomyosin properties

This paper aimed to evaluate the effects of ultrasound-assisted L-histidine marination (UMH) on meat quality and actomyosin properties of beef M. semitendinosus. Our results found that UMH treatment effectively avoided excessive liquid withdrawal, and disrupted myofibril integrity by modifying the water distribution and weakening connection of actin-myosin with increased muscle pH. The ultrasound-treated sample provided more opportunity for the filtration of L-histidine to intervene the isoelectric point and conformation of muscle protein. The activated caspase-3 and changes of ATPase activity in UMH-treated meat accelerated the postmortem ageing, and L-histidine might competitively inhibit the actin-myosin binding by the imidazole group. UMH decreased the surface hydrophobicity by shielding hydrophobic area and unfolding the actomyosin structure. In addition, the increased actomyosin solubility with smaller particle size enhanced the SH content for better cross-linking of myosin tail, and formation of heat-set gelling protein structure. Therefore, UMH treatment manifested the potential to improve beef quality.

A systematic review of clean-label alternatives to synthetic additives in raw and processed meat with a special emphasis on high-pressure processing (2018-2021)

The meat industry is continuously facing challenges with food safety, and quality losses caused by thermal processing. This systematic review reports recent clean label approaches in high-pressure production of meat. A literature search was performed using Scopus, Web of Science, PubMed, and Springer databases for studies published in 2018-2021. In this regard, 69 articles were assessed out of 386 explored research articles in the identified stage. The findings indicate that most of the earlier work on high-pressure processing (HPP) focused on physicochemical and sensorial meat quality rather than providing nutritional aspects and clean-label solutions. However, few advanced studies report effective and innovative solutions to develop low salt/fat, and reduced nitrite for raw and cured meat products. HPP could help on increasing the shell life by five times in meat products; however, it depends on the formulation and packaging, etc. HPP can also preserve nutrients by using this non-thermal technology and reduce food waste as once the shelf life of products is known, it easily reduces the shrinkage in the marketplace. This review explores the latest trend of experimental research in high-pressure processing alone, or multi-hurdle techniques employed to increase the effect of clean-label ingredients for enhanced meat safety/quality.