The color of fresh pork: Consumers expectations, underlying farm-to-fork factors, myoglobin chemistry and contribution of proteomics to decipher the biochemical mechanisms

Towards a 'One quality' approach of pork: A perspective on the challenges and opportunities in the context of the farm-to-fork continuum - Invited review

A substantial amount of research on pork production and consumption highlights an interplay between the intrinsic qualities that are inherent to the product and the extrinsic qualities related to how it is produced, which together contribute to the perception and evaluation of fresh pork. However, studies have emphasised difficulties in defining their relative importance depending on the countries, consumers' knowledge, experience and personal beliefs, as well as their dynamic changes over time. A joint and multidimensional consideration of the intrinsic and extrinsic quality dimensions is critical to achieve sustainable development goals that ensure healthy, nutritious, fair and environmentally friendly pork produced in a profitable manner. However, very few studies have investigated the synergies and antagonisms between the multiple dimensions of intrinsic and extrinsic qualities of pork. This perspective aims to define and promote the concept of 'One Quality' pork, as an approach to meeting the multiple and divergent expectations of stakeholders in the pork value chain, while jointly considering pork quality and sustainability. It aims to discuss how the changing expectations of consumers, citizens and public action including policy makers are currently promoting a holistic definition and evaluation of pork quality. It also seeks to explore how the multiple dimensions of pork quality, including their intrinsic and extrinsic dimensions, can be considered simultaneously. The opportunities and challenges of implementing a 'One Quality' approach to pork for an integrated sustainability assessment of the farming systems, i.e., by jointly addressing the intrinsic quality attributes, ensuring sustainable farming practices, economic viability for stakeholders, and alignment with consumer and citizen expectations, are then discussed along the farm-to-fork continuum.

Synergistic effects of polymethoxyflavonoids from citrus peel extracts on harmful compound formation and flavor quality in grilled beef patties

Three polymethoxyflavonoids (PMFs) from citrus peel: tangeretin (TG), isosinensetin (ISN), and 3',4',5,7-tetramethoxyflavone (TMHF) and their combination significantly inhibited heterocyclic amines (HAs) and advanced glycation-end products (AGEs) formation. In particular, ISN with five methoxyl structure and B-ring distribution was significantly effective reduce HAs to 50.1 %-77.9 %. The PMF mixture was effective reduce both HAs and AGEs at rates of 52.2 %-77.3 % and 16.4 %-66.8 %, respectively. For ISN, the radical scavenging activity and inhibitory effects of HAs and AGEs were highly correlated. However, the inhibitory action of mixed PMFs against harmful substances was related to free radical scavenging activity and their impact on water distribution. Furthermore, GC-IMS analysis revealed the PMF mixture did not significantly change the key aldehyde and ketone compounds in grilled meat. This study provides insights into the effect of PMF mixtures, which appear to synergistically regulate the formation of aromatic and harmful compounds in grilled meat products.

Antioxidant pH-sensitive films incorporating CMC/SA/starch, anthocyanins, and tea polyphenols for monitoring freshness of pork

It is important to find an intelligent packaging which can monitor pork freshness immediately and extend its shelf life in food science. The aim of this study was developing a novel pH sensitive film with high antioxidant activity based on sodium carboxymethylcellulose (CMC), sodium alginate (SA), and cassava starch (CS) incorporating Lycium ruthenicum anthocyanins (LRA), and tea polyphenols (TP). The pH response, physical properties, color stability, antioxidant activity, and the ability to monitor the freshness of pork of the films were analyzed. The results indicated that LRA was sensitive in the solution of pH 1-14. After the addition of LRA and TP, the thickness of the films was increased, the mechanical properties were affected, and the water content, and WVP were decreased. LRA and TP significantly improved the light-resistance performance. Fourier transform infrared spectroscopy revealed that CMC, SA, and CS had good compatibility, and LRA and TP were successfully incorporated into the film. TP significantly increased the antioxidant activities of the film as determined by DPPH, and FRAP methods. In addition, the film showed remarkable color change in response to the increase of volatile basic nitrogen content in pork during spoilage. The films containing 0.2 % TP obviously inhibited lipid oxidation, and extended the shelf life of pork. Our findings suggested that CSC/LRA/TP films could be applied as antioxidant materials with freshness monitor effect for pork packaging. This research provides an alternative for the visual intelligent packaging of pork.

Enhancing the quality of fat-reduced pork batter with soybean protein-chitosan nanoparticles based Pickering emulsion

This study aimed to investigate the impact of substituting pork back fat with Pickering emulsion (PE) stabilized by soybean protein isolate-chitosan (SPI-CH) nanoparticles on the quality of pork batters. Cooking loss, rheological properties, water distribution, microstructures, texture, color, and oxidative stability of pork batters were evaluated. The results revealed that replacing fat with PE led to a reduction in fat content and an increase in moisture content, as well as higher L* and b* values (P < 0.05). Furthermore, the substitution resulted in improved gel performance by enhancing rheological properties and texture, reducing water mobility and cooking loss, as well as effectively inhibiting lipid and protein oxidation in pork batters. However, no significant differences were observed in sensory acceptability. The findings suggest that using SPI-CH nanoparticles as a stabilizer for PE presents significant potential as a nutritionally improved fat alternative in meat products, offering enhanced functional characteristics.

Integrating transfer learning and spectroscopy for enhanced pork spoilage assessment using correlation analysis

Accurate Total Viable Count (TVC) detection is vital for food quality monitoring. In this study, we investigated the feasibility of using visible near-infrared (VNIR) spectroscopy (400-1000 nm) combined with transfer learning (TL) to track the chemical spoilage of pork. The base models developed using the full band for pork TVC, total volatile basic nitrogen, pH, and color showed predictability; the correlation coefficient of prediction set (RP) for all models ranged from 0.821 to 0.916; and the root mean square error of prediction set (RMSEP) of the TVC model was 0.617 (lg CFU/g). A correlation analysis of the different indexes of pork was carried out to optimize the TVC calibration model. Different TL methods for TVC optimization were designed. The results showed that multiple correlation chain stacking-partial least squares performed best with RP, RMSEP, and the relative percent deviation of 0.947, 0.425 lg CFU/g, and 2.355, respectively, the RMSEP of TVC was reduced by 31.12 % as compared to the base model. This study demonstrated the possibility of combining the VNIR spectroscopy system with TL to monitor the degree of meat's chemical spoilage.

Impacts of carob pulp (Ceratonia siliqua L.) and vitamin E on pork colour, oxidative stability, lipid composition and microbial growth

This study aimed to evaluate the impact of the dietary by-product rich in polyphenols (Carob pulp, Cp) and supra-nutritional level of vitamin (Vit) E on pork quality and shelf-life of meat stored in modified atmosphere packaging for 15 days. A total of 44 pigs (entire males and gilts, 170 ± 4.5 days of age and 127.8 ± 3.6 kg of body weight) were randomly selected from a larger group (one pig per pen). Pigs were fed ad libitum with one of four diets in a 2 × 2 factorial arrangement, with two feed inclusion levels each for Cp (0 vs. 20 %) and Vit E (30 (Low) vs. 300 IU/kg of feed (High)) for 40 days. No interactions between Cp and Vit E were detected for most variables assessed. Meat colour attributes evolved regardless of diet or sex, although metmyoglobin formation was preserved until 13 days. The Cp diets did not affect malondialdehyde nor α-tocopherol content in meat. High Vit E limited the malondialdehyde production up to 13 days and increased 1.8-fold the muscle α-tocopherol content compared to Low Vit E. The 20 %-Cp group tended to reduce total aerobic microbial count compared to 0 %-Cp group after 15 days of storage. Including Cp slightly affected the meat fatty acid (FA) profile, whereas Vit E did not modify it. Entire males presented higher content of polyunsaturated FA than gilts. Including 20 % Cp into pigs' diets does not impair meat quality, while High Vit E reduces lipid oxidation but not meat discolouration.

Identifying freshness of various chilled pork cuts using rapid imaging analysis

BACKGROUND

Determining the freshness of chilled pork is of paramount importance to consumers worldwide. Established freshness indicators such as total viable count, total volatile basic nitrogen and pH are destructive and time-consuming. Color change in chilled pork is also associated with freshness. However, traditional detection methods using handheld colorimeters are expensive, inconvenient and prone to limitations in accuracy. Substantial progress has been made in methods for pork preservation and freshness evaluation. However, traditional methods often necessitate expensive equipment or specialized expertise, restricting their accessibility to general consumers and small-scale traders. Therefore, developing a user-friendly, rapid and economical method is of particular importance.

RESULTS

This study conducted image analysis of photographs captured by smartphone cameras of chilled pork stored at 4 °C for 7 days. The analysis tracked color changes, which were then used to develop predictive models for freshness indicators. Compared to handheld colorimeters, smartphone image analysis demonstrated superior stability and accuracy in color data acquisition. Machine learning regression models, particularly the random forest and decision tree models, achieved prediction accuracies of more than 80% and 90%, respectively.

CONCLUSION

Our study provides a feasible and practical non-destructive approach to determining the freshness of chilled pork. © 2024 Society of Chemical Industry.

Electrical stimulation to improve meat quality: Factors at interplay, underlying biochemical mechanisms and a second look into the molecular pathways using proteomics

Ensuring consistent beef eating quality is paramount for meeting consumer demands and sustaining the meat industry. Electrical stimulation (ES) is a post-slaughter intervention used to accelerate post-mortem glycolysis, to avoid cold shortening, to control the tenderization rate of meat through sophisticated physical, chemical and biochemical mechanisms including proteolysis, to improve beef tenderness and to achieve normal pHu that might lead to positive impact on color. This review comprehensively examines the multifaceted effects of ES on beef quality, encompassing factors and settings influencing its efficacy and the underlying biochemical mechanisms revealed using traditional biochemistry methods. It then delves into the molecular pathways modulated by ES, as unveiled by muscle proteomics, aiming to provide a second look and an unprecedented understanding of the underlying biochemical mechanisms through an integrative proteomics analysis of low-voltage ES (LVES) proteomics studies. The proteins changing as a result of ES were gathered in a compendium of 67 proteins, from which 14 were commonly identified across studies. In-depth bioinformatics of this compendium allowed a comprehensive overview of the molecular signatures and interacting biochemical pathways behind electrically stimulated beef muscles. The proteins belong to interconnected molecular pathways including the ATP metabolic process and glycolysis, muscle structure and contraction, heat shock proteins, oxidative stress, proteolysis and apoptosis. Understanding the intricate interplay of molecular pathways behind ES could improve the efficiency of beef production, ensuring consistent meat quality and meeting consumer expectations. The integrative analysis approach performed in this study holds promise for the meat industry's sustainability and competitiveness.

Effect of gelatin edible coating with Aronia melanocarpa pomace polyphenols on the cold storage of chilled pork

In this research, the Aronia melanocarpa pomace polyphenols (AMPPs) were extracted and purified. The purified AMPPs contained the most abundant chlorogenic acid (CGA) at 36.91 mg/100 mg, followed by chrysin at 8.61 mg/100 mg. At a concentration of 60 μg/mL, the purified AMPPs exhibited stronger scavenging activity against: DPPH radical, hydroxyl radical, ABTS∙+, and also showed greater Fe3+ reducing activity than the VC control group. To solve the problem of easy spoilage of chilled meat during storage, gelatin edible coatings containing Aronia melanocarpa pomace polyphenols, referred to as G/AMPPs, were investigated for their effect on the chilled storage of pork. At a 1:1 volume ratio of 1 % polyphenol solution to 3 % gelatin solution, the G/AMPPs coating effectively curbed pH, TVB-N, TVC, drip loss, and b* value increases in chilled pork, while delaying declines in hardness, adhesion, a* value and L* value; The TVB-N content and TVC values demonstrated that the G/AMPPs coating significantly extended the shelf life of chilled pork by up to 15 days. The results showed that G/AMPPs had good preservative, antibacterial and antioxidant effects on chilled pork and thus development of G/AMPPs based coating shows appeared to offer promise for meat preservation.

Effects of Malondialdehyde on Growth Performance, Gastrointestinal Health, and Muscle Quality of Striped Catfish (Pangasianodon hypophthalmus)

Malondialdehyde (MDA) is a reactive carbonyl compound produced through lipid peroxidation during feed storage, which poses a significant threat to fish health. This study aimed to evaluate the effects of dietary MDA on the growth rate, gastrointestinal health, and muscle quality of striped catfish (Pangasianodon hypophthalmus). A basal diet (M0) containing 34% crude protein and 10.5% crude lipid was formulated. Each group was sprayed with malondialdehyde solution (0, 5, 10, 20, 40, and 80 mg/kg, on dietary crude lipid basis; 0, 0.53, 1.07, 2.13, 4.26, and 8.52 mg/kg, on dietary basis) before feeding, respectively. Each diet was randomly assigned to triplicates of 30 striped catfish (initial weight 31.38 g) per net cage. After 8 weeks, dietary inclusion of MDA regardless of level significantly depressed the growth rate and feed utilization. The extent of structural damage to the gastrointestinal tract increased progressively with increasing dietary MDA levels. The extent of damage to the intestinal biological barrier (intestinal microbial structure), chemical barrier (trypsin, lipase, amylase, and maltase activity), physical barrier (zonula occludent-2, occludin, claudin 7α, and claudin 12 relative expression), and immune barrier (contents of complement 4, complement 3, immunoglobulin M, and lysozyme activity) was dose-related to dietary MDA. Moreover, a linear decline in the activities of intestinal antioxidant enzymes (catalas, superoxide dismutase, et al.) and anti-inflammatory factor (transforming growth factor beta1, interleukin 10) relative expression was noted alongside an increase in dietary MDA content. In contrast, the relative expression levels of intestinal inflammatory factor (interleukin 8, transcription factor p65, tumor necrosis factor alpha) relative expression displayed an opposing trend. Additionally, dietary MDA exerted a linear influence on muscle color and texture characteristics. In conclusion, high doses of MDA (5-80 mg/kg) reduced the growth performance of striped catfish, attributed to linear damage to the gastrointestinal tract, a linear decrease in antioxidant function, and the occurrence of an inflammatory response. High doses of MDA (>40 mg/kg) were observed to significantly increase dorsal muscle b-value and induce muscle yellowing.

Effect of the Freeze-Drying Preservation Process on Some Quality Attributes of Pork Meat (Longissimus thoracis)

Meat preservation processes have been widely studied over time, especially those related to low temperatures (freezing and freeze-drying); however, there is very little research that directly relates the effect of these processes on the structure of meat-and the main meat proteins-and how these changes affect some attributes of the final quality. Pork loin meat (Longissimus thoracis) was used, which was frozen-thawed and freeze-dried-rehydrated to subsequently evaluate changes in its chemical composition and physicochemical parameters such as water activity (a w), pH, and water-holding capacity. Physical aspects such as color profile, surface myoglobin fraction, shear force, and histological sections were also evaluated, along with thermal analysis by modulated differential scanning calorimetry. The data obtained were analyzed through different statistical techniques. It was found that the freeze-drying process significantly modifies the interactions of water with the rest of the meat components (p < 0.05), promoting differences concerning samples that were only frozen, allowing us to establish the importance of water and its associations with each other and with proteins on their effect on meat preservation processes at low temperatures.

Antioxidative Status and Meat Quality Traits as Affected by Dietary Supplementation of Finishing Pigs with Natural Phenolics

This work investigated the effect of a plant-based phenolic supplement on the color, myoglobin forms, lipid oxidation, and antioxidative status of fresh and stored (10 days at 4 °C) meat (Longissimus thoracis et lumborum), as well as the antioxidative status of the blood and liver. The sensory quality of the meat was also evaluated for color, aroma, texture, juiciness, and palatability. Twenty-four finishing pigs, divided into two groups, were fed a basal diet and a diet with a phenolic supplement (0.1%). The supplementation increased the redness of the meat (+36% for a* and +28% for redness index), the myoglobin (Mb) content (+7%), the antioxidant activity, and the juiciness. The treatment increased the antioxidant status of meat, reflected by superoxide dismutase (SOD) activity and total glutathione (GSH + GSSG). The catalase and SOD activities and GSH + GSSG of the blood and liver were also elevated in the supplemented samples when compared to the control group. A significant effect of time was observed for all tested parameters (pH, color attributes, Mb forms, the antioxidant activity, lipid oxidation) except for the Mb content. For the stored samples, only TBARSs (thiobarbituric acid reagent substances) were affected by the diet. The slope of the plot for TBARS changes with time was significantly different between the control and treated groups (p = 0.017), which indicated a significant effect of dietary supplementation. A higher rate of lipid oxidation was observed in the control samples.

Effects of Trace Mineral Source on Growth Performance, Antioxidant Activity, and Meat Quality of Pigs Fed an Oxidized Soy Oil Supplemented Diet

This study investigates the effects of oil quality and trace mineral source on the growth performance, antioxidant activity, and meat quality of growing-finishing pigs. A total of 180 crossbred pigs (Duroc × Landrace × Large White [64.4 ± 1.95]) were randomly allocated five dietary treatments based on body weight (BW) and sex in a 30 d trial. Pigs were fed five diets: (i) fresh soy oil + inorganic trace minerals (ITMs) + inorganic selenium (FISI), (ii) oxidized soy oil + ITMs + inorganic selenium (OISI), (iii) fresh soy oil + ITMs + selenium yeast (FISY), (iv) oxidized soy oil + ITMs + selenium yeast (OISY), and (v) oxidized soy oil + organic trace minerals (OTMs) + selenium yeast (OOSY). Each dietary treatment included six replicates and six pigs per replicate (three barrows and three gilts). Feeding OISI resulted in lower average daily gain (ADG) and dressing percentage (p < 0.05). The OOSY group had a higher dressing percentage and activities of serum CAT and GSH-Px in growing-finishing pigs (p < 0.05). In addition, the relative abundance of Campylobacterota in the colonic digesta varied with the quality of soy oil and source of trace minerals (p < 0.05), but no significant differences in short-chain fatty acid concentrations were observed among all dietary groups. In conclusion, adding oxidized soy oil to the diet negatively impacted the ADG and dressing percentage of growing-finishing pigs, and replacing ITMs with OTMs and SY alleviated these negative impacts. A combination of OTMs and SY can support antioxidant capacity to mitigate the negative impacts of oxidized oil on the growth performance and dressing percentage of growing-finishing pigs.

Integrated Chemometrics and Data-Independent Acquisition Proteomics for the Discovery of Meat Authenticity Biomarkers: A Study on Early Post-Mortem Pectoralis major Muscle Proteomes of Ross 308 and Ranger Classic Chicken Produced by Organic versus Antibiotic-Free Farming Systems

Many factors, such as the farming systems and preslaughter rearing practices, can influence the physiological and metabolic functions of poultry with consequent effects on poultry meat quality. In this trial, label-free shotgun proteomics was used to analyze the early post-mortem Pectoralis major muscle proteomes of Ross 308 and Ranger Classic chicken strains raised under two divergent farming systems these being organic and antibiotic-free. The combination of chemometrics using partial-least-square discriminant analysis (PLS-DA) and shotgun proteomics allowed clear discrimination between the different groups. Chicken strains were discriminated by differences in the abundance of 73 and 62 proteins within the antibiotic-free and organic farming systems, respectively. The abundances of 71 and 52 proteins were impacted by the farming system within the Ross 308 and Ranger Classic chicken strains, respectively. The analyses allowed for the proposal of several putative biomarkers of meat authenticity, which were found to be related to muscle structure and energy metabolism pathways. This study is a significant step forward in elucidating the potential of proteomics profiling and chemometrics in chicken meat, which may provide opportunities for the efficient assessment of chicken authenticity.

Thermoforming Vacuum Packaging Influences Fresh Pork Loin Chop Characteristics

The storage duration of fresh meat products is a contributing factor leading to increased waste and loss at the retail counter. Losses of fresh pork can be linked to packaging methods that do not protect the attributes of color, taste, and odors consumers use in determining wholesome meat. Boneless pork loins (N = 63) were fabricated into 2.54-cm-thick chops and assigned to one of three vacuum treatments (VacA, VacB, VacC) or a fourth polyvinyl chloride overwrap (PVC) treatment to assess objective fresh color, cook loss, Warner-Bratzler shear force (WBSF), and lipid oxidation. Pork chops (n = 882) were evaluated at 5-day intervals (D 0, 5, 10, 15) in a randomized complete block design. Pork chop surface color was lighter (L*; p < 0.0001) when stored in a vacuum compared to PVC-packaged loin chops, regardless of storage duration. Redness (a*) values were greater (p < 0.0001) for loin chops stored in PVC than all other vacuum packaging treatments throughout the entire 15-day display period. Relative values for chroma on PVC-packaged loin chops were greater (p < 0.0001) throughout the simulated retail display period. An interaction of day and packaging treatment (p < 0.0343) occurred for WBSF. Lipid oxidation for pork chops packaged using PVC was significantly greater (p < 0.0001) from Day 10 through the completion of the storage period. Results indicate that vacuum packaging limits the deterioration of fresh pork loin chops, whereas traditional overwrapping expedites the color and lipid oxidation during refrigerated storage.

Animal board invited review: Heritability of nitrogen use efficiency in fattening pigs: Current state and possible directions

Pork, an important component of human nutrition worldwide, contributes considerably to anthropogenic nitrogen and greenhouse gas emissions. Reducing the environmental impact of pig production is therefore essential. This can be achieved through system-level strategies, such as optimising resource use, improving manure management and recycling leftovers from human food production, and at the individual animal level by maintaining pig health and fine-tuning dietary protein levels to individual requirements. Breeding, coupled with nutritional strategies, offers a lasting solution to improve nitrogen use efficiency (NUE) - the ratio of nitrogen retained in the body to nitrogen ingested. With a heritability as high as 0.54, incorporating NUE into breeding programmes appears promising. Nitrogen use efficiency involves multiple tissues and metabolic processes, and is influenced by the environment and individual animal characteristics, including its genetic background. Heritable genetic variation in NUE may therefore occur in many different processes, including the central nervous regulation of feed intake, the endocrine system, the gastrointestinal tract where digestion and absorption take place, and the composition of the gut microbiome. An animal's postabsorptive protein metabolism might also harbour important genetic variation, especially in the maintenance requirements of tissues and organs. Precise phenotyping, although challenging and costly, is essential for successful breeding. Various measurement techniques, such as imaging techniques and mechanistic models, are being explored for their potential in genetic analysis. Despite the difficulties in phenotyping, some studies have estimated the heritability and genetic correlations of NUE. These studies suggest that direct selection for NUE is more effective than indirect methods through feed efficiency. The complexity of NUE indicates a polygenic trait architecture, which has been confirmed by genome-wide association studies that have been unable to identify significant quantitative trait loci. Building sufficiently large reference populations to train genomic prediction models is an important next step. However, this will require the development of truly high-throughput phenotyping methods. In conclusion, breeding pigs with higher NUE is both feasible and necessary but will require increased efforts in high-throughput phenotyping and improved genome annotation.

Impact of the leptin receptor gene on pig performance and quality traits

The recessive T allele of the missense polymorphism rs709596309 C > T of the leptin receptor gene is associated with intramuscular fat. However, its overall impact on pork production is still partial. In this work, we investigated the all-round effects of the TT genotype on lean growth efficiency and carcass, meat and fat quality using data from an experiment that compared the performance of 48 TT and 48 C- (24 CT and 24 CC) Duroc barrows. The TT pigs were less efficient for lean growth than the C- pigs. Although heavier, their carcasses had less lean content, were shorter and had lighter loins. Apart from increasing marbling and saturated fatty acid content, changes caused by the TT genotype in meat and fat quality are likely not enough to be perceived by consumers. The effect on visual marbling score exceeded that on intramuscular fat content, which suggests a direct influence of the T allele on the pattern of fat distribution in muscle. With current low-protein diets, the T allele is expected to be cost-effective only in niche markets where a very high level of marbling is critical.

Data-independent acquisition-based SWATH-MS proteomics profiling to decipher the impact of farming system and chicken strain and discovery of biomarkers of authenticity in organic versus antibiotic-free chicken meat

In the literature, there is a paucity of methods and tools that allow the identification of biomarkers of authenticity to discriminate organic and non-organic chicken meat products. Shotgun proteomics is a powerful tool that allows the investigation of the entire proteome of a muscle and/or meat sample. In this study, a shotgun proteomics approach using Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) has been applied for the first time to characterize and identify candidate protein biomarkers of authenticity in post-mortem chicken Pectoralis major muscles produced under organic and non-organic farming systems (antibiotic-free). The proteomics characterization was further performed within two chicken strains, these being Ross 308 and Ranger Classic, which differ in their growth rate. From the candidate protein biomarkers, the bioinformatics enrichment analyses revealed significant differences in the muscle proteome between the two chicken strains, which may be related to their genetic background and rearing conditions. The results further provided novel insights on the potential interconnected pathways at interplay that are associated with the differences as a consequence of farming system of chicken strain, such as muscle contraction and energy metabolism. This study could pave the way to more in-depth investigations in proteomics applications to assess chicken meat authenticity and better understand the impact of farming systems on the chicken muscle and meat quality.

Correlation Analysis between Volatile Compounds and Quality Attributes in Pork Tenderloin in Response to Different Stir-Frying Processes

Volatile compounds and physicochemical properties of meat are significantly changed by cooking processes. This study explored the influence of different stir-frying temperatures and times on the dynamic changes of the physicochemical characteristics and volatiles of pork tenderloin and determined the correlation between them. Results showed that time played more of a role than temperature. At the same temperature, the water content decreased (p < 0.05) and the cooking loss increased (p < 0.05) with stir-frying time extending. The L* value and the b* value showed first an increasing and then decreasing trend (p < 0.05), while the a* value significantly increased (p < 0.05). The higher the cooking temperature of sample, the faster the indexes changed. In stir-fried samples, 50 volatiles were identified. Correlation analysis showed that among the quality attributes, b* value and water content had the strongest impact on volatiles. The water content was negatively correlated with most of the compounds attributed to the desired aroma of stir-fried samples, while the correlation between the b* value and these volatiles was positive. Hence, changes in the types and contents of volatiles in stir-fried pork tenderloin could be predicted by detection of b* value and water content.

Highly Sensitive Immunochromatographic Detection of Porcine Myoglobin as Biomarker for Meat Authentication Using Prussian Blue Nanozyme

This study was aimed at the sensitive immunodetection of porcine myoglobin (MG) as a species-specific biomarker in meat products. The enhanced lateral flow immunoassay (LFIA) was created in the sandwich format using monoclonal antibodies (Mab) with specificity to porcine MG and labeled by Prussian blue nanoparticles (PBNPs) as peroxidase-mimicking nanozymes. Signal amplification was provided by the colored product of oxidation catalyzed by the PBNPs. Several Mab-PBNP conjugates with different antibody loads were synthesized; the one that provided the best analytical characteristics of the LFIA was selected. Advanced optimization of the test system was carried out. As a result, the visual limit of detection (LOD) of MG was 1.5 ng/mL. Involvement of the catalytic nanozyme properties allowed the LOD to be decreased by ~9 times in comparison to the LFIA based on gold nanomarkers, and by ~27 times compared to the LFIA based on PBNP coloration. The assay time was 30 min, including catalytic enhancement. A simple technique of meat sample pre-treatment aimed at effective MG extraction and matrix disposal was proposed. The specificity of the LFIA towards the pork meat was demonstrated. The applicability of the created test system was shown by testing extracts obtained from finished meat products.