Meat Tenderness Research Articles

Effect of ultrasonic pretreatment with synergistic microbial fermentation on tenderness and flavor of air-dried duck under low nitrite process

The tenderness and flavor of meat products are critical factors influencing consumers' purchasing decisions. This study investigated the effects of ultrasonic pretreatment with synergistic microbial strain fermentation on tenderness and flavor of air-dried duck under low nitrite process. The results demonstrated that ultrasonic pretreatment combined with microbial strain fermentation improved water retention and tenderness of duck meat by disrupting the muscle microstructure, increasing muscle fiber spacing, and facilitating water migration and distribution. This primarily concerns the cavitation and mechanical effects of ultrasound and the role of lactic acid bacteria and yeasts in muscle protein hydrolysis. A total of 34 and 55 volatile flavor compounds were detected by HS-SPME-GC–MS and GC-IMS, respectively. The results indicated that acetaldehyde (stimulating, fruity, green apple), ethyl acetate (sweet, fruity, pineapple), and 3-hydroxy-2-butanone (sweet, creamy) were responsible for the improved flavor during this process, which was primarily related to the increased activity of neutral lipase (0.38 U/g protein), acidic lipase (0.48 U/g protein), and phospholipase (0.09 U/g protein). This study provides valuable insights into the synergistic effects of ultrasonic pretreatment and microbial co-fermentation, offering a theoretical basis for optimizing air-dried duck production and enhancing flavor quality.

Effects of aging methods combined with enzyme treatments on the quality parameters of beef striploins

The objective of this study was to evaluate the combined effects of different enzyme (papain, bromelain and fungal protease) treatments and aging methods (dry and wet aging) on physico-chemical and microbiological parameters, lipid oxidation, sarcomere length, colour, shear force and sensory attributes of beef striploins during 28-day aging period. For this purpose, Longissimus lumborum muscles (n=24, 12 carcasses) at 24h postmortem were subjected to dry (2±1°C, 75% relative humidity and 2 m/s air-flow) and wet (vacuum-packaged, 2±1°C) aging methods after enzyme treatments. The microbial growth (P < 0.05) and lipid oxidation (P < 0.001) in wet-aged beef were lower than dry-aged beef, and a decrease in those treated with fungal protease was observed (P < 0.05), while an increase in sarcomere length and water holding capacity, and a decrease in cooking losses were provided with dry aging (P < 0.001). Dry aging combined with papain enzyme enhanced and accelerated meat tenderization in a reduced aging time (P < 0.001), whereas an improvement in flavour and aroma was achieved with bromelain and fungal protease treatments. Surface colour of dry and wet-aged beef showed significant differences during aging period (P < 0.05), while lower b*, h* values and metmyoglobin content were recorded in enzyme-treated striploins. Consequently, combined usage of aging methods with enzyme treatments can be prefered as an effective application to improve the tenderness and palatability of beef with accelerated aging period, and provides an opportunity for meat industry to supply value adding beef in a shorter time.

Review of hemp components as functional feed and food ingredients: impact on animal product quality traits and nutritional value

This review examined the potential of hemp components as functional feed and food ingredients, focusing on their impact on the quality and nutritional value of animal products. Following hemp legalization, there was growing interest in its potential to enhance animal diets and processed animal products due to its rich nutritional profile, including high levels of polyunsaturated fatty acids (PUFA), essential amino acids, and fibre. Incorporating hemp components into feed for monogastric animals, particularly poultry, improved lipid stability, sensory attributes, and the fatty acid composition of meat and eggs. Hemp supplementation for ruminants, especially in goats, increased PUFA and conjugated linoleic acid (CLA) content in milk, improved meat tenderness, and enhanced oxidative stability. However, research on hemp supplementation for pigs and beef remained limited, indicating the need for further exploration of these species. Hemp cake, rich in protein, fibre, and essential fatty acids, was the most widely used hemp component due to its economic viability, nutritional benefits, and sustainability, contributing to improved meat and milk quality. Regulatory concerns about the transfer of tetrahydrocannabinol (THC) residues in the produced animal products restricted the use of hemp biomass. In processed animal products, hemp components were studied for their potential to enhance nutritional value, replace animal fats, and serve as natural preservatives. Although they improved the fatty acid profile and antioxidant properties of meat products, challenges such as textural changes and increased lipid oxidation needed to be addressed for optimal use. Limited studies on dairy products indicated promising nutritional enhancements, but textural issues could impact consumer acceptance. In conclusion, hemp components show significant potential for improving the quality and nutritional value of animal products. Further research is necessary to address regulatory, sensory, and formulation challenges and to expand their application across different animal species and processed animal products.

Effect of precursor amino acids for carnosine synthesis on breast fiber microstructures and myofiber differentiation-related gene expression in slow-growing chicken.

The effects of carnosine synthesis on the structural and microstructural determinants of meat quality have not been studied to date. Therefore, this study aimed to investigate the effect of supplementation with carnosine synthesis precursors on the characteristics and microstructure of breast muscle fibers in slow-growing Korat chickens (KR). Slow-growing KR were fed a non-supplemented commercial diet (control group) or a commercial diet supplemented with 1.0% β-alanine, 0.5% L-histidine, or a combination of both 1.0% β-alanine and 0.5% L-histidine. At 10 weeks, KR were slaughtered, and the breast muscle was collected. Samples were fixed and extracted to study the microstructure, fat level, and porosity of the meat using X-ray and scanning electron microscopy, and real-time polymerase chain reaction was performed to analyze the expression of genes related to myofiber differentiation. L-histidine supplementation significantly altered myofiber diameter and muscle fiber density and compactness by regulating muscle fiber-type differentiation via carnosine synthase (CARNS1) and myocyte enhancer factor 2C expression, as well as myogenic differentiation antigen and myogenic regulatory factor 5 expression. While excess L-histidine potentially stimulated CARNS1 to modify muscle fiber arrangement and tenderness in breast meat, dietary β-alanine supplementation alone or in combination with L-histidine supplementation induced a relatively less remarkable but not significant (p<0.05) effect on the breast meat characteristics studied. Interestingly, the combination of β-alanine and L-histidine supplementation had no effect on meat microstructure, meat porosity, and fat content in comparison with the control group. Thus, this combination had the best selectivity for improving meat quality. However, further studies are required to clarify the effects of carnosine levels on meat processing.

Mimicking Mechanics: A Comparison of Meat and Meat Analogs.

The texture of meat is one of the most important features to mimic when developing meat analogs. Both protein source and processing method impact the texture of the final product. We can distinguish three types of mechanical tests to quantify the textural differences between meat and meat analogs: puncture type, rheological torsion tests, and classical mechanical tests of tension, compression, and bending. Here, we compile the shear force and stiffness values of whole and comminuted meats and meat analogs from the two most popular tests for meat, the Warner-Bratzler shear test and the double-compression texture profile analysis. Our results suggest that, with the right fine-tuning, today's meat analogs are well capable of mimicking the mechanics of real meat. While Warner-Bratzler shear tests and texture profile analysis provide valuable information about the tenderness and sensory perception of meat, both tests suffer from a lack of standardization, which limits cross-study comparisons. Here, we provide guidelines to standardize meat testing and report meat stiffness as the single most informative mechanical parameter. Collecting big standardized data and sharing them with the community at large could empower researchers to harness the power of generative artificial intelligence to inform the systematic development of meat analogs with desired mechanical properties and functions, taste, and sensory perception.

Copy Number Variation and Selection Signal: Exploring the Domestication History and Phenotype Differences Between Duroc and the Chinese Native Ningxiang Pigs.

The Ningxiang pig, one of the well-known Chinese native pig breeds, has the advantages of tender meat, high intramuscular fat (IMF) content, and roughage tolerance, compared to the commercial lean pig breeds. The genetic basis for complex traits in Ningxiang pigs has been previously studied through other genetic markers, such as Single Nucleotide Polymorphism (SNP), while the characteristics of copy number variation (CNV) and the selection signal have not been investigated yet. In this study, GGP 50 k genotyping data of 2242 Ningxiang pigs (NX) and 1137 Duroc pigs (Duroc) were involved in CNV atlas construction and selection signals identification. Annotations of genes and quantitative trait locus (QTLs) were performed on the target candidate regions, as follows: (1) 162 CNVs were detected in Ningxiang pigs, while 326 CNVs were detected in Duroc pigs, and there are 21 copy number variation regions (CNVRs) shared between them; (2) The CNVRs of Duroc are more abundant, with 192 CNVRs, accounting for 1.61% of the entire genome, while those of Ningxiang pigs only have 98 CNVRs, accounting for 0.49%; (3) The QTLs annotated on CNVs and selected regions of Ningxiang pigs were mainly associated with meat quality and fertility. In contrast, the Duroc QTLs' notes relate primarily to the carcass and immunity, and explain why they have a higher slaughter rate and immunity; (4) There is a presence of high-frequency acquired CNVs, specifically in Ningxiang pigs, with 24 genes significantly enriched in the sensory receptor-related pathway in this region; (5) Based on the CNVs atlas, candidate genes such as 3 inositol 1,4,5-triphosphate receptor, type 3 (ITPR3), forkhead box protein K2 (FOXK2), G-protein coupled estrogen receptor 1 (GPER1), Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), triosephosphate isomerase 1 (TPI1), and other candidate genes related to fat deposition and differentiation were screened. In general, this study improved our knowledge about copy number variation and selection signal information of Ningxiang pigs, which can not only further explain the genetic differences between Chinese native and Western commercial pig breeds, but also provide new materials for the analysis of the genetic basis of complex traits.

Evaluation of the Physicochemical Attributes of Beef, Chicken, and Pork Muscles Injected with Microbial Proteases for Designing Senior-Friendly Processed Meat Products.

In developed countries, the growing elderly population has increased the demand for senior-friendly processed meat products. This study investigated the effects of four commercial microbial proteases (Alcalase, Flavourzyme, Neutrase, and Protamex) on the general physicochemical attributes of beef top round, chicken breast, and pork loin, which are lean muscle cuts suitable for developing senior-friendly meat products. Muscle samples were injected with microbial protease solutions (0.7% and 1.2% (w/w)), cooked, and used for analysis. The microbial protease injection significantly reduced the hardness of cooked muscles. Despite the evident degradation of the myosin heavy chain in Alcalase treatment, the lowest hardness values were observed in Protamex-treated samples, suggesting that myosin degradation alone does not fully account for tenderness improvement. Unfortunately, microbial protease treatments increased cooking loss in beef and chicken muscles (p < 0.05). The surface color characteristics, including redness and yellowness, remained unaffected by the enzymatic treatments, supporting the practical use of these proteases for meat tenderization without inducing color defects. While microbial proteases demonstrate potential for improving meat tenderness, future research should focus on mitigating cooking loss and ensuring desirable taste and flavor for the commercial production of senior-friendly processed meat products using the microbial proteases.

Dietary Pleurotus citrinopileatus Polysaccharide Improves Growth Performance and Meat Quality Associated with Alterations of Gut Microbiota in Arbor Acre Broilers.

Adding edible fungal polysaccharides to animal diets improves growth performance, meat quality, intestinal health, and immunity without adverse effects. This study aimed to evaluate the impact of Pleurotus citrinopileatus polysaccharide (PCP, including PCP250, PCP500, PCP750, and PCP1000 mg/kg) on the growth performance, meat quality, and microbial composition of Arbor Acre (AA) broilers (total 180) by metabolomics and high-throughput sequencing. The results showed that adding PCP enhanced chicken meat tenderness, redness (a*), and water retention and raised essential amino acids and flavor amino acids (such as umami and sweet amino acids) content. The metabolomics revealed that IMP, creatine, betaine, sarcosine, and taurine were related to improving meat quality in broilers by PCP addition. In addition, amino acid, purine, and lipid metabolism were the main metabolic pathways. Moreover, PCP could regulate muscle metabolism by increasing the relative abundance of Lachnospiraceae and Lactobacillus and the content of short-chain fatty acids (SCFAs). Therefore, PCP may become a promising new dietary supplement in the future, which may improve the yield and quality of broiler chickens.

Type I and III collagen contents and μ-calpain autolysis as a function of dry ageing time for eight different muscles from Hanwoo cattle.

Type I and III collagen content exert contrasting influences on meat tenderness. μ-calpain autolysis has shown a correlation with beef tenderness. Thus, the study was designed to determine the changes in these proteins. Three hundred twenty-four Hanwoo cattle, including cows and steers, and eight muscles were evaluated for proteolysis during dry ageing period. The ratios of type I and III collagen were determined by densitometric scans of bands resolved by SDS-PAGE, and μ-calpain activity was determined using casein zymography. Proteins involved in proteolysis were analysed by LC-MS/MS. The ratio of type I and III collagen in every muscle showed a significant difference with increasing ageing times (p < 0.05). In steers, the ratio decreased with increased ageing time, and in cows, except for BF and DP muscles, a similar decreasing trend was observed. Significant differences in the ratio of type I and III collagen were found between different muscles of cows at the same ageing time (p < 0.05), but no significant differences were found in steer muscles at the same ageing time (p > 0.05). Casein zymogram results showed an inverse relationship between pH values and μ-calpain autolysis in every muscle. A significant reduction in μ-calpain activity was observed in all muscles with extended ageing times, while the rate of autolysis differed greatly (p < 0.05) between muscles at the same ageing time. Interestingly, electropherogram analysis showed that cow muscles had a higher μ-calpain activity than steer muscles. Ageing time significantly influenced proteolysis, with 24 proteins showing marked changes and being identified. The ageing times significantly affect the ratio of type I and III collagen, which coincided with the rate of μ-calpain autolysis in steers. The ratio of type I and III collagen had a significant changes during the ageing period from cows, which may be related to the amount of collagen cross-linking.

CARCASS CHARACTERIZATION AND PHYSICAL PROPERTIESOF KAMPUNG CHICKENS STRAIN OF SENSI-1 AGRINAKMEAT WITH FERMENTED CORN STRAW SUBSTITUTION FEEDING

Fermentation of corn straw using Trichoderma viridecan produce enzymes that decompose crude fiber and make palatable fermented feed products because of their specific fragrance.This research was aimed to determine the carcass characteristics and physical properties of kampong chicken meat fed with fermented corn straw as a substitute for rice bran. Feedquality affects slaughter weight,weightand percentageof carcass, and meatphysical quality. In this study, 250 kampongchickens strainof SenSi-1 Agrinakwere used, which were fed rice bran (P0) with fermented corn straw (JJF). The treatment as follows: 100% P0 (R0); 95 % P0 + 5 % JJF (R1); 90 % P0 + 10 % JJF (R2); 85 % P0 + 15 % JJF (R3); 80 % P0 + 20 % JJF (R4) with six repetitions. The parameters observedconsist of quality of carcass and quality of meat. Quality of carcass includesweight,percentage, andparts percentageof carcass. Physical qualityof meatincludeswater holding capacity, cooking loss, color, textureandmeatmicrostructur. Based on the results,the subtitutionof rice bran with fermented corn straw in kampongchicken feed has a very significant effect (p&lt;0.01) on carcass quality and significant effect (p&lt;0.05) onmeat quality. The microstructure of kampongchicken meat shows the presence of coarse parts and large cavities so that it supports physical resistance as seen in the water binding capacity and texture of meat tenderness. It can be concluded thatfermented corn straw could be used in the kampongchicken feed up to 10%

The correlation between Smac, IAPs and mitochondrial apoptosis, muscle tenderness during postmortem aging of Oula Tibetan sheep meat

Oula Tibetan sheep meat has rich nutritional value but relatively poor tenderness. Recently, apoptosis of muscle cells has gradually become a research hotspot for improving meat tenderness during postmortem aging. Smac can promote the decrease of IAPs expression in tumor cells, thereby inducing mitochondrial apoptosis. However, the relationship between Smac, IAPs and mitochondrial apoptosis, muscle tenderness during postmortem meat aging is still unclear. Thus, the aim of this work was to explore the relationship between Smac, IAPs and mitochondrial apoptosis as well as muscle tenderness during postmortem meat aging. Smac concentration, IAPs concentration, pH value, ATP content, SDH activity, MPTP opening degree, MMP, caspase-3/9 activity, apoptotic rate, MFI and shear force value of Oula Tibetan sheep meat were measured at different aging times and correlation analysis was performed. Correlation analysis revealed that Smac, IAPs were markedly related to mitochondrial apoptosis and muscle tenderness during postmortem aging of Tibetan sheep meat. The results suggest that Smac may regulate IAPs to promote mitochondrial apoptosis and muscle tenderization in Oula Tibetan sheep meat during postmortem aging.

Long non-coding RNA (LncRNA) and epigenetic factors: their role in regulating the adipocytes in bovine.

Investigating the involvement of long non-coding RNAs (lncRNAs) and epigenetic processes in bovine adipocytes can provide valuable new insights into controlling adipogenesis in livestock. Long non-coding RNAs have been associated with forming chromatin loops that facilitate enhancer-promoter interactions during adipogenesis, as well as regulating important adipogenic transcription factors like C/EBPα and PPARγ. They significantly influence gene expression regulation at the post-transcriptional level and are extensively researched for their diverse roles in cellular functions. Epigenetic modifications such as chromatin reorganization, histone alterations, and DNA methylation subsequently affect the activation of genes related to adipogenesis and the progression of adipocyte differentiation. By investigating how fat deposition is epigenetically regulated in beef cattle, scientists aim to unravel molecular mechanisms, identify key regulatory genes and pathways, and develop targeted strategies for modifying fat deposition to enhance desirable traits such as marbling and meat tenderness. This review paper delves into lncRNAs and epigenetic factors and their role in regulating bovine adipocytes while focusing on their potential as targets for genetic improvement to increase production efficiency. Recent genomics advancements, including molecular markers and genetic variations, can boost animal productivity, meeting global demands for high-quality meat products. This review establishes a foundation for future research on understanding regulatory networks linked to lncRNAs and epigenetic changes, contributing to both scholarly knowledge advancement and practical applications within animal agriculture.

Muscle Proteins, Technological Properties, and Free Amino Acids of Epaxial Muscle Collected from Asian Seabass (Lates calcarifer) at Different Postmortem Durations

The aim of this study was to compare the changes in the epaxial muscle proteins of Asian seabass at two different postmortem durations. The epaxial muscles of Asian seabass were collected 1 h or 24 h postmortem (PM). Whole, ungutted fish were stored in an ice box, with the ice refilled every two hours. The results show significant increases in the MFI values and the contents of solubilized sarcoplasmic proteins, with a molecular weight of proteins of 47 kDa in the 24 h PM samples (p &lt; 0.05). Myofibrillar and alkaline-soluble proteins in the epaxial muscle remained intact 24 h postmortem. Compared with the 1 h PM samples, the 24 h PM meat exhibited lower degrees of expressible water and hardness (p &lt; 0.05), indicating superior water-holding capacity and meat tenderness. However, no differences in springiness or cohesiveness of the cooked meat were observed. Free L-glutamic acid, known as an umami-tasting amino acid, was significantly increased upon the extension of postmortem duration, and its level was above the taste threshold concentration. Overall, the findings indicated that the 24 h PM epaxial muscle of Asian seabass exhibited superior technological properties, along with higher contents of taste-related amino acids.

Genetic diversity and polymorphism of genes associated with meat quality and growth traits of A Luoi Yellow cattle in Vietnam

Background and Aim: A Luoi Yellow cattle is an indigenous cattle breed that is raised in the A Luoi District, Vietnam, characterized by its small body size, high adaptability, and meat quality favored by domestic consumers. Marker-assisted selection is an effective approach for improving breeding genetics and sustainably developing livestock production. Therefore, this study aimed to investigate the genetic diversity and polymorphism of genes associated with meat quality and productivity in the A Luoi Yellow cattle population with the goal of future breeding selection and sustainable development of the A Luoi Yellow beef brand. Materials and Methods: In this study, we genotyped six functional genes, including Leptin (LEP), Calpastatin (CAST), Calpain 1, pleomorphic adenoma gene 1, Sirtuin 1, and Sirtuin 2 (SIRT2), involved in meat quality and growth traits using polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphis. We also investigated mitochondrial DNA (mtDNA) and the Y chromosome-specific gene on the Y chromosome to elucidate the genetic diversity and paternal and maternal origin of the A Luoi Yellow cattle using Sanger sequencing. Results: The results showed that A Luoi yellow cattle have Bos indicus origin from both paternal and maternal lineages. By mtDNA analysis, we identified two new haplotypes of the I1 haplogroup that were not previously detected. The genotyping of the six functional genes indicated that A Luoi Yellow cattle carry favorable alleles that increase meat tenderness and body size, with frequencies of 0.02–0.40. In particular, the presence of desirable homozygous genotypes of the CAST, LEP, and SIRT2 genes will be important for the future selection of animals based on their potential performance in meat quality and productivity. Conclusion: The findings of this study is useful for the future breeding and sustainable development of A Luoi Yellow cattle. Keywords: A Luoi yellow cattle, growth trait, indels, meat tenderness, single nucleotide polymorphisms.

Differentiated texture and lipid-lowering effect of cooked pork belly by different cooking regimes: insights from myofibrillar protein aggregation and dissociation, micromorphology

The effects of traditional flame stewing (TFS), commercial pressure cooking (PC), and sous-vide cooking (SVC) on the texture of pork belly and the underlying mechanism were investigated. SVC treatment at a low temperature (60 °C) achieved weaker oxidation of sulfhydryl groups, lower α-helical loss, higher surface hydrophobicity, and actomyosin dissociation, which reduced the shrinkage of myofibrils and loss of immobilized water, thus contributed to a tender meat. However, the protein aggregation predominated without actomyosin dissociation during PC treatment, causing the toughening of meat. TFS and PC intensified the atrophy of adipocytes and damage of cell membranes, which helped for the softening of adipose tissue and achieved 13.82% and 17.62 % lipid loss, respectively, and contributed to a higher ratio of polyunsaturated fatty acids to saturated fatty acids (0.45–0.46) than SVC (0.34). Comparisons showed that TFS was a more suitable method to prepare cooked pork belly with tender and juicy texture, low lipid content, and high ratio of polyunsaturated fatty acids to saturated fatty acids. This study offered new insights into how cooking regimes affect the texture and lipid-lowering effects of stewed pork.

Analysis of Consumer Preferences and Satisfaction with Local Chicken Meat in Bandung City Traditional Markets (Survey of Consumers at Cibogo Market, Sukajadi)

ABSTRACT. The demand for local chicken meat in Bandung city has been decreasing over the last five years. Changes in demand for a product can be influenced by consumer preferences and satisfaction. This research was conducted to determine consumer preferences based on the attributes inherent in local chicken meat and the level of consumer satisfaction with local chicken meat. The research location was at Cibogo Market, Sukajadi District, Bandung City. Primary data was obtained from interviews with 97 local chicken meat consumers (as respondents) and secondary data was from the journals and articles research, internet, and related instance. The data analysis method used is Importance Performance Analysis (IPA) to determine preferences and Customer Satisfaction Index (CSI) to determine the level of consumer satisfaction. The results of the research showed that consumer preferences for local chicken meat at Cibogo Market are based on attributes that are included in the main priority class, namely meat tenderness, age, and weight of local chicken. The result of CSI calculation was 71.61% which means that consumers are satisfied. In conclusion, the performance of attributes that are a priority for consumers need to be improved in terms to increase consumer satisfaction to a very satisfied level.

Meat tenderness in Australian lamb: Data editing, environmental variation and their effects in genetic parameter estimation

Breeding for meat quality increases the value of lambs and requires reliable genetic parameters to achieve balanced genetic progress. Meat tenderness, accomplished by selecting for lower shear force, is an important eating quality trait because of its relationship with consumer satisfaction. Factors influencing shear force, include the pH and temperature decline post-mortem which can contribute towards higher shear force values and increased variation across contemporary groups. This study explored if genetic parameters for shear force change when post slaughter covariates and heterogeneous variance are corrected for, using data from 32,223 animals from different sheep breeds. Results showed that removing extreme individuals and contemporary groups with high mean shear force values reduced residual variance, followed by a smaller reduction in additive genetic variance and little effect on heritability. Results show that edited data performed better at predicting progeny performance and reduced potential bias introduced in the genetic evaluation due to data quality. The effect of including post-slaughter covariates in the genetic analysis was tested by estimating different model predictability through regression of estimated breeding values against offspring performance, showing that the model including hot carcass weight performed better followed by the one including both carcass weight and C-site fat depth. Our results highlight that historic and current in-plant recording practices do not provide the capacity to account for non-genetic factors associated with abattoir environment that might be impacting the ability to accurately calculate shear force breeding values. In that sense, genetic evaluation can be improved by applying more rigorous data editing.

Alterations of meat quality, lipid composition and flavor in breast meat of laying hens with fatty liver hemorrhagic syndrome

Fatty liver hemorrhagic syndrome (FLHS) has a high incidence rate in laying hens, and lots of FLHS-affected meat products enter the market every year. At the same time, the meat of laying hens is an important component of the human diet. However, the impact of FLHS on meat of laying hens is unknown, which could have a negative impact on consumers. To explore the effects of FLHS on chicken breast meat, a total of 36 twenty-five-wk-old Jingfen laying hens were used in the experiment. The hens were randomly divided into Control group and Model group, with 6 replicates per group and 3 hens per replicate. All chickens were raised in double-story step cages with individual pens. After a 3-wk acclimation period, the formal experiment began at 28 wk of age and lasted for 8 wk. Blood, liver, and breast meat samples were collected for the study of FLHS effects on breast meat. The impact of FLHS on meat quality was assessed by measuring indicators such as water-holding capacity and tenderness of the breast meat. Absolute quantitative lipidomics was employed to reveal the impact of FLHS on the lipid composition of chicken breast meat, and then validated by using RT-qPCR. Moreover, the volatilomics was utilized to detect changes in volatile organic compounds (VOCs) in chicken breast meat and to elucidate the resulting flavor changes. This research results showed that the meat quality of chicken breast meat decreased under FLHS, mainly manifested as reduced water holding capacity and decreased tenderness. The lipid content in the breast meat of FLHS-affected hens was significantly increased (P < 0.05). Among the affected lipids, 38 triglycerides exhibited notable elevation, possibly linked to heightened gene expression, such as lysophosphatidylcholine acyltransferase 3. The breast meat of laying hens with FLHS demonstrated an increased presence of VOCs, with 20 differential VOCs identified. Notably, 14 VOCs, particularly in 2-Undecenal, trans-Geranylacetone and ethyl nonanoate, exhibited substantial increases. These 3 VOCs had been identified as playing an important role in the formation of flavor in the breast meat of FLHS-affected laying hens. Correlation analysis suggested that the increase in these 3 VOCs might be related to the increase in lipid molecules such as phosphatidylethanolamine (38;3e) and acyl carnitine (10:3). In summary, FLHS reduced the breast meat quality of laying hens, altered its lipid profiles, and enhanced its flavor. These findings underscore the profound impact of FLHS on lipid and VOC profiles in chicken breast meat, offering valuable insights for chicken meat quality affected by FLHS.

Empowering informed choices: How computer vision can assists consumers in making decisions about meat quality

Consumers often find it challenging to assess meat sensory quality, influenced by tenderness and intramuscular fat (IMF). This study aims to develop a computer vision system (CVS) using smartphone images to classify beef and pork steak tenderness (1), predicting shear force (SF) and IMF content (2), and performing a comparative evaluation between consumer assessments and the method's output (3). The dataset consisted of 924 beef and 514 pork steaks (one image per steak). We trained a deep neural network for image classification and regression. The model achieved an F1-score of 68.1 % in classifying beef as tender. After re-categorizing the dataset into ‘tender’ and ‘tough’, the F1-score for identifying tender increased to 76.6 %. For pork loin tenderness, the model achieved an F1-score of 81.4 %. This score slightly improved to 81.5 % after re-categorization into two classes. The regression models for predicting SF and IMF in beef steak achieved an R2 value of 0.64 and 0.62, respectively, with a root mean squared prediction error (RMSEP) of 16.9 N and 2.6 %. For pork loin, the neural network predicted SF with an R2 value of 0.76 and an RMSEP of 9.15 N, and IMF with an R2 value of 0.54 and an RMSEP of 1.22 %. In 1000 paired comparisons, the neural network correctly identified the more tender beef steak in 76.5 % of cases, compared to a 46.7 % accuracy rate for human assessments. These findings suggest that CVS can provide a more objective method for evaluating meat tenderness and IMF before purchase, potentially enhancing consumer satisfaction.

Soybean oil, linoleic acid source, in lamb diets: carcass traits and meat quality.

We developed a study to determine the ideal level of inclusion of soybean oil (SBOil) in the diet without affecting the quantitative and qualitative parameters of the carcass and meat of lambs in a feedlot system; therefore, determining the ideal level of inclusion. Forty male lambs (Santa Inês breed) were used. The initial body weight and age averaged 34.88 ± 3.19kg and 5months, respectively. Experimental units (lambs) were randomly distributed in 5 different diets: inclusion levels of SBOil: 0, 30, 60, 90, and 120g/kg of dry matter (DM). The SOil inclusion reduced the DM intake (P < 0.001), Total digestible nutrients (P = 0.004), and crude protein (P < 0.001). Total weight gain (P < 0.001) decreased with the SBOil inclusion and subcutaneous fat thickness (P = 0.017) showed the same behaviour. The final body weight decreased by 42.9g/kgDM until the inclusion level of 30g/kgDM; from this level it was reduced by 145g/kgDM. The hot and cold carcass weights (P = 0.013) decreased by 36.6g/kgDM after including 30g/kgDM of SBOil. Meat physicochemical composition was not altered (P > 0.05). Lower meat tenderness values ​​were obtained at the levels of 60 and 90g/kgDM. The inclusion above 30g/kgDM decreased meat tenderness. It is concluded that soybean oil should be included up to 30g/kgDM in diets. It is important to note that with diets with 60% concentrate, SBOil levels greater than 30g/kgDM promote yield losses.