Utilizing genomic tools in breeding programs accelerates genetic progress, particularly for difficult/expensive to measure traits such as meat colour. This study aimed to estimate genetic parameters and identify genomic regions and candidate genes associated with meat colour traits in Canadian crossbred beef cattle. Heritability estimates for lightness ( L* ), chroma ( c* ), and hue angle ( Hu) were 0.44, 0.20, and 0.57, respectively. L* and Hu were highly phenotypically (0.86) and genetically (0.98) correlated. The genome-wide association revealed a total of 30, 24, and 25 SNP windows explaining >0.5% additive genetic variance for L*, c*, and Hu, respectively. These SNP windows collectively explained >20% of the genetic variance for the three meat colour traits. The genes GNPDA2, CALCRL, CALM1, KIT, PRKN, and PRKAA2 are the most promising candidates associated with L*, TEX37, ADAMTS9, PRKACB, TTLL7, TFAM, AGT, ACAT2, and PPP1R3C with c*, and MMP2, AKR1B1, AKR1B10, and CYP7A1 with Hu. These candidate genes are mainly involved in energy metabolism pathways, among which the most important are glucose, fatty, and lipid metabolism.

Steak samples were collected from the longissimus lumborum muscles of beef carcasses (Canada AA, n = 1505; Canada AAA, n = 1363) over a 3-year period. Steaks were aged for 14 d, and tenderness was determined by slice shear force (SSF). Metabolomic profiling of beef samples was performed using rapid evaporative ionization mass spectrometry (REIMS) (N = 2853). Thirteen machine learning algorithms were used to build predictive models. Data were reduced using two separate approaches, one being feature selection (FS) and the second principal component analysis followed by FS (PCA-FS). No models could predict SSF tenderness category using FS and PCA-FS datasets with higher accuracy than the no information rate (NIR; 59.5 %, P ≥ 0.05). Population mean and standard deviation (SD) were calculated to generate 4 SD categories (±2) for further predictions. No model could predict SD category using the FS dataset (NIR = 55.1 %, P > 0.05). Top accuracies for PCA-FS were generated from the Treebag and Random Forest (RF) algorithms (82.8 % and 83.0 %, respectively; NIR = 55.0 %, P < 0.001). Top accuracies for FS were generated from SVM Radial and XGBoost to predict quality grade (84.6 % and 85.3 %, respectively NIR = 52.5 %, P < 0.001). Top accuracies for PCA-FS were generated from SVM Radial and RF (82.8 % and 84.2 %, respectively, P < 0.001). A stepwise regression model was built to evaluate relationships between SSF values and spectra generated from REIMS. Selected REIMS bins accounted for 7.2 % of the variation in predicted SSF values (R2 = 0.072; P < 0.001). With more development, the RF algorithm could assist REIMS in rapid assessment of carcass quality.

Schizophrenia spectrum disorder (SSD) is a chronic neuropsychiatric illness accompanied by significant brain structural and functional abnormalities and higher rate of cardio- and cerebrovascular comorbidities. We hypothesized that genetic and environmental risk factors that led to SSD act throughout the body and demonstrated the association between lower integrity of peripheral vascular endothelium and white matter (WM) microstructure. Microvascular endothelial function was evaluated using brachial artery post-occlusive reactive hyperemia (PORH), in which endothelial responses are measured under reduced blood flow and after blood flow is restored. White matter microstructure was assessed by multi-shell diffusion tensor imaging in n = 48 healthy controls (HCs) and n = 46 SSD. Patients showed significantly lower PORH (F1,90 = 5.31, P = .02) effect and lower whole-brain fractional anisotropy (FA) values by diffusion imaging (F1,84 = 7.46, P = .008) with a group × post-occlusion time interaction effect (F3,90 = 4.58, P = .02). The PORH and whole-brain FA were significantly correlated in the full sample (r = 0.28, P = .01) and in SSD (r = 0.4, P = .008) separately, but not HC (r = 0.18, P = .28). This study demonstrated, for the first time, significantly lower integrity of vascular endothelium in participants with SSD and showed that it is associated with WM microstructural abnormalities. Together, these findings support the need for a more holistic, body-brain approach to study the pathophysiology of SSD.

Tenderness is considered a crucial attribute of postmortem meat quality, directly influencing consumers' preferences and industrial economic benefits. The degradation of myofibrillar proteins by endogenous enzymes within muscle fibers is believed to be the most effective pathway for meat tenderization. After animals are slaughtered and exsanguinated, there is a significant accumulation of reactive oxygen species (ROS), and a dramatic depletion of adenosine triphosphate (ATP) in muscle, leading to inevitable cell death. Caspases are activated in postmortem muscle cells, which disrupt the cell structure and improve meat tenderness through protein hydrolysis. In this review, we systematically summarized the three primary types of cell death studied in postmortem muscle: apoptosis, autophagy and necrosis. Furthermore, we emphasized the molecular mechanisms of apoptosis and its corresponding apoptotic pathways (mitochondrial apoptosis, death receptors, and endoplasmic reticulum stress) that affect meat tenderness during muscle conversion to meat. Additionally, factors affecting apoptosis were comprehensively discussed, such as ROS, heat shock proteins, calcium (Ca2+)/calpains, and Bcl-2 family proteins. Finally, this comprehensive review of existing research reveals that apoptosis is mainly mediated by the mitochondrial pathway. This ultimately leads to myofibrillar proteins degradation through caspase activation, improving meat tenderness. This review summarizes the research progress on postmortem muscle apoptosis and its molecular mechanisms in meat tenderization. We hope this will enhance understanding of postmortem meat tenderness and provide a theoretical basis for meat tenderization techniques development in the future.

Low-voltage electrostatic fields (LVEF) are recognized as a new technology that can improve the quality of frozen meat. To determine the extent to which LVEF assistance affects the quality of frozen pork for long-term storage, pork was frozen and stored at -18 and -38 degrees C for up to 5 months. Water-holding capacity, muscle microstructure, and protein properties were investigated after up to 5 months of frozen storage with and without LVEF assistance. In comparison to traditional -18 and -38 degrees C frozen storage, LVEF treatment inhibited water migration during frozen storage and thawing. As a result, thawing losses were reduced by 15.97% (-18 degrees C) and 3.38% (-38 degrees C) in LVEF-assisted compared to conventional freezing methods. LVEF helped to maintain the muscle fiber microstructure and reduce muscle protein denaturation by miniaturizing ice crystal formation by freezing. As a result of this study, LVEF is more suitable for freezing or short-term frozen storage, while a lower temperature plays a more significant role in long-term frozen storage.

The smoking rate is high in patients with schizophrenia. Brain stimulation targeting conventional brain circuits associated with nicotine addiction has also yielded mixed results. We aimed to identify alternative circuitries associated with nicotine addiction in both the general population and schizophrenia, and then test whether modulation of such circuitries may alter nicotine addiction behaviors in schizophrenia. In Study I of 40 schizophrenia smokers and 51 non -psychiatric smokers, cross-sectional neuroimaging analysis identified resting state functional connectivity (rsFC) between the dorsomedial prefrontal cortex (dmPFC) and multiple extended amygdala regions to be most robustly associated with nicotine addiction severity in healthy controls and schizophrenia patients (p = 0.006 to 0.07). In Study II with another 30 patient smokers, a proof -of -concept, patient- and rater -blind, randomized, sham -controlled rTMS design was used to test whether targeting the newly identified dmPFC location may causally enhance the rsFC and reduce nicotine addiction in schizophrenia. Although significant interactions were not observed, exploratory analyses showed that this dmPFC-extended amygdala rsFC was enhanced by 4 -week active 10Hz rTMS (p = 0.05) compared to baseline; the severity of nicotine addiction showed trends of reduction after 3 and 4 weeks (p <= 0.05) of active rTMS compared to sham; Increased rsFC by active rTMS predicted reduction of cigarettes/day (R = -0.56, p = 0.025 uncorrected) and morning smoking severity (R = -0.59, p = 0.016 uncorrected). These results suggest that the dmPFC-extended amygdala circuit may be linked to nicotine addiction in schizophrenia and healthy individuals, and future efforts targeting its underlying pathophysiological mechanisms may yield more effective treatment for nicotine addiction.

This study investigated how birth weight differences in piglets affected carcass and muscle fiber properties as well as meat quality at slaughter. Within litters, piglets were grouped according to their birth weight as either normal (NBW; 1.62-1.73 kg) or low (LBW; 1.18-1.29 kg). At 5 weeks of age, NBW piglets were randomly transitioned to control (C) or isocaloric high fat diets derived from non-dairy (HF), while LBW piglets were randomly transitioned to high fat diets derived from non-dairy (HF) or dairy sources (HFHD). Piglets were reared in individual pens under standardized housing and feeding conditions. Live weight was recorded weekly, and pigs were slaughtered at 12 weeks of age. Hot carcass weights, dressing percentages, lean meat yield, and primal cut proportions were determined. The m. longissimus thoracis was collected from the right side of the carcass for measurement of physical and chemical properties of meat and muscle fiber characteristics. Results indicated that LBW pigs compensated for their live weight compared to NBW pigs at 6 weeks of age. The mean muscle fiber diameter of LBW-HFHD group is significantly higher than NBW-C and NBW-HF group, and the type I muscle fiber diameter is significantly higher than NBW-C group. Dairy fat inclusion in LBW pig diet reduced carcass back fat thickness. This increased the calculated lean meat yield to be comparable to that of NBW pigs fed a commercial diet. Incorporating dairy-sourced high-fat into LBW pigs' diets appears to be an effective strategy for producing carcasses equivalent to NBW pigs.

Neuronal ceroid lipofuscinosis (NCL) is a neurodegenerative disease found in Border collie dogs, humans, and other animals. Disease gene studies in humans and animals provided candidates for the NCL gene in Border collies. A combination of linkage analysis and comparative genomics localized the gene to CFA22 in an area syntenic to HSA13q that contains the CLN5 gene responsible for the Finnish variant of human late infantile NCL. Sequencing of CLN5 revealed a nonsense mutation (Q206X) within exon 4 that correlated with NCL in Border collies. This truncation mutation should result in a protein product of a size similar to that of some mutations identified in human CLN5 and therefore the Border collie may make a good model for human NCL. A simple test was developed to enable screening of the Border collie population for carriers so the disease can be eliminated as a problem in the breed.

Genetic parameters were estimated for objective and subjective traits assessed after 3 and 29 days aging in meat samples of 1154 commercial beef cattle. Meat attributes [Warner-Bratzler shear force (WBSF), intramuscular fat (IMF), and pH] and sensory traits [flavor intensity (FI), off-flavor (OF), connective tissue (CT), overall tenderness (OT), sustained juiciness (SJ), and overall palatability (OP)] were available. The animal mixed model used included additive genetic and residual effects as random effects, contemporary group as fixed effect and genomic breed composition and slaughter age as covariates. Genetic parameters were estimated using airemlf90 software and single-step genomic BLUP. Heritability estimates for OT (3 and 29 d), OP (3 d) and OF (29 d) were of moderate magnitude ranging from 0.18 ± 0.07 to 0.31 ± 0.07. Heritabilities were negligible or of low magnitude for all other sensory traits with values ranging from 0.03 ± 0.05 to 0.14 ± 0.07. Among objectively measured traits, the estimate of heritability for meat pH was moderate at day 3 (0.20 ± 0.08) and negligible at 29 (0.00 ± 0.05). For IMF and WBSF the heritability estimates were 0.43 ± 0.09 and 0.54 ± 0.09, and 0.22 ± 0.07 and 0.19 ± 0.07 for day 3 and 29, respectively. Genetic correlations between days for each sensory trait tended to be of high and positive magnitude ranging from 0.54 ± 0.60 to 0.99 ± 0.28. Genetic and phenotypic correlations of subjectively assessed traits were consistent in direction and magnitude with WBSF (negative) and IMF (positive) suggesting that genetic selection based on objectively measured traits can be used for meat quality improvement and to increase consumer satisfaction. In addition, selection can be implemented using sensory traits collected after 3 days of aging.

The inhibition of starch digestion activities by peptides derived from camel milk proteins was deter-mined and the effect of their amino acids charge and/or hydrophobicity was assessed. Starch digestion by pancreatic and brush border enzymes was assessed in vitro with a peptide to starch ratio of 1:3 (w/w). Hydrolysed whey proteins were more inhibitory than hydrolysed casein. Successive chromatographic separation of peptides enriched positively charged peptides with hydrophobic amino acids. Whey pro-tein hydrolysate inhibited starch hydrolysis by 16%; peptide fractions recovered after CEX and HIC inhibited starch hydrolysis by 33-36%. Peptides in the active fractions were identified by LC-MS/MS and the inhibitory activity of 6 synthetic peptides was evaluated. Two of these six peptides, LALDIEIATYR and VLDELTLAR, inhibited starch hydrolysis by 34-37%. In conclusion, specific peptides that are produced before or during in vitro digestion can inhibit starch digestion and may moderate postprandial blood glucose levels in vivo.(c) 2023 Elsevier Ltd. All rights reserved.

Alternating electric field (AEF) technology was used during freezing-thawing-aging (FA) of beef aged for 0, 1, 3, 5 and 7 days. Color, lipid oxidation, purge loss, cooking loss, tenderness, and T2 relaxation time were determined for frozen-thawed-aged beef with AEF (AEF + FA) or without AEF (FA) and compared to aged only (OA) controls. FA increased purge loss, cooking loss, shear force values and lipid oxidation (P < 0.05) but decreased a* values compared with AEF + FA treatment. It also exacerbated the spaces between muscle fibers and contributed to the transformation of immobile water to free water. AEF served to maintain meat quality by reducing purge loss, cooking loss and increasing meat tenderness and maintaining color and lipid oxidation only in steak that was frozen before aging. This most likely occurred due to AEF increasing the speed of freezing and thawing and by reducing the space between muscle fibers compared to FA alone.

This study explores the influence of modified atmosphere packaging (MAP) on fresh lamb meat quality with respect to gas concentration, rigor state, and post-mortem aging time. A comparison was done for the quality characteristics of lamb Longissimus thoracis lumborum chops that had been packaged separately in air, 75%O-2 + 25%CO2 MAP or 50%O-2 + 50%CO2 MAP at 1, 6, and 24 h post-mortem and then stored for 6, 12, 24, 72, and 144 h post-mortem, and the quality of lamb chops had been evaluated at each post-mortem period separately. Chops packaged at 1 and 6 h post-mortem in MAP had reduced pH decline, less purge loss, and enhanced redness at early post-mortem storage times. Lamb color stability was evidently greater in 75%O-2 + 25%CO2 MAP than in 50%O-2 + 50%CO2 MAP during the early storage period when a* and R630/R580 were taken into account. Shear force values were lowest in lambs packaged at 1 h post-mortem with 75%O-2 + 25%CO2 MAP at 12 h post-mortem and then increased until 72 h post-mortem, suggesting that rigor has been delayed by such a high O2 MAP. Thus, fresh lamb quality was maintained most effectively when packaged at 1 h post-mortem in 75%O-2 + 25%CO2 MAP for consumption at 12 h post-mortem. The exact mechanisms and optimization of MAP based on Chinese retail conditions should be considered in future studies.Practical ApplicationIn this study, three slaughter patterns in the meat industry involving boning immediately after dressing (hot-boning) and chilling for a short period (warm-boning) or overnight (cold-boning) are considered, as well as the behavior of non-immediate consumption after purchase. Modified atmosphere packaging provides an effective preservation of early post-mortem muscles with enhanced color stability, water holding capacity, and texture during refrigerated storage. This could provide new insights into how to process lamb muscles in the early post-mortem period to improve and stabilize lamb quality.

BACKGROUND:Stress and depression have a reciprocal relationship, but the neural underpinnings of this reciprocity are unclear. We investigated neuroimaging phenotypes that facilitate the reciprocity between stress and depressive symptoms. METHODS:In total, 22 195 participants (52.0% females) from the population-based UK Biobank study completed two visits (initial visit: 2006-2010, age = 55.0 ± 7.5 [40-70] years; second visit: 2014-2019; age = 62.7 ± 7.5 [44-80] years). Structural equation modeling was used to examine the longitudinal relationship between self-report stressful life events (SLEs) and depressive symptoms. Cross-sectional data were used to examine the overlap between neuroimaging correlates of SLEs and depressive symptoms on the second visit among 138 multimodal imaging phenotypes. RESULTS:Longitudinal data were consistent with significant bidirectional causal relationship between SLEs and depressive symptoms. In cross-sectional analyses, SLEs were significantly associated with lower bilateral nucleus accumbal volume and lower fractional anisotropy of the forceps major. Depressive symptoms were significantly associated with extensive white matter hyperintensities, thinner cortex, lower subcortical volume, and white matter microstructural deficits, mainly in corticostriatal-limbic structures. Lower bilateral nucleus accumbal volume were the only imaging phenotypes with overlapping effects of depressive symptoms and SLEs (B = -0.032 to -0.023, p = 0.006-0.034). Depressive symptoms and SLEs significantly partially mediated the effects of each other on left and right nucleus accumbens volume (proportion of effects mediated = 12.7-14.3%, p < 0.001-p = 0.008). For the left nucleus accumbens, post-hoc seed-based analysis showed lower resting-state functional connectivity with the left orbitofrontal cortex (cluster size = 83 voxels, p = 5.4 × 10-5) in participants with high v. no SLEs. CONCLUSIONS:The nucleus accumbens may play a key role in the reciprocity between stress and depressive symptoms.

The tenderness of meat influences consumers' perceptions of its quality. Meat tenderness is a key quality characteristic that influences consumer satisfaction, repeat purchases, and willingness to pay higher prices for meat. Muscle fibers, connective tissues, and adipocytes are the main structural components of meat that contribute to its tenderness and texture. In the present review, we have focused on the role of connective tissue and its components in meat tenderness, specifically perimysial intramuscular connective tissue (IMCT) and its concept as an immutable "background toughness." The collagen contribution to cooked meat toughness can be altered by animal diet, compensatory growth, slaughter age, aging, and cooking. As well, progressive thickening of the perimysium leads to a progressive increase in shear force values in beef, pork, chicken, and this may occur prior to adipocyte formation as cattle finish in feedlots. Conversely, adipocyte accumulation in the perimysium can decrease cooked meat shear force, suggesting that the contribution of IMCT to meat toughness is complex and driven by both collagen structure and content. This review provides a theoretical foundation of information to modify IMCT components to improve meat tenderness.

Metabolic syndrome is a worldwide health issue. Previous research has revealed that low birth weight (LBW) swine fed a high fat (HF) diet were susceptible to insulin resistance and developed a preferential intestinal lipid absorption, hypertriglyceridemia and muscle steatosis. We hypothesized that fatty acid transporters such as CD36, FATP4 and FABP2 could potentially explain the development of these conditions. Additionally, dairy-derived fatty acids have been shown to be valid biomarkers to assess dairy intake, which can be utilized to investigate the muscle lipid deposition in LBW swine. The overall aim of this study was to delineate molecular transport candidates responsible for intestinal lipid absorption and muscle lipid deposition in LBW swine; and secondly to determine what dietary fatty acids might accumulate preferentially in pork muscle when consuming dairy products. At 5-weeks of age, normal birth weight (NBW) and LBW piglets were randomly assigned to three experimental diets: 1-chow diet, 2-HF diet or 3-isocaloric HF diet supplemented with full fat dairy products. At 12-weeks of age, piglets were euthanized, and carcass, fasting plasma, biceps femoris and jejunum mucosal scrapings were collected. Results showed that HF-fed LBW swine exhibited early sign of insulin resistance (fasting glucose, P < 0.05; fasting insulin, P = 0.091; HOMA-IR, P = 0.086) compared to NBW-Chow, which were attenuated with increased dairy intake. Muscle samples from HF-fed LBW swine contained significantly more triglyceride compared to Chow-fed NBW swine (P < 0.05). Increased dairy intake significantly increased myristic acid (C14:0) and DPA (C22:5n3) relative to HF feeding alone (P < 0.05). All HF-fed LBW swine (regardless of dairy intake) exhibited an upregulation of CD36 expression (but not FABP2) compared with NBW littermates in both small intestine and muscle (P < 0.05). Interestingly, increased dairy intake significantly increased Canadian Lean Yield percentage in LBW swine fed a HF diet (P < 0.05). Findings from this study provide evidence on the mechanistic pathway of intestinal and muscle lipid metabolism in an innovative LBW swine model. We have also revealed that increasing dairy intake can enhance the incorporation of dietary long-chain polyunsaturated fatty acids into pork, as well as increasing the predicted lean yield of the carcass.

BACKGROUND AND HYPOTHESIS:Mounting evidence supports cerebrovascular contributions to schizophrenia spectrum disorder (SSD) but with unknown mechanisms. The blood-brain barrier (BBB) is at the nexus of neural-vascular exchanges, tasked with regulating cerebral homeostasis. BBB abnormalities in SSD, if any, are likely more subtle compared to typical neurological insults and imaging measures that assess large molecule BBB leakage in major neurological events may not be sensitive enough to directly examine BBB abnormalities in SSD.STUDY DESIGN:We tested the hypothesis that neurovascular water exchange (Kw) measured by non-invasive diffusion-prepared arterial spin label MRI (n = 27 healthy controls [HC], n = 32 SSD) is impaired in SSD and associated with clinical symptoms. Peripheral vascular endothelial health was examined by brachial artery flow-mediated dilation (n = 44 HC, n = 37 SSD) to examine whether centrally measured Kw is related to endothelial functions.STUDY RESULTS:Whole-brain average Kw was significantly reduced in SSD (P = .007). Exploratory analyses demonstrated neurovascular water exchange reductions in the right parietal lobe, including the supramarginal gyrus (P = .002) and postcentral gyrus (P = .008). Reduced right superior corona radiata (P = .001) and right angular gyrus Kw (P = .006) was associated with negative symptoms. Peripheral endothelial function was also significantly reduced in SSD (P = .0001). Kw in 94% of brain regions in HC positively associated with peripheral endothelial function, which was not observed in SSD, where the correlation was inversed in 52% of brain regions.CONCLUSIONS:This study provides initial evidence of neurovascular water exchange abnormalities, which appeared clinically associated, especially with negative symptoms, in schizophrenia.

Decreased cerebral blood flow (CBF) may be an important mechanism associated with depression. In this study we aimed to determine if the association of CBF and depression is dependent on current level of depression or the tendency to experience depression over time (trait depression), and if CBF is influenced by depression-related factors such as stressful life experiences and antidepressant medication use. CBF was measured in 254 participants from the Amish Connectome Project (age 18–76, 99 men and 154 women) using arterial spin labeling. All participants underwent assessment of symptoms of depression measured with the Beck Depression Inventory and Maryland Trait and State Depression scales. Individuals diagnosed with a unipolar depressive disorder had significantly lower average gray matter CBF compared to individuals with no history of depression or to individuals with a history of depression that was in remission at time of study. Trait depression was significantly associated with lower CBF, with the associations strongest in cingulate gyrus and frontal white matter. Use of antidepressant medication and more stressful life experiences were also associated with significantly lower CBF. Resting CBF in specific brain regions is associated with trait depression, experience of stressful life events, and current antidepressant use, and may provide a valuable biomarker for further studies.

The prevalence of diet-related chronic conditions including hypertension and cardiovascular disease, and diabetes mellitus has increased worldwide. Research regarding the use of food-derived bioactive peptides as an alternative strategy to mitigate chronic diseases is on the rise. Milk is recognized as one of the main dietary protein sources for health beneficial bioactive compounds. Hundreds of in vitro studies have suggested that milk-derived bioactive peptides offer multiple biological and physiological benefits, and some but not all were confirmed in vivo with animal models for hypertension, hyperglycemia, and pathogen adhesion. However, only a limited number of health benefits have been confirmed by randomized clinical trials. This review provides an overview of the current clinical studies that target hypertension, postprandial hyperglycemic, and adhesion of enteric pathogen with bioactive peptides derived from bovine and camel milk, with a focus on the factors affecting the efficacy of orally ingested products.

Meat quality in the m. longissimus thoracis (LT) associated with decreased muscle temperature early post-mortem was investigated using ten Angus crossbred steer carcasses. LT chill rate of each carcass right side was increased by removing superficial subcutaneous fat and associated muscles. LT muscles were removed at 24 h post-mortem and divided into halves with the posterior portion analyzed immediately and the anterior portion analyzed after 14 days post-mortem ageing. Denuding the LT decreased its temperature by 2 °C at 3 h post-mortem and decreased intramuscular lactate concentration, sensory panel tenderness score, a*, b* and chroma values, and proportion of oxymyoglobin and increased proportions of metmyoglobin and deoxymyoglobin at day 2 post-mortem without affecting intramuscular pH, or cooked LT shear force. Small shifts in early post-mortem muscle temperature can alter the extent of anaerobic glycolysis, influencing early retail display color and sensory tenderness, emphasizing the importance of proper early post-mortem management of carcasses in controlling beef quality.

The current study investigates the influence of alternating electric field (AEF)-assisted freezing-thawing-aging sequence on the muscle microstructure and myofibrillar protein characteristics. Three treatments were used for longissimus dorsi (LD) muscle: only aging (OA), freezing-thawing-aging sequence (FA) and AEF-assisted freezing-thawing-aging sequence (EA). Compared with the FA and EA groups, the OA group showed considerably fewer cracks between muscle fibers and maintained the integrity of the Z-line as observed using scanning and transmission electron microscopy, respectively. Furthermore, the EA treatment effectively decreased myofibrillar fragmentation, myofibrillar protein aggregation, and protein oxidation, as shown by the myofibrillar fragmentation index, turbidity, and total sulfhydryl concentration. Analysis of surface hydrophobicity and the Fourier transform infrared, UV absorption, and fluorescence spectrums indicated that AEF minimized the alterations of protein secondary and tertiary structure alterations during aging after freezing.