Pork Muscle Research Articles

Frozen/thawed meat quality associated with muscle fiber characteristics of porcine longissimus thoracis et lumborum, psoas major, semimembranosus, and semitendinosus muscles

To evaluate the relationship between muscle fiber characteristics and the quality of frozen/thawed pork meat, four different muscles, M. longissimus thoracis et lumborum (LTL), M. psoas major (PM), M. semimembranosus (SM), and M. semitendinosus (ST), were analyzed from twenty carcasses. Meat color values (lightness, redness, yellowness, chroma, and hue) changed due to freezing/thawing in LTL, which showed larger IIAX, IIX, and IIXB fibers than found in SM (P < 0.05). SM and ST showed a significant decrease in purge loss and an increase in shear force caused by freezing/thawing (P < 0.05). Compared with LTL, SM contains more type IIXB muscle fibers and ST had larger muscle fibers I and IIA (P < 0.05). PM was the most stable of all muscles, since only its yellowness and chroma were affected by freezing/thawing (P < 0.05). These results suggest that pork muscle fiber characteristics of individual cuts must be considered to avoid quality deterioration during frozen storage.

Effect of sarcoplasmic proteins oxidation on the gel properties of myofibrillar proteins from pork muscles.

This study investigated the influence of sarcoplasmic proteins (SPs) treated by the oxidation system (0.1mmol/L FeCl3 , 0.1mmol/L ascorbic acid, and 0, 1, 5, 10mmol/L H2 O2 ) on the properties of pork myofibrillar proteins (MPs) gel. After oxidation treatment, the SPs showed an increased in carbonyl content and a decreased in total sulfhydryl content, coupled with the cross-linking of protein components by disulfide bonds and covalent bonds. The MPs gel with SPs oxidized at 1mmol/L H2 O2 exhibited the maximal strength while the minimal water holding capacity (WHC). The WHC of MPs gel was significantly decreased with increasing SPs oxidation, leading to the increase of free water and the decrease of immobilized water in the gel system. The microstructures of MPs gels with moderately (1mmol/L H2 O2 ) oxidized SPs showed a more compact and smaller pore gel network than MPs alone, suggesting adding oxidized SPs can expel water trapped in the gel. Furthermore, the environmental polarity of aliphatic C-H groups increased with SPs oxidation.

In-tube solid phase microextraction and determination of ractopamine in pork muscle samples using amide group modified polysaccharide-silica hybrid monolith as sorbent prior to HPLC analysis

A facile in-tube solid phase microextraction (in-tube SPME) procedure was developed to enrich ractopamine before HPLC-UV analysis. This was achieved by employing amide groups modified polysaccharide-silica hybrid monolith as an efficient sorbent. The monolith was synthesized by a simple reaction with agarose oxide and tetramethoxylisane, followed by the modification of amide groups via subsequent ring opening, “thiol–ene” click and dehydration reactions. Under the optimized extraction conditions, the enrichment factors for ractopamine, dopamine, clenbuterol, para-methylphenol and phenol were determined to be 50.5, 32.2, 4.8, 2.1 and 1.8, respectively. The monolithic column has ideal selectivity for ractopamine. Coupled with HPLC-UV, this method demonstrated a linearity within 2.0–800 ng/g for ractopamine with spiking in pork muscles (R2 = 0.9958). The LOD was 0.64 ng/g (S/N = 3) and recoveries ranged from 85.2 to 108.1% (n = 3). This approach provides a feasible way for analysis of trace ractopamine in biological samples.

Noninvasive calibrated tissue temperature estimation using backscattered energy of acoustic harmonics

PurposeA real-time and non-invasive thermometry technique is essential in thermal therapies to monitor and control the treatment. Ultrasound is an attractive thermometry modality due to its relatively high sensitivity to change in temperature and fast data acquisition and processing capabilities. A temperature-sensitive acoustic parameter is required for ultrasound thermometry in order to track the changes in that parameter during the treatment. Currently, the main ultrasound thermometry methods are based on variation in the attenuation coefficient, the change in backscattered energy of the signal (CBE), the backscattered radio-frequency (RF) echo-shift due to change in the speed of sound and thermal expansion of the medium, and change in the amplitudes of the acoustic harmonics. In this work, an ultrasound thermometry method based on second harmonic CBE (CBEh2) and combined fundamental and second harmonic CBE (CBEcomb) is used to produce 2D temperature maps, detect localized heated region generated by low intensity focused ultrasound (LIFU), and control temperature in the heated region. Materials and methodsEx vivo pork muscle tissue samples were exposed to localized LIFU heating source and 2D temperature maps were produced from the RF data acquired by a 4.2 MHz linear array probe using a Verasonics Vantage™ ultrasound scanner (Verasonics Inc., Redmond, WA) after the exposure. Calibrated needle thermocouples were also placed in the ex vivo tissue sample close to the LIFU focal zone for temperature calibration purposes. The estimated temperature maps were the established echo-shift technique. A tissue motion compensation algorithm was also used to reduce the susceptibility to motion artifacts. Results2D temperature maps were generated using CBE of acoustic harmonic and echo-shift techniques. The results show a direct correlation between the CBE of acoustic harmonics and focal tissue temperature for a range of temperatures from 37 °C (baseline) to 47 °C. ConclusionsThe findings of this study show that the CBE of acoustic harmonics technique can be used to noninvasively estimate temperature change in tissue in the hyperthermia temperature range.

Screening out important substances for distinguishing Chinese indigenous pork and hybrid pork and identifying different pork muscles by analyzing the fatty acid and nucleotide contents

Fatty acids and nucleotides are major contributors of pork flavor, which are key quality traits influencing consumers' preference. In this study, we investigated the contents of nucleotides (inosinic acid, inosine, and hypoxanthine) and 26 fatty acids by high-performance liquid chromatography and gas chromatography in longissimus dorsi and semimembranous muscle of four breeds (Dongbei Min pig, Beijing Black pig, Wuzhishan pig, and DLY pigs). Combining with multivariate statistics, we found significant differences in the nucleotides and fatty acids compositions among the breeds and muscles. Furthermore, the content of total unsaturated fatty acids and DHA were higher in native pigs than crossbred pigs. This study provides a theoretical basis for understanding the composition of flavor precursor substances, as well as for the identification of different muscles.

Tiny Cold Atmospheric Plasma Jet for Biomedical Applications

Conventional plasma jets for biomedical applications tend to have several drawbacks, such as high voltages, high gas delivery, large plasma probe volume, and the formation of discharge within the organ. Therefore, it is challenging to employ these jets inside a living organism’s body. Thus, we developed a single-electrode tiny plasma jet and evaluated its use for clinical biomedical applications. We investigated the effect of voltage input and flow rate on the jet length and studied the physical parameters of the plasma jet, including discharge voltage, average gas and subject temperature, and optical emissions via spectroscopy (OES). The interactions between the tiny plasma jet and five subjects (de-ionized (DI) water, metal, cardboard, pork belly, and pork muscle) were studied at distances of 10 mm and 15 mm from the jet nozzle. The results showed that the tiny plasma jet caused no damage or burning of tissues, and the ROS/RNS (reactive oxygen/nitrogen species) intensity increased when the distance was lowered from 15 mm to 10 mm. These initial observations establish the tiny plasma jet device as a potentially useful tool in clinical biomedical applications.

Fourier-transform infrared spectroscopy in a comparative study of animal and plant proteins

The method of infrared attenuated total reflection spectroscopy was used to compare proteins (sarcoplasmic, myofibrillar, stroma) contained in the pork muscle tissue, globular proteins obtained from industrially crushed flax seeds, as well as protein-polysaccharide complexes extracted from husked seed coats and whole seeds. Protein components were isolated from saline solutions by precipitation with a threefold excess of 96% ethanol and 5% trichloroacetic acid, as well as by isoelectric precipitation at pH = 4.2. It is shown that the use of different anatomical parts (core and seed coat), including crushed or whole forms and flax seed meal, under varying conditions of pre-treatment, extraction and isolation allow biologically active protein-containing products to be obtained. Such products - protein concentrates, peptide polysaccharides and protein-lipid-polysaccharide complexes with a variable composition and ratio of components - are valuable raw materials for the food industry, medicine, pharmacopoeia and cosmetology. A comparative study of the kinetics of air drying of crude plant and animal globular proteins at 20°C showed these proteins to be similar in terms of extreme changes in the spectra of light absorption curves and the intensity of the main characteristic bands upon moisture removal. Temperature changes, affecting the general appearance of light absorption spectra, lead to deformation of the Amide-I band, which carries information about the protein structure. Deformational changes may be promoted not only by differentiation of globular proteins (albumins and globulins), but also by packing of their polypeptide chains during reconstruction or formation of a new secondary structure destroyed as a result of various mechanical and chemical interventions. According to the obtained data, elevated temperatures have a significant effect on the structural transformations of both protein concentrates and protein-polysaccharide complexes, regardless of their nature.

Physico-chemical and sensory characteristics of porkloin roast cooked to three internal temperatures

The experiment was conducted to examine the effects of three cooking internal temperatures (65. 75 or 85'C) on the physical, chemical and sensory characteristics of pork. Pork muscle, Longissimus dorsi, used were collected immediately after slaughter dnd stored overnight at -18°C. Loins were removed, allowed to thaw at room temperature, and cut into fifteen chops with an average weight of 300g. The chops were randomly allocated to three internal temperatures, 65, 75 or 85°C and transferred into the oven where they were roast cooked until the desired internal temperature was reached. The cooked weight, cooking loss, Warner Bratzler shear value and proximate composition were determined on cooked pork. Sensory attributes were also assessed by a 10-member panel using a 9-point hedonic scale. The results of the study indicated that final internal cooking Temperature had no effect (P&gt;0.05) on cooking loss und shear value. No significant effect was observed on tenderness, juiciness and flavour. Overall acceptability was significantly p&lt;0.05) affected with pork loin cooked to internal temperature of 85'C most acceptable. While moisture and ash contact decreased with increased. The fat content was 101 consistent influenced. The final internal cooking temperatures had no effect on the proximate composition (P&gt;0.05) of the pork loin.

Фурье-спектроскопия саркоплазматических, миофибриллярных и соединительнотканных белков мышечной ткани свинины

Фурье-спектроскопия саркоплазматических, миофибриллярных и соединительнотканных белков мышечной ткани свинины

Pork Loin Chop Quality and Muscle Fiber Characteristics as Affected by the Direction of Cut.

In this study, the relationship between muscle fiber characteristics and meat quality of pork loin chops prepared using different directions of cut (vertical to the muscle length, M-Vertical; vertical or parallel to the muscle fiber orientation, F-Vertical or F-Parallel) was evaluated under different storage conditions (fresh, cold storage/aged, and freeze–thawed). Among the three groups, F-parallel displayed considerably larger size of muscle fibers, regardless of their type. This group also displayed an increase in discoloration in aged chops and a decrease in purge loss and tenderness than in other cut groups (p < 0.05). Freeze–thawing accelerated deterioration of meat quality, especially water-holding capacity and tenderness in all groups (p < 0.05), but was most prominent in F-Parallel. Therefore, to avoid excessive deterioration of fresh, aged, or frozen/thawed pork loin chops, it is important to consider the direction in which the chop is cut with respect to the muscle fiber orientation.

PSVIII-8 Effects of dietary L-arginine on growth performance, nutrient digestibility, and meat quality in finishing pigs

Abstract Arginine plays an important role in regulating arginine-nitric oxide synthase pathway, regulating lipid metabolism, and upregulating the mRNA levels of genes involved in fat synthesis in muscle in animals, and can therefore improve feed utilization for protein accretion. The objective of this study was to investigate the effects of supplementation of different concentrations of L-arginine on growth performance, nutrient digestibility, and meat quality in finishing pigs. A total of 120 crossbred [(Landrace × Yorkshire) × Duroc] pigs with an average initial body weight (BW) of 53.80 ± 1.86 kg were used in this 10-week feeding trial. The pigs were randomly allotted to 1 of 3 dietary treatments (5 pigs/pen and 8 replicates/treatment) in a randomized complete block design according to their sex (2 gilts and 3 barrows) and BW. Dietary treatments included: 1) CON, corn-soybean meal based basal diet (containing 13.81 MJ/kg metabolic energy and 0.95% lysine for entire experimental period); 2) LA0.5, CON + 0.5 g/kg L-arginine; 3) LA1.0, CON + 1.0 g/kg L-arginine. Individual body weight was measured initially and at the end of 5th and 10th week, feed consumption was recorded on pen basis during the experiment to determine growth performance. Meat samples were randomly taken from each pen (2 pigs per pen, 1 gilt and 1 barrow; 16 pigs per treatment) for determination of meat quality. All data were analysed using linear and quadratic contrast (SAS Institute Inc., Cary, NC, USA). The result showed that L-arginine did not affect pig growth performance and nutrient digestibility. However, dietary L-arginine supplementation linearly increased (P&amp;lt; 0.05) muscle marbling score, while linearly decreasing (P&amp;lt; 0.05) cooking loss and drip loss of pork muscle (Table 1). Results of present study demonstrated that 1.0 g/kg L-arginine would be beneficial in improving the meat quality in finishing pigs.

Lateral Flow Immunoassay to Detect the Addition of Beef, Pork, Lamb, and Horse Muscles in Raw Meat Mixtures and Finished Meat Products.

A lateral flow immunoassay for sensitive detection of skeletal troponin I (TnI) as a specific, thermostable marker of muscle tissue was developed. Due to the antibodies’ choice, the assay specifically detects mammalian TnI (in beef, pork, lamb, and horse) but does not detect bird TnI (in chicken or turkey), thus enabling differentiation of these types of raw meat materials. The assay is based on a sandwich format of the analysis using gold nanoparticles as labels. The time of the assay is 15 min, and the TnI detection limit is 25 ng/mL. A buffer solution is proposed for efficient extraction of TnI from muscle tissues and from finished meat products that have undergone technological processing (smoking–cooking–smoking, cooking and smoking). The possibility of detecting beef addition in minced chicken down to 1% was demonstrated.

Midfield Wireless Power Transfer for Deep-Tissue Biomedical Implants

Midfield wireless power transfer has proved its advantages in power delivery to miniature implantable medical devices located deeply in the human body; however, the delivered power level is still low. Besides, design proposals for a compact source structure concentrating the transmitter field on a miniature implant remain challenges. This letter presents a novel compact transmitting structure (TX) at the midfield band and shows the capability of focusing the magnetic field inside the human tissue. Source performance has been verified by implantable planar inverted-F antenna (PIFA) with a total size of 9 × 13 mm ${^2}$ (RX) that positioned in the heart tissue layer at a 55 mm separated distance of TX and RX. In addition, the power transfer efficiency has been demonstrated by a measurement setup using pork muscle, which obtained a good match of the transmission coefficient between the simulation and experiment results. Consequently, for 1 W of output power from the midfield transmitter, the received energy could be achieved more than 5.6 mW via the implantable antenna at a subwavelength distance.

Dermestes maculatus (Coleoptera: Dermestidae) development under fluoxetine effect using two drug administration models.

Fluoxetine is a selective serotonin reuptake inhibitor, commonly used for the treatment of a variety of psychopathological conditions. As such, fluoxetine may be expected to appear in clinical and forensic cases. Dermestes maculatus De Geer (Coleoptera: Dermestidae) has been recognized as a relevant component of the insect fauna associated with decomposing human and animal remains. Experiments were conducted to study the effect of fluoxetine on developing D.maculatus using two-drug administration models: a non-living animal model (pork muscle) and a living one (Sus scrofa L. pigs). We assessed the duration of immature stages and total life cycle, as well as morphological parameters (body length, cephalic width, and weight). The effect of fluoxetine was studied at an overdose concentration: In the non-living animal model the drug was mixed with macerated pork muscle (2000mg/kg) and in the living animal model, pigs were given the drug orally (833mg/kg). A control was used for each model. Daily observations were performed from the beginning to the end of the experiments. GC-MS was used for drug detection and quantification. There were no statistically significant differences in the duration of immature stages, life cycle, larval mortality, morphological parameters, or sex ratio, between treatment and control, regardless of the drug administration model. Given that fluoxetine had no detectable effect on the development of D.maculatus, detection of this drug in forensic situations would not compromise the accuracy of PMI estimations.

Метод ИК спектроскопии в исследовании облученной мышечной ткани свинины и ее составляющих

Метод ИК спектроскопии в исследовании облученной мышечной ткани свинины и ее составляющих

Development of Screening Method for Tetracycline Residues in Pork (Sus scrofa domesticus) Muscle and Liver Samples

Antimicrobial residues in pork products are a hazard to public health. They contribute to antimicrobial resistance (AMR) as the exposure of bacteria to trace amounts of these residues can hasten its incidence and emergence. In the Philippines, the quality of meat products is regulated by the National Meat Inspection Service (NMIS) through antimicrobial sensitivity testing (AST) via disc diffusion. Analytical methods such as the use of high-performance liquid chromatography (HPLC) may also be used in monitoring antibiotic residues in meat samples. This experimental study aims to develop a screening method for tetracycline residues in pork (Sus scrofa domesticus) muscle and liver from public wet markets; and to determine the feasibility of this method based on specified critical parameters such as LOD, LOQ, and linearity. Twenty (20) pork muscle and 14 pork liver samples were collected from stalls in three public wet markets and were subjected to AST through the NMIS and HPLC analysis. The HPLC analysis utilized an isocratic elution with a mobile phase of 85:15 0.1% formic acid in acetonitrile: 0.1% formic acid in water and a flow rate of 1.0 mL/min. The detection of tetracycline was observed at peaks with a retention time of 3.95 ± 0.15 min. The determined retention time was used to identify tetracycline in the pork samples. AST results showed no presence of tetracycline in all samples. HPLC results, however, revealed that two out of 20 pork muscle samples and eight out of 14 pork liver samples contained tetracycline. The results have demonstrated that instrumental methods of analysis such as HPLC are necessary to confirm the absence or presence of the residues and to quantify the concentration to compare it to the established MRL. Further validation studies are recommended to ensure the accuracy and specificity of the optimized method.

Magnetic solid-phase extraction modified Quick, Easy, Cheap, Effective, Rugged and Safe method combined with pre-column derivatization and ultra-high performance liquid chromatography-tandem mass spectrometry for determination of estrogens and estrogen mimics in pork and chicken samples

In this study, conventional Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method was modified by magnetic solid-phase extraction (MSPE) for purification/pre-concentration of eleven estrogens and estrogen mimics from the extracts of pork and chicken muscles, prior to dansyl chloride (DNS-Cl) derivatization coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay. Dual octadecyl- and 2-aminoethyl-3-aminopropyl- groups functionalized mesoporous silica core-shell magnetic nanoparticles (C18/NH2-Fe3O4@mSiO2 MNPs) were synthesized and employed as MSPE sorbent with remarkable aqueous compatibility in comparison with conventional C18 functionalized sorbent. The proposed MSPE is easier to handle than the traditional SPE purification process in QuEChERS method. The lab-prepared MNPs were characterized by transmission electron microscope (TEM), brunner-emmet-teller (BET), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA) and vibrating sample magnetometer (VSM). Pre-column derivatization was conducted to significantly enhance the sensitivity of the analytes in MS/MS via analyzing their derivatives in positive ion mode instead of analyzing their original forms in negative ion mode. Under the optimal sample pretreatment and instrumental analysis conditions, the approach showed low limits of detection (LODs, 0.02‒3.00 µg kg–1), appropriate recoveries (81.1‒115.4%) and acceptable precisions (0.48‒15.1%, n = 6), with good feasibility and future prospect of trace compounds analysis in complex food samples.

Comparison of variable selection algorithms on vis-NIR hyperspectral imaging spectra for quantitative monitoring and visualization of bacterial foodborne pathogens in fresh pork muscles

This research aims to verify the feasibility of developing an improved and efficient reduced spectrum model for quantitative tracking of foodborne pathogens. Rapid monitoring of bacteria foodborne pathogen (Escherichia coli O157 and Staphylococcus aureus) contamination of fresh longissimus pork muscles was implemented by employing visible near-infrared (Vis-NIR) hyperspectral imaging spectra and partial least squares regression algorithm (PLSR). Six (6) wavelength variables selection algorithms were applied to the full spectral information to determine the wavelength variables of the collected HSI spectra that provides essential and relevant information about the concentration of bacterial foodborne pathogen. Commonly used algorithms based on model population analysis (MPA) (2), Intelligent Optimization Algorithms (2), and Hybrid variable selection methods (HVSM) (2) were utilised to select characteristic wavelengths. Compared to other strategies, variable combination population analysis with genetic algorithm (VCPA – GA), and variable combination population analysis with iteratively retaining informative variables (VCPA – IRIV) considerably bettered the predictive efficiency of the model, suggesting that the updated VCPA step is a very efficient way to remove unrelated variables. Vcpa-based hybrid strategy is an effective and reliable approach for variable selection of visible near-infrared (vis-NIR) spectra. Visualising bacterial foodborne pathogen distribution map on the pork samples provided a more insightful and detailed evaluation of the bacterial contamination at each pixel, offering a novel approach for evaluating bacterial contamination of agricultural products.

Mitochondrial apoptosis and proteolytic changes of myofibrillar proteins in two different pork muscles during aging

This study aims to investigate the changes in mitochondrial apoptotic factors and proteolysis of two porcine muscles (psoas major – PM and longissimus dorsi – LD) during aging. Results found that during 2–168 h postmortem mitochondrial membrane permeability, mitochondrial lipid peroxidation, Ca2+ levels were increased, while the reduction level and abundance of cytochrome c were decreased (P < 0.05) in both muscle types. Furthermore, the activation of caspase-3 along with increases in troponin-T and desmin degradation, and μ-calpain autolysis were found (P < 0.05), regardless of muscle type. PM maintained higher mitochondrial apoptotic factors, but had more intact desmin, less troponin-T degradation and less extent of autolyzed products of μ-calpain compared to LD (P < 0.05). These results indicate that the rapid onset of mitochondrial apoptosis of PM would not lead to a subsequent impact on myofibrillar protein degradation, suggesting that the mitochondrial apoptosis mediated tenderization process could be muscle-specific.

Unique Distribution of Diacyl-, Alkylacyl-, and Alkenylacyl-Phosphatidylcholine Species Visualized in Pork Chop Tissues by Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging.

Phosphatidylcholine (PC) is the major phospholipid in meat and influences meat qualities, such as healthiness. PC is classified into three groups based on the bond at the sn-1 position: Diacyl, alkylacyl, and alkenylacyl. To investigate their composition and distribution in pork tissues, including longissimus thoracis et lumborum (loin) spinalis muscles, intermuscular fat, and transparent tissues, we performed matrix-assisted laser desorption/ionization–mass spectrometry imaging (MALDI–MSI). Eleven diacyl-, seven alkylacyl-, and six alkenylacyl-PCs were identified using liquid chromatography (LC)-tandem MS (MS/MS) analysis. Despite many alkylacyl- and alkenylacyl-PC species sharing identical m/z values, we were able to visualize these PC species using MALDI–MSI. Diacyl- and alkylacyl- and/or alkenylacyl-PC species showed unique distribution patterns in the tissues, suggesting that their distribution patterns were dependent on their fatty acid compositions. PCs are a major dietary source of choline in meat, and the amount was significantly higher in the muscle tissues. Consumption of choline mitigates age-related memory decline and neurodegenerative diseases; therefore, the consumption of pork muscle tissues could help to mitigate these diseases. These results support the use of MALDI–MSI analysis for assessing the association between PC species and the quality parameters of meat.