Sarcoplasmic Protein Content Research Articles

Effects of Modified Atmosphere Packaging with Varied CO2 and O2 Concentrations on the Texture, Protein, and Odor Characteristics of Salmon during Cold Storage.

The effect of gas ratio on the growth of bacteria has been well demonstrated, but some adverse effects of modified atmosphere packaging (MAP) on seafoods have also been found. To provide a better understanding of the effects of CO2 and O2 concentrations (CO2 from 40% to 100% and O2 from 0% to 30%) in MAP on the texture and protein contents and odor characteristics of salmon during cold storage, the physiochemical, microbial, and odor indicators were compared with those without treatment (CK). Generally, MAP treatments hindered the increase of microbial counts, total volatile basic nitrogen, and TCA-soluble peptides, and decreased the water-holding capacity, hardness, springiness, and sarcoplasmic and myofibrillar protein contents. The results also indicated that 60%CO2/10%O2/30%N2 was optimal and decreased the total mesophilic bacterial counts by 2.8 log cfu/g in comparison with CK on day 12. In agreement, the concentration of CO2 of 60% showed the lowest myofibrillar protein degradation, and less subsequent loss of hardness. The electronic nose characteristics analysis indicated that 60%CO2/20%O2/20%N2 and 60%CO2/10%O2/30%N2 had the best effect to maintain the original odor profiles of salmon. The correlation analysis demonstrated that microbial growth had a strong relationship with myofibrillar and sarcoplasmic protein content. It can be concluded that 60%CO2/10%O2/30%N2 displayed the best effect to achieve the goal of preventing protein degradation and odor changes in salmon fillets.

Effects Of High-Load Versus High-Volume Resistance Training On Muscle Sarcoplasmic, Actin, And Myosin Protein Concentrations

PURPOSE: Our laboratory has recently shown high-volume resistance training (RT) can elicit increases in skeletal muscle sarcoplasmic protein concentrations, while also causing a dilution of contractile protein concentrations (i.e., sarcoplasmic hypertrophy). The purpose of this study was to evaluate effects of 6 weeks of high-load (HL) and high-volume (HV) training on skeletal muscle sarcoplasmic and contractile protein concentrations. METHODS: Trained college-aged males (n = 15; training age = 7 ± 3 yrs; mean 1RM squat relative to bodyweight = 1.9 ± 0.4 kg) performed 6 weeks of unilateral lower-body RT, with one leg performing HV training and the contralateral leg performing HL training using leg press and leg extension. Participants underwent a period of passive recovery lasting 10 days following the training intervention. Vastus lateralis biopsies were obtained from both legs prior to the start of training (PRE), 72 hours following the last training day (POST), and 1 week following POST testing (POSTPR). Sarcoplasmic protein content was determined following differential centrifugation using bicinchoninic assays, and actin and myosin concentrations were quantified using SDS-PAGE and Coomassie staining. RESULTS: Significant main effects of time (p = 0.022) and condition (p=0.002) were observed and condition by time approached significance for sarcoplasmic protein concentrations (p = 0.088). There were no significant interactions or main effects for actin or myosin concentrations. CONCLUSIONS: Contrary to our prior data, sarcoplasmic, actin and myosin concentrations remained unaffected with HV training. However, interesting trends were observed for sarcoplasmic protein concentrations and these will be further interogated.

Combined Exercise and Leucine Supplementation Promotes Skeletal Muscle Protein Deposition in Tumor Bearing Mice

PURPOSE: To investigate the effect of concurrent exercise training and leucine supplementation on skeletal muscle protein deposition in Colon 26 tumor bearing mice. METHODS: Male BALB/c mice were divided into a control group (C, n=8), a C26 tumor bearing group (T, n=8) and a tumor bearing plus exercise and leucine supplementation group (TEL, n=8). Mice in the C and T groups were fed with normal chow diet, while mice in the TEL group were fed with formulated diet contained 5% leucine and received 30-min swimming training 3 days per week (Monday, Wednesday and Friday) and resistance training 3 days per week (Tuesday, Thursday and Saturday) for 2 weeks. At 24 hours after the last training session, blood and gastrocnemius muscle samples were collected under full anesthesia. The contents of TNF-α and IL-6 in gastrocnemius muscle and serum were determined by ELISA. maximal grip strength was measured with a commercial grip strength meter. Two-way ANOVAs and post-hoc tests were used for data analysis. RESULTS: After tumor bearing, cumulative food intake appeared to decrease, whereas body weight (20.7 g vs. 26.1 g), wet gastrocnemius muscle weight (97.3 mg vs. 128.9 mg), total protein content (35.7 mg/g vs. 51.2 mg/g), sarcoplasmic protein content (26.5 mg/g vs. 38.3 mg/g), myofibrillar protein content (28.6 mg/g vs. 43.3 mg/g) and muscle strength (82.7 g vs. 156.5 g) were significantly lower in the T group than in the C group (all p<0.01). TNF-α and IL-6 contents in serum and gastrocnemius were obviously higher in the T group than in the C group (p<0.01). After exercise and leucine supplementation, cumulative food intake and the TNF-α and IL-6 content were significantly lower in the TEL group than in the T group (p<0.05), while body weight (21.8 g), wet gastrocnemius muscle weight (111.1 mg), total protein content (40.3 mg/g), sarcoplasmic protein content (30.7 mg/g), myofibrillar protein content (34.0 mg/g) and muscle strength (112.2 g) were significantly higher in the TEL group than in the T group (p<0.05 to p<0.01). CONCLUSIONS: Combined exercise and leucine supplementation significantly ameliorated skeletal muscular protein deposition in C26 tumor bearing mice, which may be through down-regulating the inflammatory response. (Supported by Research Foundation of Sichuan Provincial Department of Education grant #18ZB0106).

Effects of olive leaf powder supplemented to fish feed on muscle protein of red sea bream.

Olive leaf is known to have the high polyphenol content of 6-9% in dry weight. We investigated the effects of olive leaf powder (OLP) supplemented to fish feed on muscle protein of red sea bream (Pagrus major). Fish reared with feed containing 8% OLP for 40days had 1.4 times higher myofibril content and 2.2 times higher acid-soluble collagen content than fish reared with control feed for the same period. On the other hand, sarcoplasmic protein content and collagenase activity of the muscle were almost the same between the control fish and OLP-diet fish. Microstructure observation of fish muscle showed that OLP-diet fish has more rigid endomysium structure than that of the control-diet fish. Since collagen fiber in endomysium is responsible for the texture of the muscle, feeding OLP to aquaculture fish will lead to a harder muscle texture. The present study suggests that OLP is a useful feed additive to enhance the texture of aquaculture red sea bream muscle through strengthening of the collagen structure in the muscle.

Effect of Heat Treatment at Different Stages of Rigor on the Quality of Pacific White Shrimp (Litopenaeus vannamei)

ABSTRACTEffect of blanching and cooking on the quality of Pacific white shrimp with skeletal muscle severed (by beheading and peeling) at different stages of rigor was evaluated. Peeling and beheading shrimp in post-rigor stage resulted in higher yields compared to shrimp in in-rigor and pre-rigor stages. Weight loss due to blanching/cooking was highest when skeletal muscle was severed in in-rigor stage followed by post- and pre-rigor stages. Highest crude and sarcoplasmic protein contents were found in the shrimp blanched or cooked while in in-rigor stage followed by pre-rigor and post-rigor stages. Hardness, springiness, and chewiness were found to be better in the shrimp blanched in pre-rigor stage. Highest sensory scores for color, appearance, succulence, and odor were found for shrimp blanched or cooked in pre-rigor followed by in-rigor stage. Instrumental analysis of color and texture confirmed the sensory scores.

Synthesis and Biological Activity of Low-Molecular-Mass Polypeptides Isolated From Extracellular Matrix of Bone Tissue

The biological properties of low-molecular-mass polypeptides isolated from the extracellular matrix of bone tissues were studied using healing of a fractured rat tibia as a model. It was found that a single injection of the test fraction near the fracture caused glycogen to accumulate and the sarcoplasmic protein content to increase in skeletal muscle of the traumatized extremity section. The healing time of the experimental fracture in rats was shortened. The results justify the creation of complex preparations designed to promote regeneration of support tissues that are composed of low-molecular-mass derivatives of collagen + growth factors.

Characterisation of muscles from Frigate mackerel (Auxis thazard) and catfish (Clarias macrocephalus)

Frigate mackerel (Auxis thazard) and catfish (Clarias macrocephalus) can be used as alternative sources for surimi production. However, the functionality of surimi is species-dependent. This study aimed to characterise certain chemical and physical compositions of dark and ordinary muscles from these species. Catfish, particularly ordinary muscle, was composed of higher contents of lipid and carotenoid than Frigate mackerel muscle (p<0.05) but ordinary muscle from Frigate mackerel had the highest phospholipid content (p<0.05). Both dark and ordinary muscles of Frigate mackerel had greater contents of myofibrillar proteins than had catfish muscle (p<0.05). Myosin heavy chain and actin were predominant proteins found in both muscle types of both species. Dark muscle from Frigate mackerel had the highest sarcoplasmic protein content, especially extractable myoglobin (p<0.05). Muscles from Frigate mackerel had greater content of sodium chloride than had catfish (p<0.05). The highest contents of iron, copper and selenium were found in Frigate mackerel dark muscle (p<0.05). The pH of ordinary muscle from both species was higher than that of dark muscle (p<0.05). Frigate mackerel, especilly dark muscle, exhibited the most dark-red colour, as shown by the lowest L* and b* values with the highest a* value and redness index (a*/b*) (p<0.05).

Effect of hydrostatic high-pressure treatment on proteins, lipids and nucleotides in chilled farmed salmon (Oncorhynchus kisutch) muscle

The effect of a previous hydrostatic high-pressure (HHP) treatment on hydrolysis, breakdown and aggregation events in chemical constituents of chilled farmed coho salmon (Oncorhynchus kisutch) was studied. Three different HHP conditions were applied (135 MPa-30 s; 170 MPa-30 s; 200 MPa-30 s; treatments T-1, T-2 and T-3, respectively) and compared to untreated fish for a 20-day chilled storage. Nucleotide degradation was important during the chilled storage in all kinds of samples; however, the K value did not afford differences related to previous pressure applied. HHP treatment led to an increased free fatty acid (FFA) formation (day 0 values); on the contrary, an inhibitory effect on FFA formation could be observed at the end of the storage (15–20 days) in T-3-treated fish as a result of microbial activity inhibition. A marked decrease in sarcoplasmic protein content was evident in samples corresponding to T-2 and T-3 treatments; the SDS–PAGE analysis of such protein fraction showed a partial loss of a band corresponding to 29 kDa. This band was excised, digested with trypsin, analysed by tandem mass spectrometry and identified as phosphoglycerate mutase.

The effect of myofibrillar/sarcoplasmic protein ratios on the properties of round scad muscle protein based film

The effect of the ratios of myofibrillar protein (MP) to sarcoplasmic protein (SP) from round scad (Decapterus maruadsi) muscle on the properties of the resulting films was investigated. Tensile strength (TS) of films decreased with increasing SP content (p < 0.05). Films prepared from MP/SP ratio of 10:0 (w/w) exhibited the highest TS (p < 0.05). Elongation at break (EAB) of films prepared with SP content greater than 30% had the decreased EAB (p < 0.05). Water vapor permeability (WVP) of films increased when SP content increased up to 20% and decreased with increasing SP content up to 30% (p < 0.05). Solubility of films decreased but protein solubility increased with increasing SP contents (p < 0.05). The a*-value and ΔE* of film increased with increasing SP content. Films with all MP/SP ratios exhibited the negligible transmission to the light in UV range. Therefore, it is suggested that the type and ratio of proteins in fish muscle, both SP and MP, influenced the properties of film from round scad muscle. Results suggested that the removal of sarcoplasmic protein from fish muscle by thorough washing was an effective means to improve the mechanical properties as well as color of the fish muscle protein-based film.

Proteolysis, physicochemical characteristics and free fatty acid composition of dry sausages made with deer ( Cervus elaphus) or wild boar ( Sus scrofa) meat: A preliminary study

In order to contribute to typifying delicatessen made with game meat, the proteolysis, physicochemical characteristic and free fatty acid composition were determined in 10 commercial dry sausages, chorizos and saucissons, made with deer or wild boar meat. The a w and pH values were similar for all the samples; however, the results for dry matter, protein nitrogen, fat, ash, sodium chloride, phosphorus, and sodium nitrite content showed great variation among the samples tested. The myofibrillar protein content was higher than the sarcoplasmic protein content in all samples analysed. The electrophoretic profiles of sarcoplasmic and myofibrillar proteins were different among samples. Principal components analysis, run on the relative density of myofibrillar and sarcoplasmic proteins, separated the chorizo and saucisson samples. Chorizo samples were a homogeneous group in the analysis of myofibrillar proteins, which indicated similar proteolysis effects for all samples. The majority acids were oleic, palmitic, linoleic and stearic in all samples. Chorizos differed from saucissons in the greater quantity ( P < 0.05) of polyunsaturated fatty acids.

Biochemical correlates of growth and condition in juvenile Atlantic cod (Gadus morhua) from Newfoundland

The aim of this study was to examine how the biochemical composition of tissues varied with growth rate and condition in juvenile Atlantic cod (Gadus morhua) caught in the wild and kept in captivity. The hepatosomatic index, brain water content, and muscle sarcoplasmic protein content as well as the activities of phosphofructokinase, lactate dehydrogenase, nucleoside diphosphate kinase, and citrate synthase in the muscle, nucleoside diphosphate kinase and citrate synthase in the intestine, and cytochrome c oxidase and citrate synthase in the brain increased with growth rate or condition factor. Conversely, liver and muscle water contents were lower in fish with a higher growth rate. A multiple regression model that included the hepatosomatic index, water content of muscle and brain, and citrate synthase activity in the intestine explained 79.7% of the variability of growth in mass under our conditions. A similar model, using liver water content instead of muscle water content, explained 82.5% of the variability of growth in length. These easy to measure variables may be used in fisheries management to estimate the growth rate of fish in the wild.

Supercritical CO2 Extraction of Oil and Residual Proteins from Atlantic Mackerel (Scomber scombrus) as Affected by Moisture Content

ABSTRACTLipid composition of supercritical CO2 (SC‐CO2) extracts, residual oil in muscle and changes in sarcoplasmic proteins after extraction of Atlantic mackerel were characterized. Dehydration of the muscle to 10.2% (w/w) resulted in high oil yield with minimum changes in protein content and composition. Sarcoplasmic protein content of fish muscle following SC‐CO2 treatment was lower than that of original muscles at all moisture levels (3.8–64%, w/w). Analysis of sarcoplasmic proteins by capillary electrophoresis indicated aggregation of low molecular weight proteins during SC‐CO2 extraction. SC‐CO2‐extracted muscle also had lighter color than original samples. The SC‐CO2 extraction showed potential to provide high quality oil and protein meal.

Sarcoplasmic and myofibrillar proteins in white trunk muscle of salmon ( Salmo salar) after estradiol treatment

1. 1. Proteins from skeletal muscle of Atlantic salmon ( Salmo salar) were separated into two fractions, sarcoplasmic and myofibrillar, the sarcoplasmic proteins amounting to 47%. 2. 2. The actomyosin linkage of the myofibrillar proteins was broken by adding ATP MgCl 2 and myosin was brought into solution in high ionic strength buffer. 3. 3. The method was applied to fish treated with 17-β estradiol. The sarcoplasmic protein content per g wet wt or per mg of DNA was unchanged. The myofibrillar proteins decreased by 17%. Myosin heavy chain decreased to a simila extent as the total myofibrillar proteins. 4. 4. The advantage of the methods described is to relate changes in muscle protein metabolism to specific physiological functions of the tissue.

Toxic impact of phosphamidon on protein degradation in phasic and tonic muscles of marine prawn,Penaeus indicus(H. Milne Edwards)

Levels of various protein fractions, (sarcoplasmic, myosin, actin, non-collagen and collagen) and the rate of their degradation by proteases were studied in phasic and tonic muscles of marine prawn, Penaeus indicus following acute (2 d) and chronic (15 d) exposure to sublethal concentration of phosphamidon. During exposure, greater decrease in sarcoplasmic protein fraction was observed in phasic muscle as compared to other myofibrillar proteins. But the sarcoplasmic protein content showed an elevation in tonic muscle. The changes in protein fractions were more pronounced during acute exposure than chronic exposure both in phasic and tonic muscles. These changes were correlated with the elevation of the acidic, neutral and basic protease activities during acute and chronic exposure. Free amino acids were increased during acute exposure, while they showed a significant decrease during chronic exposure in both the muscles. These results indicate that protein metabolism in both phasic and tonic muscles was significantly altered following phosphamidon exposure. These differential responses observed at acute and chronic exposure indicate the operation of compensatory mechanisms to mitigate the phosphamidon toxic stress.

Protein degradation and protease activity of chum salmon (Oncorhynchus keta) muscle during spawning migration

Sarcoplasmic protein content decreased significantly and myosin heavy chain was degraded gradually during spawning migration of chum salmon (Oncorhynchus keta).Acid and neutral proteinase activities increased significantly during spawning migration. These proteinase activities were higher in females than in males. High levels of acid proteinase were not caused by the injury of lysosomal membranes. Considering the physiological states of chum salmon, neutral proteinase activity might be related to the degradation of muscle protein.As the changes in serum sex steroids were similar to those in the protease activities during spawning migration, it was considered that high levels of protease activity during spawning migration were closely related to the serum levels of androgens.

Deterioration of chum salmon muscle during spawning migration. XI. Biochemical characteristics of chum salmon muscle during spawning migration.

The relation between gonadosomatic index (GSI) value and proximate composition of muscle of chum salmon at each migration stage did not markedly differ with the date and locality of capture. This might suggest that the situation of proximate composition can be characterized by the GSI value. The relation between GSI value and proximate composition was statistically evaluated by multiple regression analysis. Total protein and sarcoplasmic protein contents of the muscle markedly decreased during spawning migration, while the contents of ninhydrin positive substances of non-protein nitrogenous compounds increased. A high level of muscle autolytic activity was observed in the muscle of the fish during spawning migration. The composition of muscle protein fractions at the same migratory stage did not differ greatly from fish to fish, regardless of the date and locality of capture. Judging from the fact that proximate composition, protein composition, and autolytic activity of chum salmon muscle at the same migratory stage were almost the same regardless of the date and locality of capture, the changes described above during spawning migration were considered to be closely related to their physiological states.

Effect of Starvation and Refeeding on Activity of a Ca2+-Dependent Protease in Rat Skeletal Muscle

The effects of starving, refeeding, and restarving rats for different periods on content of sarcoplasmic and contractile proteins and on activity of the Ca2+-dependent proteinase (CAF) in skeletal muscle was determined. Groups of five to six male rats, 8 to 11 weeks old, were starved up to 8 days, refed up to 6 days, and in two experiments, restarved up to 10 days. CAF activity was assayed in P0–45 crude CAF fractions prepared so as to remove a protein inhibitor of CAF; the assays were demonstrated to be specific for CAF. Sarcoplasmic protein content of rat skeletal muscle changed little until after 6 days of restarvation when it decreased to 68–89% of control level (P < 0.05). Contractile protein content decreased to 65% of control level (P < 0.01) after 8 days of starvation, remained at this level for 4 days of refeeding, then increased to approximately 80% of control level after 6 days of refeeding, remained at this level for 2 days of restarvation, and then decreased to approximately 65% of control level (P < 0.01) after 6 and 8 days of restarvation. Muscle CAF activity did not change during the first 8 days of starvation but increased to 113% above control level (P < 0.01) after 6 days refeeding and then decreased to only 29% of control level (P < 0.01) after 8 days of restarvation. These changes in muscle CAF activity are consistent with the proposed role for CAF in initiating metabolic turnover of contractile proteins, but because actual measurements of myofibrillar protein were not made and because in vivo CAF activity is difficult to assess, they do not prove this role for CAF nor do they exclude participation of other proteinases.