Fish Muscle Proteins Research Articles

Improvement of pellet quality with proteins recovered from whole fish using isoelectric solubilization-precipitation

Muscle proteins are known to form thermally induced gel networks and may bind particles such as feed constituents. Dietary incorporation of functional proteins may improve pellet quality. Muscle proteins were recovered from rainbow trout by using isoelectric solubilization-precipitation. The objectives of this study were 1) to determine the proximate composition and amino acid content, AMEn, TMEn, and true amino acid digestibility of trout protein isolate and paste (TPP), and 2) to determine the effects of TPP on feed manufacturing, pellet quality, and true amino acid digestibility of broiler diets formulated to include TPP. Four treatments, consisting of 1) a control, 2) 5% TPP (HTPP), 3) 2.5% TPP (LTPP), and 4) 3.9% added moisture (MOIS), were manufactured at the West Virginia University pilot feed mill using a Latin square design. Five percent TPP had the highest pellet quality, followed by LTPP, MOIS, and the control. The improvement in pellet quality could be attributed to gelation of the recovered proteins. Addition of TPP reduced pellet mill production rate. Relative electrical energy usage decreased with MOIS but increased with HTPP relative to the control and LTPP treatments. Negative effects of increased viscosity likely associated with TPP were absent with LTPP. Digestibility of Asp, Glu, Pro, Ile, and Leu were lower for HTPP than the control. However, Ala digestibility was decreased in LTPP compared with the control. Therefore, fish muscle proteins incorporated at less than 5% of the diet may be beneficial to the broiler industry as a pellet binder and nutritive feed additive.

Flocculation-enhanced protein recovery from fish processing by-products by isoelectric solubilization/precipitation

Abstract Muscle proteins were recovered from rainbow trout processing by-products (fish meat leftover on bones, head, skin, and etc.) by isoelectric solubilization/precipitation. Muscle proteins precipitated at pH 5.5 are typically recovered by high-speed centrifugation at a laboratory scale, which appears to impede process scale-up. Our objective was to investigate the effect of flocculants on separation of precipitated proteins from process water (supernatant). Flocculants with different surface charge properties and molecular weights (Mw) were added to precipitated proteins. Protein separation was evaluated by determining optical density (OD) of the supernatant using Bradford dye-binding method. A high Mw anionic flocculent at 100 mg/L resulted in excellent protein separation following 10 min reaction. The OD of the supernatant was comparable to that of clear water, suggesting that even water-soluble fish muscle proteins were removed from the process water. Freeze–thaw cycles, commonly encountered in the fish processing industry, resulted in even more rapid flocculation reaction. This flocculent could be added to a bio-reactor that precipitates muscle proteins at pH 5.5 in a continuous isoelectric solubilization/precipitation system. However, effects of the flocculants on human and animal health should be determined and appropriate approvals obtained before the recovered muscle proteins can be used in human food products and/or animal feeds.

The Acid and Alkaline Solubilization Process for the Isolation of Muscle Proteins: State of the Art

The acid and alkaline solubilization processes for isolating muscle protein from ground fish raw materials are investigated by scrutinizing the literature. Following an introduction to the processes, with some underlying chemistry, patents related to the acid and alkaline solubilization process are described together with previously patented methods for processing of protein isolates. Focus is then placed on comparing a range of factors important in fish muscle protein isolation between the acid and alkaline solubilization processes, and classic washing-based surimi technology. The factors addressed were: protein yield, gel quality, color, lipid reduction, lipid oxidation, microbial stability, and frozen storage stability. A long series of studies made with different fish/shellfish species have been used for this purpose. Certain results are summarized in table form (protein yields, gel strength, and whiteness), others only in text form. From this part of the review, it is obvious that the acid process often has certain advantages (e.g., protein yield) and the alkaline process other ones (gel strength, whiteness, lipid removal, lipid oxidation, and total microbial count). Thus, the choice of method depends on the application. It is clear that most species respond differently to acid and alkaline solubilization, which is why the two methods are initially compared. In a section about new processing attempts, the use of the acid and alkaline methodology for isolating proteins from whole fish/shellfish and fish by-products is reviewed together with attempts to recover waste water proteins and attempts to modify the process. Tentative uses of the new protein isolates, e.g., as coatings, protein brines, and emulsifiers are finally described together with some conclusions and future opportunities for the acid and alkaline processes.

Electrical conductivity as a tool for identification of metal contaminated fish protein

Fish acts as a good bioindicator for metal contamination. The contaminated metal ions are bonded into the protein biologically. The doping concentration and its properties were analyzed by the tools of electrical conductivity. For the analysis of fish species, Clarius batrachus was selected, subjected to metal-dissolved solution and studied for its muscle conductivity in both raw and pelletised forms. The various parameters analyzed were electrical conductivity and temperature dependent electrical conductivity on fish muscle protein in its unpelletised (natural) and pelletised form, when metals like copper, cadmium and lead were doped to the muscle protein. The studies carried out were atomic absorption spectroscopy (AAS), thermo gravimetric analysis (TGA) and electron paramagnetic resonance (EPR). The results showed that conductivity in muscle as well as its pelletised temperature dependent conductivity is a very good mechanism for the identification of cadmium, lead and copper contamination level.

알칼리 처리하여 회수한 냉동깡치 어육 단백질의 Lysinoalanine 함량

The formation of lysinoalanine (LAL) in protein recovered from the belanger's croaker, Johnius grypotus, using a pH shifting process was measured by amino acid analysis. The LAL peak was detected at 49.24 min, between phenylalanine and histidine peaks in the amino acid analyzer. LAL was not detected in the fish muscle or in protein recovered using the alkaline pH shifting process. LAL was not formed in protein recovered after storage for up to 9 hrs at pH 11, but was detected in the soluble protein fraction at pH 11, followed heating at <TEX>$90\;^{\circ}C$</TEX>. The myosin heavy chain decreased with storage time at pH 11. The results suggest that the alkaline shifting process for recovering fish muscle protein is safe, and that no LAL forms.

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.

Changes in Structural and Functional Attributes of Fish Mince Proteins in Presence of Cosolvent During Frozen Storage

The effect of polyhydric alcohol, mannitol, on the properties of proteins from Sardinella longiceps has been investigated. Calcium ATPase activity of the proteins decreased during frozen storage. Ca2+ATPase activity of mannitol treated samples was higher up to 60 days of storage as compared to untreated samples. Emulsion capacity of proteins decreased as a function of storage. Thermal denaturation profile of proteins revealed no change in apparent thermal transition temperature (app.Tm) from a control value of 57.5°C, in presence of mannitol. Scanning electron micrographs showed an increase in porosity of muscle tissues in the presence of mannitol. These results indicate the stabilizing effect of mannitol at low temperature on the fish muscle protein by retaining structure and functional properties of the muscle during frozen storage.

Water Soluble Proteinous Substances as Free Radical-Scavengers in Fish

The role of high molecular weight compounds in the radical-scavenging activity of horse mackerel muscle was evaluated. After denaturation by boiling or by adding TCA solution, 30% of the total activity remained in the water extract. Fractions containing high molecular weight compounds showed both 1,1-diphenyl-2-picrylhydrazyl and peroxy radical-scavenging activity. These results indicate that water-soluble protein in fish muscle is responsible for the radical-scavenging activity.

Effect of Fish Meat Quality on the Properties of Biodegradable Protein Films

Fish muscle protein films were prepared from blue marlin (Makaira mazara Jordan & Evermann) meat which had been stored at 30°C to intentionally lower the meat quality. In this study, the effects of meat quality and pH on the formation of these protein films were investigated. Moreover, ε-polylysine was added to the film-forming solutions to reduce the microbial population of films. The mechanical properties of the films were slightly affected by acidic and alkaline pHs. However, the water vapor permeability of muscle protein films was not affected by either the quality of the fish meat or the pH of the film-forming solutions. SDS-PAGE (sodium dodecyl sulfate- polyacrylamide gel electrophoresis) showed the degradation of myosin heavy chain in acidic films and polymerization in alkaline films. It was revealed that biodegradable films can be produced even from very low quality fish meat, and that the bacterial population of films could be drastically reduced by the addition of ε-polylysine.

건조 어육 단백질 분말의 식품학적 기능성

Functionalities of drum-dried fish muscle protein from pH shifting process have been investigated by determining solubility, emulsion activity, rehydration, fat-adsorption capacity, viscosity, and color. Solubility was higher in recovered protein at pH 7.0 than that at pH 5.5, and not dependent on ionic strength. Solubility of the dried protein recovered at pH 7.0 depended on pH of solvent, and lowest in the range of pH 3 to pH 6. The dried protein showed relatively low emulsion capacity in all the samples. Emulsion stability, foam capacity and foam stability were not observed in the samples. Viscosity was in the range of 50,200～39,000 cP. Rehydration and fat-binding capacities were 2.63～2.89 g-water/g and 2.13～2.17 g-oil/g, respectively, and not dependent on particle size and pH. Drum-dried fish muscle protein has a potential application as an ingredient of meat patty products.

Size-fractionated fish hydrolysate as feed ingredient for rainbow trout ( Oncorhynchus mykiss) fed high plant protein diets. I: Growth, growth regulation and feed utilization

Six experimental diets were fed to rainbow trout to examine the effect of fish hydrolysate and ultra filtered fish hydrolysate on growth performance, feed utilization and growth regulation using diets low in dietary fish meal inclusion. One diet contained a high level of plant protein sources (90.6% of total dietary protein) and a low level of fish meal (9.4% of dietary protein). Two diets contained different levels of hydrolysate in exchange for the plant protein sources, reducing the plant protein level to 73.9% and 57.2%, respectively. Two further diets were identical in composition except that the hydrolysate was ultra filtered to remove low molecular weight compounds. A moderate level of fish meal was used in the sixth diet which had a dietary plant protein level of 57.0%. All diets were made equal in protein, lipid, energy and lysine. The feeding trial lasted for 90 days and for the fastest growing group, fed moderate level of fish meal, the fish increased in weight from 149 g at start to a final weight of 443 g. All groups showed significant differences in growth and feed utilizations. Specific growth rates were; 0.30% day − 1 for the plant protein diet, 0.98% day − 1 for the high hydrolysate diet, 0.72% day − 1 for the group containing the high level of ultra filtered hydrolysate, and 1.21% day − 1 for the moderate fish meal diet. Feed efficiencies (g fish weight gain per g feed intake) were found to be 0.57 for plant protein diet, 0.97 for high level of hydrolysate, 0.83 for ultra filtered hydrolysate and 1.03 for the moderate fish meal diet. Half dietary inclusions of hydrolysate and ultra filtered hydrolysate revealed values between the plant protein diets and high levels of these ingredients, respectively. Feed consumption in percentage of average fish weight per day, correlated with the feed efficiency for all groups. PER, PPV and BV correlated with the differences in growth. Protein digestibilities were equal for all groups, while the moderate fish meal diet showed higher lipid and energy digestibilities than the plant protein diets. Although some of the differences may be due to growth inhibitors in plant resources other explanations may be relevant. Plasma growth hormone (GH) levels were significantly higher in fish fed the plant protein diet than fish fed the fish meal or high hydrolysate diet, which is most likely a result of their poor feeding status. Plasma IGF-I levels were not affected by diet. Comparisons of groups with similar inclusion of plant ingredients, and thus equal level of growth inhibitors, show that in removing small molecular weight compounds from fish hydrolysate, the growth and feed efficiency were significantly reduced. Some of these small compounds in fish hydrolysate thus seem to be essential for biological performance. Further, as fish meal revealed the best performance, fish muscle protein is not the only nutrient that makes fish meal an essential ingredient in aqua feed for carnivorous fish. This information is important in the work to find replacement of fish meal in a sustainable growing global aquaculture industry.

Effect of pH‐Shift Processing and Surimi Processing on Atlantic Croaker (Micropogonias undulates) Muscle Proteins

ABSTRACT: Extraction and recovery of fish muscle proteins with the pH‐shift process was investigated for Atlantic croaker and compared to a laboratory scale surimi process. The acid‐aided process led to higher recoveries (P &lt; 0.05) than the alkali‐aided process, which in turn led to higher recoveries (P &lt; 0.05) than surimi processing. Lipid reductions were highest (P &lt; 0.05) for the alkali‐aided process, followed by the acid‐aided process, with surimi giving the least reduction. No major differences in recovered proteins could be seen for the three processes, except both pH‐shift processes had a protein band (∼150 KDa) possibly representing partial hydrolysis of myosin. Oscillatory rheology on protein pastes during heating and cooling showed the highest storage moduli for the alkali‐aided isolate, followed by the acid aided isolates and surimi. Torsion testing on protein gels demonstrated significantly higher strain and stress values for gels made from frozen isolates with added cryoprotectants compared to fresh gels without added cryoprotectants. Gel stress was significantly higher (P &lt; 0.05) for the frozen gels with added cryoprotectants made from the isolates, compared to surimi. Although isolate pastes had higher (P &lt; 0.05) lightness values than surimi pastes, surimi gels had higher (P &lt; 0.05) lightness than isolate gels. The acid‐aided gels had higher levels of yellowness than the other treatments. Both surimi and alkali‐aided isolates had significantly (P &lt; 0.05) lower oxidation levels compared to the ground raw material. The acid isolate had poor oxidative stability and gave higher oxidation values than the raw material. Surimi and alkali‐aided pastes and gels also had higher oxidative stability than acid‐aided gels.

Proteins and proteolytic activity changes during refrigerated storage in sea bass (Dicentrarchus labrax L.) muscle after high-pressure treatment

Contrary to other preservation methods like thermal treatments, high pressure can destroy microorganisms without affecting the nutritional quality, color, or food texture. The firm texture of fish flesh is an important quality parameter. During the refrigerated storage, the tissue becomes softer and the muscle is deteriorated by different proteases. The aim of this study was to study the modification of the fish muscle proteins after high-pressure treatment during the refrigerated storage and to evaluate the effect of high-pressure treatment level on the post-mortem protein changes and enzyme activities. The calpain activity decreased with the high-pressure treatment and evolved differently during the refrigerated storage, depending on the level of pressurisation. Its inhibitor, the calpastatin was not affected by high pressure, but its inhibiting potential decreased during the post-mortem storage. The activities of cathepsins were modified by the high-pressure treatment and the time of storage, but depended according to their class. The electrophoresis profiles showed that sarcoplasmic proteins were modified according both the high-pressure treatment and the period of storage. For the myofibrillar proteins, the only changes were due to the high-pressure treatment.

Separation of Muscle Membrane from Alkali-Solubilized Fish Muscle Proteins

Treatment with Ca2+ and citric acid improved membrane removal from muscle homogenates solubilized at pH 10.5 by centrifugation at 4000 g for 15 min. The percentage of phospholipid removed from muscle homogenates increased with increasing Ca2+ concentrations at 1 mM citric acid. More than 85% phospholipid and 45% protein in the muscle homogenates were removed at Ca2+ concentrations of >20 mM in the presence of 1 mM citric acid. At 8 mM Ca2+, addition of citric acid at 5 mM improved phospholipid removal to approximately 78% from 58% in its absence. Because treatment with 8 mM Ca2+ alone can remove significant amounts of phospholipid, it is likely that Ca2+ played the major role in membrane removal in muscle homogenates solubilized at pH 10.5.

Separation of Membranes from Acid-Solubilized Fish Muscle Proteins with the Aid of Calcium Ions and Organic Acids

Calcium chloride, and to a lesser extent MgCl2, aided in the separation of membranes by centrifugation from cod (Gadus morhua) muscle homogenates solubilized at pH 3 in the presence of citric acid or malic acid but not lactic acid. Adding citric acid and Ca2+ before solubilizing the cod muscle homogenates was needed for the effect. At 1 mM citric acid, 70-80% of the phospholipid and 25-30% of the protein were removed at 10 mM Ca2+. At 8 mM Ca2+, citric acid showed an optimal effect on phospholipid removal at 5 mM with 90% of the phospholipid and 35% of the protein removed. The treatment with citric acid and Ca2+ was also effective in separating the membrane from solubilized herring (Clupea harengus) muscle homogenate. Ca2+ and citric acid might exert their influence by disconnecting linkages between membranes and cytoskeletal proteins.

Monitoring Food Quality by Microfluidic Electrophoresis, Gas Chromatography, and Mass Spectrometry Techniques: Effects of Aquaculture on the Sea Bass (Dicentrarchus labrax)

Monitoring food quality is a critical task for analytical chemistry and an important way to preserve human health. Fish is a valuable source of highly digestible proteins and contains large amounts of polyunsaturated fatty acids and fat-soluble vitamins. Since the world's wild fish stocks are limited, farmed fish is nowadays proposed as an alternative to consumers. It is now emerging that the fish muscle protein content is assuming great importance from an aquaculture perspective. Many data have been collected on the physiology and biochemistry of fish muscle, but few proteomic studies are available on farmed fish. Application of proteomics to aquaculture may play a key role in the development of new farming strategies. In this paper, a proteomic approach based on SDS-PAGE separation of proteins, in situ protein hydrolysis, de novo sequencing of peptides by MALDI and ESI MS(2), protein identification, and relative quantitation of protein by denaturing capillary electrophoresis was coupled with the determination of fatty acids and metal ions content by GM-MS and ICPMS in farmed and wild sea bass filet. Our results show that aquaculture could induce significant chemical and biochemical differences in fish muscle that may have an impact on food quality.

魚類筋肉タンパク質の構造安定性に関する生化学的研究―サメ類筋原線維タンパク質の尿素抵抗性―

魚類筋肉タンパク質の構造安定性に関する生化学的研究―サメ類筋原線維タンパク質の尿素抵抗性―

Evaluating Viscosity of Surimi Paste at Different Moisture Contents

Abstract The steady and dynamic shear viscosity of fish muscle protein paste obtained from Alaska pollock surimi at 95%, 90%, 85%, 80%, and 75% of moisture contents were measured in the temperature range of 5°C to 20°C. To estimate the steady shear viscosity at high shear rate from dynamic shear viscosity, the modified Cox-Merz rule was applied by introducing a frequency shift factor. The concentration dependence of zero-shear viscosity showed power-law dependence with an exponent of 3.5, and the universal behavior of viscosity at different protein concentrations was observed by a introducing reduced variables. The Carreau model was applied to describe the shear- thinning behavior of the surimi paste, and the model parameters estimated empirically showed moisture content dependence. The viscous flow behavior was independent of temperature (5°C to 20°C), and addition of starch decreased the flow index and viscosity of the paste, compared to the pure surimi paste.

ROLE OF pH IN SOLUBILITY AND CONFORMATIONAL CHANGES OF PACIFIC WHITING MUSCLE PROTEINS

This study was conducted to better understand biochemical changes of fish muscle proteins as affected by novel surimi process, acid- or alkali-aided solubilization. At 10 mM NaCl, between pH 5 and 10, the solubility of Pacific whiting muscle proteins was low but increased dramatically as the pH was shifted to either acidic or alkaline pH. At 600 mM NaCl, the isoelectric point was shifted to the acidic direction by about 2 pH units, resulting in aggregation of proteins at low pH, but improving the solubility of MHC (myosin heavy chain) between pH 6 and 10. ANS surface hydrophobicity (ANS-SO) showed much greater values than PRODAN surface hydrophobicity (PRODAN-SO) for samples treated at pH 2 - 4 perhaps due to an enhancement of the electrostatic interactions between the ANS probe and proteins. At very high pH, according to hydrophobicity results, proteins were partially refolded when the ionic strength increased. Under acidic conditions, SDS-PAGE demonstrated the degradation of MHC at 10 mM NaCl. The formation of MHC polymers was observed under alkaline treatment with a concomitant decrease of SH content.

Preliminary study on puffer fish proteome-species identification of puffer fish by two-dimensional electrophoresis.

The aims of this work were to determine the differential characterization of the urea soluble protein components of puffer fish species and to establish a preliminary proteomic database using an immobilized pH gradient two-dimensional electrophoresis (2DE) technique. The puffer fish muscle proteins resolved into 171-260 spots in the 2DE gels, with a pI range of 3-10 and molecular mass range of 7.4-205.0 kDa, following Comassie blue staining. Puffer fish muscle proteins fell in the region with pI values of 3.5-7.0, and molecular masses of 7.4-45.0 kDa were well-resolved and were good for species comparison. The more acidic proteins of lower molecular masses showed species specific characteristics. Therefore, the species of puffer fish can be differentiated from the comparison of the characteristic 2DE protein patterns.