Salt-soluble Proteins Research Articles

Effects of fatty acid saturation degree on salt-soluble pork protein conformation and interfacial adsorption characteristics at the oil/water interface

The aim of this study was to explore the effect of fatty acid saturation degree on the adsorption behavior of salt-soluble pork proteins at the oil/water interface and to reveal the mechanism between the conformational change of adsorbed proteins and the interfacial adsorption characteristics. Protein conformation, interfacial protein concentration (Γs), interfacial pressure, interfacial rheology and emulsion stability were measured in the oleic acid/linoleic acid/linolenic acid emulsions (OAE/LAE/LNAE). The results showed that the fluorescence intensity of the emulsions all decreased, which implied that tryptophan residues were exposed to the external polar environment and fatty acids influenced the polarity of micro-environment. α-Helix content in the emulsifying layer of OAE was significantly higher (P < 0.05) while β-sheets and β-turns in the emulsifying layer of OAE were significantly lower (P < 0.05) than those in the emulsifying layers of LAE and LNAE. As the saturation degree decreased, α-helices decreased, β-sheets and β-turns increased, and surface hydrophobicity decreased, implying that spatial conformational re-arrangement occurred and the number of exposed hydrophobic groups influenced the formation of interfacial protein film. In addition, the interfacial pressure of OAE/LAE/LNAE all increased as a function of adsorption time. Moreover, OAE and LAE had higher increasing adsorption rates and interfacial pressures during the initial step (0–3000 s) before interfacial pressures gradually reached the equilibrium, which indicated that low unsaturation degree facilitated the diffusion and adsorption of salt-soluble proteins. The elastic modulus (Ed) of the OAE and LAE increased rapidly within 0–1200 s, and gradually decreased. The viscous modulus (Ev) of the OAE and LAE increased. Fatty acids with low unsaturation degree could facilitate faster improvement of viscoelastic properties and the denser gel-like network structures, thus enhancing the emulsification stability.

Effects of sodium bicarbonate on the gel properties, water distribution and mobility of low-salt pork batters

To study the potential use of sodium bicarbonate in low-salt pork batters, the gel properties, rheology and water holding capacity of pork batters with various amounts of sodium chloride (0.7–1.74%) and sodium bicarbonate (0–0.42%) were investigated. The results showed that the pH, salt-soluble protein concentration, cooking yield, b* values and G′ values at 80 °C were significantly (P < 0.05) increased in the batters with sodium bicarbonate. Their textural properties were significantly (P < 0.05) increased, except for 0.42% sodium bicarbonate. Partial replacement of sodium chloride by sodium bicarbonate increased the denaturation temperature of the myosin tails, and the relaxation times of T2b, T21 and T22 were faster (P < 0.05). The mobility of the water was lower, and the immobilized water was increased, except at 0.42% sodium bicarbonate. Excessive addition of sodium bicarbonate produced carbon dioxide that destroyed the gel structure during heating. Overall, partial replacement of sodium chloride by sodium bicarbonate enabled low-salt pork batters to have a better water holding capacity and textural properties.

High-pressure pretreatment in albacore (Thunnus alalunga) for reducing freeze-driven weight losses with minimal quality changes.

This research evaluates the application of high-pressure processing (HPP) before freezing to reduce weight loss related to thawing and cooking of frozen albacore steaks (Thunnus alalunga) with a minimal impact on fish quality (color, texture, soluble protein, lipid oxidation). Albacore steaks were HPP pretreated (200, 250, and 300 MPa for 0, 2, 4 and 6 min), frozen (-20 °C, 5 m s-1 ), thawed (4 °C; 24 h), and then analyzed. At lower pressures (200 MPa) there was a clear effect of pressurization time on most of the fish quality parameters tested (thawing loss, L* value, b* value, ΔE, adhesiveness, springiness, salt-soluble protein content), whereas at higher pressures (300 MPa) similar changes took place independently of the pressurization time. High-pressure processing had no impact on lipid oxidation . A pressure of 200 MPa applied for 6 min decreased thawing, cooking, and total weight losses (53.7%, 55.4%, and 51.0% lower than the frozen control, respectively) although it led to noticeable changes in color. A pressure of 200 MPa applied for 2 min decreased thawing, cooking, and total weight losses by 23.2%, 44.0% and 33.7% with respect to the frozen control, respectively, with only minor changes in color. High-pressure processing pretreatment could be a promising tool for reducing weight loss in frozen fish when HPP conditions are properly selected. A pressure of 200 MPa applied for 2 min could be a good compromise treatment, cutting thawing and cooking losses in albacore, and reducing HPP-mediated color alterations and the related possible consumer rejection. © 2020 Society of Chemical Industry.

The characteristics of gelation of myofibrillar proteins combined with salt soluble Rhodotorula glutinis proteins by enzymatic crosslinking

Some microbial single-cell proteins are capable of producing synergistic crosslinking interactions with edible proteins by rational regulation. Herein, we reported that salt soluble proteins (RGP) extracted from Rhodotorula glutinis in an alkaline and saline system may combine with myofibrillar proteins (MP) by transglutaminase (TG) polymerization to form improvable irreversible thermal co-gels. The combination of MP, RGP, and TG, namely restructured MP gels, led to significantly enhanced water holding capacity (WHC), up to 90.76 ± 1.88% (% of retained water) and textural properties (hardness, springiness, and adhesiveness) as well as decreases of ‘gauche-gauche-gauche’ SS bonds and α-helix conformations and increases of ‘gauche-gauche-trans’ SS bonds and β-fold conformations, compared to MP and MP-RGP groups. Differential scanning calorimetry analysis validated that thermostability of myosins and actins from MP was reduced after using RGP, TG, and their combination, and unfolding and denaturation of myosin occurred easily during thermal co-gelation by TG and/or RGP.

Effect of heat treatment on physicochemical state and in vitro digestion of salt-soluble protein from Pacific oyster (Crassostrea gigas)

The current research extracted oyster salt-soluble protein (OSSP) from Pacific oyster (Crassostrea gigas) and investigated the effect of heat treatment (35–100 °C) on the physicochemical state and in vitro digestion of OSSP. Gel electrophoresis results indicated that OSSP was mainly composed of myofibrillar proteins. The denaturation temperature and enthalpy of OSSP were 54.88 °C and 5.49 J/g, respectively. Heating resulted in significantly decreased protein solubility and increased surface hydrophobicity and carbonyl content of OSSP (p < 0.05). Meanwhile protein oxidation and increasing surface hydrophobicity led to the change of OSSP aggregation state. The results of in vitro digestion showed that the digestion of OSSP was inhibited by protein oxidation and aggregation. However, this inhibition was only reflected in protein content, but not in molecular weight distribution. Proteome analysis indicated that identified peptides mainly came from myosin heavy chain striated muscle, paramyosin and tropomyosin, and the types of peptides were determined by OSSP amino acids composition.

Effects of ultra-high pressure treatment on the protein denaturation and water properties of red swamp crayfish (Procambarus clarkia)

This study aimed at understanding the effects of ultra-high pressure (UHP) treatment on the quality, protein structure and water distribution of red swamp crayfish. After pressurization (100–500 MPa, 5 min), shear force, sulfhydryl (total and reactive) and carbonyl content of myofibrillar protein extracted from crayfish muscle were significantly increased (P < 0.05) with the elevated pressure, while salt soluble protein content and Ca2+-ATPase activity decreased (P < 0.05), and the secondary structure was not affected by the pressure level. After pressurization at 300 MPa, the Ca2+-ATPase activity decreased by 0.65 fold comparing with the control (P < 0.05), while the shear force, drip loss, total and reactive sulfhydryl and carbonyl content increased by 0.34, 0.32, 0.36, 0.36 and 1.56 fold, respectively (P < 0.05). Besides, SDS-PAGE of percolate displayed the decrease of actin band (42 kDa) intensity and appearance of new bands (25–40 kDa) at 300 MPa. The increased T21 (immobilized water) and T22 (free water) of samples treated at high pressure (below 400 MPa) suggested the redistribution of water compartments, which was further confirmed with the images of proton compartments. Overall, moderate UHP treatments (less than 300 MPa) could be applied to modify the protein structure and water distribution of crayfish muscle.

Application of High Pressure Processing After Freezing (Before Frozen Storage) or Before Thawing in Frozen Albacore Tuna (Thunnus alalunga)

This work was focused on the application of high pressure processing (HPP) in frozen albacore tuna as a pretreatment before the frozen storage (BFS) or before thawing (BT) to minimize the negative effects of these conventional processes. Two different HPP pretreatments were evaluated (200/6: 200 MPa for 6 min; 600/0: 600 MPa for 0 min) and, after up to 45 days of frozen storage, thawing loss, color, texture, salt-soluble protein content, and lipid oxidation were analyzed once thawed. The application of HPP before thawing or before frozen storage reduced the thawing losses with respect to controls. For example, after 45 days of frozen storage, thawing loss of 600/0 BT and 600/0 BFS samples were 1.0 ± 0.1% and 1.8 ± 0.2%, whereas in the controls it was 5.0 ± 0.4%. After 45 days of storage, HPP BT samples presented lower thawing losses than the HPP BFS ones. Since non-important differences were detected in the rest of the studied parameters between both kinds of treatments, the application of HPP before thawing would be the best option. Regarding the tested HPP pretreatments, although 600/0 decreased thawing loss in a major extent than 200/6, this pretreatment led to sharp changes in color than 200/6 (higher L* and b* values) and texture (higher hardness and chewiness). Therefore, according to the results, the application of 200/6 BT would be a compromise option for reducing thawing loss in albacore with minimal changes on quality.

Effects of γ-polyglutamic acid on the physicochemical properties and microstructure of grass carp (Ctenopharyngodon idellus) surimi during frozen storage

The cryoprotective effects of γ-polyglutamic acid (γ-PGA) on grass carp surimi during frozen storage at −20 °C were investigated. The results showed that γ-PGA significantly maintained the quality traits of frozen grass carp surimi. Among the different concentrations of γ-PGA, treatment with 0.8% γ-PGA represented highest cryoprotective effect on the grass carp surimi during frozen storage, and its cryoprotective effect was also better than that of a conventional cryoprotectant (SS treatment). During freeze-thaw process, the gel strength and Ca2+-ATPase activity treated with 0.8% γ-PGA were 40.7% and 31% higher than those of the control group, respectively. Moreover, after 84 days frozen storage, the addition of 0.8% γ-PGA increased the gel strength, salt-soluble protein content, Ca2+-ATPase activity and the whiteness by 87.1%, 50%, 70.8% and, 11.9%, respectively, compared to the control. Meanwhile, treatment with 0.8% γ-PGA primely maintained the gel structure and sensory score of frozen grass carp surimi as well. These results indicated that γ-PGA was a potential cryoprotectant applying for the production, storage and transportation of surimi.

Deterioration mechanism of minced mutton induced by Fenton oxidation treatment

This study aims to investigate the effects of protein oxidation on the quality characteristics of minced mutton oxidized at 1, 3 and 5 h in Fenton oxidation system. The results showed that with the extension of oxidation time, the cooking loss, freeze-thaw loss and pH value of the minced mutton significantly increased, while the emulsification performance decreased. Compared with the control group, the peak area of immobilized water (T22) and free water (T23) in the oxidation treatment group gradually decreased. Scanning electron microscope (SEM) showed that the hole number of the minced mutton increased and the surface became uneven with the extension of oxidation time. The solubility of salt-soluble proteins showed a decreasing trend with the extension of the oxidation time. Compared with the control, the secondary structure of the protein in the oxidized samples were destroyed. As the oxidation time increased, the α-helix content of minced mutton protein significantly reduced, while the percentage of random coils significantly increased. These results indicated that minced mutton protein had undergone significant oxidation in the Fenton oxidation system, resulting in the changes of quality and structure.

Deciphering the immunogenic potential of wheat flour: a reference map of the salt-soluble proteome from the U.S. wheat Butte 86

BackgroundWithin the complex wheat flour proteome, the gluten proteins have attracted most of the attention because of their importance in determining the functional properties of wheat flour doughs and their roles in human health conditions such as celiac disease and food allergies. However, certain non-gluten proteins also trigger immunological responses but may be present in flour in low amounts or obscured by the more abundant gluten proteins in two-dimensional gels of total protein preparations.MethodsNon-gluten proteins were preferentially extracted from the flour with a dilute salt solution and separated by two-dimensional gel electrophoresis. Proteins in 173 gel spots were identified by tandem mass spectrometry after cleavage with trypsin or chymotrypsin. Transgenic wheat lines in which specific groups of gluten proteins were suppressed by RNA interference were used to estimate the amount of carry-over of gluten proteins in the salt-soluble protein fraction.ResultsFifty-seven different types of non-gluten proteins were identified, including 14 types that are known or suspected immunogenic proteins. The predominant proteins in 18 gel spots were gluten proteins. Some of these also contained non-gluten proteins. Analysis of the salt-soluble proteins from a transgenic line in which omega-1,2 gliadins were eliminated by RNA interference indicated that certain omega-1,2 gliadins were present in large amounts in the salt-soluble fraction and obscured relatively small amounts of beta-amylase and protein disulfide isomerase. In comparison, analysis of a transgenic line in which alpha gliadins were absent revealed that glyceraldehyde-3 phosphate dehydrogenase was a moderately abundant protein that co-migrated with several alpha gliadins.ConclusionsIn this study, we constructed a proteomic map of the non-gluten protein fraction of wheat flour from the US wheat Butte 86 that complements a proteomic map of the total flour proteins developed previously for the same cultivar. Knowing the identities of low abundance proteins in the flour as well as proteins that are hidden by some of the major gluten proteins on two-dimensional gels is critical for studies aimed at assessing the immunogenic potential of wheat flour and determining which wheat proteins that should be targeted in future gene editing experiments to reduce the immunogenic potential of wheat flour.

The prospects for the use of proteinase from Bacillus pumilus for processing raw meat

The purpose of the work was to assess the prospects of using the microbial proteinase from Bacillus pumilus for processing meat raw materials with a high content of connective tissue fibers. This proteinase has broad substrate specificity and is capable of deep hydrolysis of proteins. The effect of protease from Bacillus pumilus on meat raw materials was studied with the prospect of using in the production technology. Proteinase is very effective at the structural elements of meat raw materials, in particular water-soluble and salt-soluble protein complexes, as confirmed by spectrophotometric studies. Enzymatic treatment with proteinase from B. pumilus destructively affects cellular structures, leads to swelling and loosening of collagen fibers. The accumulation of free amino acids was recorded during processing, the degree of hydrolysis was estimated, which amounted to an average of 15-20% depending on the type of protein fraction. The positive effect of the use of proteinase to improve the functional and technological properties of raw meat was established, which resulted in an increase in its water-binding and water-holding capacity, as well as the yield of finished products after heat treatment. Based on the results of the work, it was concluded that proteinase from B. Pumilus is promising for the processing of meat raw materials with reduced functional and technological properties, which is unsuitable for the production of meat products without additional processing.

The drying temperature and the moisture content at harvest affect the apparent metabolisable energy of two maize varieties in broiler chickens

ABSTRACT 1. The grain drying process may affect the feeding value of maize but until now, no general consensus has been reached. This knowledge is essential to manage maize nutritional value in feed and ensure optimal growth performance of broiler chickens. 2. A total of 72 male Ross 308 were used in a complete randomised block design to assess the effect of initial moisture content (MC) at harvest (high or low MC after the appearance of the black layer) and drying temperature (54°C, 90°C or 125°C) on the apparent faecal digestibility and the AMEn value of two maize grain types (flint and flint-dent varieties). Moreover, the relationship between in vitro dry matter digestibility coefficient (IVDMD) and salt-soluble protein (SSP) content of dried maize grain with AMEn was assessed. 3. High drying temperature (125°C) significantly decreased the AMEn (by 0.41 MJ/kg) of the maize. Maize with high-moisture content at harvest had significantly higher AMEn than maize with low moisture content (0.38 MJ/kg) depending on the variety. Based on the combination of MC at harvest and drying temperature, an AMEn difference of about 0.65 MJ per kg of dry matter was measured during this experiment. The faecal digestibility of starch remained close to 98% with low variation between the treatments. The decrease in AMEn at high drying temperature was related to the decrease in non-starch organic matter retention (NSOMR). IVDMD and SSP content were not correlated with AMEn of dried maize (R2 < 0.1). 4. This study showed that using drying temperature below 90°C for maize grain harvested at high MC, just after the black layer development, can enhance its AMEn. The IVDMD and SSP content failed to predict the AMEn of the dried maize, but further research is required to validate the results of this study.

Short-term capture-based aquaculture of Atlantic cod (Gadus morhua L.) generates good physicochemical properties and high sensory quality during frozen storage

The annual global catch of Atlantic cod (Gadus morhua L.) is above 1,000,000 tons, and a large proportion is preserved and sold as frozen products. In Greenland, a new innovative fishing method centred on capture-based aquaculture has been developed. To compare the new fishing and processing method with the conventional method, the texture, colour, water holding capacity, salt soluble proteins and sensory properties of fillets were evaluated during 12 months of frozen storage. High quality life (HQL) and practical storage life (PSL) were determined for each fishing and processing method based on sensory evaluation, and by using water holding capacity and the salt soluble protein fraction as indices of quality. Capture-based aquaculture fishing and related processing increased frozen storage durability regarding texture attributes, blood content and sensory properties compared to the conventional method. Lowering the storage temperature to −40 °C increase the HQL to >12 months compared to a HQL of 4–6 months at −20 °C.

Effect of processing on protein degradation and quality of emulsion sausages

The impact of processing on the protein degradation and quality of emulsion sausages was studied. Analysis of SDS-PAGE, water-soluble nitrogen, and non-protein nitrogen showed processing affected protein degradation, and the degree of degradation was increased with increasing cooking temperatures. The significant increase of Tyr, Lys, Cys, Asp and Glu as free amino acids content confirmed the protein degradation during processing. Color and texture parameters showed significant changes with processing. Sausages (90 °C) had more flower, green, and fruity flavors, while sausages at 120 °C had more oil, fat, and warm flavors. Pearson correlation analysis showed that protein degradation had a significant effect on the quality of emulsion sausages during processing. The changes in morphology of water-soluble and salt-soluble proteins can explain the protein turbidity and texture changes at a microscopic level during processing. Furthermore, a label-free strategy was used to investigate the changes in the proteomes between 0 and 120 °C sausages. Differentially expressed proteins, and disappearing and emerging proteins affected the quality of sausages directly or indirectly. These proteins could be regarded as important factors affecting sausages.

Exogenous α-amylase supplementation reduces the variability of ileal digestible energy in broiler chickens fed complete diets with maize batches of variable protein solubility

This study evaluated the relationship between salt-soluble protein (SSP) of maize and the apparent ileal digestibility (AID) of complete diets in response to exogenous α-amylase supplementation in broiler chickens. Samples of 12 maize batches originating from the mid-north and northeast of China were analyzed for SSP. Six of the 12 sources of maize with a wide variation of SSP (from 21.1 % to >50 %) were selected. Six maize-soybean meal basal diets were formulated, including each source of maize with or without the addition of α-amylase (Ronozyme® HiStarch; DSM Nutritional Products). A total of 960 day-old male Arbor Acres Plus broiler chickens were randomly allocated to 12 treatments with 8 replicates per treatment in wired cages and fed experimental diets in 2 phases (d 1−14; d 15−28). At d 28, 4 birds selected from each cage were euthanized for evaluation of apparent ileal digestibility (AID) of starch and energy. The addition of α-amylase reduced the feed conversion ratio (FCR) of chickens from 1 to 28 d (1.407 vs. 1.426) compared to the basal diets across maize batches, particularly from 1 to 7 d (1.049 vs. 1.078). An interaction between maize batch and α-amylase supplementation on FCR was detected only at 7 d, when the batch with the lowest SSP exhibited the greatest response to α-amylase. Neither a main effect of α-amylase nor an interaction with maize batch on AID of starch were detected (P > 0.05). Nonetheless, α-amylase supplementation increased ileal digestible energy (IDE) from 12.21 to 12.50 MJ/kg dry matter across maize batches. These increments were mainly driven by the maize batch with the lowest SSP. α-amylase supplementation reduced the variability of IDE from a coefficient variance (CV)=5.2 % to a CV=0.7 % across maize batches. Interestingly, there was a strong negative correlation (r<-0.95; P < 0.001) between the initial IDE of maize and the IDE response to α-amylase, and a less strong correlation between SSP and the IDE response to α-amylase (r=-0.78, P = 0.07). SSP was not a predictor of starch digestibility at this age. Dietary α-amylase supplementation has the potential to significantly reduce the variability in the energy value of maize-based diets in commercial poultry production by improving the nutritional value of poorly digestible maize.

Interactions between beef salt-soluble proteins and elephant foot yam (Amorphophallus campanulatus) flour in heat-induced gel matrix development.

The objective of this study was to observe the interactions between salt-soluble proteins extracted from beef and elephant foot yam (Amorphophallus campanulatus) flour in heat-induced gel matrix development. The effect of salt concentration; 0.5%, 1.0%, 1.5%, and 2.0% in weight/weight basis (w/w), during protein extraction on pH, salt-soluble protein concentration and myofibril fractions of beef extract was determined firstly, and no significant effect was found. The beef salt-soluble proteins extracted using salt solution at different concentrations were then added with elephant foot yam flour at 5%, 10%, and 15% w/w, gelatinized at 90°C for 20 min, and cooled down at 4°C for 12 h. The interactions between beef salt-soluble proteins and elephant foot yam flour resulted in an improved gel strength (p < 0.01) and the addition level of elephant foot yam flour affected the pH, instrumental color, moisture, crude protein, and ash content significantly. The addition of elephant foot yam flour also reduced the size of the pores in the gel matrix as shown by scanning electron microscope (SEM) photographs. These suggest that elephant foot yam flour well interacts with beef salt-soluble proteins to form gel matrix.

Beef Salt-Soluble Proteins and Seaweed (Eucheuma cottonii) Flour Interactions to the Quality of Heat-Induced Gel Matrix Development

The objective of this study was to observe the interactions between salt-soluble proteins from beef and seaweed (Eucheuma cottonii) flour and its effect to the quality of the produced protein gel. The study was conducted as experimental research with two factorials completely randomized design. The effect of different NaCl (2.0%; 2.5%; 3.0%; and 3.5%) and Eucheuma cottonii flour (5%; 10%; and 15%) concentrations was observed to the physical and proximate quality of the protein gel matrix. The observed gel quality variables include pH, gel strength, color (L, a*, and b*), moisture, protein, and fat content. The gel was gelatinized at 90°C for 20 min and cooled down at 4°C for 12 h. The results showed that there was no interaction effect found on all of observed variables. However, a highly significant effect (P<0.01) was found on the ash content with different salt concentrations, while different Eucheuma cottonii flour concentrations improved the gel strength (P<0.01) and significantly gave darker (P<0.01) color. The effect of Eucheuma cottonii flour on the physicochemical properties of the gel was concentration dependent. Therefore, this study concludes that Eucheuma cottonii flour showed a potential as binding or filling agent to form strong gel matrix in processed meat products.

Characteristic of baltic cod mince Gadus Morhua Callarias washed with electrochemical activated water with different concentration of active chlorine ions

The relevance of the above technological process makes it possible to reduce intensity of fish smell and taste, to improve color, to form a more dense structure and to increase shelf life of minced cod. For the first time minced cod was washed by Electrolyzed – water (EW-water) containing various concentrations of active chlorine, as well as free radicals. The influence of different concentration of active chlorine ions on physical and chemical characteristics of washed minced cod was determined. The optimum concentration of active chlorine ions was determined. The amount of removed water-soluble proteins depends on the type of water and the concentration of active chlorine in it. Pure and electrolyzed - water was characterized before and after washing minced cod. The rheological characteristics of minced cod washed by EW - water with different concentrations of active chlorine ions do not change significantly at a concentration in the range from 25 to 150 mg/l. With a concentration of active chlorine ions more than 200 mg / l, the ultimate shear stress increases significantly, the texture of minced cod becomes too dense, which negatively affects the sensory characteristics. Dependence of ratio of protein coefficient and suitability level of minced cod for preparation of high-quality food product was determined. It was found that washing of the minced cod removes water-soluble proteins, which leads to a change in their ratio with salt-soluble proteins, as a result of which the protein coefficient increases by 1.5-2.4 times. The advantage of washing minced cod by electrolyzed – water, which differs in better rheological characteristics compared to minced cod washed with pure water, was justified.

Evolution of quality parameters of high pressure processing (HPP) pretreated albacore (Thunnus alalunga) during long-term frozen storage

The aim of this work was to study the application of high pressure processing (HPP) before freezing for maintaining as much as possible the fresh characteristics of albacore steaks after long-term storage. HPP treatments were applied at 200 MPa for 0–6 min. Then, samples were immediately frozen (−20 °C) and stored (−20 °C) for up to 12 months. Once thawed (4 °C; 24 h), weight losses, color, texture, lipid oxidation (TBARS) and salt-soluble protein content were analyzed.After 12 months of frozen storage, 200 MPa for 6 min minimized thawing loss inherent to freezing and frozen storage and decreased TBARS (53.9%) with respect to the control. However, it resulted in changes in color (higher L*, b* and ΔE values) and texture (higher adhesiveness and springiness) and decreased the salt-soluble protein content with respect to non-pretreated samples. Nevertheless, after cooking, there were no differences in color and texture between HPP pretreated fish and the controls.

Quality Assessment of Frozen Solenocera crassicornis Treated with Sodium Metabisulphite bySoaking or Spraying

The present work was carried out to evaluate the safety of shrimp ( Solenocera crassicornis ) treated with different concentrations of sodium metabisulfite (SMB) by soaking or spraying during frozen storage. Shrimps soaked in higher concentrations of SMB showed higher sensory scores, lower total color differences, and better anti-melanosis effects than shrimps in the control and other treatment groups throughout frozen storage (−18°C). Lower total volatile basic nitrogen and thiobarbituric acid reactive substances and higher salt soluble protein contents were detected in shrimp soaked with high doses of SMB compared with other samples. In addition, lower counts of total aerobic plates and psychrotrophic bacteria were observed in shrimp treated by soaking with higher doses of SMB than those in control shrimp and shrimp treated with other methods during frozen storage (−18°C). However, the SO 2 content of 5% SMB-soaked samples exceeded the maximum allowable limit of 100 mg kg −1 . Overall, the use of 1.5% SMB soaking to treat shrimp results in good antioxidant and antimicrobial effects and, thus, may be suggested to preserve S. crassicornis under frozen conditions. The results of this study present important guidance on the use of SMB to maintain the quality of marine-trawling shrimp from manufacturing to consumption.