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ABSTRACT Ecosystem models predict changes in productivity and status for multiple species, and are important for incorporating climate‐linked dynamics in ecosystem‐based fisheries management. However, fishery regulations are primarily informed by single‐species stock assessment models, which estimate unexplained variation in dynamics (e.g., recruitment, survival, fishery selectivity, etc) using random effects. We review the general benefits of estimating random effects in ecosystem models: (1) better representing biomass cycles and trends for focal species; (2) conditioning interactions upon observed biomass for predators and prey; (3) easier replication of model results using formal estimation rather than informal model “tuning;” and (4) attributing process errors via comparison amongst different models. We then demonstrate these by introducing a new state‐space model EcoState (and associated R‐package) that extends mass balance dynamics from Ecopath with Ecosim. This model estimates mass balance (Ecopath) and time‐dynamics (Ecosim) parameters directly via their fit to time‐series data (biomass indices and fisheries catches) while also estimating the magnitude of process errors using RTMB. A real‐world application involving Alaska pollock (Gadus chalcogrammus) in the eastern Bering Sea suggests that fluctuations in krill consumption are associated with cycles of increased and decreased pollock production. A self‐test simulation experiment confirms that estimating process errors can improve estimates of productivity (growth and mortality) rates. Overall, we show that state‐space mass‐balance models can be fitted to time‐series data (similar to surplus‐production stock assessment models), and can attribute time‐varying productivity to both bottom‐up and top‐down drivers including the contribution of individual predator and prey interactions. [ABSTRACT FROM AUTHOR]

The processes before heating in surimi gel production, such as grinding and molding, are performed below 10 °C to prevent unintentional protein gelation (suwari or setting) catalyzed by endogenous transglutaminase. Adding transglutaminase and protease inhibitors contributes to obtaining surimi gel with superior breaking properties after suwari suppression. However, the impact of suwari suppression and enzyme inhibitors on the water holding capacity (WHC) of surimi gel remains unclear. This study investigated changes in the WHC of surimi gel during long-term suwari suppression by adding enzyme inhibitors at 25 °C and clarified its mechanism. The expressible drip of samples with EGTA, a transglutaminase inhibitor, increased with heating time at 25 °C to 12.3% owing to proteolysis. The use of N-ethylmaleimide and E-64, cysteine protease inhibitors, further increased the expressible drip of samples (18.9–19.4%) because of protein conformational changes which were observed by DSC analysis and salt solubility measurement. However, this increase was inhibited by a modified grinding method where NaCl was mixed with surimi before adding enzyme inhibitors. This modified method prevented the reduction in protein salt solubility due to protein conformational changes, thereby maintaining WHC in surimi gel with suwari suppression. [ABSTRACT FROM AUTHOR]

Deep frying (DF) is a popular cooking technique resulting in desirable sensory quality. However, DF also results in negative perception related to increased fat uptake and thus poor nutritional quality. In this study, a development of a novel strategy for fat reduction in DF surimi without additives and coatings was attempted. Novel pre-baking and pre-roasting were applied to surimi prior to DF. This novel pre-treatment strategy for DF surimi has not been reported in literature. Total, free, and bonded fat contents and corresponding fat reductions in DF surimi were determined. Cook and moisture losses as well as water holding capacity, expressible moisture, in addition to color and texture were also investigated. Fat uptake during DF of surimi was reduced (P 0.05) affect cook and moisture losses, water holding capacity, expressible moisture, color, and texture. However, pre-roasting increased (P

BACKGROUND: Dried and salt‐fermented fish products are important sources of N‐nitrosodimethylamine (NDMA) exposure for human. As a potent carcinogen, NDMA was frequently detected in roasted Alaska pollock fillet products (RPFs), which is among the most common fish products in China. Until now, the occurrence and development of NDMA and its precursors (nitrites, nitrates and dimethylamine) in RPFs during processing and storage were not well elucidated, and safety evaluation of this fish product is also urgently needed. RESULTS: The presence of precursors in the raw material was verified and significant increase of nitrates and nitrites during processing was observed. NDMA was found generated during pre‐drying (3.7 μg kg−1 dry basis) and roasting (14.6 μg kg−1 dry basis) process. Continuous increase in NDMA content can also be found during storage, especially at higher storage temperature. The 95th percentile of Monte Carlo simulated cancer risk (3.73 × 10−5) surpassed the WHO threshold (1.00 × 10−5) and sensitivity analysis implies the risk was mainly attributable to NDMA level in RPFs. CONCLUSION: The occurrence of NDMA in RFPs was mainly a result of endogenous factors originating in Alaska pollock during processing and storage rather than exogenous contamination, and temperature played a pivotal role. The preliminary risk assessment results suggest that long‐term consumption of RPFs would impose potential health risks for consumers. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

We assessed the bacterial diversity in five Alaska pollock surimi samples using 16S rRNA sequencing to plan the pre-processing of fermenting surimi. The viable bacterial count of the surimi samples was approximately 104-105 cfu/g. Phylogenetic tree analysis revealed that the surimi bacterial profile was dominated by phylum Pseudomonadota, with the dominant genera being Pseudomonas and Psychrobacter. Only one strain of spore-producing bacteria was isolated from the five surimi samples. These results suggest that pasteurization before inoculation of bacterial starters was necessary for stable and hygienic fermentation of Alaska pollock surimi. [ABSTRACT FROM AUTHOR]

Summary: Alaska pollock (Gadus chalcogrammus) is a marine fish that lives in the North Pacific Ocean. G. chalcogrammus contains high nutritional value, especially protein. Alaska pollock proteins (APP) and its peptides have been reported to have biological activities. However, the biological activities of APP have not been reviewed so far. The aim of this study was to review the published research on APP and its peptides, as well as their potential biological activities, using the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. We used ScienceDirect, PubMed and Web of Science to identify the relevant references. In total, 43 studies were obtained and reviewed after the filtering process. Most of the research has focused on APP's prospective biological activities. The current study revealed that APP possesses biological activities, including skeletal muscle hypertrophy, anti‐obesity, anti‐cholesterol, blood glucose‐lowering and anti‐non‐alcoholic fatty liver effects. Peptides that are hydrolysed from APP possess biological activities, such as ACE inhibition, antioxidant effects, immunomodulation, anti‐diabetic, mineral chelation and wound healing activities. Only a few clinical studies were available on either APP or the respective peptides. Therefore, further study is needed to completely understand the potential of APP and the associated peptides as novel nutraceutical and functional food, as well as to evaluate their effects in humans. [ABSTRACT FROM AUTHOR]

Fish paste products such as kamaboko (KB) are traditional Japanese foods prepared from fish meat. The health-promoting properties of fish proteins and their lysates include improving glucose and lipid metabolism. Although the KB manufacturing process and quality have been examined, limited studies have reported the health-promoting function of KB. This study aimed to evaluate the effects of processing Alaska pollock protein (APP) into KB protein (KBP) on serum lipids levels and postprandial glucose tolerance. Obese male Zucker fa/fa rats were fed on different diets for 4 weeks as follows: APP group, fed on a diet in which APP constituted 25% of total protein intake; KBP group, fed on a diet with APP-processed protein as the protein source; control group, fed on a diet with 100% casein as the protein source. Compared with those in the control group, the serum total cholesterol (TC) level was reduced and the elevated postprandial blood glucose level was mitigated during the high-carbohydrate meal tolerance test in the APP and KBP groups. Further, KBP exerted significantly higher effects on serum TC levels and glucose tolerance than APP. [ABSTRACT FROM AUTHOR]

A new microsporidian infecting Gadus chalcogrammus Pallas, 1814 (Gadidae), is described based on morphological, ultrastructural, and molecular studies. This microsporidian parasite develops inside intramuscular spindle-shaped lesions measuring approximately 1–2 mm in width and 4–8 mm in length. Infected cells encapsulated by a host-produced wall containing a sponge-like acellular zone. Sporogony presumably proceeds via segmentation of sporogonial plasmodium, resulting in a variable number of spores. Sporogonial stages develop in sporophorous vesicles (SVs), abutting a moderately electron-dense thick walled coat of a homogeneous amorphous material. SVs space contains rare granular and tubular inclusions. Neighboring SVs often interconnected by bridges of the host cell cytoplasm that were limited by membrane comparable with SV coat. The elongate-ovoid spores, measuring 4.29 ± 0.38 × 2.51 ± 0.26 μm (N 104), possess a bipartite polaroplast and polar tube with 15–16 coils arranged in 2–3 layers. The angle of tilt of the polar tube coils is less than 30°. The sequence analysis of SSU rDNA coding region showed that the studied microsporidians differs from other fish muscle-infecting species at least in 17 bp (2.58%) and is closely related to Microsporidium cypselurus Yokoyama et al. (2002) infecting the flying fish from East China Sea. The parasite is provisionally positioned as Microsporidium theragrae sp. n. [ABSTRACT FROM AUTHOR]

To enhance the value of surimi, efforts have been made to develop a fermentation method with lactic acid bacteria (LAB) to proteolyze fish protein. However, fermenting unheated surimi poses a spoilage risk due to its high bacterial content. Surimi heat treatment can prevent spoilage, but gel formation induced by heating introduces another technical issue: it hinders uniform fermentation. Thus, this study aims to observe the proteolysis and enhance the functionality of seafood product through lactic acid fermentation of kamaboko, a heated surimi. Upon analyzing the kamaboko fermented with Lactobacillus helveticus JCM1004, we observed that LAB produced protease, resulting in the degradation of myosin heavy chain and actin during fermentation. Lactic acid fermentation significantly augmented the peptide content of kamaboko, subsequently elevating the angiotensin Ⅰ-converting enzyme (ACE) inhibitory activity in 200-fold diluted extract of fermented kamaboko to approximately 70% and higher. Notably, our investigation revealed that proteolysis was confined to the surface of kamaboko, as evidenced by SDS-PAGE analysis. This observation implies that the surface area of kamaboko influences the ACE inhibitory activity. Through a comparative analysis of various bacterial strains, we demonstrated that the increase in ACE inhibitory activity is contingent on the protease generated by LAB. These results suggest that LAB-mediated proteolysis of fish proteins liberates bioactive peptides, thereby manifesting in the ACE inhibitory activity. In summary, this study underscores that the fermentation of kamaboko employing proteolytic LAB holds promise in the development of novel functional seafood products.

Introduction: initial references of products made with surimi date back in Japan to the 12th century. The technological process was developed in 1972. It is essential to use fresh fish to preserve the nutritional and technological quality of its myofibrillar protein. The highest quality species for elaborating surimi is Alaska pollock, belonging to the cod family. The best part of the fish regarding quality are its fillets or loins. Objectives: to evaluate the protein quality of surimi and its omega-3 fatty acid content, and to review the scientific evidence for the role of surimi in relation to health. Results: the amino acid score pattern of surimi is above 100 for the 9 essential amino acids, showing good assimilation and digestibility, even higher than that of homologous products such as meat, fish, and eggs. Surimi contributes considerably to the intake of omega-3 fatty acids eicosapentaenoic (EPA) and docosahexaenoic (DHA). Different studies link surimi consumption with positive effects on body composition: increase in skeletal muscle and reduction in white adipose tissue, as well as a tendency to improved muscle motor function. EPA and DHA have a function on both cardiovascular and cognitive parameters. Conclusions: one of the main reasons to consume surimi is its excellent protein quality, highlighting its easy assimilation and digestibility. Likewise, surimi’s natural content in omega-3 fatty acids EPA and DHA is of great nutritional interest. These components are related to functional effects on body composition, metabolic syndrome parameters, and cognitive level. [ABSTRACT FROM AUTHOR]

Alaska pollock is one of the most economically valuable and consumed cod species, but the adulterants in the market affect its quality and value. This study used a combination of FT-NIR spectroscopy and chemometrics to construct a qualitative and quantitative analysis model. Before the establishment of detection models, different pre-processing techniques were used to eliminate background interference. Principal component analysis (PCA) and analysis of variance (ANOVA) showed the feasibility of spectral methods for the detection of Alaska pollock adulteration. The modeling results show that the RF classification model had the most suitable prediction results (accuracy: 92.18%, precision: 98.04%, recall: 92.59%, and F1-score: 95.29%), and SVR was the optimal prediction model for quantitative analysis, with an R C 2 of 0.941, an RMSEC of 0.060, an R P 2 of 0.946, and an RMSEP of 0.062. These results indicate that, based on the developed detection model, adulterants in Alaska pollock could be rapidly detected and accurately quantified. In addition, it provides a reliable basis for rapid and non-destructive detection of and has great potential for determining other seafood species. [Display omitted] • Innovative application of FT-NIR with chemometrics in detecting Alaska Pollock. • The importance of spectral preprocessing and multivariate statistical methods was studied. • Qualitative and quantitative models based on FT-NIR were constructed and compared for the first time. • The accuracy of both prediction models is> 95%, over than the current methods. [ABSTRACT FROM AUTHOR]

The changes in protein degradation behavior in fish surimi upon addition of different protease inhibitors were examined, with the aim of identifying the proteases involved in the modori reaction in different species and grades of fish and at different temperatures. The modori reactions at 40, 50, and 60°C in four frozen surimi samples: grades FA and KA blue grenadier and grades SA and RA Alaska pollock were investigated. In the grade FA blue grenadier surimi, the modori reaction primarily involved metalloproteases at 40°C, serine proteases and cysteine proteases at 50°C, and cysteine proteases at 60°C. The reaction in the grade KA blue grenadier surimi involved multiple proteases at 40°C, and metalloproteases and cysteine proteases at 50 and 60°C. In the Alaska pollock surimi, multiple proteases were suggested to be equally involved in the modori reaction at 40, 50, and 60°C in both grades SA and RA samples.

Fish paste products such as kamaboko (KB) are traditional Japanese foods prepared from fish meat. The health-promoting properties of fish proteins and their lysates include improving glucose and lipid metabolism. Although the KB manufacturing process and quality have been examined, limited studies have reported the health-promoting function of KB. This study aimed to evaluate the effects of processing Alaska pollock protein (APP) into KB protein (KBP) on serum lipids levels and postprandial glucose tolerance. Obese male Zucker fa/fa rats were fed on different diets for 4 weeks as follows: APP group, fed on a diet in which APP constituted 25% of total protein intake; KBP group, fed on a diet with APP-processed protein as the protein source; control group, fed on a diet with 100% casein as the protein source. Compared with those in the control group, the serum total cholesterol (TC) level was reduced and the elevated postprandial blood glucose level was mitigated during the high-carbohydrate meal tolerance test in the APP and KBP groups. Further, KBP exerted significantly higher effects on serum TC levels and glucose tolerance than APP.

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Parvalbumin (PV) is one of the major allergens in fish. The aim of our present work was to research the influence mechanism of glycation with different reducing sugars (glucose, fructose, ribose, lactose, and galactose) on the immunoglobulin E (IgE) and immunoglobulin G (IgG) binding capacity and structure changes of PV in Alaska Pollock. PV glycated with glucose or fructose (PV‐Glu/ PV‐Fru) exhibited the higher IgE/IgG binding capacities than that of ribose, galactose, or lactose. During glycation, the lysine (Lyr), tyrosine (Tyr), and phenylalanine (Phe) of PV were gradually embed into core area of three‐dimensional structure of protein, which reflected in the ultraviolet (UV) spectrum and fluorescence spectra. Moreover, the increase of surface hydrophobicity had confirmed the conformation alteration of glycated PV. These results suggest that there is a specific association among the change of PV in glycation and in potential allergenicity. The types and conformation of reducing sugar greatly influenced the IgE/IgG binding capacity of PV, and glycation with ribose and galactose was a promising approach for reducing the IgE/IgG binding capacity of PV from Alaska Pollock. Practical applications: Parvalbumin (PV), the major allergen of fish, it can not only maintain the physiological activity of cells, but also cross react with human amyloid protein to alleviate Alzheimer's disease and Parkinson's syndrome. This study revealed that the IgE/IgG binding capacity and structural changes of PV from Alaska Pollock modified by glycation with different reducing sugars. This will help us to understand the sensitization and structural change of the glycated products after the reaction of PV with different reducing sugars. It provides an effective carbonyl source for the preparation of low antigenicity PV based on glycation and lays a foundation for glycation modification of other food allergens. [ABSTRACT FROM AUTHOR]

Alaska pollock (AP) surimi paste was prepared (0–3% salt and 76–84% moisture). The density, specific heat, and thermal conductivity were measured and modelled in temperatures between 25 and 90 °C (R2 > 0.92). The thermal diffusivity (α) function showed a strong dependence on the moisture content and a unique salt dependence at 84% of the moisture content and applied to the heat transfer simulation of surimi paste. The simulation model coupled with the empirical thermal properties accurately predicted the heat penetration curves during heating with RMSE values ranging from 0.43 to 1.22 °C. The salt dependence on thermal diffusivity was identified and modeled only at 84% moisture content. With a model for 84% moisture content, the RMSE value of 3% salt content decreased from 1.11 °C to 0.56 °C. This study demonstrated that an accurate prediction of the heat transfer of the surimi paste needs to be coupled with the nonlinear thermal diffusivity functions. [ABSTRACT FROM AUTHOR]

The composition of muscle tissues of a deep-sea species, the giant grenadier (Albatrossia pectoralis), and a mesopelagic species, the Alaska pollock (Theragra chalcogramma), are compared. Grenadier is proved to have a higher moisture content (91.7%) and lower protein (7.4%) and lipid (0.3%) contents. The factors responsible for the softening and moisture separation during processing of grenadier are identified. Contents of some fractions of non-protein nitrogenous components, including trimethylamine oxide (TMAO) and free amino acids, are clarified. The proportion of the main myofibrillar proteins myosin and actin, which is considered as an indicator of efficiency of structure formation in fish muscle tissue during processing, is almost 20% lower in giant grenadier than in pollock. The effects of endogenous protease, Ca2+-ATPase and transglutaminase on the processes of autolysis, denaturation, and possibility of myofibrillar proteins cross-linking were also studied. The proposed technology of getting a nutritionally balanced, gel-like, ready-to-use foodstuff from grenadier fillet includes its enrichment with pollock muscle tissue and supplementing with a binary structure-forming agent containing collagen and chitosan. Nutritional value of the products is assessed by the method of biological assay and by determining the denaturation changes of myofibrillar proteins. The modes of fine mincing and thermal processing, as well as the shelf-life of the finished product are justified. The developed technology of producing a ready-to-eat food from giant grenadier will allow a more efficient use of this underutilized resource. [ABSTRACT FROM AUTHOR]

Waste from fish cutting (heads, swim bladders, fins, skin, and bones) is a high-value technological raw material for obtaining substances and products with a wide range of properties. The possibility of using waste from cutting fish of the Gadidae family: the Alaska pollock (Gadus chalcogrammus) and the Pacific cod (Gadus macrocephalus), processed in the coastal zone, is scientifically substantiated. In this work, a technology has been developed for processing accumulated waste from fish cutting in order to obtain fish gelatin, which is characterized by high protein content (more than 80.0%) and a full set of essential and nonessential amino acids. We studied the quality of fish gelatin obtained from wastes from cutting the fish of the Gadidae family. The possibility of using fish gelatin as a component of fish products is shown; the dose of its introduction into the fish products is substantiated. The data obtained made it possible to recommend the use of fish processing waste products as a gelling component and a source of amino acids in multicomponent food systems.

Copyright of CyTA: Journal of Food is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• ETGase activity in Alaska pollock roe decreased during frozen storage. • Mechanical properties of the salted Alaska pollock roe was improved using MTGase. • Adding 0.5% MTGase was the optimum to enhance the texture of the salted roe. • MTGase can be used to improve the texture of aquatic processed food at 5 °C. The aim of our study was to improve the texture quality of salted Alaska pollock (Theragra chalcogramma) roe product using microbial transglutaminase (MTGase). Thus, the effect of 0–1.0% MTGase on the physical properties of the salted roe was assessed. Endogenous TGase activity in the roe, which contributes to improving its texture, decreased at −20 °C during frozen storage. Mechanical properties of the salted roe, such as roe firmness and egg breaking strength, were improved using MTGase, the optimum concentration of which was 0.5%. Protein polymerizations using SDS-PAGE and decreasing of protein solubilities in SDS–urea solution were observed in the salted roe with MTGase. Therefore, the texture of salted Alaska pollock roe can be significantly enhanced by adding 0.5% MTGase because of catalyzing protein crosslinking. Additionally, this study most likely indicates that MTGase can be used to improve the texture of aquatic processed foods at low temperatures, especially 5 °C. [ABSTRACT FROM AUTHOR]

Highlights • A method was established for the quantitative analysis of Alaska pollock from processed seafoods. • 16S rRNA region was used as a DNA marker for quantitative analysis. • A formula was devised to determine the weight of Alaska pollock based on the DNA copy number. • The method was applied successfully to the analysis of 15 processed seafoods. Abstract A highly accurate quantitative method, based on the new technique, droplet digital PCR (ddPCR), was applied to determine the content of Alaska pollock (Gadus chalcogrammus) in seafood products. Using this method, we found a linear relationship among raw sample weight, DNA concentration and DNA copy number. We also established a formula to calculate the raw sample weight, based on the number of DNA copies. To confirm the accuracy and applicability of this method, mixed samples of known composition were analyzed. Results from this study indicated that the ddPCR method described is suitable for quantifying Alaska pollock in seafood products and has the potential applied to a variety of tasks in food quality certification. [ABSTRACT FROM AUTHOR]

The effect of heating rates (3, 60 and 160 °C/min) on textural and physical properties of Pacific whiting (PW) and Alaska pollock (AP) surimi gels mixed with diced carrot (0%, 3%, 6%, and 9%) were investigated. Surimi-carrot mixed pastes were heated ohmically from 5 to 90 °C under three different heating rates and chilled immediately in ice/water. As heating rate increased, the hardness and cohesiveness value of PW surimi gels increased and those of AP surimi gels decreased. The hardness and cohesiveness value of PW and AP surimi gels prepared with diced carrot significantly decreased as the carrot content increased at all heating rates ( P < 0.05). The shear force value of carrot heated at 160 °C/min showed the highest value in both species. The moisture loss (%) of surimi and carrots heated at 160 °C/min was significantly lower than other samples heated slowly. Scanning electron microscope revealed that the heating rate significantly influenced the microstructure of surimi gel and carrot in both species. [ABSTRACT FROM AUTHOR]

Research has estimated associations between water temperature and the spatial distribution of marine fishes based upon correlations between temperature and the centroid of fish distribution (centre of gravity, COG). Analysts have then projected future water temperatures to forecast shifts in COG, but often neglected to demonstrate that temperature explains a substantial portion of historical distribution shifts. We argue that estimating the proportion of observed distributional shifts that can be attributed to temperature vs. other factors is a critical first step in forecasting future changes. We illustrate this approach using Gadus chalcogrammus (Walleye pollock) in the Eastern Bering Sea, and use a vector-autoregressive spatiotemporal model to attribute variation in COG from 1982 to 2015 to three factors: local or regional changes in surface and bottom temperature ('temperature effects'), fluctuations in size-structure that cause COG to be skewed towards juvenile or adult habitats ('size-structured effects') or otherwise unexplained spatiotemporal variation in distribution ('unexplained effects'). We find that the majority of variation in COG (including the north-west trend since 1982) is largely unexplained by temperature or size-structured effects. Temperature alone generates a small portion of primarily north-south variation in COG, while size-structured effects generate a small portion of east-west variation. We therefore conclude that projections of future distribution based on temperature alone are likely to miss a substantial portion of both the interannual variation and interdecadal trends in COG for this species. More generally, we suggest that decomposing variation in COG into multiple causal factors is a vital first step for projecting likely impacts of temperature change. [ABSTRACT FROM AUTHOR]

Physical properties of Alaska pollock surimi paste were investigated as affected by pH (4.0 and 6.0-10.0) and heating conditions (slow and fast). The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. The effect of pH was strikingly high at pH 7.5 when gels were prepared using 2-step heating, indicating the pH dependence of endogenous transglutaminase. However, the highest gel strength was obtained at pH 8.0 when gels were prepared in fast heating. Whiteness value (L − 3b*) increased significantly ( p < .05) as pH increased from 6.0 to 6.5, but thereafter decreased significantly ( p < .05) as pH increased. L* value (lightness) and b* value (yellowness) continuously decreased as the pH is shifted from 6.0 to 10. Fast heated gels showed the lowest yellowness, resulting in whiter appearance, probably due to the effect of reduced browning reaction. Practical applications The uniqueness of this study was to measure the combined effect of pH and heating conditions on the gel texture and color. There were various studies dealing with pH or heating conditions independently. As the primary character for surimi seafood is gel texture and color. The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. Whiteness value (L − 3b*) increased significantly as pH increased from 6.0 to 6.5, but thereafter decreased significantly as pH increased. L* value (lightness) and b* value (yellowness) continuously decreased as the pH is shifted from 6.0 to 10. Fast heated gels showed the lowest yellowness, resulting in whiter appearance. [ABSTRACT FROM AUTHOR]

O interesse pela produção de óleo de pescado para consumo humano é crescente. No Alasca, EUA, uma grande quantidade de subprodutos tem sido usada como matéria-prima. Entre os subprodutos, o fígado de Alaska pollock (Theragra chalcogramma) apresenta interesse particular em razão de seu alto teor de lipídios. Normalmente, a temperatura usada para extração do óleo de pescado é elevada e potencialmente incompatível com a estabilidade lipídica. O objetivo deste trabalho foi avaliar o processamento do óleo de fígado de Alaska pollock, extraído a baixas temperaturas. Como confirmado, a matéria-prima obtida na primavera (40%) apresentou um conteúdo lipídico menor que a de outono (50%). A extração foi realizada cinco vezes para quatro combinações de tempo (15 e 30 minutos) e temperatura (50 e 60 ºC). Foram analisadas duas bateladas de óleo de fígado e vísceras de pollock, produzido em navio processador. O rendimento do processo foi semelhante (aproximadamente 52%), os óleos de fígado produzidos se apresentaram mais claros, com coloração amarela, comparados aos de vísceras de pollock produzidos no outono. Os ácidos graxos livres foram similares para óleos de fígado e de vísceras nas duas estações, atingindo, no máximo, 0,4%; o índice de peróxidos, o valor de anisidina e o valor de ácido tiobarbitúrico determinados nos óleos apresentaram 2-14 meq.kg-1, 20-26 e 0,4-0,6 mg dialdeído malônico.kg-1, respectivamente. Todos os óleos investigados foram compostos principalmente por triacilgliceróis (88-100%), com o conteúdo de fósforo não excedendo, em média, 15 ppm.

Russia supports the sixth largest fisheries worldwide, which grew 25% during the last decade and is forecasted to grow 40% more up to 2020. Such voluminous and fast growing fisheries cause challenges for their sustainability. Marine Stewardship Council (MSC) voluntary certification is now the most recognized system aimed to achieve sustainability of fisheries through informed choice of consumers. The certified fisheries benefit through recognition of MSC logo by consumers. The certificate is awarded to fisheries with a good status of target species and limited impact to structure and function of ecosystems, and to protected species. The recent research showed that MSC certified fisheries in average refer to healthier stocks than non-certified ones. Russia entered the program in the second half of the 2000s, and the first certificate was awarded in 2009. Now the MSC process in Russia is very intensive and currently involves thirteen fisheries, seven of them already are certified. The certified fisheries can be subdivided into three groups: (i) set net Pacific salmon fisheries of the Far East, (ii) bottom trawl codfish fisheries in the Barents Sea, and (iii) pelagic trawl Alaska pollock fisheries in the Sea of Okhotsk. The total catch of fisheries involved in the MSC program now is about one-third for Pacific salmon, most of codfish and about a half for Alaska pollock. Process of MSC certifications in Russia faces various problems, caused by differences between western and Russian traditions of fishery management, difficulties of access to scientific information, insufficient support from governmental institutions, illegal fishing, insufficient independent observance, influence of hatcheries on salmon wild stocks and others. We believe that to improve sustainability of Russian fisheries, it is needed to demonstrate economical benefits of certification for those fisheries which are not involved in the program, to involve new fisheries in the process, and to develop home market of sustainable seafood.

Surimi wash-water (SWW) contains a high concentration of protein resulting in a negative environmental impact and high disposal costs. Isoelectric point precipitation has been used for protein recovery from SWW. Here, we show an improved protein recovery method combining pH shift and heat treatment for Alaska pollock SWW. In a laboratory-scale experiment, a pH shift from neutral to pH 5 precipitated 63% of the SWW protein and subsequent heat treatment at 60°C precipitated almost all of the remaining protein. In a factory-scale experiment, the optimized pH shift and heat treatment yielded a 21% protein pellet with a 79% moisture content. The SWW protein gel thus obtained showed suitable quality as a surimi product as determined by the similar whiteness and strength as gel prepared from low-grade surimi. The optimized method combining pH shift with heat treatment improves the protein yield from SWW and prevents environmental pollution. [ABSTRACT FROM AUTHOR]

Characteristics of surimi slurries and their films made from fish myofibrillar protein were investigated. Films made from fish protein slurries consisting of Alaska pollock surimi (15% and 20%) and sodium chloride (0%, 2%, and 5%) were either adjusted to different pH (7, 9, and 11) or mixed with sodium tripolyphosphate (STP) (1.0%, 1.5%, and 2.0%). Increasing pH from 7 to 9 led to higher viscosity and exposed sulfhydryl sites, while further pH increase 9–11) reduced the viscosity values and surface reactive sulfhydryl groups. NaCl and STP addition decreased slurry viscosity. In most treatments involving the roles of pH and either sodium chloride or sodium tripolyphosphate in film formation, sodium chloride addition contributed to lower puncture strength and puncture distance. Meanwhile, there was a tendency for elevated tensile strength and reduced elongation at break as sodium chloride concentration was increased from 0% to 5%. Shifting pH to a more basic condition contributed to higher puncture strength and distance. As STP concentration in the surimi slurries increased up to 2%, puncture and tensile strength increased, but puncture distance and elongation at break decreased. [ABSTRACT FROM AUTHOR]