Fra restråstoff til verdifulle råvarer

Laying hens are commonly not slaughtered and utilized for food purpose. Slaughtered hens may be hydrolyzed (e.g. at 50°C for 1-2 hours, with additions of enzymes)to produce soluble proteins and oils. Sediments after such hydrolysis are valuable fertilizers, whereas the oil and proteins are valuable food ingredients of high quality

A new fluorimetric method for simultaneous determination of lipid and protein hydroperoxides in muscle foods with the use of diphenyl-1-pyrenylphosphine (DPPP)

A new fluorimetric assay for simultaneous determination of lipid and protein hydroperoxides in muscle foods by the use of diphenyl-1-pyrenylphosphine (DPPP) was proposed in the study. Non-fluorescent DPPP that reacts with hydroperoxides stoichiometrically to yield fluorescent DPPP oxide, was used as a fluorescent dye to determine lipid and protein peroxidation in fish samples during frozen storage. The novel sensitive DPPP-assay developed for analysis under fluorescence microscopy conditions was based on this reaction. A good linear correlation between the amount of lipid hydroperoxides measured by the developed DPPP-assay and the peroxide value measured by iodometric titration was observed. Also, increase in fluorescence intensity from the reaction of DPPP with protein hydroperoxides in fish samples showed linear relation to the amount of cumene hydroxide added over a wide concentration range. The method was successfully applied on fish samples and can be used for fast assessment of primary oxidation stress in muscle foods.publishedVersion© 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).

The Effects of Freezing and Thawing of Saccharina latissima and Alaria esculenta

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Extraction of proteinaceous components and biominerals from cold water fish fileting side streams: a review

Fileting is a popular form of processing methods and in addition to being sold fresh or frozen, filets are used for preparation products battered and breaded filets. This generates considerable amount of side streams like skin, frames, and cut-offs which forms around 30–70% of the total body weight. The European Waste Framework Directive 2008 and recent amendments [EU WFD (2018/851)] stipulates comprehensive regulations which the manufacturers must follow while handling the side streams generated during the processing. This demands a detailed compilation of information regarding the yield, classification and valorization potential of side streams associated with the fileting operations of the cold-water finfishes. The side streams are a rich source of proteins including structural proteins like collagen and biominerals such as hydroxyapatite which find multiple application in food and pharmaceutical industry. Previously, the recovery of these components was performed by extensive chemical treatment with acids or bases, including subsequent washing steps. Nowadays, green extraction methods, defined as technologies with reduced energy and chemical consumption, should be considered to achieve a green shift in the food industry. Nevertheless, industrial upscaling of green extraction methods and subsequent refinement of the isolated compounds must be further evaluated and improved in order to achieve a green shift in food industry by using side-stream derived compounds as ingredients. Moreover, legislations as well as national and international regulations must be considered and evaluated. Even though a number of articles are recently available regarding seafood side stream valorization, this review focus on side streams generated predominantly from cold water fish species and also discusses sustainable green technologies to be included during the recovery process.publishedVersio

Green Chemistry to Valorize Seafood Side Streams: An Ecofriendly Roadmap toward Sustainability

A major challenge facing sustainable seafood production is the voluminous amounts of nutrient-rich seafood side streams consisting of by-catch, processing discards, and process effluents. There is a lack of a comprehensive model for optimal valorization of the side streams. Upcoming green chemistry-based processing has the potential to recover diverse valuable compounds from seafood side streams in an ecofriendly manner. Microbial and enzymatic bioconversions form major green processes capable of releasing biomolecules from seafood matrices under mild conditions. Novel green solvents, because of their low toxicity and recyclable nature, can extract bioactive compounds. Nonthermal technologies such as ultrasound, supercritical fluid, and membrane filtration can complement green extractions. The extracted proteins, peptides, polyunsaturated fatty acids, chitin, chitosan, and others function as nutraceuticals, food supplements, additives, etc. Green processing can address environmental, economic, and technological challenges of valorization of seafood side streams, thereby supporting sustainable seafood production. Green processing can also encourage bioenergy production. Multiple green processes, integrated in a marine biorefinery, can optimize valorization on a zero-waste trade-off, for a circular blue economy. A green chemistry-based valorization framework has the potential to meet the Sustainable Development Goals (SDGs) of the United Nations.acceptedVersio

Biochemical changes in superchilled storage of salmon (Salmo salar) fillets

Biochemical changes of Atlantic salmon (Salmo salar) fillets during superchilled storage were evaluated. Due to the significant differences in ice crystal sizes observed, the biochemical changes were evaluated both at the top and centre parts of the superchilled samples. No significant differences were found in biochemical changes between top and centre parts of the superchilled samples. The amount of cell tissue fluid (CTF) increased significantly from day 1 to 3 in the top and centre parts of the superchilled samples. The amount of CTF was stable between day 3 and 14 but increased significantly from day 21 to 28. A significant increase in the activity of β-N-acetyl-glucosaminidase in the CTF at the top was observed between day 3 and 7, while at the centre at day 7 of storage. There was also a significant increase in β-N-acetyl-glucosaminidase both at the centre and the surface of the superchilled samples between day 21 and 28 of storage whereby the activity in these samples was on the same level as in the frozen samples. In the superchilled samples, the cathepsin B activity in CTF and homogenates were stable for the first one week of storage. There was significant increase in activity of cathepsin B in cell tissue fluid and homogenates between day 21 and 28 for both chilled and superchilled samples. These findings provides valuable information on the quality of food products for the food industry in relation to ice crystallisation/recrystallisation during superchilled storage.publishedVersionCopyright © 2018 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.

Chapter 2. Peptides and Proteins

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Extraction, partial purification and characterization of alkaline protease from rainbow trout (Onchorhynchus Mykiss) viscera

In this study, crude alkaline proteases were recovered from rainbow trout (Oncorhynchus mykiss) viscera and partially purified by use of different saturation of ammonium sulfate. The enzyme exhibited highest yield, purity and activity when precipitated at a saturation of 40–60% compared to other ranges of saturation. Molecular weight for extracted protease was between 8-24 kDa. The protease had caseinolytic activity over a wide range of temperatures (30-55 °C) and pH (4-12). Soybean trypsin inhibitor and trypsin-chymotrypsin inhibitor strongly inhibited the enzyme activity but it was stable in the presence of surfactant, oxidizing reagents and organic solvents. The proteases had serine protease activity but no collagenase activity was detected. The current study showed that partially purified protease from the digestive tract of rainbow trout could be applicable in food and detergent industry because of its good activity over a wide temperature and pH range and its good thermal stability.acceptedVersion© 2018. This is the authors’ accepted and refereed manuscript to the article. Locked until 24.10.2020 due to copyright restrictions. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0

Determination of apparent diffusion coefficient in balls made from haddock mince during brining

Salting is one of the main processes of preservation in meat and fish industry. Knowledge of how salt affects the muscle microstructure is needed both to model diffusion and to obtain the desired salt concentration in the product. Diffusion of sodium chloride was studied in a gelled minced fish ball-brine system. Systems with both closed circulation of the brine and static conditions were used to study and compare the salt transport process. Effective diffusion coefficients (De) for diffusion of sodium chloride into fish balls made from fresh and frozen haddock mince were determined. A numerical calibration of an analytical model based on Fick's second law was performed, in which salt diffusion follows a non-steady-state process. Critical experimental parameters for the estimation of diffusion coefficients were: size of balls, initial solute concentration in the bulk of brine, freezing of the material before the treatment, and stirring of the brine. The result of experiment shows that a simple fish ball–brine system can be used to model mixing of salt in brining processes.submittedVersionThis is a submitted manuscript of an article published by Elsevier Ltd in Journal of Food Engineering, 2 December 2015