Hurtig metode for å estimere buksprenging i pelagisk fisk ombord

Buksprenging er en kvalitetsforringende prosess hvor bukområdet hos fisken brytes ned post mortem. Denne rapporten oppsummerer arbeidet med utviklingen av en anvendelig hurtigtest for å estimere enzymlekkasje som forårsaker buksprenging i pelagiske fiskearter. Måleutstyret er kommersielt tilgjengelig og krever lite opplæring før bruk. Metoden er brukervennlig og gir en objektiv vurdering av protein-nedbrytende aktiviteter i fisken. Metoder for prøveuttak, reaksjonstemperatur og inkubasjonstid samt tidspunkt for prøveuttak under ombordtaking av fangsten ble testet og optimalisert i prosjektet. Det er foreslått en ny skala som graderer enzymatiskaktiviteten i fiskebuken. Denne skalaen er tenkt integrert med dagens skala. Det mangler imidlertid noen resultater for at denne skalaen kan ferdigstilles. Det er nødvendig å teste metoden med sterk åte for å kunne definere skalaen for ulike grader av buktæring og sannsynligheten for buksprenging. Disse måledataene trengs for å ha basis for implementering av målemetodikken. Det neste steget i arbeidet er å implementere den nye objektive metoden og koble resultater fra målinger med kvalitetsendringer i tidsrommet fra fangst til levering mottaksanlegget

The Effect of Sous-Vide Cooking Parameters, Chilled Storage and Antioxidants on Quality Characteristics of Atlantic Mackerel (Scomber scombrus) in Relation to Structural Changes in Proteins

Svrha je ovog istraživanja bila utvrditi utjecaj kuhanja u vakuumu (sous vide) pri različitim temperaturama te dodatka dvaju komercijalnih antioksidanasa (ekstrakta ružmarina i smjese ekstrakta ružmarina i askorbil palmitata) na kakvoću atlantske skuše (Scomb¬er scombrus) tijekom hladnog skladištenja. Fileti skuše tretirani su antioksidansima i kuhani u vakuumu 10 ili 20 min pri 70 ili 80 °C, te skladišteni 1, 3, 9 ili 15 dana pri (0±1) °C. Pomoću višestruke regresijske analize praćene su promjene u udjelu suhe tvari i pepela, kalo, oksidacija i topljivost proteina te promjene u teksturi kuhanih fileta skuše kuhanih tijekom skladištenja. Zaključeno je da dulje vrijeme hladnog skladištenja najviše smanjuje kalo, vjerojatno jer denaturirani proteini ponovno apsorbiraju vodu koju su otpustili tijekom kuhanja. Istovremeno se povećala karbonilacija proteina u uzorcima skuše, čime se smanjila topljivost proteina te povećala čvrstoća mišića ribe. Međutim, utvrđeno je da se dodatkom antioksidansa karbonilacija proteina u ispitanim uzorcima smanjila.The aim of the present study is to assess the influence of different sous-vide time-temperature regimes and use of two types of commercial antioxidants (rosemary extract and rosemary extract with ascorbyl palmitate) on quality parameters of Atlantic mackerel (Scomber scombrus) during chilled storage. The mackerel fillets were treated with the antioxidants, exposed to sous-vide cooking at 70 and 80 °C for 10 and 20 min, and further stored for 1, 3, 9 and 15 days at (0±1) °C. Changes in dry matter and ash, cook loss, protein oxidation and solubility, as well as texture parameters in sous-vide cooked mackerel during storage, were assessed by application of multiple regression analysis. It was revealed that duration of chilled storage had the highest contribution to the decrease in cook loss due to a possible reabsorption of water released during cooking by unfolded proteins. At the same time, this parameter increased protein carbonylation in mackerel samples, resulting in a decreased protein solubility due to aggregation of proteins and subsequent toughening of the fish muscle. However, the use of antioxidants has shown to be highly efficient in decreasing the protein carbonylation in the analysed fish samples

Senzorna i fizikalno-kemijska kakvoća popečaka od bakalara obogaćenih atlantskom skušom

Research background. It is desirable to increase the consumption of pelagic fish rich in long-chain omega-3 fatty acids. Partial replacement of traditionally used white fish species by pelagic fish will increase the content of omega-3 fatty acids, and thus improve the nutritional value but it may also affect the consumer acceptance. The aim of this study is to assess the physicochemical and sensory quality of novel fish cake prototypes prepared from haddock and mackerel mince. Experimental approach. Fillets of haddock and Atlantic mackerel were used as raw material for preparation of fish cakes. The fish fillets were minced, mixed together (in haddock/mackerel mass ratio of 100:0, 75:25 and 50:50%) with salt, potato starch, pepper and full fat milk. Physicochemical and sensory analyses were further performed. Results and conclusions. The fatty acid composition analysis showed that the recommended daily intake of 250 mg of eicosapentaenoic acid and docosahexaenoic acid can easily be reached by consumption of fish cakes enriched with mackerel. The oxidation levels of all fish cakes were low in terms of peroxide value and thiobarbituric acid reactive substance assay (TBARS). Fish cakes prepared with higher mass fraction of mackerel mince (>50%) had significantly (p50%) fish cakes due to higher myoglobin content in the fish muscle. Moreover, fish cakes with higher amount of mackerel mince had increased yellowness due to the accumulation of water-soluble (r=0.990, p<0.05) and fat-soluble (r=0.976, p<0.05) TBARS. Metabolites relevant for taste and quality were quantified by using 1H nuclear magnetic resonance (NMR) spectroscopy. The mass fraction of anserine, trimethylamine oxide and β-alanine decreased, while the mass fraction of histidine, glutamic acid and alanine increased with the addition of mackerel. Sensory tests have shown the addition of mackerel did not reduce consumer acceptability towards the new fish cakes. Novelty and scientific contribution. The research demonstrated that Atlantic mackerel can be successfully used for partial replacement of white fish species in fish cake formulations to produce healthy and tasty ready-to-cook products and increase the consumption of small pelagic fish in Europe.Pozadina istraživanja. Bilo bi poželjno povećati udjel pelagične ribe bogate dugolančanim omega-3 masnim kiselinama u prehrani. Djelomičnom zamjenom tradicionalno korištene bijele ribe pelagičnom ribom povećao bi se udjel omega-3 masnih kiselina, a time i hranjiva vrijednost proizvoda, no to može utjecati na prihvatljivost proizvoda kod potrošača. Svrha je ovoga rada bila procijeniti fizikalno-kemijska i senzorna svojstva ribljih popečaka, pripremljenih prema novim recepturama od smjese bakalara i skuše. Eksperimentalni pristup. Fileti bakalara i atlantske skuše korišteni su kao sirovina za pripremu ribljih popečaka. Fileti su samljeveni, pomiješani u omjerima bakalara i skuše od 100:0, 75:25 i 50:50, dodani su im sol, krumpirov škrob, papar i punomasno mlijeko, te su ispitana fizikalno-kemijska i senzorna svojstva dobivenih popečaka. Rezultati i zaključci. Analiza sastava masnih kiselina pokazala je da se preporučena dnevna doza od 250 mg eikozapentaenoične i dokozaheksaenoične kiseline može vrlo lako postići konzumacijom ribljih popečaka obogaćenih skušom. Peroksidni broj i udjel reaktivnih spojeva tiobarbiturne kiseline potvrdili su da je stupanj oksidacije svih uzoraka popečaka bio nizak. Riblji popečci s većim udjelom mesa skuše (50 %) imali su bitno (p<0.05) mekaniju teksturu od ostalih uzoraka zbog većeg udjela masti. Osim toga, ti su uzorci bili tamniji od onih s većim udjelom bakalara (50 %), zbog većeg udjela mioglobina u mišiću ribe. Povrh svega, riblji popečci s većim udjelom mljevene skuše imali su intenzivniju žutu boju zbog nakupljanja reaktivnih spojeva tiobarbiturne kiseline topljivih u vodi (r=0.990, p<0.05) i u masti (r=0.976, p<0.05). Metaboličkim profiliranjem NMR spektara određen je maseni udjel 30 metabolita u uzorcima ribljih popečaka. Nakon dodatka mesa skuše smanjili su se udjeli anserina, trimetilamin N-oksida i β-alanina, a povećali udjeli histidina, glutamina i alanina. Senzorni su testovi pokazali da se nakon dodatka skuše nije smanjila prihvatljivost popečaka kod potrošača. Novina i znanstveni doprinos. Ovo je istraživanje pokazalo da atlantska skuša može uspješno zamijeniti dio mesa ribe u recepturama za riblje popečke, radi dobivanja zdravih i ukusnih polugotovih proizvoda s kojima se može povećati konzumacija male pelagične ribe u Europi

Influence of high-pressure processing on quality attributes of haddock and mackerel minces during frozen storage, and fishcakes prepared thereof

peer-reviewedThe study focused on assessing quality parameters of haddock and mackerel minces subjected to a high-pressure treatment (HP) at 200 and 300 MPa and frozen storage at −40 °C. Dry matter, water-holding capacity, protein solubility and oxidation, lipid oxidation, microbiological parameters, low molecular weight metabolites (LMW) and color parameters, were analyzed. The texture of fishcakes prepared on the basis of these fish minces was also studied, showing a decrease in firmness along with an increase in pressure. A marked inhibition of microbial growth was observed in fish minces when increasing the pressure level of HP-treatment. However, no significant effect (p < 0.05) on the content of primary and secondary lipid oxidation products was observed between untreated and 300 MPa-pressurized fish samples. The results suggested that HP-treatment could be successfully applied to both lean and fatty fish samples for reduction of microbial growth with minor changes in product quality. Industrial relevance. The application of high pressure (HP) treatment of 200 and 300 MPa could be successfully applied to both lean and fatty fish species before freezing for reduction of microbial growth. The degree of lipid oxidation is decreasing with an increase in pressure as a result of inactivation of prooxidative endogenous enzymes. Fish minces become slightly lighter and softer after HP-treatment conducted at 200 MPa due to denaturation of proteins, thus enhancing sensory properties of fishcakes prepared thereof

Sensory shelf life for protein products made from salmon backbones.

The main goal of this project was to determine the sensory shelflife of proteins with neutral taste. Proteins were isolated from both the solid phase (sludge) from salmon oil production and from cooked salmon backbones. From both raw materials proteins were isolated after bone removal and subsequent removal of unwanted taste components by washing with warm water or warm water and ethanol. Effect of adding different antioxidants on the lipid oxidation in the protein products were studied. The best antioxidant were used in shelf life experiments where the lipid oxidation and sensory shelf-life of the products were studied. The best antioxidants for the isolated protein products were BHT, propyl gallate and alfa-tocopherols. Methal chelators like EDTA and citrate had no effect. A commersial mixture of tocopherols where used for the shelf life study. During the accelerated shelf life test (50'C and 570 hours) no lipid oxidation was detected, neither by Schaal test nor by sensory analysis. This holds for all teted proteins powders with and without antioxidants. The shelf life dependence on temperture was estimated by comparison of shelf at both 50' C and 70 'C through the use of the Arrhenius equation. This estimation indicates a shelf life of approximately 2 years at 20'C for the isolated salmon proteins. Two Norwegian companies have expressed interest in the results and wants to participate in developing this technology further towards industrial Production.FHF,publishedVersio

Sensory shelf life for protein products made from salmon backbones.

The main goal of this project was to determine the sensory shelflife of proteins with neutral taste. Proteins were isolated from both the solid phase (sludge) from salmon oil production and from cooked salmon backbones. From both raw materials proteins were isolated after bone removal and subsequent removal of unwanted taste components by washing with warm water or warm water and ethanol. Effect of adding different antioxidants on the lipid oxidation in the protein products were studied. The best antioxidant were used in shelf life experiments where the lipid oxidation and sensory shelf-life of the products were studied. The best antioxidants for the isolated protein products were BHT, propyl gallate and alfa-tocopherols. Methal chelators like EDTA and citrate had no effect. A commersial mixture of tocopherols where used for the shelf life study. During the accelerated shelf life test (50'C and 570 hours) no lipid oxidation was detected, neither by Schaal test nor by sensory analysis. This holds for all teted proteins powders with and without antioxidants. The shelf life dependence on temperture was estimated by comparison of shelf at both 50' C and 70 'C through the use of the Arrhenius equation. This estimation indicates a shelf life of approximately 2 years at 20'C for the isolated salmon proteins. Two Norwegian companies have expressed interest in the results and wants to participate in developing this technology further towards industrial Production

Oxidation of marine phospholipids in liposomes

Marine phospholipids contain a high amount of n-3 polyunsaturated fatty acids (PUFAs), which have documented beneficial effect on human health. Due to this, marine phospholipids have a high potential for use in products for human consumption. However, due to the high amount of n-3 PUFAs, marine phospholipids are very susceptible to lipid oxidation, which cause loss of sensory and nutritional value in foods, some oxidation compounds are even toxic. A successful incorporation of marine phospholipids in processed foods would most probably be in the form of lipid dispersions, where some common constituents such as iron would be present. Iron, which is a very important mineral from a nutritional point of view, is also a very strong prooxidant. Studies of oxidation in oil/water systems catalysed by iron would provide valuable information on oxidation kinetics. This thesis summarises the work done on oxidation of marine phospholipids in liposomes. Measurement of dissolved oxygen uptake was chosen as the main method to study lipid oxidation. This fast and simple method enabled screening of the influence of different conditions on oxidation. The mechanism for iron catalyzed oxidation in liposomes is discussed. When Fe2+ was added to liposomes, an initial drop in dissolved oxygen followed by a slower linear oxygen uptake, was observed. Addition of Fe3+ induced only the linear oxygen uptake. The initial fast drop in dissolved oxygen was due to breakdown of preexisting lipid peroxides by Fe2+. In this reaction alkoxy radicals were formed and Fe2+ was oxidised to Fe3+. Fe3+ formed was further reduced by peroxides to Fe2+ at a slow rate (compared to Fe2+ oxidation rate). When equilibrium between Fe2+ and Fe3+ was achieved, the linear oxygen uptake was observed and Fe3+ became the rate limiting factor in the circulation between Fe3+ and Fe2+. Both alkoxy and peroxy radicals are presumably formed by breakdown of peroxides by Fe2+ and Fe3+. These radicals react with fatty acids giving a lipid radical reacting with oxygen. The rate of slower linear oxygen consumption followed Arrhenius kinetics and the variation in activation energy found (60 – 87 kJ/moles*K). The rate of slower linear oxygen uptake in liposomes was proportional to the concentration of iron and the lipid concentration in the assay mixture. The oxygen consumption rate was dependent on pH with a maximum observed between pH 4 and 5. The pH effect was explained by the iron availability and Zeta potential changes at different pH. Different salts had different influence on the linear oxygen uptake in liposomes. Cations (Na+, K+, Ca+, Mg+) did not influence the rate of oxidation in the tested range (Ionic strength (I) 0 - 0.14 M). Among the tested anions: sulphates and nitrates did not change oxygen uptake rate significantly, but chlorides (KCl, NaCl, CaCl2) reduced the oxidation rate down to approximately 45 % and dihydrogen phosphate down to 14 %, when I=0.14M. The effect of Cl- and H2PO4 - was additive. When the liposomes contained different concentrations of chlorides, a linear relationship between oxygen uptake rate and Zeta potential was observed. When phosphate was added, the oxygen uptake rate was not related to the changes in Zeta potential. The influence of pH, temperature, concentration of NaCl, phospholipids and Fe2+ on slower linear rate were described by mathematical equations. The modelled data based on the described equations fitted within 10% standard deviation with observed values

Sildeomega3 - Produksjon av høykvalitets sildeolje

Målet med prosjektet var å se på mulighetene for å utnytte silderestråstoff til produkter til helsekostmarkedet. Prosjektet ble ledet av EPAX og arbeidspakken som omhandlet produksjon av oljen ble ledet av SFH. Resultatene fra prosjektet viser at restråstoff fra sild kan benyttes til å produsere en olje av god kvalitet som kan benyttes i produkter til humant konsum. Oljen hadde lav oksidasjonsstatus (PV = 2,6 meq/kg lipid, AV=1,3) verdier som ligger langt under verdiene som er rapportert for kommersielle råoljer på markedet. I tillegg så tilfredsstilte oljene kravene for raffinerte fiskeoljer selv om oljen ikke hadde gjennomgått en renseprosess. &nbsp; Antioksidanter blir tilsatt til råoljen etter produksjon for å øke stabiliteten. Imidlertid så kan oksidasjon forekomme under produksjon av oljen. Tilsetning av antioksidanten til råstoffet før prosessering kan være en strategi for å redusere oksidasjon under prosessering og lage en olje med lav oksidasjonsstatus og høy stabilitet. Tilsats av antioksidanter (BHT, propyl gallat eller sitronsyre) til råstoffet før produksjon resulterte i en olje med redusert oksidasjonsstatus (opptil 70% reduksjon i total oksidasjon). Tilsats av antioksidanter før produksjon førte også til økt oljestabilitet.Sildeomega3 - Produksjon av høykvalitets sildeoljeEPAXpublishedVersio

A non-invasive approach to assess texture changes in sous-vide cooked Atlantic mackerel during chilled storage by fluorescence imaging

The aim of this study was to investigate the potential of fluorescence microscopy coupled with chemical, physical and data analysis methods for reliable and non-invasive detection of changes in texture parameters of sous-vide cooked Atlantic mackerel during chilled storage. Fluorescence micrographs of cook loss and connective tissue of the fish samples after sous-vide treatment at 60 °C and 75 °C for 10, 15 and 20 min taken in the 1st, 3rd and 7th day of chilled storage were acquired. The obtained images were numerically processed and the resulting data was directly correlated (R = 0.960) with the total collagen content determined by a chemical method. Partial least squares analysis was applied to derive statistically significant regression models revealing the influence of each of sous-vide regime parameters on changes in total collagen content and texture parameters of Atlantic mackerel during chilled storage. Results showed that both collagen integrity and firmness of mackerel flesh were significantly (p < 0.05) affected by the temperature of sous-vide treatment and duration of chilled storage, leading to gradual softening of the fish tissue due to degradation of collagenous tissue.acceptedVersio

Regulations on the use of rest raw materials from seafood processing in EU and India - ReValue Project Deliverable 4.2 - 2020:00471 A

Surimi processing generates rest raw materials (RRM) including viscera, skin, filleting frame, bone and wash water, which potentially could be used in preparation of valuable ingredients like marine proteins and oil, protein hydrolysate, and gelatine for food or feed application. The report gives and overview over regulations for the rest raw materials, and handling and processing to the final products such as protein powders, fish meals, oils etc. The review focuses on the legislations adopted by the EEA, national legislation in Norway and India. Concluding, if the raw material (in this case rest raw material after fish processing) produced in human grade factories are processed under food hygiene legislation, the final product can be used for food application. The requirements for the raw material, handling and processing and final product for human consumption are very similar both in EEA and India and discussed in report. By-product definition is regulated only in EU, for India no specific definitions of by-product categories exit. By-products or RRM can be used for feed application under specific regulations discussed in the report. In India Bureau of Indian Standards issues regulations for quality of animal feed ingredients such as fish meal.publishedVersio