Merki: Geymsluþol

Skýrslur

Effect of improved design of wholesale EPS fish boxes on thermal insulation and storage life of cod loins – simulation of air and sea transport

Útgefið:

01/08/2010

Höfundar:

Björn Margeirsson, Hélène L. Lauzon, Kolbrún Sveinsdóttir, Eyjólfur Reynisson, Hannes Magnússon, Sigurjón Arason, Emilía Martinsdóttir

Styrkt af:

EU (contract FP6-016333-2) Chill-on, AVS Fund of Ministry of Fisheries in Iceland (project no. R037-08), Technology Development Fund of the Icelandic Centre for Research (project. no. 081304508), University of Iceland Research Fund

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

Effect of improved design of wholesale EPS fish boxes on thermal insulation and storage life of cod loins – simulation of air and sea transport

Markmið tilraunanna var að rannsaka hve vel tvær tegundir frauðkassa verja þorskhnakkastykki fyrir dæmigerðu hitaálagi í flugflutningskeðju frá framleiðanda á norðanverðu Íslandi til kaupanda í Evrópu. Notast var við hitamælingar, skynmat, efna- og örverumælingar til að bera frauðkassana saman og kanna mikilvægi staðsetningar flakabita innan kassa (horn og miðja). Að lokum var geymsluþol hnakkastykkja, sem urðu fyrir dæmigerðu flugflutningshitaálagi, borið saman við geymsluþol hnakkastykkja við stöðuga -1 °C geymslu sem er raunhæfur möguleiki við gámaflutninga með skipum. Nýi frauðkassinn, sem hannaður var með FLUENT varmaflutningslíkani, reyndist betri en eldri kassinn með tilliti til varmaeinangrunar. Hitaálagið á fyrsta degi tilraunarinnar olli því að hæsti vöruhiti í hornum hækkaði í 5.4 °C í eldri gerðinni en einungis í 4.5 °C í þeirri nýju. Munur milli hæsta vöruhita í miðjum og hornum kassa var um 2 til 3 °C. Með skynmati var sýnt fram á að geymsla í nýja frauðkassanum leiddi til tveggja til þriggja daga lengra ferskleikatímabils og eins til tveggja daga lengra geymsluþols m.v. geymslu í eldri frauðkassanum. Munurinn milli kassanna var þó ekki staðfestur með efna- og örverumælingum. Staðsetning innan kassa (horn og miðja) hafði ekki marktæk áhrif á niðurstöður skynmats og var einungis um lítinn mun að ræða milli staðsetninga í mælingum á TVB-N og TMA. Hermun flug- og sjóflutnings (hitasveiflur og stöðugur hiti) leiddi í ljós að fyrir vel forkælda þorskhnakka má vænta eins til fimm daga lengra ferskleikatímabils og um þriggja til fimm daga lengra geymsluþols í vel hitastýrðum sjóflutningi miðað við dæmigerðan flugflutningsferil frá Norðurlandi. Þar sem sjóflutningur frá Íslandi tekur oft um fjórum til fimm dögum lengri tíma en flugflutningur (háð m.a. vikudegi og staðsetningu vinnslunnar) sýnir þetta að sjóflutningur er raunhæfur möguleiki fyrir íslenska ferskfiskframleiðendur. Með notkun á nýju frauðkössunum í flugflutningi á fiskurinn þó eftir lengra ferskleikatímabil þegar hann kemst í hendur kaupenda erlendis en í skipaflutningi.

2. útgáfa, mars 2011

Í fyrri útgáfu skýrslunnar þótti ekki nógu skýrt koma fram að sá umhverfishitaferill, sem líkja átti eftir sjóflutningi, miðaðist í raun við nokkurn veginn bestu mögulegu aðstæður í sjóflutningskeðjum ferskra fiskafurða frá Íslandi. Hitamælingar í kæliverkefnunum Hermun kæliferla og Chill-on hafa sýnt fram á að forflutningi innanlands fylgir oft óæskilegt hitaálag í nokkrar klst. hvort sem um er að ræða flug- eða sjóflutningskeðjur. Til þessa hitaálags var tekið tillit í tilfelli flugkeðjunnar en ekki sjóflutningskeðjunnar í fyrstu útgáfu skýrslunnar. Mest áhersla var á lengd geymsluþols í fyrri útgáfu skýrslunnar en bætt er við umfjöllun um ferskleikatímabil í nýrri útgáfu hennar.

The aim of the study was to investigate the performance of two different types of EPS boxes in protecting pre-chilled, fresh fish products subjected to temperature conditions, which are likely to occur during air- and land based, multimodal transport from a processor in North-Iceland to a wholesaler in Europe. The performance of the EPS boxes was evaluated by means of temperature monitoring, chemical- and microbial measurements and finally sensory evaluation. Furthermore, effect of fillet positions inside the wholesale fish packages (corner vs. middle) were investigated by means of the aforementioned methods. Finally, the shelf life of the air-transported simulation fish loins was compared to the shelf life of fish loins stored at around -1 °C, which can be achieved during non-interrupted and well temperature-controlled, containerised sea transport. The new box, designed with a numerical FLUENT heat transfer model, proved to be better with regard to thermal insulation than the old box. The thermal load during the first day of the experiment caused the maximum product temperatures in the bottom corners of the top and second top to rise to 5.4 °C and 4.5 °C for the original and new boxes, respectively. The maximum temperature in the middle of the boxes was around 2 to 3 °C lower than the maximum temperature in the bottom corners. According to sensory evaluation, storage in the new boxes resulted in approximately two to three days longer freshness period and one to two days longer shelf life than storage in the old boxes. The difference between the two box types is not as clear with regard to chemical and microbial measurements.

The sampling location (corner versus middle), did not significantly affect the sensory quality and only minor differences were noticed in TVB-N and TMA between sampling locations in the new box. Comparing the steady and dynamic storage in the old boxes it can be concluded that the increased freshness period (around 1-5 days) and shelf life (around 3-5 days) at steady temperature could compensate for the longer transport time by sea instead of air freight. This makes containerised sea transport a worthy choice for Icelandic fresh fish manufacturers depending on the week day and location of processing. However, for maximum remaining freshness period at the time of delivery to the buyer in Europe the results showed that air transport with the new boxes is the more advantageous transport mode relying on shorter transport time and improved thermal protection of the new boxes.

Skoða skýrslu

Skýrslur

Þróun gæðastuðulsaðferðar og geymsluþol á þíddum makríl (Scomber scombrus) / Development of Quality Index Method and storage life of thawed mackerel (Scomber scombrus)

Útgefið:

01/07/2010

Höfundar:

Kolbrún Sveinsdóttir, Patricia Miranda Alfama, Aðalheiður Ólafsdóttir, Emilía Martinsdóttir

Styrkt af:

AVS rannsóknasjóður í sjávarútvegi, UNU Sjávarútvegsskóli Háskóla Sameinuðu þjóðanna

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

Þróun gæðastuðulsaðferðar og geymsluþol á þíddum makríl (Scomber scombrus) / Development of Quality Index Method and storage life of thawed mackerel (Scomber scombrus)

QIM aðferðin (Quality Index Method) er hlutlæg, fljótleg og áreiðanleg skynmatsaðferð sem þróuð hefur verið til að meta ferskleika fisks. Markmið rannsóknarinnar var að útbúa QIM einkunnaskala fyrir þíddan makríl (Scomber scombrus) sem geymdur var í ís við 0°C og prófa notkun hans í geymsluþolstilraun. Makríllinn var metinn með skynmati eftir QIM og DA aðferð (generic descriptive analysis), einnig voru taldar örverur (TVC og H2S myndandi) og mælt histamín í allt að 9 daga frá uppþíðingu. Niðurstaða rannsóknarinnar var QIM aðferðin fyrir þíddan makríl sem var þróuð og prófuð í geymsluþolsrannsókn. Gæðastuðull – QI (heildarsumma einkunna) jókst línulega með geymslutíma á ís. QIM aðferðin fyrir þíddan makríl byggir á mati á gæðaþáttum einsog útliti á roði, áferð, lit og formi augna, lit og lykt tálkna, útlit slíms í tálknum og tálknblaða og upplausn innyfla og getur heildarsumma fisksins orðið 19 að hámarki. Í verkefninu var einnig þróuð aðferð (general descriptive analysis-DA) til að meta soðinn makríl. Helstu einkenni makrílsins strax eftir þíðingu var lykt og bragð af ferskri olíu, málmlykt og sæt lykt/bragð sem dofnaði heldur með geymslutímanum. Það sem takmarkaði geymsluþolið voru skynrænir eiginleikar sem lýsa skemmdareinkennum, einsog þráalykt og –bragð sem getur verið áberandi í feitum fiski eftir lengri frystigeymslu. Samkvæmt skynmati á soðnum makrílflökum er geymsluþol þídds makríls eftir fimm mánaða frystigeymslu um 4-6 dagar. Heildarfjöldi örvera og H2S myndandi örvera var minni en yfirleitt sést við lok geymsluþols af völdum örvera. Histamín mældist ekki (< 5 ppm) í þíddum makríl á geymslutímanum sem var 9 dagar á ís.

The Quality Index Method (QIM) is an objective, rapid and reliable sensory method. The aim of the present study was to develop a QIM scheme for frozenthawed Atlantic mackerel (Scomber scombrus) stored in ice at 0°C and evaluate the scheme in a shelf life study. The mackerel was evaluated with sensory evaluation (QIM and generic descriptive analysis (DA)), microbial counts (Total viable counts (TVC) and H2S-producing bacteria) were estimated and histamine measured for up to nine days. The main result of this study vas the QIM scheme to evaluate freshness of frozen-thawed Atlantic mackerel storage in ice which was developed and tested in a shelf life study. The quality index – QI (sum of scores) increased linearly with storage time on ice. The QIM for thawed mackerel is based on the evaluation of quality parameters dealing with the appearance on back and belly side, texture, colour and form of eyes, mucus, colour and odour of gills and appearance of gill filaments and dissolution of viscera. The maximum sum of scores (QI) can be 19. A method to evaluate cooked mackerel was also developed (general descriptive analysis-DA). Newly thawed mackerel had fresh oil, metallic and sweet odours and flavours. The main limitation of length of shelf life in chilled storage after thawing were sensory characteristics describing spoilage such as rancid odour and flavour which can be prominent in fatty fish species after extended frozen storage. According to sensory evaluation of cooked mackerel, the shelf life of thawed mackerel after five months of frozen storage is around 4-6 days. Counts of TVC and H2S producing bacteria were relatively low at the end of shelf life. Histamine was not detected (< 5 ppm) in the thawed mackerel during the storage time of nine days on ice.

Skoða skýrslu

Skýrslur

Geymsluþol reyktra síldarflaka í lofttæmdum umbúðum / Shelf life of vacuum‐packed smoked herring fillets

Útgefið:

01/06/2010

Höfundar:

Franklín Georgsson, Margeir Gissurarson

Styrkt af:

AVS rannsóknasjóður í sjávarútvegi

Geymsluþol reyktra síldarflaka í lofttæmdum umbúðum / Shelf life of vacuum‐packed smoked herring fillets

Markmið rannsóknarinnar var að kanna geymsluþol reyktra síldarflaka í lofttæmdum umbúðum og athuga hvaða áhrif það hefur á geymsluþol vörunnar ef rotvarnarefni er ekki notað sem og ef sorbat er notað í stað bensóats, sem notað er í hefðbundinni framleiðslu. Í þessari rannsókn kom fram að notkun rotvarnarefna hefur veruleg áhrif á lengd geymsluþols reyktra síldarflaka. Jafnframt kom fram að sorbat meðhöndlun síldarflaka veitti bestu rotvörn gegn örveruvexti og einnig reyndist sorbat meðhöndlun síldarflaka koma best út í óformlegu skynmati. Hvort þetta stafar af hindrun sorbatsins á örveruvöxt eða að það dragi úr hraða efna‐  og eðlisfræðilegra niðurbrotsþátta í samanburði við síldarflök með bensóati eða án rotvarnarefna þarfnast frekari rannsókna.

The object of this project was to evaluate the shelf life of vacuum packed smoked herring fillets and to evaluate whether the use of the preservatives benzoate or sorbate had any effect on the shelf life of the product Results showed that treatment of the smoked herring fillets with preservatives greatly affected the shelf life and that sorbate treatment of the herring fillets provided the best defence for bacteria growth and also gave best results in an informal sensory testing during the shelf life study. Whether this is due to inhibitory role of sorbate on bacteria growth or that sorbate slows down chemical and physical degradation in comparison to herring fillets with benzoate or without any preservatives needs further investigation.  

Skoða skýrslu

Skýrslur

The effect of cooling methods at processing and use of gel-packs on storage life of cod (Gadus morhua) loins – Effect of transport via air and sea on temperature control and retail-packaging on cod deterioration

Útgefið:

01/05/2010

Höfundar:

Emilía Martinsdóttir, Hélène L. Lauzon, Björn Margeirsson, Kolbrún Sveinsdóttir, Lárus Þorvaldsson, Hannes Magnússon, Eyjólfur Reynisson, Arna Vigdís Jónsdóttir, Sigurjón Arason, Maria Eden

Styrkt af:

EU (contract FP6-016333-2) Chill-on, AVS, R&D Fund of Ministry of Fisheries in Iceland, the Technology Development Fund at the Icelandic Centre for Research

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

The effect of cooling methods at processing and use of gel-packs on storage life of cod (Gadus morhua) loins – Effect of transport via air and sea on temperature control and retail-packaging on cod deterioration

Tilgangur tilraunanna var að kanna áhrif mismunandi kælingar við vinnslu og hitasveiflna í flutningi með og án kælimottu á geymsluþol þorskhnakka. Í vinnslu var borið saman að nota enga forkælingu fyrir flökun, vökvakælingu og roðkælingu (CBC) sem alltaf er með vökvakælingu. Áhrif hitasveiflna þar sem líkt var eftir í hitabreytingum í flutningi (RTS) voru borin saman við geymslu við stöðugt hitastig (-1 °C). Einnig voru metin áhrif þess að nota kælimottu í geymslu og flutningi. Sýni voru gæðametin með skynmati, örveru- og efnamælingum. Fylgst var með hitastigi með hitasíritum. Roðkældir þorskhnakkar í frauðplastkössum voru fluttir til Bremerhaven með flugi og skipi þar sem þeim var endurpakkað í loft og loftskiptar pakkningar (MAP) og þær geymdar við 1 °C. Gerðar voru efna- og örverumælingar til að fylgjast með gæðabreytingum. Hitastig roðkældra hnakka var lægra en hinna fyrstu 2 daga tilraunarinnar. Kælimotturnar höfðu ákveðin áhrif til lækkunar hitastigs þegar hitasveiflur voru í ferlinu og lægri hiti hélst gegnum allan geymslutímann. Samt sem áður hafði notkunin ekki áhrif á lengd ferskleikatíma eða geymsluþols samkvæmt skynmati. Örverufjöldi var heldur lægri ef hitasveiflur urðu í ferlinum en lítill munur var við stöðugt hitastig. Geymsla við stöðugt, lágt hitastig (-1 °C) lengdi geymsluþol um ca. 3 daga samkvæmt skynmati og var það í samræmi við örverutalningar og mælingar á TVB-N og TMA. Í tilraunum í Bremerhaven kom fram að örverufjöldi var yfirleitt lægri þegar notaðar voru loftskiptar umbúðir í samanburði við fisk í lofti. Þetta var sérstaklega áberandi í flugfiskinum. Fiskurinn sem fluttur var með skipi geymdist samt jafn lengi og fiskurinn sem fluttur var með flugi. Þetta orsakast af því að flugfiskurinn varð fyrir meiri hitasveiflum í flutningi og yfirborðshiti hans mældist 4 °C við komuna til Bremerhaven. Flutningstími með skipi var miklu lengri (+48 klst) en yfirborðshiti mældist undir 2 °C við móttöku. Notkun kælimotta hafði lítil áhrif á hitastigið í flutningi en samt sem áður var yfirborðshiti aðeins lægri í fiski með kælimottum við komuna til Bremerhaven bæði með flugi og skipi.

The main aim of the experiment was to investigate the effects of different cooling techniques during processing and temperature fluctuations during transport on the storage life of cod loins with and without gel packs. The following cooling techniques were studied: combined blast and contact (CBC) cooling (with liquid cooling prior to the CBC cooling), only liquid cooling and where no special cooling was used prior to deskinning and trimming. The effect of real temperature simulation (RTS) during storage was compared to a steady storage temperature of -1 °C. The samples were analysed with sensory, microbial and chemical methods. The temperature was monitored from packaging using temperature loggers. CBC cooled loins were transported to Bremerhaven via air and ship freight after packaging in EPS boxes. The fish was repacked in air and modified atmosphere and stored at 1 °C. Deteriorative changes were evaluated by microbial and chemical indicators. CBC cooling resulted in a lower temperature profile the first two days of the experiment. The use of gel packs lowered somewhat the temperature increase in the products when RTS was applied and lower temperature was maintained during the entire storage period. According to sensory evaluation, the use of gel packs did not result in prolonged freshness period or shelf life. According to microbial and chemical analysis no marked difference was seen whether gel packs were used or not in groups stored at a steady temperature. However, microbial counts were somewhat lower and slower formation of TVB-N and TMA occurred in RTS groups where gel packs were used compared to no gel packs. Storage at a steady -1 °C resulted in prolonged shelf life of three days according to sensory evaluation. This was confirmed by microbial and chemical analysis as lower microbial counts, TVB-N and TMA values were generally obtained in the steady temperature group than in the group receiving the RTS treatment. The storage studies carried out at Bremerhaven on modified atmosphere vs. air packed loins showed generally lower microbial counts, especially in the air transported fish. Deterioration process of air and sea freight fish was however similar. Re-packaging of sea freight fish at a later stage did not significantly affect its deteriorative process compared to re-packed air freight fish. This might be due to the fact, that the air freight fish was subject to high temperatures during transport and surface temperature reached over 4 °C. The sea freight fish had a much longer transport phase, but arrived with surface temperatures below 2° C. This shows that not only the time of re-packaging but also the temperature profile during transport are important factors influencing the deteriorative process and shelf life. Gel packs did not have significant cooling effect in this experiment. However the surface temperature in boxes with a gel pack was slightly lower than in boxes without a gel pack independently of transport mode used.

Skoða skýrslu

Skýrslur

SSS PREDICTION Námskeið / SSS PREDICTION WORKSHOP

Útgefið:

29/04/2010

Höfundar:

Paw Dalgaard, Anna Kristín Daníelsdóttir, Steinar B. Aðalbjörnsson

Tengiliður

Anna Kristín Daníelsdóttir

Aðstoðarforstjóri / Rannsókna- og nýsköpunarstjóri

annak@matis.is

SSS PREDICTION Námskeið / SSS PREDICTION WORKSHOP

Námskeið í notkun á spáforritum í sjávarútvegi: SSS (Seafood Spoilage and Safety) Prediction version 3.1 2009 (http://sssp.dtuaqua.dk/), Combase (www.combase.cc) and Pathogen Modeling forrit (http://pmp.arserrc.gov/PMPOnline.aspx). Kennari er Dr. Paw Dalgaard frá Tækniháskólanum í Danmörku (DTU) og fer kennslan fram á ensku. Forritið nýtist vísindamönnum, yfirvöldum og iðnaði í sjávarútvegi.

Workshop on the practical use of computer software to manage seafood quality and safety. It includes presentations and hands-on computer exercises to demonstrate how available software can be used by industry, authorities and scientists within the seafood sector. Examples with fresh fish, shellfish and ready-to-eat seafood (smoked and marinated products) are included in the workshop. Special attention is given to: (i) the effect of storage temperature and modified atmosphere packing on shelf-life and (ii) management of Listeria monocytogens according to existing EU regulations (EC 2073/2005 and EC 1441/2007) and new guidelines from the Codex Alimentarius Commission. The presentations included in the workshop are given in English by Paw Dalgaard from the Technical University of Denmark. Participants will use their own laptop computers for the PC-exercises included in the workshop. Instruction for download of freeware will be mailed to the participants prior to the start of the workshop.

Skoða skýrslu

Skýrslur

The effect of different precooling media during processing and cooling techniques during packaging of cod (Gadus morhua) fillets

Útgefið:

01/04/2010

Höfundar:

Björn Margeirsson, Hannes Magnússon, Kolbrún Sveinsdóttir, Kristín Líf Valtýsdóttir, Eyjólfur Reynisson, Sigurjón Arason

Styrkt af:

AVS Fund of Ministry of Fisheries in Iceland, The Technology Development Fund at the Icelandic Centre for Research, University of Iceland Research Fund

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

The effect of different precooling media during processing and cooling techniques during packaging of cod (Gadus morhua) fillets

Tilgangur tilraunanna var að kanna áhrif mismunandi kælimiðla við forkælingu fyrir pökkun á hitastýringu, gæði og geymsluþol þorskflaka. Eftirfarandi kælimiðlar voru kannaðir og bornir saman við enga sérstaka forkælingu fyrir pökkun:

  1. pækill með lágu saltinnihaldi, 2) krapaís með lágu saltinnihaldi.

Auk þess voru könnuð áhrif þess að nota annars vegar ísmottur og hins vegar þurrís við geymslu flakanna. Fylgst var með breytingum á hitastigi með hitanemum á öllum stigum. Sýni voru gæðametin með skynmati, örveru- og efnamælingum í allt að 13 daga frá vinnslu og pökkun (16 daga frá veiði). Flökin voru geymd við ofurkældar aðstæður (undir 0 °C) mestan hluta geymslutímans. Lægra hitastig krapaíss en pækils leiddi til lægra hitastigs flaka við pökkun auk þess sem hiti vökvapækilsins reyndist hækka hratt þegar hlé var gert á vinnslu. Mismunandi meðhöndlun leiddi til sambærilegs ferskleikatíma samkvæmt skynmati. Hins vegar reyndist notkun vökvapækils við forkælingu fyrir pökkun leiða til 1 – 2 daga skemmra geymsluþols samanborið við enga forkælingu eða forkælingu með krapaís. Rekja má ástæður þessa til þess að pækillinn innihélt töluvert magn örvera, m.a. H2S-myndandi gerla sem eru virkir framleiðendur á trímetýlamíni (TMA). Samanburður á vökvakældu flökunum sýndi að notkun á þurrís lengdi geymsluþol um 1 dag í samanburði við ísmottur. Niðurstöður örveru- og efnamælinga voru í samræmi við þessar niðurstöður.

The aim of the experiment was to investigate effects of two cooling media during precooling at processing on temperature control, quality and storage life of cod fillets. The two cooling media compared to no special precooling during processing (NC) were: 1) liquid brine (LC) and 2) slurry ice (SIC). In addition, the influence of using either dry ice or ice packs during storage was studied. The samples were kept at superchilled conditions during most of the trial. The environmental and product temperature history of each group was studied using temperature monitors. The samples were analysed with sensory evaluation, microbial and chemical methods for up to sixteen days from catch (thirteen days from processing). Lower temperature of the slurry ice than the liquid brine resulted in lower fillet temperature at packaging and the liquid brine temperature increased rapidly during a processing break, which seems to be a weakness of the liquid brine tank. Results from sensory, microbial and chemical analysis all showed that immersing the skinless cod fillets in liquid cooling brine prior to packaging resulted in one to two days reduction of shelf life in comparison with fillets that were not immersed in liquid brine (no cooling) or in slurry ice. This could be attributed to the fact that the cooling brine carried considerable amounts of microbes including H2Sproducing bacteria which are active producers of trimethylamine (TMA). Comparison of the groups receiving liquid cooling showed that dry ice appeared to extend the shelf life of one day as compared to ice packs. The length of the freshness period was, however, similar in all experimental groups according to sensory evaluation. These results were confirmed by total volatile bases (TVB-N) and TMA analysis and microbial counts.

Skoða skýrslu

Skýrslur

Optimal storage conditions for fresh farmed tilapia (Oreochromis niloticus) fillets

Útgefið:

01/12/2009

Höfundar:

Emilía Martinsdóttir, Cyprian Ogombe Odoli, Hélène L. Lauzon, Kolbrún Sveinsdóttir, Hannes Magnússon, Sigurjón Arason, Ragnar Jóhannsson

Styrkt af:

Tækniþróunarsjóður

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

Optimal storage conditions for fresh farmed tilapia (Oreochromis niloticus) fillets

Tilgangur tilraunanna var að finna bestu geymsluaðstæður fyrir fersk tilapíuflök með því að ákveða geymsluþol með skynmati, örverutalningum og eðlis- og efnafræðilegum mælingum. Nílartilapía (Oreochromis niloticus) alin í endurnýtanlegu vatnshringrásarkerfi var flökuð og pökkuð í 100% lofti og loftskiptum pakkningum 50% CO2: 50% N2 MA fyrir geymslu við 1˚C og -1˚C. Lýst er þróun QIM-einkunnaskala og skynmatseiginleikum ferskra og soðinna tilapíuflaka og notkun skalans í geymsluþolstilraun. Línulegt samband fannst milli gæðastuðuls og geymslutíma (r > 0.93) fyrir alla geymsluhópa. Niðurstöður skynmats og örverutalninga sýndu að flök sem pakkað var í lofti höfðu geymsluþol 13-15 daga við 1˚C og 20 daga við -1˚C. Við lok geymsluþols í loftpakkningum var heildarörverufjöldi og fjöldi pseudomonads örvera log 7 CFU/g í holdi. Í flökum í loftskiptum pakkningum var lagfasi lengri og heildarfjöldi örvera var undir log 4 CFU/g eftir 27 daga geymslu bæði við 1˚C og -1˚C. Samt sem áður höfðu loftskiptar aðstæður slæm áhrif á lit flaka skömmu eftir pökkun en litur flaka hefur veruleg áhrif á val kaupenda. Efnafræðilegar mælingar eins og TVB-N og TMA voru ekki góður mælikvarði á skemmd tilapiuflaka. Bestu geymsluaðstæður fyrir tilapíuflök er pökkun í lofti og geymsla við stöðugt lágt hitastig -1°C. Skýrsla þessi er byggð á helstu niðurstöðum úr meistaraprófsverkefni Cyprian Ogombe Odoli.

The main aim was to establish optimal storage conditions for fresh tilapia fillets by determining its shelf life by sensory and microbiological evaluation, as well as monitoring its physical-chemical properties. Nile tilapia (Oreochromis niloticus) farmed in recirculation aquaculture system was filleted and packaged in 100% air and 50% CO2: 50% N2 MA prior to storage at different temperature; 1˚C and -1˚C. This report further describes the development of a Quality Index Method (QIM) scheme and a sensory vocabulary for fresh and cooked tilapia fillets accordingly and application in a shelf life study. The application of the QIM scheme for tilapia fillets showed a linear relationship between QIM scores and storage time (r > 0.93) for all samples. The results from sensory analysis of cooked samples as well as microbial growth indicated that fillets packaged in 100% air had a shelf life of 13-15 days during storage at 1˚C and 20 days during storage at -1˚C. At the end of shelf life in 100% air packaged groups, TVC and pseudomonads counts reached log 7 CFU/g in flesh. In MA packaged fillets, the lag phase and generation time of bacteria was extended and recorded total counts below the limit for consumption (< log 4 CFU/g) up to 27 days of storage at both 1˚C and -1˚C. However, MA packaging affected negatively the colour characteristics of the fillets soon after packaging (as from d6) but colour is an important indicator of quality and a major factor in influencing retail purchase decisions. Chemical analyses (TVB-N and TMA) were not good indicators of spoilage of tilapia fillets in the present study. 100% air packaging at -1˚C storage temperature is the optimal storage conditions for fresh tilapia fillets. The report is based on the master thesis of Cyprian Ogombe Odoli.

Skoða skýrslu

Skýrslur

Sprautun og pæklun tilapíuflaka / Injection and brining of tilapia fillets

Útgefið:

01/12/2009

Höfundar:

Kristín Anna Þórarinsdóttir, Kolbrún Sveinsdóttir, Þóra Valsdóttir, Irek Klonowski, Aðalheiður Ólafsdóttir, Hannes Magnússon, Arnljótur Bjarki Bergsson, Ragnar Jóhannsson, Emilía Martinsdóttir

Styrkt af:

Tækniþróunarsjóður Rannís / Technology Development Fund, RANNIS ‐ Icelandic Centre for Research

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

Sprautun og pæklun tilapíuflaka / Injection and brining of tilapia fillets

Markmið verkefnisins var að kanna áhrif sprautunar og pæklunar á nýtingu, geymsluþol og eiginleika tilapiuflaka. Framleiddir voru þrír afurðaflokkar: kældar afurðir, frystar afurðir (með óverulegum breytingum á saltinnihaldi) og léttsaltaðar, frystar afurðir. Við vinnslu kældra afurða voru flök með roði sprautuð með daufum pækli (1% salt) sem innihélt smækkaðan þorskmarning (2% prótein í pækli). Léttsöltuð flök voru í upphafi sprautuð með 4% saltpækli, síðan pækluð yfir nótt. Hluti flaka var frystur eftir pæklun en sambærilegt magn sprautað með próteinlausninni eftir pæklun. Nýting jókst við sprautun og pæklun, verulegur munur var þyngdarbreytingum á frystum flökum og léttsöltuðum flökum vegna mismunar í saltinnihaldi þessara tveggja afurðaflokka. Vatnsheldni flaka var lakari eftir frystingu heldur en eftir geymslu í kæli. Geymsluþol afurða var stutt og eru mögulegar ástæður fyrir því ræddar í skýrslunni. Örveruvöxtur og niðurbrotsferlar voru að mestu óháð sprautun og pæklun.

The objective of the project was to study effect of injection and brining on the yield, storage life and characteristics of tilapia fillets. Three different product groups were produced: chilled. Frozen (with small salt changes) and lightly salted products. During processing of chilled products fillets with skin were injected with brine containing minced cod (2%) protein in brine. Lightly brined fillets were at the beginning injected with 4% brine and then brined overnight. A part of the fillets was frozen after brining but similar part was injected with protein solution after brining. The yield increased with injection and brining, distinct difference was in the weight changes of frozen and lightly salted fillets because of the difference of the salt content of these two product groups. Water holding capacity of the frozen fillets was lower than for chilled fillets and the storage life was very short. Microbial growth was mostly not depending on the injection and brining.

Skoða skýrslu

Skýrslur

The effect of liquid cooling at processing and different cooling techniques during transport of cod (Gadus morhua) fillets

Útgefið:

01/11/2009

Höfundar:

Hannes Magnússon, Lárus Þorvaldsson, Kolbrún Sveinsdóttir, Hélène L. Lauzon, Kristín Anna Þórarinsdóttir, Sigurjón Arason, Emilía Martinsdóttir

Styrkt af:

AVS R&D Fund of Ministry of Fisheries in Iceland, the Technology Development Fund at the Icelandic Centre for Research and EU (contract FP6-016333-2)

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

The effect of liquid cooling at processing and different cooling techniques during transport of cod (Gadus morhua) fillets

Tilgangur tilraunanna var að kanna áhrif mismunandi kælitækni og áhrif hitasveiflna á gæði og geymsluþol þorskflaka. Eftirfarandi kælitækni var könnuð: Vökvakæling í pækli við vinnslu miðað við enga kælingu og áhrif hitasveiflna við geymslu í samanburði við stöðugt hitastig (-1°C). Auk þess voru könnuð áhrif þess að nota annars vegar ísmottur og hins vegar þurrís við geymslu flakanna. Fylgst var með breytingum á hitastigi með hitanemum á öllum stigum. Sýni voru gæðametin með skynmati, örveru- og efnamælingum í allt að 14 daga frá veiði (11 daga frá vinnslu og pökkun). Mismunandi meðhöndlun leiddi til mismunandi ferskleikatíma og geymsluþols samkvæmt skynmati. Hópar sem voru vökvakældir við vinnslu höfðu um 2-3 daga skemmra geymsluþol en flök sem ekki voru kæld á þennan hátt. Rekja mátti ástæður þessa til þess að kælipækillinn innihélt töluvert magn örvera m.a. skemmdargerilinn Photobacterium phosphoreum sem er mjög virkur framleiðandi á trímetýlamíni (TMA). Samanburður á vökvakældu flökunum sýndi að notkun á þurrís lengdi geymsluþol um 1-2 daga í samanburði við ísmottur. Geymsla við -1°C hafði ekki merkjanleg áhrif á ferskleikatíma og geymsluþol í samanburði við flök þar sem hitasveiflum var beitt samkvæmt skynmati. Niðurstöður örveru- og efnamælinga voru í samræmi við þessar niðurstöður.

The aim of the experiment was to investigate the effects of different cooling techniques and temperature fluctuations on the storage life of cod fillets. The following cooling techniques were studied: liquid cooling in brine at plant as compared to no special cooling at processing. The effect of real temperature (RTS) simulation during storage was compared to a steady storage temperature at -1°C. Additionally, the influence of using either dry ice or ice packs during storage was studied. The temperature history of each group was studied using temperature loggings. The samples were analyzed with sensory evaluation, microbial and chemical methods for up to 14 days from catch (11 days from packaging). The different treatments of the groups resulted in different lengths of freshness period and maximum shelf life according to sensory evaluation. Liquid cooling resulted in a 2-3 days shorter maximum shelf life than the group that was not receiving liquid cooling. This could be attributed to the fact that the cooling brine carried considerable amounts of microbes including the spoilage bacterium Photobacterium phosphoreum which is an active producer of trimethylamine (TMA). Comparison of the groups receiving liquid cooling showed that dry ice appeared to extend the shelf life of 1-2 days as compared to ice packs. Storage at -1°C did not have much influence on the freshness period or maximum shelf life. These results were confirmed by total volatile bases (TVB-N) and TMA analysis and microbial counts.

Skoða skýrslu

Skýrslur

The effect of different cooling techniques and temperature fluctuations on the storage life of cod fillets (Gadus morhua)

Útgefið:

01/08/2009

Höfundar:

Hannes Magnússon, Hélène L. Lauzon, Kolbrún Sveinsdóttir, Björn Margeirsson, Eyjólfur Reynisson, Árni Rafn Rúnarsson, María Guðjónsdóttir, Kristín Anna Þórarinsdóttir, Sigurjón Arason, Emilía Martinsdóttir

Styrkt af:

AVS R&D Fund of Ministry of Fisheries in Iceland, the Technology Development Fund at the Icelandic Centre for Research and EU (contract FP6-016333-2)

Tengiliður

Kolbrún Sveinsdóttir

Verkefnastjóri

kolbrun.sveinsdottir@matis.is

The effect of different cooling techniques and temperature fluctuations on the storage life of cod fillets (Gadus morhua)

Tilgangur tilraunanna var að kanna tvo kælimiðla um borð í veiðiskipi, að nota mismunandi kælitækni við vinnslu, m.a. svonefnda CBC (combined blast and contact) kælingu og kanna áhrif hitastigssveiflna við geymslu í samanburði við stöðuga geymslu við -1 °C. Lítill munur var á örveru- og efnamælingum hvort sem notaður var plötuís eða vökvaís fyrir vinnslu en samkvæmt skynmati reyndist hópurinn sem var kældur með vökvaís hafa eins dags lengri ferskleikatíma og geymsluþol. Hitastig var yfirleitt aðeins hærra í hópnum þar sem plötuís var notaður fyrir vinnslu yfir geymslutímann. Samkvæmt skynmati, örverutalningum og efnamælingum reyndist CBC kæling best til lengingar á ferskleikatíma og geymsluþoli. Hitastig reyndist vera lægra í þeim hópum þar sem CBC kæling var notuð. Örverufjöldi var svipaður í þeim tveimur hópum þar sem CBC kæling var ekki notuð við vinnsluna (vökvakæling og engin kæling). Þessar niðurstöður voru í samræmi við niðurstöður skynmats. TMA gildi voru aðeins hærri á geymsludögum 12-19 í hópnum sem var vökvakældur. Niðurstöður hitastigsmælinga yfir geymslutímann voru svipaðar. Svipaður örverufjöldi reyndist vera í hópum sem geymdir voru við stöðugt hitastig (um -1 °C) annars vegar og í hópum þar sem hitastigssveiflum var beitt fyrri hluta geymslutímans hins vegar. Fyrstu 15 daga geymslunnar reyndust TVB-N og TMA gildi vera svipuð í hópunum. Þeir hópar sem geymdir voru við stöðugt hitastig fóru ekki í skynmat. Örverumælingar sem gerðar voru með hinni fljótvirku aðferð qPCR voru í góðu samræmi við ræktunaraðferðir m.t.t. til Pseudomonas spp. og Photobacterium phosphoreum.

The purpose of this experiment was to examine two different cooling methods on board fishing vessel, to apply different cooling techniques during processing at fish plant including the CBC (combined blast and contact) cooling and to compare storage of packed cod fillets kept either at steady temperature (-1 °C) or under temperature fluctuations. No marked difference was seen in microbial and chemical measurements whether plate ice or liquid ice was used prior to filleting but according to sensory analysis, the experimental group where liquid ice was used had one day extension in freshness and shelf life compared to the group with plate ice. Temperature was usually slightly higher in the plate ice group than the liquid ice group during storage. According to sensory, microbiological and chemical analysis, the CBC cooling clearly resulted in longer freshness period and shelf life extension in comparison to the two groups where this technique was not applied during processing. Temperature was lower in these groups during the storage period. Similar microbial counts were found between the two experimental groups where CBC was not applied during processing (liquid cooling and no cooling). These results were in agreement with results from sensory analysis. TMA values were however higher on storage days 12 to 19 in the group with liquid cooling. Temperature measurements during storage of these two groups were very similar. No marked difference was seen in microbial counts between groups that were stored at a constant temperature around -1 °C compared to groups where temperature fluctuations were used during early phases of storage. During the first 15 days of storage, TVB-N and TMA values were very similar for these groups. Sensory analysis was not done on the two groups kept at -1 °C. The rapid qPCR analysis was generally in good agreement with the cultivation methods for Pseudomonas spp. and Photobacterium phosphoreum.

Skoða skýrslu
IS
EN IS