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Doctoral dissertation in food science at the Faculty of Food and Nutrition at the School of Health Sciences, University of Iceland. Effects of different processes of action on the physical and chemical properties of fully processed salted fish.

On Wednesday 14 December. is defending his doctoral dissertation at the Faculty of Food and Nutrition, University of Iceland. Food scientist Minh Van Nguyen is defending his doctoral dissertation "The Effects of Different Processing Methods on the Physicochemical Properties of Heavily Salted Cod".

Opponents are dr. José Manuel Barat Baviera, Professor of Food Science, Universidad Politécnica de Valencia in Spain, and dr. Hörður G. Kristinsson, division and research director of Matís ohf. The instructor was Sigurjón Arason, Associate Professor at the Faculty of Food and Nutrition, University of Iceland and Chief Engineer at Matís ohf.

Dr. Inga Þórsdóttir, professor and president of the Faculty of Food and Nutrition, will chair the ceremony, which will take place in the Celebration Hall of the University of Iceland in the Main Building and will begin at 14:00.

Abstract from the study
Salted fish has been produced in Iceland and other countries since the 16th century. In recent years, the salting process of salted fish has developed a lot with the aim of improving the utilization and maintaining the quality of salted products during transport and storage. The process consists of different stages of salting and processing. It starts with pre-salting, spraying and / or pickling followed by dry salting. Appearance is a key factor when it comes to classifying products by quality. Jaundice that can be traced to muscle development can cause severe deterioration in quality. As a result, manufacturers' interest in the use of additives (such as polyphosphate) that can reduce development has increased. At present, however, phosphates have not been authorized as additives in salted fish processing. Scientific information on the activity and fate of phosphate in salted cod products is very limited.

The aim of this study was to gain a deeper knowledge of salted fish processing, with observations of mass flow and changes in the structure of proteins at different salt concentrations during pre-salting, as well as anti-corrosion properties and phosphate degradation in salted fish products. Furthermore, the effect of potassium ferrocyyanide (CN), a salt antifouling agent, on the oxidation (oxidation) of fats was investigated. In addition, the quality changes of salted cod were monitored at different storage temperatures.

The salinity of brine in pre-salting had a significant effect on the flow of salt and water into the muscle and thus on utilization and salting rate. Changes in protein imaging were dependent on the salinity of the muscle phase of the muscle Z- (NaCl), which could be explained by the salting-in of low-salt proteins (Z- (NaCl) <6%) and the de-salting-out of high-salt proteins ( Z- (NaCl)> 6%). The results showed that at Z- (NaCl) = 15%, the separation of dehydration and dehydration of proteins by brine was.

The results also showed that yellowing during salted fish processing is due to development and breakdown of fat. Development became faster with higher CN strength. However, the use of phosphate in the pre-salting process significantly decreased. To monitor the evolution (oxidation) of fat during the salting and storage of salted fish, measurements of fat derivatives (TBARS), spectra (b * values) and fluorescence were found. For) bestar. This study confirms that fluorescence measurements give a good picture of the amount of third-degree images during the development of salted fish products. It is not recommended to store products below -1 ° C. Storage at -4 ° C had a negative effect on quality, the color was darker and the amount of TVB-N higher than at the normal storage temperature (2 ° C).

Changes in the amount and composition of phosphate were determined by ion chromatography (IC) and spectrophotometric method. The added tri- and pyrophosphates decomposed in the salting process, i.e. pre-salting, dry salting, storage and dehydration. Most of the added and natural phosphates were flushed out of the muscle during dehydration. However, residues of added phosphates in dehydrated products could still be detected. There were differences in the results according to measurement methods, with IC the total amount of phosphate was lower than with light absorption measurement.

The doctoral dissertation is based on six scientific articles, of which four articles are already published in international scientific journals and two more have been submitted for publication.

In addition to the supervisor were on the doctoral committee Guðjón Þorkelsson, Associate Professor at the Faculty of Food and Nutrition, University of Iceland and Head of Department at Matís ohf., dr. Ágústa Guðmundsdóttir, professor at the Faculty of Food and Nutrition, University of Iceland, and dr. Kristín Anna Þórarinsdóttir, specialist manager at Matís ohf.

The United Nations University School of Fisheries awarded Minh Van Nguyen a scholarship and Matís ohf. provided his research facilities. The study belonged to projects funded by the AVS Fisheries Research Fund and the Technology Development Fund.

Starts: 14/12/2011 - 14:00
Location: Main building
Further location: Celebration hall

About the doctoral dissertation
Minh Van Nguyen was born in 1977 in Vietnam. He earned a bachelor's degree in food science in 2000 and an MS degree in 2004 from the Faculty of Aquatic Products Processing, Nha Trang University (NTU) in Vietnam. Since 2000, Minh Van Nguyen has been a lecturer in food science at Nha Trang University (NTU).

Minh Van Nguyen is married to Hoang Hai Yen and they have daughters Nguyen Thai Ha Anh and Nguyen Thai Ha Linh.

For further information Sigurjón Arason at Matís and the University of Iceland website, www.hi.is.

Recently, a textbook was compiled by Matís on grain and important aspects concerning grain cultivation in Iceland.

Build (Hordeum vulgare L.) has been cultivated for over 10,000 years. Barley is the type of grain that needs the shortest growing time to reach maturity and is therefore grown in northern areas. In Iceland, interest in the utilization of domestic grain for food production has increased in recent years. Icelandic barley is an interesting raw material but it offers many possibilities in the food industry and cooking. Domestic barley has gained a foothold in the country's bakeries, as the competition for bread of the year 2009 organized by the company Kornax entails. Bread from Icelandic barley is now available in various bakeries in the country. There are opportunities in the use of barley for special products all over the country, so-called district registers. The tourism industry can benefit from such a development.  

Food grain is more valuable than feed grain, so grain farmers are still struggling to bring part of their harvest to food production. It must be borne in mind that more demands are made on food barley than on feed barley. Quality requirements have been set for barley for food production. The quality requirements were prepared by Matís ohf and the Agricultural University of Iceland in a project funded by the Agricultural Productivity Fund. The quality requirements are conceived as a reference in business so that both buyers and sellers have the same understanding of the product.

The entire textbook can be found here.

The educational material is published with the support of the Vocational Education Council. Reports quoted in the issue can be found on Matís' website, www.matis.is/utgafa/matis/skyrslur/

For further information Ólafur Reykdal.

New processes have been developed for the processing of lightly salted products from farmed cod in a project funded by AVS (R 11 006-010).

Farmed fish are usually processed before death, but this has caused certain problems with salt uptake and weight changes in products. It has now been shown that a salt uptake comparable to that in wild fish processed after death hardening can be achieved by controlling the composition of the brine and the salting methods.

There is a difference in the processing of farmed cod and wild cod, which lies in the fact that farmed cod is processed before death. The reason is that there is a greater risk of release if farmed cod is processed after death. In addition, the control of raw material procurement is easier than in traditional wild fish ice fishing, as various external factors, such as distance to the center, make it impossible to process wild fish before death. This difference in processing timing has meant that it has not been possible to transfer the processes used for wild fish to farmed fish as its processing properties differ from wild fish. 

The main products from cod farming are fresh neck pieces that are transported to mainland Europe, but some of the products are also frozen. The advantage of selling aquaculture products is greater security of supply, as the control of raw material procurement is easier, raw material is fresher as it can be processed immediately after slaughter and the shelf life of products is longer. The chemical composition of farmed cod is similar to that of wild cod, but their physical characteristics are different. This means that changes in the muscle during processing, storage and cooking are different, such as there is a risk that farmed cod will be tougher and drier when boiled than wild fish. 

The market for lightly salted products is desirable and is well suited for farmed cod, which is often whiter and thicker than wild cod. In Spain, a market has been built for lightly salted frozen cod products alongside traditional salted fish products. Lightly salted fish is often whiter and the symptoms of action are much milder than in salted fish.

The timing of processing of firefish has caused problems with salting, as salt uptake and weight gain are poorer than when fish have undergone death freezing. This has been one of the main barriers to the production of lightly salted products in the same way as in the case of wild fish. Therefore, it was decided to better investigate the effect of salting methods and the composition of brine on the utilization, quality and chemical content of products, in the project "New processes in the processing of farmed cod" (R 11 006-010). Experiments were made with different composition of brine, salt concentration, as well as the use of phosphates and a mixture of citrate and ascorbate. The substances can affect the waterproofing properties of the muscle, partly due to the effect on ionic strength but also due to the specific activity of the substances:

• Citrate binds divalent ions such as calcium (Ca²⁺) and magnesium (Mg²⁺) and thus has a positive effect on water resistance. The substance is thought to inhibit the breakdown of glycogen (energy reserves) to some extent, but at the same time, evidence has also been found that it accelerates muscle gain. The substance alone can lower the muscle acidity, which is negative in terms of water resistance, but is offset by the inhibitory effect of the substance on the decrease in acidity due to death stiffness. 
• Phosphate can have a positive effect on acidity, bind divalent ions and reduce the cross-linking between actin and myosin. Therefore, the contraction of the muscle may be less. 
• Salt (NaCl) can increase muscle contraction with death stiffness, but release decreases and less force is needed to remove pin-bones. Salt has a positive effect on water resistance as salt ions bind to muscle proteins and increase the repulsive force between them. This reduces the risk of water loss from the muscle and it can even increase its weight.

The project showed that great results can be achieved in terms of salt uptake and utilization by controlling the salting technique and brine concentration. The results indicated that the use of phosphate and a combination of citrate and ascorbate could reduce the development, according to measurements of the development of the subjects. However, these effects were not observed in color measurements or sensory evaluation. Injection results in more micro-organisms spreading across the muscle and therefore the shelf life of thawed fillets is shorter than in the case of untreated fillets. When injection was followed by pre-freezing brine, the efficacy symptoms of lightly salted fillets became stronger after 3-6 months in frost. With longer storage or up to 9 months, the difference decreased compared to fillets that were only injected before freezing. In general, symptoms such as cravings, odor of cold storage and taste of cold storage became more pronounced over time, regardless of the salting methods or the composition of the brine.

The project was a joint project of Hraðfrystihús - Gunnvarar hf in Súðavík and Matís ohf in Reykjavík. The AVS Research Fund financially supported the project. AVS reference number: R 006-10

For further information Kristín Anna Þórarinsdóttir at Matís.

Matís, in collaboration with Lýsir hf., Contributes to assisting the company's employees in maintaining good bone health.

Every morning, Matís employees are given the opportunity to get Omega-3 + D-vitamins from Lýs hf. thus securing 10 micrograms of vitamin D in one tablet. It is not known that companies in Iceland have assisted their employees in this way.

As has probably not gone unnoticed, many Icelanders struggle with vitamin D deficiency at some stage, at least during the winter months when sunlight is limited. As most people know, vitamin D is essential for the body to absorb calcium from its diet. Without adequate amounts of vitamin D and calcium, our bone health will not be as good as it could be. Every exercise, where we carry our own body weight, helps to maintain bone health, but we also need the above ingredients to maximize bone health and prevent osteoporosis and osteoporosis.

Vitamin D is not found in many foods that Icelanders regularly consume. Vitamin D is mainly found in fatty fish, multivitamin tablets and other supplements and then in fish oil. When a fish is consumed that contains vitamin D, that amount of vitamin D is often only enough for the day the fish is consumed. It is therefore necessary to examine how to obtain a reasonable amount of vitamin D every day and then possibly by other means than just by consuming fish.

As things stand today, 10 micrograms is the recommended amount to consume each day, but the recommendations will probably change in the coming months and the recommended daily dose will probably increase.

If and when the government announces a general vitamin D supplementation in food, Matís will review whether there is a need to offer this product to its employees. Until then, the company contributes and ensures that Matís employees receive at least part of the amount of vitamin D every day that is necessary for good bone health.

For further information Steinar B. Aðalbjörnsson, Marketing Manager at Matís, tel. 858-5111.

In Borgir in Akureyri, Matís rents premises and would like to offer exciting partners to rent part of that space for their operations.

The accommodation available is a total of 24.4 sqm in size and is a specially designed laboratory with a window for the entire short side, two openable window frames, fume cupboard, large sink, benches on all walls, cabinet under the sink table and gas pipes (various types of gas used in the house and can be linked to them).

Borgir has a number of progressive companies and institutions, such as the Icelandic Innovation Center (IMPRA), the National Energy Authority and the University of Akureyri. There are therefore great opportunities in collaboration and synergies for forward-looking knowledge companies in this environment of interdisciplinary knowledge.

Here you can see some pictures of the premises, but there is also the possibility of renting office space.

For more information Rannveig Björnsdóttir, Matís' station manager in Akureyri and Oddur Már Gunnarsson, Head of Operations and Business Development at Matís.

A report has been published that Matís prepared for the Consumer Association. The report contains the results of an audit of frozen fish in stores. The audit was conducted between July and November 2011.

The quality of frozen and packaged fish in supermarkets in the capital area was examined. Information on the packaging of the fish products was recorded and then measurements were made of the weight of the fish and packaging, ice skin, water loss during thawing, water content, proteins, salt, phosphates and boiling efficiency.

The report can be found here.

Further information on the Consumer Association's website, www.ns.is.

Issue no. 24/2011 in Icelandic Agricultural Sciences (IAS) and there are many interesting scientific articles on Icelandic agriculture and land use. Helga Gunnlaugsdóttir at Matís is a member of the IAS editorial board, but in addition, this edition contains articles by several Matís employees.

The scientific journal Icelandic Agricultural Science, or IAS, is an international journal on life sciences related to agriculture and land use.

IAS has now got a new website www.ias.is. On this page you can access all the scientific articles that have appeared in the publication since the beginning in 1988 in electronic form.

IAS is the only international scientific journal published in Iceland on research related to forestry, fisheries, land reclamation, agriculture and other land use.

In his time, the editorial board changed IAS the name of the publication into English and further increased the requirements for the quality of scientific articles. All articles published in the publication are in English and are peer-reviewed by at least one foreign expert (and one domestic), as well as an editor. In connection with this change, several directors of the institutions responsible for publishing the publication, such as the director of forestry, have agreed to evaluate the publication in their institutional agreements as "Peer-reviewed international scholarly journal".