How to limit cook loss when preparing cod (Gadus morhua): The constraints of temperature and time

publishedVersio

Weakly supervised semantic segmentation for MRI: exploring the advantages and disadvantages of class activation maps for biological image segmentation with soft boundaries

publishedVersio

Diffusion tensor imaging for spatially-resolved characterization of muscle fiber structure in seafood

The fiber structure of tissue in meat and seafood has a significant impact on their perceived quality. However, quantifiable description of muscle structure is challenging. We investigate diffusion tensor imaging (DTI) magnetic resonance imaging (MRI) as a method to quantitatively describe tissue structure. DTI measures the anisotropy of water molecule diffusion within muscle fibers. A pilot study evaluated three different cod loin samples: one of high-quality, one of medium-quality, and one of poor-quality. DTI parameters such as fractional anisotropy, axial diffusion and radial diffusion showed clear differences between the sample qualities. Changes in the DTI metrics consistent with freezing and thawing damage to the tissue were observed. The DTI maps were compared to T2-weighted images and DTI detected significant details that were not visible in T2-weighted images. Overall, these results indicate that DTI is a promising method for spatially-resolved characterization of tissue structure in seafood and meat

Predicting liquid loss of frozen and thawed cod from hyperspectral imaging

publishedVersio

Liquid loss in thawed cod—Deconvoluting the effects of freezing-rate, freezing cycles, frozen storage time, and thawing-rate through a full factorial design

Fish is a highly perishable product and freezing is the obvious way to increase shelf life. The freezing process involves the initial freezing, a frozen storage period and thawing—all of which influence the quality of the end product. In this study, the quantity of liquid loss is used as an indication of the structural damage induced by these processes. A full factorial experiment design addresses the effects of freezing and thawing rates (fast vs. slow), number of freezing cycles (1 vs. 2) and frozen storage (1 year vs. 1 week). The results show strong evidence that fast processes of freezing and thawing reduce the subsequent liquid loss. However, 1 year frozen storage at −20°C induces high liquid loss independently of the freezing and thawing rates. Adding a second freezing cycle also adds to the liquid loss upon final thawing. By increasing the number of processing steps (additional freezing cycles) the strain put upon the samples progressively increases. This leaves samples at the end of long sequences of processing especially sensitive to damage caused by ice crystals. In this way, the thawing protocol might be of high importance, especially during the last freezing cycle of twice frozen samples. Practical Application In order to minimize liquid loss through production of frozen seafood, it is imperative that producers use the best practice at every stage. Liquid loss influences yield through production, but it also contributes to quality parameters relevant to both producers and consumers. Every stage of the production impacts liquid loss, and examining and classifying the different processing steps separately is the common approach to assess the effect. For the final product however, the impact of one isolated step is entangled in the combined effect off all the different processing steps. In this study, we have examined the processing continuum from the first freezing to the last thawing, including the effects of an extra freeze cycle and frozen storage period. In this way, we demonstrate the risk of pitfalls through such processing and also highlight the process combinations that are synonymous with low liquid loss

Non-invasive assessment of packaged cod freeze-thaw history by hyperspectral imaging

acceptedVersio

Weakening Pin Bone Attachment in Fish Fillets Using High-Intensity Focused Ultrasound

publishedVersio

Detection of blood in fish muscle by constrained spectral unmixing of hyperspectral images

acceptedVersio

Optimalisering av radiofrekvens (RF) – temperering og tining av hvitfisk. Faglig sluttrapport

I de senere år har RF (radiofrekvens) tining blitt tilgjengelig kommersielt og blant annet brukt på farseprodukter i Norge. Hovedmålet med dette prosjektet var å dokumentere og optimalisere RF-behandling og påfølgende tining av blokkfrosset HG (sløyd og hodekappet) torsk med hensyn på kvalitet og utbytte. Dette prosjektet viser at RF-behandlingen kan brukes som en viktig del i tining av HG-blokker i stor skala. Våre resultater antyder at den avsluttende konvensjonelle tiningen (i vann) påvirker holdbarheten i større grad enn RF-behandlingen. En måte å redusere tiden i vannkaret er å øke bidraget fra RF-behandlingen siden dette vil redusere behovet for påfølgende vanntining. RF-behandlingen tilfører energien mye raskere enn konvensjonell tining (hvor energien må inn via overflaten) og dette gir kortere eksponering for bakterier ved en tilsvarende kortere påfølgende vanntining i tillegg til en totalt sett mer tidsbesparende prosess. I tillegg kommer effekten av at blokkene kan splittes etter RF-behandlingen, noe som gjør at effektiviteten i tineprosessen øker ytterligere