Liquid Holding Capacity and Structural Changes During Heating of Fish Muscle: Cod (Gadus morhua L.) and Salmon (Salmo salar)

The loss of water and fat in cod and salmon muscle was studied as a function of heating temperature from 5-70 C. The liquid-holding capacity was measured by a low speed centrifugation net test leading to the separation of released liquid. To obtain a better understanding of the liquid-holding properties, the microscopic changes of the samples were evaluated by light microscopy. Two different preparation techniques were used . Cod lost twice as much water as salmon upon beating. After an initial delay , the water loss increased at 20-35°C, attained a maximum at 45-50°C, and thereafter decreased in both fish species. Salmon muscle was more heat-stable than cod muscle. Since the main structural changes appeared in the connective tissue at low temperatures (5-40°C), the water loss at these temperatures is probably mainly due to denaturation and melting of collagen. The maximum water loss was attained when the muscle cell shrank due to denaturation of myosin. The reduced water loss at higher temperatures (50-70°C) is probably caused by aggregates of sarcoplasmic proteins stabilizing the aqueous phase

Liquid Holding Capacity and Structural Changes During Heating of Fish Muscle: Cod (Gadus morhua L.) and Salmon (Salmo salar)

The loss of water and fat in cod and salmon muscle was studied as a function of heating temperature from 5-70 C. The liquid-holding capacity was measured by a low speed centrifugation net test leading to the separation of released liquid. To obtain a better understanding of the liquid-holding properties, the microscopic changes of the samples were evaluated by light microscopy. Two different preparation techniques were used . Cod lost twice as much water as salmon upon beating. After an initial delay , the water loss increased at 20-35°C, attained a maximum at 45-50°C, and thereafter decreased in both fish species. Salmon muscle was more heat-stable than cod muscle. Since the main structural changes appeared in the connective tissue at low temperatures (5-40°C), the water loss at these temperatures is probably mainly due to denaturation and melting of collagen. The maximum water loss was attained when the muscle cell shrank due to denaturation of myosin. The reduced water loss at higher temperatures (50-70°C) is probably caused by aggregates of sarcoplasmic proteins stabilizing the aqueous phase

Characterization of vasskveite (water halibut) syndrome for automated detection

In recent years, cases of vasskveite (water halibut) syndrome in halibut have been increasing. At the moment, there exists no way to screen for the syndrome immediately after capture, which is problematic for both exporters and purchasers. In this article, we compared good quality halibut and halibut exhibiting the syndrome using a variety of techniques. Hyperspectral imaging was used to quantify the relative amounts of fat and water in the tissue. Diffusion tensor imaging was used to characterize tissue structure. Histology was performed to provide direct visual characterization of the tissue. Results indicate the muscle fibers in afflicted fish exhibit disordered growth and the tissue is lacking in fat. These results are in line with the current theory that the syndrome stems from a nutritional deficiency in the halibut diet. Hyperspectral imaging appears to be a promising technology to rapidly identify afflicted halibut immediately after capture

Monitoring Secondary Structural Changes in Salted and Smoked Salmon Muscle Myofiber Proteins by FT-IR Microspectroscopy

Fourier transform infrared (FT-IR) microspectroscopy and light microscopy were used to study changes in the myofibrillar proteins and microstructure in salmon muscle due to dry salting and smoking. Light microscopy showed that the myofibers of the smoked samples were more shrunken and their shape more irregular and edged than for the nonsmoked samples. FT-IR microspectroscopy showed that salting time mostly contributed in the amide I region, revealing that secondary structural changes of proteins were primarily affected by salting. The main variation in the amide II region was caused by smoking. As it is known that smoke components can react with amino acid side chains and that the contribution of the side chain in the amide II region is larger than that in amide I, it is concluded that the observed differences are due to interactions between carbonyl compounds of smoke and amino acid side chains.Monitoring Secondary Structural Changes in Salted and Smoked Salmon Muscle Myofiber Proteins by FT-IR MicrospectroscopyacceptedVersio

Monitoring Protein Structural Changes and Hydration in Bovine Meat Tissue Due to Salt Substitutes by Fourier Transform Infrared (FTIR) Microspectroscopy

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Characterization of Collagen Structure in Normal, Wooden Breast and Spaghetti Meat Chicken Fillets by FTIR Microspectroscopy and Histology

Recently, two chicken breast fillet abnormalities, termed Wooden Breast (WB) and Spaghetti Meat (SM), have become a challenge for the chicken meat industry. The two abnormalities share some overlapping morphological features, including myofiber necrosis, intramuscular fat deposition, and collagen fibrosis, but display very different textural properties. WB has a hard, rigid surface, while the SM has a soft and stringy surface. Connective tissue is affected in both WB and SM, and accordingly, this study’s objective was to investigate the major component of connective tissue, collagen. The collagen structure was compared with normal (NO) fillets using histological methods and Fourier transform infrared (FTIR) microspectroscopy and imaging. The histology analysis demonstrated an increase in the amount of connective tissue in the chicken abnormalities, particularly in the perimysium. The WB displayed a mixture of thin and thick collagen fibers, whereas the collagen fibers in SM were thinner, fewer, and shorter. For both, the collagen fibers were oriented in multiple directions. The FTIR data showed that WB contained more β-sheets than the NO and the SM fillets, whereas SM fillets expressed the lowest mature collagen fibers. This insight into the molecular changes can help to explain the underlying causes of the abnormalities.publishedVersio