Lipid and Protein Changes Related to Quality Loss in Frozen Sardine (Sardina pilchardus) Previously Processed Under High-Pressure Conditions

Effects of static magnetic field (SMF) and alternating magnetic field (AMF) assisted freezing on the microstructure and protein properties of channel catfish (Ictalurus punctatus) fillet

The effect of static and alternating magnetic fields assisted freezing with intensity of 1, 2, and 3 mT on the microstructure and protein properties of channel catfish fillet were investigated. The results showed that the magnetic field treatment shortened the phase transition time of freezing, and significantly reduced the size of the formed ice crystals. The changes of trichloroacetic acid-soluble peptide, Ca2+-ATPase activity, particle size, and Zeta potential, which represented solubility, denaturation and aggregation of protein, indicated that magnetic field treatment could improve the protein stability. The chemical force analysis, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Fourier transform infrared spectroscopy (FTIR) results proved that the magnetic field could change the structure of protein. Furthermore, these changes had effects on the thermal stability of catfish meat protein which reflected by increasing of the transition temperature and enthalpy. However, the waveform and intensity of magnetic field affected the stability of protein structure.

High-pressure processing of fish and shellfish products: Safety, quality, and research prospects

Seafood products have been one of the main drivers behind the popularity of high-pressure processing (HPP) in the food industry owing to a high demand for fresh ready-to-eat seafood products and food safety. This review provides an overview of the advanced knowledge available on the use of HPP for production of wholesome and highly nutritive clean label fish and shellfish products. Out of 653 explored items, 65 articles published during 2016-2021 were used. Analysis of the literature showed that most of the earlier work evaluated the HPP effect on physicochemical and sensorial properties, and limited information is available on nutritional aspects. HPP has several applications in the seafood industry. Application of HPP (400-600 MPa) eliminates common seafood pathogens, such as Vibrio and Listeria spp., and slows the growth of spoilage microorganisms. Use of cold water as a pressure medium induces minimal changes in sensory and nutritional properties and helps in the development of clean label seafood products. This technology (200-350 MPa) is also useful to shuck oysters, lobsters, crabs, mussels, clams, and scallops to increase recovery of the edible meat. High-pressure helps to preserve organoleptic and functional properties for an extended time during refrigerated storage. Overall, HPP helps seafood manufacturers to maintain a balance between safety, quality, processing efficiency, and regulatory compliance. Further research is required to understand the mechanisms of pressure-induced modifications and clean label strategies to minimize these modifications.

High-pressure pretreatment in albacore (Thunnus alalunga) for reducing freeze-driven weight losses with minimal quality changes

BACKGROUND

This research evaluates the application of high-pressure processing (HPP) before freezing to reduce weight loss related to thawing and cooking of frozen albacore steaks (Thunnus alalunga) with a minimal impact on fish quality (color, texture, soluble protein, lipid oxidation). Albacore steaks were HPP pretreated (200, 250, and 300 MPa for 0, 2, 4 and 6 min), frozen (-20 °C, 5 m s^-1 ), thawed (4 °C; 24 h), and then analyzed.

RESULTS

At lower pressures (200 MPa) there was a clear effect of pressurization time on most of the fish quality parameters tested (thawing loss, L* value, b* value, ΔE, adhesiveness, springiness, salt-soluble protein content), whereas at higher pressures (300 MPa) similar changes took place independently of the pressurization time. High-pressure processing had no impact on lipid oxidation . A pressure of 200 MPa applied for 6 min decreased thawing, cooking, and total weight losses (53.7%, 55.4%, and 51.0% lower than the frozen control, respectively) although it led to noticeable changes in color. A pressure of 200 MPa applied for 2 min decreased thawing, cooking, and total weight losses by 23.2%, 44.0% and 33.7% with respect to the frozen control, respectively, with only minor changes in color.

CONCLUSION

High-pressure processing pretreatment could be a promising tool for reducing weight loss in frozen fish when HPP conditions are properly selected. A pressure of 200 MPa applied for 2 min could be a good compromise treatment, cutting thawing and cooking losses in albacore, and reducing HPP-mediated color alterations and the related possible consumer rejection. © 2020 Society of Chemical Industry.

Macroelements and Trace Elements Content in Brine-Canned Mackerel (Scomber colias) Subjected to High-Pressure Processing and Frozen Storage

This study analysed the effect of prior high-pressure processing (HPP; 200-600 MPa, 2 min), freezing (-30 °C, 48 h), and frozen storage (-18 °C, 6 months) on the macroelement and trace element content in brine-canned mackerel (Scomber colias). Most elements (Na, Ca, Ba, Mn, Fe, Cu, Cd, Sn, As, S, and Se) showed an increased (p < 0.05) presence in mackerel muscle canned after freezing. A content increase (p < 0.05) was also observed for Na and Sn if prior frozen storage was also applied; on the contrary, Ca, Ba, Mn, Fe, Cd, S, and Se showed a content decrease (p < 0.05) as a result of such storage. Freezing, frozen storage, and canning led to lower values (p < 0.05) in canned fish for K, Mg, Pb, and P. Prior HPP led to relevant content decreases (p < 0.05) for K, Mg, Ca, Ba, Mn, Fe, Pb, and P contents in fish canned after the freezing step; HPP provoked additional decreases (p < 0.05) in Ca, Ba, and Mn levels in samples corresponding to 6-month frozen storage. On the contrary, prior HPP led to marked increases (p < 0.05) for Cd, S, and Se contents in all canned samples. Content changes are explained on the basis of modifications of other constituents and liquor losses from muscle.

Comparative effect of a previous 150-MPa treatment on the quality loss of frozen hake stored at different temperatures

BACKGROUND

This study addresses the quality loss of European hake (Merluccius merluccius) during frozen storage. Its objective was to comparatively analyse the effect of a previous high-pressure processing (HPP) (150 MPa for 2 min) when different storage temperatures (-10, -18 and -30 °C) were employed.

RESULTS

Most chemical quality indices (trimethylamine, TMA; dimethylamine, DMA, formaldehyde, FA; free fatty acids, FFAs) provided a marked content increase with freezing and frozen storage time, values being higher by increasing the storage temperature. Previous HPP led to an inhibitory (P < 0.05) effect on the TMA, DMA, FA and FFA formation in frozen fish kept at -10 and -18 °C, the preservative effect being higher at the highest temperature tested; however, in agreement to the low damage development, no effect could be proved on samples stored at -30 °C. Concerning lipid oxidation, peroxides formation was found low, although a slight increasing effect (P < 0.05) was implied in fish corresponding to all temperatures as a result of the previous HPP; furthermore, an inhibitory effect (P < 0.05) on fluorescent compounds formation (tertiary lipid oxidation) was evident after freezing and at month 9 for -10 °C samples.

CONCLUSION

It is concluded that a 150-MPa high-pressure treatment may inhibit the formation of degradative molecules such as DMA, FA, TMA and FFAs during the frozen storage at -18 °C (maximum recommended) and -10 °C. However, results have indicated that lowering the storage temperature showed to be more effective than the current HPP (150 MPa for 2 min). © 2020 Society of Chemical Industry.

Effect of vacuum pressure on Yamú fish (Brycon amazonicus) meat during cold storage

Abstract This study aimed to assess the cryoprotectant effect of vacuum packaging (35 and 45 kPa) on cold preserved (0 °C and -18 °C) fillets of Yamú (Brycon amazonicus), during 5 days of storage. We analyzed the physicochemical and microbiological changes in the fillets during storage time. Yamú’s water holding capacity, nitrogenated bases content (TVB-N) and texture (N) were affected (p ≤ 0.05) by time and temperature. Bacterial colonies in fillets did not represent a risk for human health after five days of storage. In conclusion, vacuum packing positively (p ≤ 0.05) reduces the effect of cold over Yamú fillets properties.

Effect of high-pressure processing pretreatment on the physical properties and colour assessment of frozen European hake (Merluccius merluccius) during long term storage

Fish freshness is lost by autolytic degradation produced by endogenous enzymes. Frozen storage is one of the most used methods to preserve fish properties. However, protein denaturation has shown to be a major problem for frozen European hake (Merluccius merluccius), leading to texture losses and off-odour development. The aim of this work was to study the changes produced by high-pressure processing (HPP) before freezing on quality of frozen European hake stored at -21 °C for 12 months. The effect of HPP (150-450 MPa) on mechanical properties and expresible water was evaluated in raw and cooked fish samples. The effect on colour (L*, a* and b*) was assessed only in raw fish. Results showed that HPP before freezing is beneficial to maintain expresible water in good levels up to 6 months. The luminosity significantly increased with pressure level. Textural profile of raw samples showed that HPP increased hardness, adhesiveness and springiness of frozen hake. Cooked samples were also affected by HPP, being the best results obtained at 300 MPa for 6 months of frozen storage. Overall, results showed that HPP improves the quality of frozen hake.