Effects of high pressure processing on protein fractions of blue crab (Callinectes sapidus) meat

The application of ice glazing containing D-sodium erythorbate combined with vacuum packaging to maintain the physicochemical quality and sweet/umami non-volatile flavor compounds of frozen stored large yellow croaker (Pseudosciaena crocea)

Ice glazing containing 0.3 % D-sodium erythorbate (DSE), combined with vacuum packaging, was used as a method to maintain the quality of large yellow croaker during frozen storage. This study aimed to assess various aspects, including water properties (water holding capacity and moisture distribution), protein-related characteristics (secondary and tertiary structure of myofibrillar protein), freshness indicators (K value and total volatile base nitrogen (TVB-N)), and non-volatile flavor compounds (free amino acids (FAAs) and nucleotides) in samples stored for 300 days at -23 °C. The results showed that vacuum packaging had a significant inhibitory effect on the growth of ice crystal. Notably, it successfully maintained the cross-sectional area of nearly all ice crystals below 20,000 μm2, effectively curtailing water loss. Simultaneously, the combination of vacuum packaging with the complex ice glaze effectively mitigated the degradation of IMP and free amino acids, maintaining low levels of K value (12.85 %) and TVB-N (11.28 mg N/100 g) throughout the 300-day frozen storage, retaining first-class freshness. Among the various treatment modalities assessed, the combined application of vacuum packaging and 0.3 % DSE-infused ice glazing emerged as the most effective in terms of preservation outcomes. This efficacious combination shows promising potential for the frozen storage of aquatic products and is therefore recommended for practical implementation.

Pilot Scale Assessment of High-Pressure Processing (HPP) to Enhance Microbiological Quality and Shelf Life of Fresh Ready-to-Eat (RTE) Blue Crab Meat

Blue crab (Callinectes sapidus) is a highly valuable wild fishery species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico. The annual commercial production of live blue crabs is approximately 50,000 metric tons with a dockside value of USD 200 million. Presently the US blue crab processing industry sells crab meat in three basic forms: fresh crab meat, pasteurized crab meat, and frozen crab meat. By far "Fresh" is the most desirable form of crab meat. However, fresh crab meat has a limited shelf life. This study evaluated the effects of high-pressure processing (HPP) on enhancing the microbiological quality and shelf life of blue crab meat. Live blue crabs were pressure-cooked in a retort (≥115 °C for 4-6 min). The crab meat was handpicked, packed in plastic containers with seals, subjected to HPP treatment, and stored at 4 °C. Container integrity and water leakage issues were examined by observation in addition to weight comparison before and after HPP treatment; the shelf life of crab meat with and without HPP treatments was examined via microbiological tests and sensory evaluations. Results show that polypropylene containers sealed with 10K OTR (oxygen transmission rate) film could withstand high pressure without water leakage issues; HPP treatment at 600 MPa for 3 min could extend the shelf life of fresh, cooked, and handpicked crab meat from 6 days to 18 days based on the strictest APC (aerobic plate account) limit (APC ≤ 100,000 CFU/g). The sensory quality of the HPP-treated crab meat was well accepted throughout the 3-week storage period. The results support the use of HPP as an effective non-thermal processing technology to enhance the microbiological quality and extend the shelf life of fresh RTE blue crab meat.

Chickpea protein hydrolysate as a novel plant-based cryoprotectant in frozen surimi: Insights into protein structure integrity and gelling behaviors

Chickpea protein (CP) and its enzymatic hydrolysates are one of the most widely consumed pulse ingredients manifesting versatile applications in food industry, such as binders, emulsifiers, and meat protein substitutes. Other than those well-known functionalities, however, the use of CP as a cryoprotectant remained unexplored. In this study, we prepared the chickpea protein hydrolysate (CPH) and investigated its cryoprotective effects to frozen surimi in terms of the protein structure integrity and gelling behaviors. Results indicated that CPH could inhibit myofibrillar protein (MP) denaturation and oxidation during the freeze-thaw cycling, as evidenced by their increased solubility, Ca²⁺-ATPase activity, sulfhydryl concentration, and declined content of disulfide bonds, carbonyl concentration and surface hydrophobicity. Freezing-induced changes on MP secondary structures were also retarded. Moreover, gels prepared from CPH-protected frozen surimi demonstrated more stabilized microstructure, uniform water distribution, enhanced elasticity, gel strength and water holding capacity. The CPH alone, at a reducing addition content of 4% (w/w), exhibited comparable cryoprotective performance to that of the commercial formulation (4% sucrose and 4% sorbitol). Therefore, this study provides scientific insights for development of pulse proteins as novel and high-performance food cryoprotectants.

The inhibition mechanism of nanoparticles-loading bilayer film on texture deterioration of refrigerated carp fillets from the perspective of protein changes and exudates

Herein, the protective pattern of bilayer film on the texture stability of fillets was discussed in terms of endogenous enzyme activity, as well as protein oxidation and degradation. The texture properties of fillets wrapped with nanoparticles (NPs) bilayer film were greatly improved. NPs film delayed protein oxidation by inhibiting the formation of disulfide bond and carbonyl group as evidenced by the increase of α-helix ratio (43.02%) and the decrease of random coil ratio (15.87%). The protein degradation degree of fillets treated with NPs film was lower than that of control group, specifically with a more regular protein structure. The exudates accelerated the degradation of protein, while NPs film effectively absorbed exudates to delay protein degradation. Overall, the active agents in the film were released into the fillets to play an antioxidant and antibacterial roles, and the inner layer of film could absorb exudates, thus maintaining the texture characteristics of fillets.

Chitosan from crab shell waste for soft lithography of bioplastic diffraction gratings

Bioplastic diffraction gratings are fabricated from chitosan prepared from crab shells through a soft lithography replication process. Atomic force microscopy and diffraction experiments with the chitosan grating replicas indicate the successful copying of periodic nanoscale groove structures corresponding to densities of 600 and 1200 lines/mm. First-order efficiency of bioplastic gratings is comparable to the output of elastomeric grating replicas.

The Effects of Malonaldehyde on Quality Characteristics and Protein Oxidation of Coregonus peled (Coregonuspeled) during Storage

The effects of changes in the malondialdehyde (MDA) content on the quality of fish during the low-temperature storage period are unclear. Therefore, the effects of the MDA content on Coregonus peled quality and protein changes were investigated following storage under refrigeration (4 °C) and super chilling (-3 °C) for 15 days (d). The results showed that the MDA content continued to increase during storage and that the highest content was produced at 1.42 mg/kg during refrigeration. The fillet pH, drip loss, texture (hardness and elasticity), and myofibril fragmentation index deteriorated significantly during the storage period. Increased oxidation of the myofibrillar protein (MP) was observed in the 15 d storage period, and the MP carbonyl content was 1.19 times higher under refrigeration than in super chilling, while the protein α-helix structure decreased by 12.48% and 12.20% under refrigeration and super chilling, respectively. Electropherograms also showed that myosin degradation was particularly severe in the refrigeration storage period of 15 d. Overall, the MDA formed at the refrigeration and super chilling storage temperatures could promote structural changes in, and the oxidative degradation of, proteins to different degrees, leading to the deterioration of the fillet quality. This study provides a scientific basis for investigating the relationship between fish quality and changes in the MDA content during low-temperature storage.

Effects of High Hydrostatic Pressure and Storage Temperature on Fatty Acids and Non-Volatile Taste Active Compounds in Red Claw Crayfish (Cherax quadricarinatus)

The effects of high hydrostatic pressure (treated with 200, 400 and 600 MPa) and storage temperatures (4 °C and −20 °C) on the fatty acids and flavor compounds of red claw crayfish were studied. HHP decreased the PUFA, GMP, IMP and AMP, citric and lactic acids, and PO43− contents, but the FAA, Ca2+ and Cl− contents increased in HHP-treated crayfish compared to untreated crayfish at 0 d. Storage at −20 °C could restrain the fatty acids and flavor contents compared to those stored at 4 °C. The GMP, AMP, citric acid and PO43− contents decreased, and Ca2+ and Cl− contents increased after storage at 4 °C for 15 d (p < 0.05). HHP at 200 and 400 MPa increased EUC on 0 d. No significant changes in EUC were observed after storage at −20 °C for 15 d, significant decreases were noted at 4 °C than the crayfish stored for 0 d (p < 0.05), except for the untreated group. Generally, HHP at 200 or 400 MPa, and storage at −20 °C is beneficial according to the shelling rates and EUC of crayfish.

Effect of High-Pressure Processing on the Packaging Properties of Biopolymer-Based Films: A Review

Suitable packaging material in combination with high-pressure processing (HPP) can retain nutritional and organoleptic qualities besides extending the product’s shelf life of food products. However, the selection of appropriate packaging materials suitable for HPP is tremendously important because harsh environments like high pressure and high temperature during the processing can result in deviation in the visual and functional properties of the packaging materials. Traditionally, fossil-based plastic packaging is preferred for the HPP of food products, but these materials are of serious concern to the environment. Therefore, bio-based packaging systems are proposed to be a promising alternative to fossil-based plastic packaging. Some studies have scrutinized the impact of HPP on the functional properties of biopolymer-based packaging materials. This review summarizes the HPP application on biopolymer-based film-forming solutions and pre-formed biopolymer-based films. The impact of HPP on the key packaging properties such as structural, mechanical, thermal, and barrier properties in addition to the migration of additives from the packaging material into food products were systemically analyzed. HPP can be applied either to the film-forming solution or preformed packages. Structural, mechanical, hydrophobic, barrier, and thermal characteristics of the films are enhanced when the film-forming solution is exposed to HPP overcoming the shortcomings of the native biopolymers-based film. Also, biopolymer-based packaging mostly PLA based when exposed to HPP at low temperature showed no significant deviation in packaging properties indicating the suitability of their applications. HPP may induce the migration of packaging additives and thus should be thoroughly studied. Overall, HPP can be one way to enhance the properties of biopolymer-based films and can also be used for packaging food materials intended for HPP.

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.

Effects of high hydrostatic pressure (HHP) and storage temperature on bacterial counts, color change, fatty acids and non-volatile taste active compounds of oysters (Crassostrea ariakensis)

The effects of HHP and storage temperature on bacterial counts, color, fatty acids and flavor compounds of oysters Crassostrea ariakensis were investigated. Counts of Vibrio vulnificus and Vibrio parahaemolyticus decreased to undetectable levels in ≥ 400 MPa-treated oysters. Storage at -20 °C significantly restrained microbial growth compared to 4 °C (P < 0.05). L* values of HHP-treated oysters significantly increased compared to raw oysters (P < 0.05). Storage slightly affected the color according to total color difference (ΔE*) values. Fatty acid profiles and betaine contents in 400 and 600 MPa-treated oysters at 0 and 15 d were almost the same as raw samples. Contents of total free amino acids (FAAs), Na⁺ and Ca²⁺ were significantly higher in 400 and 600 MPa-treated oysters than those in raw oysters at 0 d (P < 0.05), while the opposite results were observed in 5'-adenosine monophosphate (AMP), 5'-guanosine monophosphate (GMP), citric acid, succinic acid, K⁺ and PO₄^3- (P < 0.05). At 400 and 600 MPa, FAAs significantly decreased after 15-d storage at 4 °C and -20 °C (P < 0.05), while no significant changes were observed in nucleotides, organic acids and inorganic ions.

Improving the Quality of Frozen Lamb by Microencapsulated Apple Polyphenols: Effects on Cathepsin Activity, Texture, and Protein Oxidation Stability

This study aimed to evaluate the efficiency of microencapsulated apple polyphenols (MAP) in controlling cathepsin activity and texture, as well as inhibiting protein oxidation and metmyoglobin formation in lamb meat during frozen storage at −18 °C for 40 weeks. The effects of degradation in vitro on cathepsin and the microstructure in lamb were also evaluated. Results indicated that relative to the control group, the lamb treated with MAP exhibited increased cathepsin activity and inhibited metmyoglobin production. Textural characteristics, such as hardness and springiness, significantly changed (p < 0.05). Treatment with 0.2–1.6 mg/mL of MAP effectively reduced the mean particle size, increasing the zeta potential, delaying the conversion of α-helices to random coils, and maintaining the integrity of the tissue structure. However, treatment with 3.2 mg/mL of MAP damaged the protein structure. Degradation in vitro indicated that protein oxidation hindered the effect of cathepsin and was a dominant factor affecting protein during the frozen storage. These results demonstrated that microencapsulation can potentially be used for meat preservation and replace chemical antioxidants in the meat industry.

EGCG-gelatin biofilm improved the protein degradation, flavor and micromolecule metabolites of tilapia fillets during chilled storage

The protein degradation, flavor and micromolecule metabolites changes of (-)-epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on chilled tilapia fillets in 21 days were investigated. Morphology observations revealed EGT protected good connective myofibrillar protein. It maintained protein secondary structure by significantly increasing the proportion of α-helix (15.20%) and decreasing the ratio of random coils (22.02%) in the EGT group compared to the control (CON) group (P < 0.05). Metabolomics with UHPLC-Q-TOF/MS analysis indicated a distinct separation between the CON and treatment groups at the end of storage. Small peptides analysis demonstrated that the EGT group increased the level of sweet peptides. Additionally, the EGT group significantly reduced the formation of amino acid derivatives and esters and off-flavor development. Overall, EGT effectively improved flavor, inhibited fish protein oxidation/degradation, and verified metabolomics results. This study unveiled the potential of metabolomics to analyze metabolites determined by tilapia and monitor the changes during storage.

Structural and Emulsifying Properties of Soybean Protein Isolate-Sodium Alginate Conjugates under High Hydrostatic Pressure

Soybean protein isolate (SPI) is a kind of plant derived protein with high nutritional value, but it is underutilized due to its structural limitations and poor functionalities. This study aimed to investigate the effects of high hydrostatic pressure (HHP) treatment on SPI and sodium alginate (SA) conjugates prepared through the Maillard reaction. The physicochemical properties of the conjugate synthesized under 200 MPa at 60 °C for 24 h (SPI–SA–200) were compared with those of the conjugate synthesized under atmospheric pressure (SPI–SA–0.1), SPI-SA mixture, and SPI. The HHP (200 MPa) significantly hindered the Maillard reaction. This effect was confirmed by performing SDS-PAGE. The alterations in the secondary structures, such as α-helices, were analyzed using circular dichroism spectroscopy and the fluorescence intensity was determined. Emulsifying activity and stability indices of SPI-SA-200 increased by 33.56% and 31.96% respectively in comparison with the SPI–SA–0.1 conjugate. Furthermore, reduced particle sizes (356.18 nm), enhanced zeta potential (‒40.95 mV), and homogeneous droplet sizes were observed for the SPI-SA-200 emulsion. The present study details a practical method to prepare desirable emulsifiers for food processing by controlling the Maillard reaction and improving the functionality of SPI.

A comprehensive review on impact of non-thermal processing on the structural changes of food components

Non-thermal food processing is a viable alternative to traditional thermal processing to meet customer needs for high-quality, convenient and minimally processed foods. They are designed to eliminate elevated temperatures during processing and avoid the adverse effects of heat on food products. Numerous thermal and novel non-thermal technologies influence food structure at the micro and macroscopic levels. They affect several properties such as rheology, flavour, process stability, texture, and appearance at microscopic and macroscopic levels. This review presents existing knowledge and advances on the impact of non-thermal technologies, for instance, cold plasma treatment, irradiation, high-pressure processing, ultrasonication, pulsed light technology, high voltage electric field and pulsed electric field treatment on the structural changes of food components. An extensive review of the literature indicates that different non-thermal processing technologies can affect the food components, which significantly affects the structure of food. Applications of novel non-thermal technologies have shown considerable impact on food structure by altering protein structures via free radicals or larger or smaller molecules. Lipid oxidation is another process responsible for undesirable effects in food when treated with non-thermal techniques. Non-thermal technologies may also affect starch properties, reduce molecular weight, and change the starch granule's surface. Such modification of food structure could create novel food textures, enhance sensory properties, improve digestibility, improve water-binding ability and improve mediation of gelation processes. However, it is challenging to determine these technologies' influence on food components due to differences in their primary operation and equipment design mechanisms and different operating conditions. Hence, to get the most value from non-thermal technologies, more in-depth research about their effect on various food components is required.

Evaluating the Performances of Interval Starting Accessibility Drying (ISAD) through Protein and Total Polyphenol Contents of Blue Crabmeat (Portunus segnis)

Blue crab (Portunus segnis) proliferation on Tunisian coasts started in 2014/2015. It has heavily impacted the balance of other species, local biodiversity, and fishing activity. Limiting these drawbacks may be achieved through ways promoting crabmeat. For this purpose, two different drying modes were tested: Conventional convective drying (CCD) and interval starting accessibility drying (ISAD) under 45 °C and relative humidity of 40%. Several air velocities were assayed under CCD: 1.5, 2.5, 3.5, and 5 m.s−1. Two different ISAD tests were run with different time-related conditions: drying period of 15 s and tempering period of 15 or 60 s. Drying modes and operating conditions performances were compared through proteins and total polyphenol contents (TPCs) evolution during the treatment. Important polyphenol and protein losses were observed between raw and processed crabmeat. Airflow velocities have a significant effect on crabmeat quality preservation. ISAD method under 15 s/60 s allowed the best preservation of these quality parameters. TPC and proteins losses and kinetics during drying under CCD or ISAD were modelled and correlations were established between the quality parameters, the residual water content at all drying times, and the evaporation rate.

Effect of rutin on the physicochemical and gel characteristics of myofibrillar protein under oxidative stress

The effects of rutin (6, 30, and 150 μmol/g_pro ) on the physicochemical, structural properties and gel characteristics of myofibrillar protein (MP) under oxidative stress were investigated. The addition of rutin significantly promoted the formation of oxidized MP carbonyl derivatives and dimer tyrosine, but it cannot prevent the loss of sulfhydryl groups (-SH). With increasing rutin concentration, the hydrophobic area was gradually shielded and rutin acted as a quencher to reduce the fluorescence intensity of oxidized MP. Under the oxidative stress, rutin increased the particle size and aggravated the cleavage of protein molecules. SDS-polyacrylamide gel electrophoresis revealed that rutin further aggravated oxidized MP degradation and cross-linked form polymer which cross-linked with protein to the maximum extent at 150 μmol/g_pro rutin content. Moderate cross-linking between protein and rutin could improve the gel strength and water holding capacity (WHC) of oxidized MP gel. For rutin concentrations of 6 and 30 μmol/g_pro , the gels had denser network structures, as observed by scanning electron microscopy. PRACTICAL APPLICATIONS: Polyphenols of the type and dosage can change the properties of the product itself and optimize the quality of product processing. Certain polyphenols may promote the oxidation process of protein-rich products, but this does not affect the improvement of product quality. The application of natural polyphenols is the promising business direction in the development of Coregonus peled industry.

Effects of high-pressure treatment on the muscle structure of salmon (Salmo salar)

High pressure (HP) is a non-thermal treatment that is generally used to reduce the microbiological contamination of food products, such as Atlantic salmon (Salmo salar). However, HP is known to alter the stability of proteins and can therefore affect the quality of salmon flesh. In this study, the effects of HP treatment for 5 min at 200, 400 and 600 MPa on the structure of Atlantic salmon were investigated. Transversal histological sections revealed a decrease in the fibre size from 200 MPa associated with an expansion of the extracellular spaces. Connective tissue was found to be modified from 400 MPa, resulting in an increase in its surface area. Fourier transform infrared (FT-IR) microspectroscopy revealed a reduction in the α-helix content and an increase in the aggregated β-sheet structure content with increasing pressure, reflecting a change in the secondary structure of proteins from 200 MPa.

Effect of Active Coatings Containing Lippa citriodora Kunth. Essential Oil on Bacterial Diversity and Myofibrillar Proteins Degradation in Refrigerated Large Yellow Croaker

The research evaluated the effects of locust bean gum (LBG) and sodium alginate (SA) active coatings containing 0.15, 0.30 or 0.60% lemon verbena (Lippa citriodora Kunth.) essential oil (LVEO) on the bacterial diversity and myofibrillar proteins (MPs) of large yellow croaker during refrigerated storage at 4 °C for 18 days. Variability in the dominant bacterial community in different samples on the 0, 9th and 18th day was observed. Pseudomonas and Shewanella were the two major genera identified during refrigerated storage. At the beginning, the richness of Pseudomonas was about 37.31% and increased for control (CK) samples during refrigerated storage, however, the LVEO-treated samples increased sharply from day 0 to the 9th day and then decreased. LBG-SA coatings containing LVEO treatments significantly delayed MPs oxidation by retarding the formation of free carbonyl compounds and maintaining higher sulfhydryl content, higher Ca²⁺-ATPase activity, better organized secondary (higher contents of α-helix and β-sheet) and tertiary structures during refrigerated storage. The transmission electron microscope (TEM) images showed that the integrity of the sarcomere was damaged; the boundaries of the H-, A-, and I-bands, Z-disk, and M-line were fuzzy in the CK samples at the end of storage. However, the LVEO-treated samples were still regular in appearance with distinct dark A-bands, light I-bands, and Z-disk. In brief, LBG-SA active coatings containing LVEO treatments suggested a feasible method for protecting the MPs of large yellow croaker during refrigerated storage.

High-Pressure Processing for the Production of Added-Value Claw Meat from Edible Crab (Cancer pagurus)

High-pressure processing (HPP) in a large-scale industrial unit was explored as a means for producing added-value claw meat products from edible crab (Cancer pagurus). Quality attributes were comparatively evaluated on the meat extracted from pressurized (300 MPa/2 min, 300 MPa/4 min, 500 MPa/2 min) or cooked (92 °C/15 min) chelipeds (i.e., the limb bearing the claw), before and after a thermal in-pack pasteurization (F₉₀¹⁰ = 10). Satisfactory meat detachment from the shell was achieved due to HPP-induced cold protein denaturation. Compared to cooked or cooked-pasteurized counterparts, pressurized claws showed significantly higher yield (p < 0.05), which was possibly related to higher intra-myofibrillar water as evidenced by relaxometry data, together with lower volatile nitrogen levels. The polyunsaturated fatty acids content was unaffected, whereas the inactivation of total viable psychrotrophic and mesophilic bacteria increased with treatment pressure and time (1.1-1.9 log₁₀ CFU g^-1). Notably, pressurization at 300 MPa for 4 min resulted in meat with no discolorations and, after pasteurization, with high color similarity (ΔE* = 1.2-1.9) to conventionally thermally processed samples. Following further investigations into eating quality and microbiological stability, these HPP conditions could be exploited for producing uncooked ready-to-heat or pasteurized ready-to-eat claw meat products from edible crab.

Can Microplastics Influence the Accumulation of Pb in Tissues of Blue Crab?

The study of microplastics (MPs) and associated pollutants is essential for a better understanding of some of the factors that threaten marine ecosystems. The main objective of this study was thus to assess Pb distribution and accumulation in the tissues of blue crabs (Callinectes sapidus) exposed to MPs. Blue crabs were collected from the mouth of the river Segura (Guardamar, Spain) and fed on mussels from two Mediterranean areas with different levels of Pb contamination: Portmán Bay and San Pedro del Pinatar (Murcia, Spain). In addition, a batch of each group were exposed to MPs. After seven days of exposure, the crabs were euthanised, and tissues and faeces were analysed. The hepatopancreas was found to be the best tissue for measuring Pb concentrations after feeding; muscle tissue did not provide information on environmental quality. The meat (muscle) consumption of blue crabs from zones with high Pb content does not seem to constitute a risk for consumers, although the risk is not totally negated if all soft tissues are ingested. The presence of MPs in the water does not seem to increase the accumulation of Pb in these tissues of C. sapidus.

Quality characteristics of shucked crab meat (Eriocheir sinensis) processed by high pressure during superchilled storage

High-pressure processing (HPP) at 300 MPa for 20 min at 25°C was used for shucking Chinese mitten crab. The shelf-life, quality as well as internal protein changes in HPP-shucked meat were investigated during superchilled storage at -4^o C. Upon 3-week storage, the lightness and whiteness of HPP-shucked crab meat start to decline, while no significant changes were observed in the hardness, gumminess, and chewiness. Sensory and microbial evaluation suggested that HPP-shucked crab meat can be generally preserved in an acceptable manner within 3 weeks, although a negative influence on drip loss was found. The loss of entrapped water in crab meat as revealed by low field nuclear magnetic resonance was responsible for the relatively high thawing drip loss. The severe deterioration of meat quality and sensory occurred at 4-week storage probably as a result of exacerbated myofibrillar protein oxidation, denaturation, and crosslinking. PRACTICAL APPLICATIONS: It has been confirmed that HPP shucking can maintain the fresh-state of the crab meat and save energy compared to the conventional treatment, which could meet consumers' demand for minimally processed seafood products. In this work, the shelf-life of HPP-shucked crab meat stored at -4^o C was evaluated to be 3 weeks and HPP shucking combined with superchilling can be an effective way to preserve the crab meat. These results can provide basic knowledge for the storage and distribution of HPP-shucked crab meat.

Quality changes in high pressure processed tan mutton during storage

The current study investigated the effects of high pressure (HP) treatment at 200 MPa and 500 MPa on quality characteristics of post-rigor tan mutton stored for 7 days at 4 °C, and textural changes were monitored during storage by means of the stress relaxation test. Application of 500 MPa high pressure significantly increased the elasticity and stiffness of meat after 7 days of storage (P < 0.05), accompanied by a lighter and less red appearance and markedly enhanced centrifugal loss during storage campared to untreated (P < 0.05). High pressure treatment at 200 MPa also substantially increased the lightness of samples throughout storage (P < 0.05), and showed a significant increase in stiffness at the end of storage (P < 0.05). Immunoblotting and electrophoresis (SDS-PAGE) analysis of key structural proteins revealed that myosin heavy chain denaturation began at 200 MPa, while actin denaturation occurred at 500 MPa. Troponin-T was continuously degraded in different treatments as storage progressed, and 200 MPa treatment and untreated represented similar degradation patterns, while 500 MPa treatment displayed more intense intact troponin-T at 38 kDa degradation. Results suggest that HP induced changes in cytoskeleton proteins, thereby affecting texture, water holding properties and lightness.

Monitoring Thermal and Non-Thermal Treatments during Processing of Muscle Foods: A Comprehensive Review of Recent Technological Advances

Muscle food products play a vital role in human nutrition due to their sensory quality and high nutritional value. One well-known challenge of such products is the high perishability and limited shelf life unless suitable preservation or processing techniques are applied. Thermal processing is one of the well-established treatments that has been most commonly used in order to prepare food and ensure its safety. However, the application of inappropriate or severe thermal treatments may lead to undesirable changes in the sensory and nutritional quality of heat-processed products, and especially so for foods that are sensitive to thermal treatments, such as fish and meat and their products. In recent years, novel thermal treatments (e.g., ohmic heating, microwave) and non-thermal processing (e.g., high pressure, cold plasma) have emerged and proved to cause less damage to the quality of treated products than do conventional techniques. Several traditional assessment approaches have been extensively applied in order to evaluate and monitor changes in quality resulting from the use of thermal and non-thermal processing methods. Recent advances, nonetheless, have shown tremendous potential of various emerging analytical methods. Among these, spectroscopic techniques have received considerable attention due to many favorable features compared to conventional analysis methods. This review paper will provide an updated overview of both processing (thermal and non-thermal) and analytical techniques (traditional methods and spectroscopic ones). The opportunities and limitations will be discussed and possible directions for future research studies and applications will be suggested.

Litter in alien species of possible commercial interest: The blue crab (Callinectes sapidus Rathbun, 1896) as case study

Marine litter levels were measured in the stomach contents, hepatopancreas, and gonad tissues of crustacea decapod (Callinectes sapidus Rathbun, 1896; n = 6), a widespread alien species affecting the Lesina lagoon. Results highlight a mean of 2.5 (SD = 1.6) items/animal and indicate the presence of metals fragments (13%) and plastics (13% PE; 6.7% PET) in the stomach contents of collected individuals. No microplastic particles were detected in the hepatopancreas or in muscle tissue, while microplastic fibres (nylon, rayon, polyester) were found present in female specimen gonads. The presence of synthetic fibres in the investigated species reflects the relative contamination level in this habitat type and suggests that the blue crab could be considered a model organism for evaluating the contamination status of the study area.

The inhibition mechanism of the texture deterioration of tilapia fillets during partial freezing after treatment with polyphenols

The inhibition mechanism of the texture deterioration of tilapia fillets after treatment with polyphenols during partial freezing for 49 days was studied. Carnosic acid (CA), procyanidin (PA), quercetin (QE), and resveratrol (RSV) treatments had significantly higher hardness values (over 230 g) than the control group (183 g) on day 49 (P < 0.05). Polyphenol treatments were effective in delaying the protein degradation, lipid oxidation and spoilage microbe growth. Moreover, the kinetic model showed that the predicted shelf life of tilapia fillets treated with PA (102 d) was extended by 25 d compared to the control group (77 d). It was the proposed possible mechanism that polyphenols comprehensively maintained the protein conformation (increased hydrogen bonds and decreased disulfide bonds) and retarded protein denaturation and degradation, protecting the texture of the fillets. Therefore, polyphenols can be used to maintain texture and extend the shelf life of tilapia fillets during partial freezing.

Extraction Methods for Obtaining Natural Blue Colorants

Background:

Blue is a color not often present in food. Even so, it is especially attractive to children. Today, most blue coloring agents used by the food industry are synthetic. With increasing health issues concern by the scientific community and the general population, there is a trend to look for natural alternatives to most synthetic products. There only exist few natural blue colorants, which are presented in a literature survey, along with the methods currently used for their recovery from natural sources. The best extraction methods and process parameters for the extraction of blue anthocyanins, iridoids and phycocyanin are discussed.

Methods:

A literature survey was conducted to detect the main sources of blue colorants found in nature. The focus was on the extraction methods used to recover such molecules, with the objective of finding efficient and environmentally safe techniques for application at industrial level, and, thus, allowing the production of natural blue colorants at scale high enough for food industry consumption.

Results:

The main natural blue colorants found in literature are anthocyanins, phycocyanin, and genipin. While anthocyanins can be recovered from a variety of plants, the source of phycocyanin are algae, and genipin can be obtained specifically from Gardenia jasminoides Ellis and Genipa americana L. Several extraction techniques have been applied to recover blue colorants from such sources, from classical methods using organic solvents, to more sophisticated technologies as ultrasoundassisted extraction, supercritical fluid extraction, pressurized liquid extraction, high-pressure extraction, and enzyme-assisted extraction.

Conclusion:

There is great potential for anthocyanins, phycocyanin and genipin use as natural food additives with health benefits, besides imparting color. However, the technologies for the colorants recovery and application are not mature enough. Therefore, this area is still developing, and it is necessary to evaluate the economic feasibility of the proposed extraction processes, along with the safety and acceptance of colored food using these additives.

Effect of high hydrostatic pressure challenge on biogenic amines, microbiota, and sensory profile in traditional poultry- and pork-based semidried fermented sausage

The processing of traditional poultry- and pork-based semidried fermented smoked sausages needs to be modernized to improve product quality and further extend its shelf life. The aim of the present study was to apply different combinations of high pressure (300 to 600 MPa) and time (154 to 1,800 s) on the sausages using an experimental design based on response surface methodology. The chemical, microbial, and sensory characteristics of sausages treated with high-pressure processing (HPP) were investigated. HPP application to semidried fermented sausages resulted in color changes, which could be dependent on the ingredients, formulation, and smoking conditions used. Nevertheless, none of the HPP treatments applied resulted in detectable changes in sensory properties, as tested in a triangle test and confirmed by the analysis of focus groups assessment. Significant differences were detected for lactic acid bacteria (LAB) counts from 344 MPa and 1,530 s onward, with a marked decrease for the combination of 600 MPa and 960 s (P < 0.05). Coagulase-negative staphylococci showed higher tolerance to the increase in pressure than LAB. HPP induced a microbial reduction on Enterobacteriaceae, molds, and yeasts, minimizing the production of the main biogenic amines. However, the polyamines (spermine and spermidine) increased since their metabolic use by microorganisms did not occur. Given the reduction of the main spoilage microbial indicators with no detectable sensory changes observed with the binomial condition of 600 MPa and 960 s, this was chosen as the optimal combination to be further applied. PRACTICAL APPLICATION: The results from sensory analysis revealed that any of the HPP treatments applied resulted in detectable changes in sensory properties, as tested in a triangle test and confirmed by the analysis of the focus groups speeches.

Physicochemical Properties and Consumer Acceptance of High-Pressure Processed, Sous Vide-Cooked Lobster Tails

Sous vide (SV) and high-pressure processing (HPP) are promising techniques in the development of high-quality seafood products. The objectives of this study were to evaluate the impacts of HPP on the physicochemical quality and consumer acceptance of subsequently SV-cooked lobster tails. Raw shucked lobster tails were processed at 150 or 350 MPa for 5 or 10 min. Subsequently, half were SV cooked to a core temperature of 65 °C/10 min. Texture profile analysis, shear force, color, salt soluble protein content, water-holding capacity (WHC), moisture content, and weight loss were analyzed. Pressurization at 150 MPa/10 min decreased (P < 0.05) the hardness of raw lobsters compared to non-HPP-treated controls. However, 350 MPa for 5 or 10 min increased (P < 0.05) the shear force in raw and SV-cooked samples. HPP increased (P < 0.05) the L^* values but did not affect moisture content, WHC, or weight loss of raw or SV-cooked lobsters. Lobsters were subjected to consumer acceptability testing using a 9-point hedonic scale. Although panelists rated the flavor, texture, and overall liking of the 350 MPa/10 min samples higher than the control and 150 MPa/10 min samples, there were no significant differences among treatment means, indicating that physicochemical changes induced by HPP did not affect consumer acceptance. In addition, approximately 84% of panelists reported that the 350 MPa product met their expectations compared to approximately 75% for the control and 150 MPa treatments. These results suggest that HPP has the potential to be applied in combination with SV cooking to produce consumer-acceptable, value-added lobster products. PRACTICAL APPLICATION: Lobsters are an expensive menu item in restaurants. However, they are susceptible to being overcooked using conventional methods, producing a tough and rubbery texture. Sous vide cooking is reported to provide evenly cooked lobsters with a succulent and juicy texture. In this study, lobsters were sous vide cooked to reach a core temperature of 65 °C, and then maintained at that temperature for 10 min. The application of moderate processing pressures to vacuum-packaged raw lobsters prior to SV cooking altered some physicochemical attributes but has the potential to increase the availability of high-quality, minimally processed seafood with good consumer acceptability.