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Chitosan nanoparticle is becoming an excellent carrier for the delivery of bioactive components due to the advantages of simple preparation, low cost and high biocompatibility. Previous studies have shown that chitosan/sodium tripolyphosphate (CS/TPP) and chitosan/flaxseed gum (CS/FG) nanoparticles loaded with bighead carp peptides (BCP) have the advantages of small particle size, high encapsulation rate and significant slow-release effect. This study explored the effects of ionic strength, pH, simulated digestion and storage time on the preparation of chitosan/sodium tripolyphosphate (CS/TPP-BCP) and chitosan/flaxseed gum (CS/FG-BCP) nanoparticles, and evaluated the extracellular lactate dehydrogenase content and antioxidant capacity in vivo of Caco-2 cells treated with the chitosan nanoparticles and their cellular uptake. The results showed that the two kinds of chitosan nanoparticles were stable under acidic conditions and sensitive to a solution with opposite charges. The stability of the nanoparticles loaded with bighead peptides was higher than that of free peptides and both nanoparticles showed higher biocompatibility and cell uptake.

Salt content is essential for the quality of aquatic products, especially for the water-holding capacity and textural properties of salted products and the gel properties of surimi-based products. However, the salt content in traditional aquatic products is generally too high to meet consumers’ demand for healthy convenience foods with low salt content. Reducing the salt content will decrease the storage stability, eating quality and processing properties of aquatic products. Therefore, reducing the salt content without sacrificing the quality is an important issue faced by the aquatic product processing industry. The premise and basis of effectively controlling the quality of aquatic products with low salt content is to clarify the effect and mechanism of NaCl on the quality of aquatic products. In the present paper, we review the role of NaCl in the processing and storage of aquatic products and the latest progress of salt reduction technologies from the aspects of NaCl substitution, novel salt reduction technologies, and sodium release/perception enhancement technologies, and we discuss the problems with the processing of salt-reduced aquatic products. The present article may provide valuable information for high-quality processing of lightly salted aquatic products.

In order to study the effect of ultrasound-assisted thawing on the quality of Antarctic krill (Euphausia superba) and its changes during cold storage, frozen Antarctic krill was placed into net bags or polyethylene (PE) bags and thawed by water immersion with or without ultrasound treatment. The quality changes of thawed samples during cold storage were evaluated in terms of sensory scores, microbial growth, hardness, total volatile basic nitrogen (TVB-N) content, polyphenol oxidase (PPO) activity and trypsin activity as well as the signal intensity of hydrogen protons in low field nuclear magnetic resonance. The thawing time was 105 and 145 min for net bag and plastic bag packaging combined with water immersion thawing, respectively, while it took only 65 and 75 min for net bag and plastic bag packaging combined with ultrasound-assisted immersion thawing. After thawing, the sensory score of Antarctic krill continued to decline during storage at 4 ℃ and reached an unacceptable level after 24 h of storage. However, the total viable count remained less than 2.5 (lg (CFU/g)) before and after thawing and during subsequent cold storage for 28 h, but the activity of PPO and trypsin increased firstly and decreased at the end of storage, while TVB-N content increased during storage. The quality of thawed Antarctic krill contained in net bags deteriorated more slowly than in plastic bags. Collectively, net bag packaging combined with ultrasound-assisted thawing can not only accelerate the thawing rate, but also improve the storability of Antarctic krill.

Summary: In this study, the effect of different fermenters on the quality and flavour of fermented mandarin fish was investigated via pH, salt content, moisture content, thiobarbituric acid, microbial community, free amino acids and volatile compounds. The results demonstrated that the inoculated fermentation effectively suppressed fish fat oxidation, resulting in significantly higher levels of umami amino acids in mandarin fish compared to the natural fermentation group (P < 0.05). Additionally, certain bitter amino acids were also inhibited. Moreover, the total amino acid content of the mixed inoculated fermentation group was significantly elevated compared to other groups, reaching 300.21 ± 5.37 mg/100 g. The synergistic effect of free amino acids and flavour‐enhancing nucleotides significantly influenced the taste of the fermented fish, with the mixed inoculation fermentation group exhibiting a significantly higher Equivalent umami concentration (EUC) value compared to other groups, reaching 216.06 ± 20.13 mgMSG/100 g on the sixth day of fermentation. A total of 47 volatile compounds were detected by using headspace gas chromatography‐ion mobility spectrometry (HS‐GC‐IMS), and the results demonstrated that inoculated fermentation positively influenced the development of fish flavour, and mixed inoculated fermentation proved to be more effective. This study provides a theoretical foundation for the industrial production of fermented fish products and offers potential avenues for technical enhancement. [ABSTRACT FROM AUTHOR]

The effects of adding cellulose with different particle sizes and proportions on the gel properties of three common surimi products, namely fish balls, fish intestines, and fish cakes, were studied, and the best particle sizes and proportions were selected. This experiment determined the best particle size and proportion by studying the effects of adding different particle sizes and proportions of cellulose on the whiteness, water holding capacity, gel strength, total texture analysis, water distribution, and sensory aspects of fish balls, fish intestines, and fish cakes. The experiment found that the addition of cellulose could effectively improve the whiteness, water retention, gel strength, and texture characteristics of three common surimi products, and reduce the content of free water. The water holding capacity of fish balls, fish intestines, and fish cakes, gel strength, hardness, chewiness, and the proportion of water that was difficult to flow would increase with the increase of cellulose particle size, and first increase and then decrease with the increase of the addition proportion. It was found that the particle size of cellulose was 200 μm. When the addition ratio was 2%, the sensory evaluation would be more popular with consumers. After comprehensive consideration, the particle size of added cellulose was 200 μm. When the addition ratio was 2%, the quality of three common surimi products could be improved to the greatest extent, and the water holding capacity of fish balls, fish intestines and fish cakes can be increased by 14.5%, 22.1%, and 8.9% respectively. Gel strength increased by 121.9%, 108.7%, nd 65.5%. Hardness increased by 97.5%, 107.0%, and 158.8%. The proportion of non-flowing water increased by 0.8%, 1.7%, and 1.7%. [ABSTRACT FROM AUTHOR]

The effects of ultrasonic power (0, 150, 300, 450, and 600 W) on the extraction yield and the structure and rheological properties of pepsin-soluble collagen (PSC) from albacore skin were investigated. Compared with the conventional pepsin extraction method, ultrasonic treatment (UPSC) significantly increased the extraction yield of collagen from albacore skin, with a maximum increase of 8.56%. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that peptides of low molecular weight were produced when the ultrasonic power exceeded 300 W. Meanwhile, secondary structure, tertiary structure, and X-ray diffraction analyses showed that the original triple helix structure of collagen was intact after the ultrasonic treatment. The collagen solutions extracted under different ultrasonic powers had significant effects on the dynamic frequency sweep, but a steady shear test suggested that the collagen extracted at 150 W had the best viscosity. These results indicate that an ultrasonic power between 150 and 300 W can improve not only the extraction yield of natural collagen, but also the rheological properties of the collagen solution without compromising the triple helix structure. [ABSTRACT FROM AUTHOR]