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The antioxidant and anti-inflammatory properties of astaxanthin (AST) enable it to protect against oxidative stress-related and inflammatory diseases with a range of biological effects. These activities provide the potential to develop healthier food products. Therefore, it would be beneficial to design delivery systems for AST to overcome its low stability, control its release, and/or improve its bioavailability. This review discusses the basis for AST's various biological activities and the factors limiting these activities, including stability, solubility, and bioavailability. It also discusses the different systems available for the targeted delivery of AST and their applications in enhancing the biological activity of AST. These include systems that are candidates for preventive and therapeutic effects, which include nerves, liver, and skin, particularly for possible cancer reduction. Targeted delivery of AST to specific regions of the gastrointestinal tract, or more selectively to target tissues and cells, can be achieved using targeted delivery systems to increase the biological activities of AST. [ABSTRACT FROM AUTHOR]

Hyperuricemia (HUA) is a metabolic disorder caused by abnormal uric acid (UA) metabolism, which is a complex physiological process involving multiple organs (liver, kidney, and intestine). Although UA metabolism in the liver and kidneys has been elucidated, only a few studies have focused on the process in the intestine. With our growing knowledge of the effects of gut microorganisms on health, the gut microbiota has been identified as a new target for HUA treatment. In this review, the relationship between HUA and the gut microbiota is elucidated, and anti-hyperuricemia mechanisms targeting the intestine are discussed, such as the promotion of purine and UA catabolism by the gut microbiota, increases in UA excretion by the gut microbiota and its metabolites, regulation of UA absorption or secretion in the intestinal tract by certain transporters, and the intestinal inflammatory response to the gut microbiota. Additionally, probiotics (Bifidobacteria and Lactobacilli) and prebiotics (polyphenols, peptides, and phytochemicals) with UA-lowering effects targeting the intestinal tract are summarized, providing reference and guidance for further research. [ABSTRACT FROM AUTHOR]

Mandarin fish that have been prepared and chilled have a shelf life of 4 days at 4°C storage, according to the total volatile basic nitrogen values. During the storage process, we observed that the texture characteristics of these fish significantly deteriorated. Certain low-abundance proteins were degraded during the shelf life, which resulted in changes in protein conformation and protein-water interaction patterns. The water-holding capacity of the fish decreased during 4°C storage; nuclear magnetic resonance analysis showed that the binding of water in fish was weakened as shelf storage prolonged and a portion of the free water was also "squeezed" to the surface of the fish in the later stages of storage. A correlation analysis showed that a decrease in the immobilized water content and mobility was associated with quality deterioration of the fish, which may be a result of increase in hydrophobic interaction and disulfide bonds in the fish during storage. [ABSTRACT FROM AUTHOR]

Polyphenoloxidase (PPO) from prawns (Penaeus vannamei) was purified by ammonium sulphate precipitation, ion-exchange column, and gel filtration chromatography. The specific activity of PPO increased by 9.51 fold to 575.03 U/mg, and the molecular weight of PPO was 66 kDa. The optimal temperature and pH were around 45°C and 6.8, determined by L-β-(3,4-dihydroxylphenyl) alanine (L-DOPA) as substrate. Km and Vmax values were found to be 2.5 mM and 0.062ΔA/min. The effect of thermal treatment on the activity, conformation, and microstructure of the PPO was investigated. Thermal stability of PPO was measured at 40°C, 50°C, 60°C, 70°C, and 80°C, and the half-life values of PPO were 105, 39.6, 13.4, 8.9, and 3.1 min, respectively. PPO activity slightly decreased at 60°C, while the relative enzyme activity remained 9.4% after 80°C for 10 min. The result of differential scanning calorimetry showed that the denatured temperature of PPO was 65°C. Thermal treatment resulted in the changes in the tertiary structure of PPO, and the λmax of fluorescence spectra was red-shifted with decreasing intensity. Curve-fitting analysis showed that α-helix and β-sheet decreased, but β-turns and random coil increased with increased temperature. Atomic force microscopy revealed that PPO molecules aggregated remarkably at 60°C. Moreover, the formation of large globular aggregates occurred as the temperature increased. [ABSTRACT FROM AUTHOR]

The physical properties and nanostructure of fish skin gelatin with and without whey protein isolate (WPI) were investigated. The addition of low concentrations of WPI (1 and 3%, w/v) into fish gelatin decreased the gel strength and textural properties. The addition of 5% WPI did not significantly influence textural properties but increased the melting and gelling temperatures of fish skin gelatin and improved the appearance of gelatin gels. X-ray diffraction indicated that a higher degree of crystallinity with an ordered structure or ordered structure snippets occurred with increasing WPI concentrations in line with the slight decrease in the loss factor (tan δ) with time sweeps. Fish gelatin had a spherical nanostructure, and a homogeneous nanostructure was observed in gelatin with 3% WPI. The addition of 5% WPI led to large aggregates in gelatin gels. The results indicated that whey protein could affect the nanostructure of fish skin gelatin gels and thus change their gelation properties and texture in food and pharmaceutical applications. [ABSTRACT FROM PUBLISHER]

Changes in the biochemical, nutritional, and sensory properties of the low salt fermented shrimp paste during fermentation were studied. The total volatile base nitrogen (TVB-N) content and total viable counts significantly increased. The pH value significantly decreased, while thiobarbituric acid (TBA) content significantly increased over 14 days. The lightness (L*) value significantly decreased during the initial 7 days of fermentation and significantly increased thereafter. The redness (a*) and yellowness (b*) values and astaxanthin content of the low salt fermented shrimp paste gradually increased during the 30 days of fermentation. C16:0, C18:0, C18:1n9t, C20:1n7c, C20:5n3, and C22:6n3 were the predominant fatty acids, while aspartate, glutamate, alanine, leucine, lysine, arginine, and proline were the predominant amino acids in the shrimp paste. N-containing compounds, such as pyrazine, comprised the majority of the volatile compounds. The results obtained from quantitative descriptive analysis showed that low salt fermentation can improve the flavor of the shrimp paste and is, therefore, a promising method to industrially prepare the shrimp paste. [ABSTRACT FROM PUBLISHER]

The effects of thermal treatment on the ultrastructure and quality of Chilgoza pine nuts stored at near-freezing temperature were investigated. The moisture content of pine nuts was adjusted to 13.3%, compared to the initial 17.3% moisture content. Thermal treatment improved the storage stability. The hydrolysis of lipids was delayed in low-moisture pine nuts, resulting in a significant inhibition of free fatty acid accumulation in pine nuts. Low-moisture pine nuts also showed lower peroxide and thiobarbituric acid (TBA)​ values compared with the control. Ultrastructure characterization revealed that thermal treatment maintained the cell integrity, deferred the degradation of the plasmalemma and protected the internal lipid droplet. Thermal treatment better retained the antioxidant components, including total phenolics and vitamin E, and reduced the activities of lipase and lipoxygenase in pine nuts. These results indicated that thermal treatment could retard the senescence and deterioration of quality in pine nuts stored at a near-freezing temperature. [ABSTRACT FROM PUBLISHER]

Changes in quality of low-moisture conditioned pine nuts (Pinus gerardiana) under near freezing temperature storage were investigated. Nuts were adjusted to different moisture content (17.3% ± 0.42, 15.1% ± 0.26, and 13.3% ± 0.24) with 35°C, 20%RH, sealed in air-tight jars and stored at −3 and −1°C for 12 months. In general, free fatty acid content and peroxide value of the nuts increased, while sensory quality decreased during the storage. Low-moisture nuts had lower respiration, free fatty acid content, and peroxide value. Nuts stored at −3°C had less visible mold infection and browning percentage than at −1°C. Low-moisture treatment exerted a slight negative effect on texture, but had significant preservative effects on color, odor, and taste during storage. Overall, integration of low-moisture conditioning and near freezing temperature storage can be a promising non-chemical way for maintaining the postharvest quality and extending shelf-life of pine nuts. [ABSTRACT FROM PUBLISHER]