Characteristics of hairtail surimi gels treated with myofibrillar protein-stabilized Pickering emulsions.

BACKGROUND: Hairtail (Trichiurus haumela) surimi exhibits poor gelation properties and a dark gray appearance, which hinder its utilization in high-quality surimi gel products. The effect of Pickering emulsions stabilized by myofibrillar proteins (MPE) on the gel properties of hairtail surimi has been unclear. In particular, the impact of MPE under NaCl and KCl treatments on the quality of hairtail surimi gels requires further elucidation. RESULTS: Pickering emulsions stabilized by myofibrillar proteins and treated with NaCl or KCl (Na-MPE, K-MPE) were added to hairtail surimi in amounts of 10-70 g kg-1. The addition of 50 g kg-1 Na-MPE and K-MPE improved the gel strength, textural properties, whiteness, and water-holding capacity (WHC) of hairtail surimi. The relative content of ß-turn and ß-sheet in the surimi gels increased and the relative content of random coils and α-helix decreased with the addition of oil. The addition of Na-MPE and K-MPE did not affect the secondary structure of surimi gels but stimulated the gelation of hairtail surimi gels. Hairtail surimi containing K-MPE demonstrated similar performance in terms of hardness, microstructure, and WHC compared with the addition of Na-MPE. CONCLUSION: The quality of hairtail surimi gels can be improved by the addition of Na-MPE or K-MPE. The K-MPE proved to be an effective option for enhancing the properties of hairtail surimi gels at 50 g kg-1 to replace Na-MPE. © 2024 Society of Chemical Industry.

Translocation and transformation of uranium along the aquatic food chain: New insights into uranium risks to the environment.

Uranium pollution in aquatic ecosystems poses a threat to organisms. However, the metabolism and toxicity of uranium along aquatic food chains remain unknown. Here, we established an artificial aquatic ecosystem to investigate the fate of uranium along the food chain and reveal its potential toxicity. The results displayed a dose- and time-dependent toxicity of uranium on algae, leading to cell deformation and impeding cell proliferation. When uranium-exposed algae are ingested by fish, uranium tends to concentrate in the intestinal system and bones of fish. Comparatively, direct water uranium exposure resulted in a remarkable uranium accumulation in the head, skin, and muscles of fish, suggesting different toxicity depending on distinct exposure pathways. High-level uranium pollution (20 mg L-1) intensifies the toxicity to fish through food intake compared to direct water exposure. It has also revealed that approximately 25 % and 20 % of U(VI) were reduced to lower valence forms during its accumulation in algae and fish, respectively, and over 10 % of U(IV, VI) converted to U(0) ultimately, through which uranium toxicity was mitigated due to the lower solubility and bioavailability. Overall, this study provides new insights into the fate of uranium during its delivery along the aquatic food chain and highlights the risks associated with consuming uranium-contaminated aquatic products.

Dietary Clostridium butyricum and 25-Hydroxyvitamin D3 modulate bone metabolism of broilers through the gut-brain axis.

Leg disorders have become increasingly common in broilers, leading to lower meat quality and major economic losses. This study evaluated the effects of dietary supplementation with Clostridium butyricum (C. butyricum) and 25-hydroxyvitamin D3 (25-OH-D3) on bone development by comparing growth performance, tibial parameters, Ca and P contents of tibial ash, bone development-related indicators' level, and cecal short-chain fatty acids in Cobb broilers. All birds were divided into four treatment groups, which birds fed either a basal diet (Con), basal diet + 75 mg chlortetracycline/kg (Anti), basal diet + C. butyricum at 109 CFU/kg (Cb), basal diet + C. butyricum at 109 CFU/kg and 25-OH-D3 at 25 µg/kg (CbD), or basal diet + 25-OH-D3 at 25 µg/kg (CD). Our results suggest that the dietary supplementation in Cb, CbD, and CD significantly increased the body weight (BW) and average daily gain (ADG), and reduced the feed-to-weight ratio (F/G) at different stages of growth (P < 0.05). Dietary supplementation in Cb, CbD, and CD prolonged (P < 0.05) the behavioral responses latency-to-lie (LTL) time, reduced (P < 0.05) the levels of osteocalcin (BGP) and peptide tyrosine (PYY), and increased (P < 0.05) serotonin (5-HT) and dopamine (DA). Treatment with Cb increased (P < 0.05) the levels of acetic acid, isobutyric acid, butyric acid, and isovaleric acid compared with those in Con group. The cecal metagenome showed that Alistipes spp. were significantly more abundant in Cb, CbD, and CD groups (P < 0.05). A total of 12 metabolic pathways were significantly affected by supplementation, including the signaling pathways of glucagon, insulin, and PI3K-AKT; primary and secondary bile acid biosynthesis; and P-type Ca 2+ transporters (P < 0.05). Hence, the CbD supplementation modulates bone metabolism by regulating the mediators of gut-brain axis, which may inform strategies to prevent leg diseases and improve meat quality in broilers.

The Optimization of Assay Conditions and Characterization of the Succinic Semialdehyde Dehydrogenase Enzyme of Germinated Tartary Buckwheat.

In this study, the conditions for optimizing the determination of succinic semialdehyde dehydrogenase (SSADH, EC 1.2.1.79) activity in germinated Tartary buckwheat were investigated. Based on a single-factor test, the effects of temperature, pH, and succinic semialdehyde (SSA) concentration on the enzyme activity of germinated buckwheat SSADH were investigated by using the response surface method, and optimal conditions were used to study the enzymatic properties of germinated buckwheat SSADH. The results revealed that the optimum conditions for determining SSADH enzyme activity are as follows: temperature-30.8 °C, pH-8.7, and SSA concentration-0.3 mmol/L. Under these conditions, SSADH enzyme activity was measured as 346 ± 9.61 nmol/min. Furthermore, the thermal stability of SSADH was found to be superior at 25 °C, and its pH stability remained comparable at pH levels of 7.6, 8.1, and 8.6 in germinated Tartary buckwheat samples; however, a decline in stability was observed at pH 9.1. Cu2+, Co2+, and Ni2+ exhibited an activating effect on SSADH activity in germinating Tartary buckwheat, with Cu2+ having the greatest influence (p < 0.05), which was 1.21 times higher than that of the control group. Zn2+, Mn2+, and Na+ inhibited SSADH activity in germinating Tartary buckwheat, with Zn2+ showing the strongest inhibitory effect (p < 0.05). On the other hand, the Km and Vmax of SSADH for SSA in germinated Tartary buckwheat were 0.24 mmol/L and 583.24 nmol/min. The Km and Vmax of SSADH for NAD+ in germinated Tartary buckwheat were 0.64 mmol/L and 454.55 nmol/min.