Background/Objectives: Excessive reactive oxygen species (ROS) can lead to oxidative stress, which has become an urgent problem requiring effective solutions. Due to the drawbacks of chemically synthesized antioxidants, there is a growing interest in natural antioxidants, particularly antioxidant peptides. Methods: By reviewing recent literature on antioxidant peptides, particularly those extracted from various parts of fish, summarize which fish by-products are more conducive to the extraction of antioxidant peptides and elaborate on their characteristics. Results: This article summarizes recent advancements in extracting antioxidant peptides from fish processing by-products, Briefly introduced the purification and identification process of antioxidant peptides, specifically focusing on the extraction of antioxidant peptides from various fish by-products. Additionally, this article comprehensively reviews the relationship between amino acid residues that compose antioxidant peptides and their potential mechanisms of action. It explores the impact of amino acid types, molecular weight, and structure–activity relationships on antioxidant efficacy. Conclusions: Different amino acid residues can contribute to the antioxidant activity of peptides by scavenging free radicals, chelating metal ions, and modulating enzyme activities. The smaller the molecular weight of the antioxidant peptide, the stronger its antioxidant activity. Additionally, the antioxidant activity of peptides is influenced by specific amino acids located at the C-terminus and N-terminus positions. Simultaneously, this review provides a more systematic analysis and a broader perspective based on existing research, concluded that fish viscera are more favorable for the extraction of antioxidant peptides, providing new insights for the practical application of fish by-products. This could increase the utilization of fish viscera and reduce the environmental pollution caused by their waste, offering valuable references for the study and application of antioxidant peptides from fish by-products.

Antrodia cinnamomea is a precious and popular edible and medicinal mushroom. It has attracted increasing attention due to its various and excellent bioactivities, such as hepatoprotection, hypoglycemic, antioxidant, antitumor, anticancer, anti-inflammatory, immunomodulation, and gut microbiota regulation properties. To elucidate its bioactivities and develop novel functional foods or medicines, numerous studies have focused on the isolation and identification of the bioactive compounds of A. cinnamomea. In this review, the recent advances in bioactivity, isolation, purification, and identification methods of active compounds from A. cinnamomea were summarized. The present work is beneficial to the further isolation and discovery of new active compounds from A. cinnamomea.

In this work, it is presented for the first time that nitrogen and chlorine co-doped carbon nanodots (N,Cl-CDs) were synthesized by simply mixing glucose, concentrated hydrochloric acid (HCl), and 1,2-ethylenediamine (EDA). No external heat was employed; the neutralization reaction served as the heat source. The glucose served as the carbon source while EDA and HCl were the N and Cl dopants, respectively. The fluorescence of N,Cl-CDs was adequately quenched by hexavalent chromium Cr(VI) based on a combination of dynamic quenching and inner filter effect (IFE). Accordingly, an efficient N,Cl-CDs-based fluorescence probe was established for sensitive and selective detection of Cr(VI). The proposed fluorescence sensor provides a linear recognition range for Cr(VI) determination from 3 to 40 µM with a limit of detection (LOD) of 0.28 µM (14.6 µg/L). The proposed fluorescence method was successfully utilized to detect Cr(VI) in different water samples with satisfactory results. The spike recoveries vary from 97.01% to 103.89% with relative standard deviations (RSDs) of less than 0.82%. This work highlights the development of a simple, ultrafast, and energy-saving one-step synthetic route to fabricate N,Cl-CDs for highly selective and sensitive detection of Cr(VI) in real water samples. It is anticipated that the proposed fluorescence method could be further explored and widely used for Cr(VI) detection in the environmental industry.

Vibrio parahaemolyticus is a key foodborne pathogen in seafood that poses health risks to consumers. The application of phages and organic acids is considered an alternative strategy for controlling bacterial contamination in foods. In the present study, the genome features of five previously isolated virulent V. parahaemolyticus phages (VPpYZU64, VPpYZU68, VPpYZU81, VPpYZU92, and VPpYZU110) were characterized, and their bacteriostatic effects in combination with citric acid were analyzed. Genome sequencing of the five phages showed a total genome length of 76,153–144,768 bp. No virulent or drug-resistant genes were detected in the five phages. Bacterial inhibition testing of salmon fillets stored at 25 °C for 12 h showed that the number of V. parahaemolyticus decreased by 2.02 and 3.84 log CFU/g after treatment with a phage mixture, VPpMIx, and the combination of phage mixture VPpMIx and citric acid. In addition, phage VPpYZU64 combined with 600 μg/mL citric acid exhibited the highest biofilm reduction rate for V. parahaemolyticus. Collectively, our results show that combining phages and citric acid is a natural and efficient method of controlling V. parahaemolyticus growth in seafood.

Cronobacter sakazakii is a dangerous pathogen easily found in powdered infant formula (PIF), causing severe infections and even death in infants. Herein, a bacteriophage-immobilized magnetic nanozyme (Fe₃O₄@EspYZU13) was prepared for C. sakazakii detection. Bacteriophage EspYZU13 isolated and identified by our group exhibits specific lytic capacity. Fe₃O₄@EspYZU13 possesses remarkable enrichment capacity towards C. sakazakii, efficiently enriching different concentrations of C. sakazakii from a mixed bacterial solution. Furthermore, Fe₃O₄@EspYZU13 shows peroxidase-like activity, which can catalyze the 3,3′,5,5′-tetramethylbenzidine (TMB) chromogenic reaction in the presence of H₂O₂. Upon introduction of C. sakazakii, it can be specifically captured by Fe₃O₄@EspYZU13, inhibiting its peroxidase-like activity. Based on it, C. sakazakii ranging from 3.2 × 10¹ to 3.2 × 10⁷ CFU mL⁻¹ can be determined, offering a detection limit (LOD) of 26 CFU mL⁻¹. Moreover, this reaction system keeps high specificity towards C. sakazakii, which can resist interferences of other possible coexisting bacteria. C. sakazakii in the artificially contaminated PIF can be detected, offering good recoveries (96.76% to 103.13%). These results indicate that our proposed reaction system demonstrates its practical application potential for efficient enrichment of C. sakazakii from complex samples and accurate determination of C. sakazakii in PIF.