This research prepared chitosan–PLA plastic films by extrusion, analyzed the physical and mechanical properties and antibacterial activity of the fabricated plastic films, and used them to preserve grouper fillet. We added chitosan (220 kDa, 93% DD) in the weight ratio of 0.5–2% into the PLA to prepare the chitosan–PLA films. With the increasing chitosan dosage, both the water vapor transmission rate and moisture content of chitosan–PLA films increased. Among the three doses of chitosan (0.5%, 1%, and 2%) added to PLA, 0.5% chitosan–PLA film had the highest antibacterial activity. This plastic film had an inhibitory efficiency of over 95% against Escherichia coli, Pseudomonas fluorescens, and Staphylococcus aureus. The action of covering the fish fillet with 0.5% chitosan–PLA film significantly reduced several microbes’ counting (i.e., mesophiles, psychrophiles, coliforms, Pseudomonas, Aeromonas, and Vibrio) and total volatile basic nitrogen (TVBN) value in the grouper fillets stored at 4 °C. Thus, such action prolongs the fish fillets’ shelf life to up to at least nine days, and this 0.5% chitosan–PLA film shows promising potential for preserving refrigerated fish.

This study aimed to increase the antibacterial activity of chitosan-polylactic acid (PLA) composite film by adding nisin and ethylenediaminetetraacetic acid (EDTA). We evaluated the mechanical, physicochemical, and antibacterial properties of various PLA composite films, as well as the enhancement effect of PLA composite films with EDTA + nisin on the preservation of grouper fillets. Films of PLA alone, PLA plus chitosan (C5), PLA plus nisin + EDTA (EN2), and PLA plus chitosan plus nisin + EDTA (C5EN1 and C5EN2) were prepared. The addition of EDTA + nisin to the chitosan-PLA matrix significantly improved the antibacterial activity of the PLA composite film, with C5EN1 and C5EN2 films showing the highest antibacterial activity among the five films. Compared with the fish samples covered by C5, the counts of several microbial categories (i.e., mesophilic bacteria, psychrotrophic bacteria, coliforms, Aeromonas, Pseudomonas, and Vibrio) and total volatile basic nitrogen content in fish were significantly reduced in the samples covered by C5EN1. In addition, the counts of samples covered by C5EN1 or C5 were significantly lower compared to the uncovered and PLA film-covered samples.

Botryocladia leptopoda is a red macroalga known for its bioactive compounds with antioxidant, anti-inflammatory, and skin-regenerative properties. The study aimed to examine their effects on UV protection, collagen synthesis, fibroblast proliferation, and pigmentation modulation. Bioactive compounds were extracted using two solvents, producing ethanol extract (FE) and alkaline extracts (AE). Methods involved characterizing extracts using mass spectrometry and assessing their effects on human fibroblasts under UVB-induced damage. UV absorbance, ROS production, and collagen synthesis were evaluated. The FE extract, which comprised 4-hydroxyquinoline, phytosphingosine, and docosapentaenoic acid, reinstated procollagen type I synthesis to 113% of baseline levels and reduced TGF-β1-mediated fibroblast proliferation to 87.78%. FE also suppressed Smad2 and α-SMA by 71% and 68%, respectively, indicating modulation of fibrosis-associated pathways. AE, containing 4-hydroxyquinoline and phenylalanine betaine, demonstrated dose-responsive cellular repair, reducing fibroblast proliferation to 97.86% and collagen Type I expression by 73% at 1000 μg/mL. Both extracts decreased ROS production, with FE and AE reducing levels by 21.4% and 19.7%, respectively, under UVB-induced oxidative stress. FE showed superior scar inhibition, while AE excelled in skin regeneration and pigmentation management.

Background: Sustainable, dual-action ergogenic strategies are underexplored; most products target a single pathway and rarely upcycle seafood sidestreams. We therefore tested an upcycled formulation combining grouper bone hydrolysate and Undaria pinnatifida extract (GU) for ergogenic and microbiota effects in mice. We tested the ergogenic and microbiota modulating effects of GU in mice versus a vehicle and a BCAA control. Methods: GU was prepared via enzymatic hydrolysis of marine by-products and administered to male ICR mice for 4 weeks. Mice were divided into five groups (n = 7/group), receiving a vehicle control, a branched-chain amino acid (BCAA) supplement, or GU at three dose levels (1X, 2X, 3X) based on human-equivalent conversion. Exercise performance was assessed via grip strength and treadmill tests. Biochemical markers of fatigue, body composition, and safety indicators were also analyzed. Gut microbiota was evaluated using 16S rRNA sequencing and constrained principal coordinates analysis (CPCoA). Results: Four weeks of GU supplementation significantly enhanced exercise performance [(treadmill time ↑ Δ = 10.2–11.7 min versus vehicle (q ≤ 0.0002), grip strength ↑ Δ = 40.4–48.5 g (q ≤ 0.05)] and lean body mass [FFM ↑ at GU-1X (Δ = +0.80%, q = 0.0123)], surpassing the commercial BCAA control. Biochemical analyses indicated reduced exercise-induced lactate accumulation [(post-exercise lactate ↓ Δ = −2.71/−2.18 mmol·L⁻¹, q = 0.0006)]. Gut microbiota profiling revealed distinct shifts in community composition in GU-treated groups, notably with an increased abundance of beneficial taxa such as Lactobacillus and Muribaculum. These alterations reflect the prebiotic activity of seaweed-derived polysaccharides, promoting a healthier gut microbial profile. Notably, GU improved metabolic markers (aspartate aminotransferase, [AST]; lactate dehydrogenase, [LDH]) without inducing toxicity. Conclusions: These findings indicate that GU functions as a dual-action supplement, coupling amino acid-mediated muscle anabolism with microbiome modulation to enhance physical performance and metabolic health. As an upcycled marine product, it presents a sustainable and effective strategy for exercise support. Future studies should include 90-day safety, mechanistic assays, and a preregistered human pilot.