Passakorn Kingwascharapong

This study aimed to optimize the synthesis of chitosan-derived carbon dots (CS-CDs) and incorporate them into gelatin capsule waste/Gum Arabic (Gel/GA) composite films for sustainable active packaging of minced fish. CS-CDs were synthesized hydrothermally at 180, 200, and 220 °C for 4, 5, and 6 h. The optimal condition was 200 °C for 6 h, producing spherical nanoparticles below 10 nm with strong blue fluorescence, a maximum absorbance at 293 nm, and antioxidant activities of 56% (2,2-diphenyl-1-picrylhydrazyl: DPPH) and 66% (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid): ABTS) at a concentration of 20% (v/v), together with antibacterial activity against S. aureus, S. enteritidis, and E. coli. The optimized CS-CDs were incorporated into Gel/GA films at 0–2% (w/v), significantly increasing tensile strength from 2.20 to 4.19 MPa and improving water resistance (p < 0.05). Antioxidant and antimicrobial activities increased with CS-CD concentration. Gel/GA/CD-2 exhibited the best overall performance and effectively preserved minced fish at room temperature for up to 48 h by reducing microbial growth and lipid oxidation. Overall, integrating CS-CDs with upcycled gelatin capsule waste provides a promising approach for developing multifunctional biodegradable active packaging with enhanced mechanical, antioxidant and antimicrobial properties for seafood preservation.

Peach palm (Bactris gasipaes) heart is a sustainable, fiber- and polysaccharide-rich ingredient with potential for plant-based food structuring. This study investigated peach palm heart powder (PPHP) as a functional co-ingredient in soy protein isolate (SPI)-based inks for extrusion-based 3D food printing, focusing on rheology, printability, microstructure, molecular interactions, texture, and in vitro digestibility. Increasing PPHP concentration enhanced apparent and complex viscosity, storage modulus (G′), deformation resistance, and structural recovery while maintaining strong shear-thinning behavior, improving printing performance; PPHP8 showed the lowest dimensional deviation (0.25%) and highest shape fidelity (100.25%). PPHP was progressively incorporated into the SPI matrix, forming a denser protein–polysaccharide network primarily through non-covalent interactions, as indicated by microstructural and SDS–PAGE analyses. PPHP reduced hardness, gumminess, chewiness, and resilience but maintained springiness, enabling texture modulation, and FTIR/PCA revealed a shift from α-helical toward β-sheet-rich protein conformations, consistent with enhanced hydrogen bonding. Protein hydrolysis during simulated digestion and B. longum subsp. longum viability were not significantly compromised by PPHP incorporation. These findings demonstrate that PPHP can be strategically incorporated to tailor the rheological and textural properties of SPI-based inks for 3D printing without compromising nutritional functionality, supporting its potential as a sustainable structuring ingredient for next-generation plant-based printed foods.

Low-molecular-weight chitosan may exhibit improved dispersion and biological accessibility compared with high-molecular-weight chitosan, but direct comparisons in Asian seabass remain limited. This study evaluated dietary low-molecular-weight chitosan produced by combined gamma irradiation and hydrogen peroxide depolymerization. The untreated and degraded preparations had apparent GPC-derived molecular weights of approximately 85 and 10 kDa, respectively. Juvenile Asian seabass (Lates calcarifer) were fed a Control diet of 1.0% high-molecular-weight chitosan or low-molecular-weight chitosan at 0.25%, 0.5%, or 1.0% for four weeks. Growth, serum antioxidant and humoral immune parameters, tissue-specific gene expression, and resistance to Photobacterium damselae were evaluated. No treatment significantly affected growth or feed utilization. Both high- and low-molecular-weight chitosan reduced serum MDA relative to the Control, whereas selected antioxidant and immune responses differed among inclusion levels. The 0.5% low-molecular-weight treatment increased GSH and GPx activity, the 1.0% low-molecular-weight treatment produced the highest CAT activity, and the 0.25% low-molecular-weight treatment produced the highest total serum IgM. Low-molecular-weight chitosan generally produced broader tissue-specific transcriptional responses than 1.0% high-molecular-weight chitosan. Following bacterial challenge, all chitosan treatments improved survival relative to the Control, with the highest numerical RPS observed in the 0.5% low-molecular-weight group. These results indicate that molecular-weight reduction influenced the biological response to dietary chitosan. Among the tested levels, 0.5% produced the most consistent combined response, although the optimal level was endpoint-specific and requires longer-term validation.

A low-sodium soaking solution for Pacific white shrimp was developed by partially substituting sodium tripolyphosphate (STPP) with potassium tripolyphosphate (KTPP) or tetrapotassium pyrophosphate (TKPP) (0.5–2.5%, w/v) in combination with L-lysine (2%, w/v). The effects on physicochemical properties, microstructure, and consumer acceptance were evaluated in comparison with a non-soaked control and a positive control (3% STPP, w/v). The results indicated that partial substitution of STPP with KTPP or TKPP could be effectively achieved while maintaining processing yield, color, and water-holding capacity (WHC) comparable to the positive control. Scanning electron microscopy revealed a more relaxed and expanded muscle structure, indicating enhanced water retention and reduced shear force. However, no significant differences in shear force were observed between the substitution treatments and the positive control. Substitution with KTPP or TKPP significantly reduced phosphate content and the Na/K ratio. Sodium levels decreased by 23.5–47.0% with KTPP and 28.8–59.5% with TKPP, while potassium content increased in the treated shrimp. This substitution did not adversely affect consumer acceptance, with improved taste characteristics, particularly enhanced saltiness and umami, detected by electronic-tongue analysis. Overall, replacing STPP with KTPP or TKPP shows potential as a strategy for developing reduced-sodium shrimp products while maintaining product quality.

Bacterial diseases caused by Flavobacterium covae (Fc), Vibrio harveyi (Vh), Vibrio vulnificus (Vv) and Photobacterium damselae (Pd) seriously constrain Asian seabass aquaculture. Here we dissect the mucosal immune mechanisms engaged by a five-month sequential vaccination strategy that combines nanoemulsion immersion priming with multivalent oral hydrogel boosting. Juvenile seabass were vaccinated, then challenged with F. covae by freshwater immersion and with a Vibrio–Photobacterium (Vh/Vv/Pd) mix by immersion or intraperitoneal injection. Gills were sampled after immersion challenges and intestine after injection, and profiled by RNA sequencing and label-free quantitative proteomics, with selected genes validated by RT-qPCR. Principal component analysis showed clear separation of vaccinated and control fish in all tissues and challenges, indicating a strong and coherent transcriptional reprogramming. Vaccination markedly increased the number of upregulated genes, with Gene Ontology enrichment revealing dominant signatures of ribosome biogenesis, RNA processing, lysosomal organization and immune response. KEGG analysis highlighted cytokine receptor interaction; NOD and Toll-like receptor signaling; oxidative phosphorylation; and phagosome, lysosome and cell adhesion molecule pathways, consistent with heightened antimicrobial readiness. Volcano plots and focused heatmaps showed strong induction of interferon-stimulated genes, cytokines and chemokine receptors, complement components, macrophage mannose receptor, epithelial barrier mediators and numerous immunoglobulin transcripts, with tissue- and challenge-specific patterns. Proteomics corroborated these trends, demonstrating a higher abundance of immunoglobulin heavy chains, complement proteins, cathepsins, heat shock and redox chaperones, ribosomal proteins and cytoskeletal and adhesion regulators in vaccinated mucosae. Integrated pathway mapping linked endothelial adhesion molecules and leukocyte integrins with T cell costimulation networks and an intestinal immune network for immunoglobulin production, including enhanced pIgR-mediated transcytosis. Overall, the sequential vaccination regimen was associated with coordinated transcriptomic and proteomic signatures related to epithelial responses, innate immunity, and humoral immune functions across gill and intestinal tissues. These molecular patterns were accompanied by improved survival following bacterial challenge; however, the present data do not directly demonstrate the functional activity of the inferred immune mechanisms in Asian seabass.

This study evaluated the potential of synergistically degraded low-molecular-weight chitosan (LMW-CS) as a functional feed additive to promote growth, antioxidant capacity, innate immunity, and disease resistance in Pacific white shrimp (Litopenaeus vannamei). High-molecular-weight chitosan (HMW-CS, approximately 85 kDa) was degraded using γ-irradiation in combination with H₂O₂ to produce LMW-CS with improved functional properties. Shrimp were fed five experimental diets for 4 weeks: a control diet, HMW-CS0.4 (0.4% w/w), LMW-CS0.1 (0.1% w/w), LMW-CS0.2 (0.2% w/w), and LMW-CS0.4 (0.4% w/w). Growth performance, oxidative stress markers, antioxidant enzyme activities, lysozyme activity, immune-related gene expression, bacterial load, and survival after Vibrio parahaemolyticus challenge were evaluated. The results indicate that dietary LMW-CS supplementation improved growth performance and feed utilization, with LMW-CS0.2 showing significantly higher final weight, total weight gain, and average daily gain than the control group (p < 0.05). Antioxidant assays showed that LMW-CS reduced malondialdehyde levels and increased reduced glutathione, nitric oxide, glutathione reductase, catalase, superoxide dismutase, glutathione peroxidase, and glutathione-S-transferase activities in both plasma and hepatopancreas (p < 0.05). Lysozyme activity was significantly enhanced, particularly in the LMW-CS0.4 and HMW-CS0.4 groups (p < 0.05). Gene expression analysis revealed upregulation of genes associated with growth regulation, antimicrobial defense, pathogen recognition, and prophenoloxidase activation, including igf2, cstn, lgbp, lyz, and propo2. Gut microbiota profiling showed that chitosan supplementation altered bacterial community composition, reduced the relative abundance of some Vibrio-associated taxa, and descriptively lowered predicted pathogenic and stress-tolerant bacterial phenotypes. Following the Vibrio parahaemolyticus challenge, shrimp fed LMW-CS0.4 showed the lowest bacterial load and highest survival rate, indicating improved disease resistance (p < 0.05). Overall, synergistically degraded LMW-CS enhanced growth, redox balance, innate immune competence, gut microbial structure, and resistance to V. parahaemolyticus, supporting its potential as an antibiotic-free functional feed additive for sustainable shrimp aquaculture.

Aquaculture production of Asian seabass is increasingly threatened by recurrent bacterial diseases, while practical vaccination strategies that provide protection against bacterial challenges involving multiple pathogens during extended grow-out periods remain limited. This study evaluated the immunological and protective effects of a sequential mucosal vaccination strategy in juvenile Asian seabass (Lates calcarifer; 200 fish per treatment, distributed among four replicate tanks of 50 fish) against four major bacterial pathogens: Flavobacterium covae, Vibrio harveyi, Vibrio vulnificus, and Photobacterium damselae. The vaccination regimen consisted of two nanoemulsion-based immersion vaccination events administered 14 days apart, followed by three oral chitosan–alginate hydrogel vaccination courses administered for 7, 5, and 3 consecutive days. Bacterial challenge experiments were conducted at three post-vaccination time points using immersion and intraperitoneal injection models. Growth performance and feed conversion were evaluated using replicate-tank means as the experimental units. Sequential vaccination did not significantly affect final body weight, weight gain, average daily gain, specific growth rate, or feed conversion ratio (p > 0.05). Vaccinated fish showed significantly higher antigen-specific IgM levels in skin mucus, intestinal mucus, and serum across the evaluated challenge conditions. Correspondingly, ighm, ighd, and ight expression was increased in the gills, skin, head kidney, and intestine, indicating enhanced immunoglobulin-associated responses in mucosal and lymphoid tissues. Full-length 16S rRNA gene sequencing showed vaccine-associated changes in gill and intestinal bacterial community composition, including a lower relative representation of several challenge-associated taxa and a higher relative representation of selected commensal-associated taxa. Vaccinated fish showed significantly higher cumulative survival following F. covae immersion, mixed V. harveyi/V. vulnificus/P. damselae immersion, and mixed-pathogen injection challenges (p < 0.05). These findings demonstrate that sequential nanoemulsion immersion priming and oral hydrogel boosting enhanced pathogen-specific humoral responses and increased immunoglobulin-gene expression. The sequential vaccination strategy improved survival following a separate Flavobacterium covae challenge and a combined Vibrio harveyi/Vibrio vulnificus/Photobacterium damselae challenge during the experimental period without adversely affecting growth. This needle-free strategy warrants further evaluation under commercial aquaculture conditions.

The rapid global transition toward sustainable food systems has intensified interest in alternative protein ingredients derived from both terrestrial plants and blue foods. However, a critical bottleneck in the commercialization of these proteins is the stabilization of flavor profiles during dehydration. Drying technologies ranging from conventional hot-air and heat pump drying to microwave and vacuum freeze-drying inevitably induce structural reorganization and oxidative modifications. These transformations fundamentally modulate how volatile flavor compounds are bound, retained, and released within the food matrix. This review proposes a comprehensive structure–process–function framework that mechanistically connects intrinsic protein architectures, drying-induced denaturation, and flavor-binding behavior. The review first contrasts globular plant proteins (e.g., soy, pea, and emerging tropical crops) with fibrous marine myofibrillar and collagenous proteins, emphasizing their distinct hierarchies, amino acid compositions, and oxidative vulnerabilities. It then critically evaluates how varying drying modalities drive protein unfolding, aggregation, and carbonylation, and how these transformations alter binding pocket accessibility, surface hydrophobicity, and lipid–protein–flavor crosstalk. Furthermore, it highlights the emerging role of hybrid plant–marine protein matrices as a strategy to optimize techno-functionality. By integrating structural biophysics with computational approaches such as molecular docking and structure-based modeling, this review provides a predictive conceptual map for designing flavor–protein interactions under specific dehydration histories. Ultimately, the proposed framework offers practical design principles for selecting protein sources and tailoring drying strategies to produce high-quality, sensorially superior, and sustainable next-generation food products.

Gelatin capsule waste (GCW), a protein-rich by-product, represents a promising substrate for the generation of potential bioactive substances, including free amino acids and other soluble substances generated during enzymatic hydrolysis. In this study, gelatin hydrolysates with degrees of hydrolysis (DH) ranging from 10% to 40% were produced using the commercial enzymes NS AC0106 (endopeptidase) and NS AC0107 (aminopeptidase) to enhance their functional properties. Increasing DH significantly improved antioxidant activity, surface hydrophobicity, and emulsifying capacity (p < 0.05), while sterilization further enhanced antioxidant capacity. Structural analyses confirmed extensive protein degradation and conformational modifications, as evidenced by SDS–PAGE (formation of low-molecular-weight substances), FTIR (shifts in the amide I region), and NMR (release of free amino acids). Electronic tongue analysis indicated that enzymatic hydrolysis enhanced umami and salty taste attributes. Notably, hydrolysis using NS AC0107 at 40% DH resulted in the highest antioxidant activity, together with pronounced umami taste and low bitterness. Overall, GCW-derived hydrolysates show considerable potential as functional ingredients and provide a sustainable strategy for the valorization of protein-rich industrial by-products.