The industrial production and storage of unwashed surimi continue to face significant challenges in gel quality control. This study investigated the protective effects of theaflavins extract (TFs) on oxidative denaturation of myofibrillar protein (MP) and sarcoplasmic protein (SP), as well as on the gel properties of unwashed surimi during freeze-thaw cycles. The results showed that MP underwent more significant oxidative denaturation than SP after freeze-thaw treatment. Notably, the addition of 1 g/kg TFs provided greater protection against protein denaturation and surimi gel damage compared to 2 g/kg TFs. Supplementation with 1 g/kg TFs significantly mitigated freeze-induced changes in MP solubility, Ca2+-ATPase activity, carbonyl content, and conformation (P < 0.05). These changes resulted in improved surimi gel microstructure and functional properties, including gel strength, water distribution, and water-holding capacity. These findings provided valuable insights and practical guidance for applying TFs to enhance protein oxidative stability and improve the quality of unwashed frozen surimi.

This study investigated the dynamic changes of cytoskeletal proteins during drying and their relationships with texture and rehydration property from biochemical and microstructural perspectives. Nebulin degraded first (0-4 h), accompanied by severe deformation of I-band and A-band. Subsequently, degradation of myosin heavy chain (MHC) and tropomyosin (8-16 h) led to the gradual blurring of I-band and A-band. Finally, the degradation of desmin and the denaturation of actin (32-48 h) further disrupted sarcomere structure. After 16 h of drying, the hardness and shear force increased significantly (p < 0.05). Samples with greater cytoskeletal protein structural integrity (8 h and 16 h) exhibited superior rehydration properties. Random forest prediction and Mantel test analysis revealed that MHC and nebulin were the cytoskeletal proteins most strongly correlated with texture and rehydration properties, followed by actin and tropomyosin. These findings will provide practical guidance for improving the texture and rehydration quality of dried fish products.

Long-term quality deterioration remains a major challenge for the frozen dough industry. This study evaluated an isothermal-buffered frozen storage (IFS) against conventional air frozen storage (AFS) over 60 days. Results showed that the high thermal storage capacity of IFS acted as a physical barrier, reducing temperature fluctuations by 2.7-fold compared to AFS. This thermal stability effectively inhibited ice recrystallization, minimizing mechanical stress on the gluten-starch network and yeast cells. Consequently, IFS delayed the migration of bound water to a freezable state, preserving dough hydration. Bread from IFS-treated dough exhibited 15.69% higher specific volume and superior crumb uniformity. Mechanistically, the thermal buffering effect of IFS mitigates environmental temperature fluctuations, thereby limiting ice recrystallization and reducing subsequent mechanical damage to the gluten-starch matrix and yeast cells. This study offers a feasible strategy to enhance the stability of frozen dough against the unavoidable temperature variations commonly encountered in cold chain logistics.

This study aimed to comprehensively explore the effects of trehalose, precooking methods, freeze-thaw treatments, and reheating on the texture and flavor of crayfish products. The combination of trehalose treatment and frying precooking helped to maintain integrity of muscle fiber structure and effectively retarded transformation of bound water into free water during freeze-thaw cycles and contributed to improvement of color and texture of the crayfish products. Total quantity of amino acids decreased in the precooked (steamed and fried) crayfish. However, proportion of umami-associated amino acids increased from 2.470 mg/100 g to 4.460 mg/100 g in fried crayfish. The oxidative breakdown and degradation of unsaturated fatty acids, such as oleic acid, linoleic acid and linolenic acid during precooking promoted formation of octanal, nonanal and 1-octen-3-ol, while the formation of 1-octen-3-ol, 3-methylbutanal, hexanal, 1-hexanol, octanal were higher in the frying products than that in the steaming products. Reheating treatment of the frozen precooked crayfish induced generation of warmed-over flavor (WOF) compounds, and compared to the steamed crayfish, reheating treatment promoted generation of higher levels of WOF compounds in the fried crayfish. These findings provide valuable insights for optimizing of crayfish processing and consumption procedures.​

ObjectiveTo control the gel property and warmed-over flavor formation of hairtail surimi products.MethodsSurimi gel is prepared using hairtail as the raw material. Then, by examining changes in sensory evaluation, microstructure, gel property, moisture content, and volatile flavor substances, this study investigates the effects of yeast extract addition and reheating methods on gel property and warmed-over flavor formation in hairtail surimi products.ResultsYeast extract addition significantly promotes internal structural cross-linking and reduces the number of pores in the product, thereby enhancing the gel properties, including gel strength, hardness, and elasticity. Specifically, an optimal gel property is observed at a 1.00% addition level. Microwave reheating after freeze-thaw results in a denser microstructure. Furthermore, volatile substance analysis reveals that 2-hexenal, d6-acetone, 2-nonanone, ethyl propionate, and ethyl butyrate are the main flavor substances imparted by the yeast extract to fresh hairtail surimi products. The primary warmed-over flavor components in hairtail surimi products formed after reheating are heptanal, 2-methylpentanal, (E)-2-octenal, 1-octen-3-ol, (E, Z)-2,6-nonadienal, 2,3-butanedione, and 2-undecanone (based on odor activity value>100). Microwave reheating generates less warmed-over flavor than the water-boiling reheating groups (based on odor activity value>1).ConclusionMicrowave reheating combined with an addition of 1.00% yeast extract can improve the gel property and inhibit warmed-over flavor formation of hairtail surimi products.

This study aimed to screen and characterize antifreeze peptides (AFPs) from silver carp parvalbumin (ScPV). Enzymatic hydrolysis enhanced the cryoprotective activity of ScPV, as evidenced by improved yeast viability after freeze‑thaw cycles. Using an integrated strategy combining ultrafiltration, peptidomics, in silico screening, and functional validation, a potent PV‑AFP‑2 (ADSFNHK) was screened out from the most active ultrafiltration fraction (UF1). The UF1 fraction itself showed strong cryoprotection, with yeast viability retention rates of 80.6% and 57.3% after 2 and 3 freeze‑thaw cycles, respectively, and exhibited the highest thermal hysteresis (TH) activity (1.22°C) among all fractions. The purified synthetic PV‑AFP‑2 demonstrated significant TH (0.89 °C) and ice recrystallization inhibition activities. Structural analysis and molecular dynamics simulations revealed that PV‑AFP‑2 adopts a coiled, amphipathic structural/sequence feature, and inhibits ice growth (simulated rate = 6.85 cm/s), via a dual mechanism involving hydration-shell stabilization and specific ice-surface adsorption. This work provides a novel peptide candidate for cryoprotection and establishes a rational screening framework for discovering functional peptides from food‑derived proteins.

This study elucidates the structure-digestibility relationship of wheat starch subjected to moisture-controlled heat treatment (HMT) and explores its application in enhancing the quality of steamed sponge cake. Treatment at varying moisture levels (20-30%) induced significant structural reorganization in the starch granules. Specifically, the 30% moisture treatment elevated the resistant starch (RS) content from 23.75% to 44.42% (P < 0.05) and shifted the pasting temperature from 55.82 °C to 78.35 °C. These functional changes were driven by enhanced crystalline perfection and short-range molecular order, alongside intensified starch-protein interactions, which restricted enzymatic accessibility. In the food matrix, the application of HMT flour significantly retarded moisture migration and staling rates in steamed sponge cakes under storage. Consequently, moisture-controlled HMT serves as a robust clean-label strategy to tailor the supramolecular structure of wheat starch, yielding functional ingredients with reduced glycemic impact and superior shelf-life stability.

This study investigated the effects and related mechanisms of silver carp parvalbumin (ScPV) on enhancing freeze-thaw (FT) tolerance of yeast, using an integrated approach combining experimental assays, transcriptomics, and computational simulations. After 2 FT cycles, ScPV-treated yeast showed significantly higher viability and survival rate (24.0 % vs. 0.5 % in the control) and a 3-fold retention in mitochondrial membrane potential. Further analysis revealed that ScPV exhibits a thermal hysteresis activity of 0.72 degrees C and strong ice recrystallization inhibition. It also reduced intracellular ice formation and lowered the extracellular ice formation temperature of yeast suspension from -9.9 degrees C to -14.7 degrees C. Ultrastructural observations suggested that ScPV may alleviate FT-induced damage and helped maintain cell wall and membrane integrity. Moreover, transcriptomic analysis indicated that ScPV regulates the transcription of key genes (e.g., SLT2, FKS1), modulating stress-response pathways related to cell wall reinforcement and repair. Molecular docking and dynamics simulations suggested that ScPV binds to critical proteins such as Mpk1, stabilizing their conformation and function to protect cellular integrity. For the first time, these findings establish ScPV as a novel antifreeze protein and elucidate its multifaceted role in enhancing cryotolerance in yeast.

This study evaluated the combined effect of a silver carp muscle hydrolysate (SCMH) /chitosan coating and immersion frozen storage (IFS) on the quality of crayfish during frozen storage. Samples treated with the combined strategy (SCMH + IFS) were compared with those under traditional air-frozen storage (AFS) over 60 days. Quality was assessed based on sensory attributes, physicochemical properties, endogenous enzyme activities, and ice crystal morphology. The SCMH + IFS treatment achieved rapid freezing, reduced temperature fluctuation (± 0.21 °C), and better maintained sensory quality. After 60 days, the SCMH + IFS group showed lower drip loss (10.2

This study investigated the cryoprotective effects and mechanisms of antifreeze peptides derived from silver carp parvalbumins (PV-AFPs) in a yeast model, employing a combined experimental and computational approach. Results showed that PV-AFPs significantly enhanced yeast survival rate (9.1-46.8 fold) after 1-3 freeze-thaw cycles, improved intracellular protein preservation, reduced structural damage, and maintained mitochondrial membrane potential (5.3-fold higher retention than control). PV-AFPs also reduced freezable water content, inhibited intracellular ice formation, and depressed the extracellular ice formation temperature from -16.6 to -21.4 °C. Molecular docking and molecular dynamics simulations revealed that PV-AFPs stabilized membrane protein Ehs1p by binding to polar and hydrophobic residues, thereby preserving cell membrane/wall integrity. This study demonstrates, for the first time, the dual cryoprotective mechanism of PV-AFPs, involving ice formation inhibition and cell membrane/wall stabilization. Further validation in real dough systems and clarification of individual peptide contributions remain key objectives for future work.

This study investigated the formation and dynamic changes of taste-active compounds during semi-dried silver carp drying. TCA-soluble peptides and free amino acids significantly increased after 8-16 h at traditional commercial drying temperature of 45 °C. Umami amino acids Glu exhibited the greatest increases from 1.85 mg/100 g (fresh) to 127.38 mg/100 g (48 h-dried). Umami nucleotide adenosine 5'-monophosphate (AMP) significantly increased after 8-16 h, as did bitter nucleotides hypoxanthine riboside (HxR) and hypoxanthine (Hx). Metabolomic analysis showed amino acid and nucleotide metabolism predominated in the first 8 h, contributing to distinctive savory taste. The synergistic balance of key taste-related metabolites, including oligopeptides (umami and bitter), amino acids (umami, sweet, bitter), nucleotides (umami and bitter), and organic acids (sourness and umami), played a key role in taste perception. Sensory evaluation confirmed the 8 h sample exhibited the highest taste acceptance. These findings provide valuable insights for taste regulation in semi-dried fish products.

Crucian carp (Carassius auratus) soup is a traditional Chinese functional food known for health benefits. Hefang crucian carp 2 (WR2) is a newly bred hybrid with enhanced nutritional value. In this study, WR2 soup processing was optimized using single-factor and response surface methods. The best conditions-a 1:5.46 solid-to-liquid ratio, 1.12 h boiling time, and 0.71% salt-produced superior sensory quality. Compared with soups from hybrid crucian carp (Carassius carassius) & times; common carp (Cyprinus carpio) (CC), Micropterus salmoides (LMB) and Megalobrama amblycephala (BSB), WR2 soup exhibits the highest DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, hydroxyl radical scavenging activity, total reducing power and ABTS [2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activity. Proteomic analysis identified 201 proteins mainly related to metabolism and immune function, highlighting its nutritional potential. Additionally, 61 volatile compounds, including aldehydes, ketones and alcohols create a complex fragrance with fresh fruity notes and rich milk flavors coexisting, contributed to its rich, distinctive flavor. These results demonstrate that WR2 fish soup inherits the traditional health benefits of crucian carp while offering superior nutritional and functional characteristics, supporting its development as a high-value product in the aquatic food industry.

Antarctic krill (Euphausia superba) is a nutrient-dense resource, yet its myofibrillar proteins (AKMP) often exhibit poor thermal gelation. Building on our previous macroscopic findings, this study investigates the regulatory mechanisms governing the heat-induced aggregation of AKMP. Micro-rheological analysis revealed that κ-carrageenan (κCG) shifted the critical sol-gel transition temperature from 60 °C to 50 °C, as evidenced by the transition of particle motion from free diffusion to restricted entrapment. This facilitated network initiation was accompanied by a concentration-dependent increase in aggregate size (P < 0.05), signifying the formation of robust macromolecular structures. Conformational analyses (using myosin as a representative model) suggested that κCG may induce α-helix rearrangement and the exposure of buried functional groups (e.g., sulfhydryl and hydrophobic clusters), thereby strengthening intermolecular cross-linking. These findings suggest that κCG acts as a molecular scaffold that directs the AKMP aggregation pathway towards a more ordered and stable network. This work provides a preliminary mechanistic framework for the polysaccharide-mediated modulation of krill protein aggregation, offering theoretical guidance for the high-value utilization of Antarctic krill resources.

The industrial production and storage of unwashed surimi continue to face significant challenges in flavor quality control. This study investigated the effective control of theaflavins (TFs) on odor deterioration of unwashed surimi products during gel processing and frozen storage based on two-dimensional gas chromatography-time-offlight mass spectrometry (GC & times; GC-TOFMS). Multivariate statistical analysis revealed 66 differential markers potentially governing flavor profile evolution. Odor activity value (OAV) quantification identified 18 key odoractive compounds, among which 1-octen-3-ol, (E, Z)-2,6-nonadienal, heptanal, hexanal, and octanal made critical contributions to the fishy or warmed-over flavor (WOF) notes of frozen surimi products. Correlation analysis demonstrated that the oxidation and degradation of unsaturated fatty acids and amino acids were pivotal control notes for odor deterioration. TFs treatment effectively delayed the formation and accumulation of fishy or WOF odors through mitigating the oxidation and degradation of unsaturated fatty acids during surimi gel processing and frozen storage. These findings provide a natural and safe method for flavor control in unwashed surimi production and storage.

To address the critical industrial challenges of ice recrystallization and gluten network degradation, this study systematically evaluated a dual-protection strategy integrating an isothermal-buffered frozen storage (IFS) with silver carp parvalbumin (PV). Compared to trehalose-air frozen storage (T-AFS), the PV-IFS significantly mitigated crumb hardening (2065 g vs. 2560 g) and loss of specific volume (1.82 mL/g vs. 1.70 mL/g) throughout a 60-day period. Microstructural analysis suggested that the PV-IFS combination helped preserve the gluten matrix, resulting in a higher crumb cell density (+11.79 cell/cm2 vs. T-AFS). This improvement is hypothesized to stem from the combined efficacy of macroscopic thermal stability, which preserves yeast vitality (OD600 = 1.28), and microscopic biochemical protection, where PV potentially inhibits ice growth (mean area 13.21 mu m2 vs. 16.24 mu m2 in T-AFS) and reinforces gluten via non-covalent interactions. This joint action ensures the preservation of the dough's gas-production and gas-holding capacities during long-term storage. These findings suggest that the combination of thermal-buffer technology with bio-derived antifreeze proteins provides enhanced quality preservation in the frozen bakery industry.

In this paper, the effects of Soy protein isolate fibril aggregates (SPIF) on in vitro digestibility, structure and retrogradation of starch in reconstituted rice were systematically studied. Incorporation of 10 % SPIF significantly reduced the glycemic index (eGI) from 84.12 to 74.39 (p < 0.05). Microstructural and XRD analyses revealed that SPIF preserved starch granular integrity during extrusion, maintaining the highest relative crystallinity by mitigating gelatinization. SPIF further stabilized amylopectin by inhibiting the conversion of medium chains to short chains and reinforcing short-range molecular order, as evidenced by chain length distribution and FT-IR analysis. Notably, 10 % SPIF delayed short-term retrogradation (5 h at 4 °C), yielding minimal hardness (1312.26 g) and crystallinity (18.86 %) (p < 0.05), though long-term retrogradation (24 h at 4 °C) was accelerated due to enhanced amylopectin reorganization. These findings highlight dual role of SPIF as a hydrocolloid modifier in starch-based matrices, offering structural protection during processing while modulating digestibility and retrogradation patterns. The work shed light on the potential of SPIF for designing extruded foods with mitigated glycemic responses and improved functional attributes.

Fish breeding, including distant hybridization and backcrossing, can reinforce fish growth performance and flesh quality. Using the intercrossing and backcrossing, two improved crucian carps, WR1 and WR2, were generated with a fast growth rate and high-quality flesh. The present study focused on the metabolomic profiles of two genetically improved fish species and investigated the mechanisms of advanced traits underlying metabolic changes by comparing them to their original parents. By comparing WR1 with its parents, 65 differentially expressed metabolites (DEMs) showed significantly higher expression levels in both parental species, whereas 281 DEMs exhibited significantly lower expression levels in both. Among them, LysoPC 18:3, deoxycholic acid, and uric acid were significantly higher, whereas inosine was significantly lower in WR1. In WR2, 75 metabolites were significantly higher in the parents than in WR2, while 413 metabolites were significantly lower in the parents than in WR2. l-Carnitine, creatine, choline, and seven di-/tripeptides were upregulated in WR2. The higher levels of creatine in the muscle of WR2 compared to WR1 and the Weighted Gene Co-expression Network Analysis (WGCNA) results suggest that creatine is the key node that regulates a module containing 72 metabolites. The concentration of creatine in WR2 reached to 28.58 ± 3.01 μmol/g indicating the high concentration of creatine in WR2 was related with its growth performance and high-quality flesh. In conclusion, this study provides the first clues for genetic breeding to reconstruct the metabolic profiles of crucian carp, implying a metabolic mechanism for reinforcing growth performance and flesh quality.

This study aimed to investigate the improvement effects of a silver carp muscle hydrolysate (SCMH) on freeze-thaw (FT) tolerance of baker's yeast and the related mechanism. Yeast cells with or without addition of SCMH were subjected to 0 to 6 FT cycles, and their cell viability, leavening activity, growth kinetics, morphology, and transcriptome were examined. The results showed that the SCMH-added yeast had significantly higher cell viability (40.7 %), leavening activity (473.2 mL kg-1·h-1), and maximum specific growth rate (2.63 h-1) than those in control (CK) group (0 %, 287.2 mL kg-1·h-1, and 1.74 h-1, respectively), after 6 FT cycles. Frozen-thawed yeast with SCMH also exhibited better cell structural integrity compared to that of the CK yeast. Transcriptomic analysis revealed that the incorporation of SCMH led to significantly increased counts of differentially expressed genes (DEGs) in yeast cells after 6 FT cycles, and transcriptionally regulated the pathways associated with ribosome biogenesis and function, amino acid metabolism, carbohydrate metabolism, and lipid metabolism. Therefore, the SCMH could help yeast withstand FT stress, likely via a dual mechanism for inhibiting ice growth and inducing some freeze-adapted transcriptional regulation.

This study investigated the synergistic effects of trehalose incorporation, precooking methods (steaming and frying) and reheating on optimizing the textural and flavor profiles of frozen precooked Chinese shrimp (Fen-neropenaeus chinensis) products. Incorporating trehalose soaking before precooking treatments imparted the shrimp attractive red-yellow coloration while achieved notable reductions in cooking loss (steamed: 22.87 %-> 17.31 %; fried: 32.57 %-> 25.58 %) and freeze-thaw loss (steamed: 5.92 %-> 2.29 %; fried: 2.68 %-> 1.07 %). Steaming pretreatment combined with trehalose soaking effectively inhibited ice crystal formation in the shrimp, resulted in relatively intact fibrous tissue during frozen storage and promoted the production of taste and odor in the products. Subsequent microwave reheating substantially enriched desirable flavor compounds of the frozen precooked shrimps. The results indicated that synergistic application of trehalose soaking and steaming precooking effectively mitigated the quality deterioration of precooked shrimp during frozen storage. These findings established an innovative processing strategy that enhanced both the sensory quality and commercial viability of frozen precooked shrimp products.

This study investigated reheating methods (water bath, WB; steam, SM; microwave, MW) on formation and development of undesired warmed-over flavor (WOF) in precooked surimi products. MW resulted in shrinkage of surimi gel, while SM caused large pores on disrupted structure. Unsaturated fatty acids, mainly oleic (308.15 mg/100 g) and linolenic acid (103.44 mg/100 g), were significantly higher in MW, followed by SM and WB (P < 0.05). Octanal, nonanal, decanal and 6 other odorants were major contributors to WOF of all reheated samples based on odor active values. MW contributed less to WOF formation, whereas SM induced generation of the largest variety of unpleasant odor-active substances, in which (E,E)-2,4-decadienal, 1-pentanethiol, 2-undecanone and (E)-2-octen-1-ol were uniquely found. Sensory evaluation verified the strongest WOF perception of SM. Odorant docking suggested the key WOF compounds could dock to three representative olfactory receptors. These findings provided guidance for flavor regulation of precooked surimi products.