Atherosclerosis is the primary pathological foundation of various cardiovascular and cerebrovascular diseases. Although existing treatment strategies exhibit certain efficacy, they still encounter limitations such as pronounced side effects and a single-target approach. The oceans have nurtured a rich diversity of organisms, and the secondary metabolites they generate possess novel structures, diverse activities, and unique mechanisms of action, offering new prospects for the development of anti-atherosclerotic drugs. This paper reviews advancements related to research on marine-derived active substances that possess anti-atherosclerotic activity, as well as current challenges in research on active substances, with the objective of laying a foundation for the development of anti-atherosclerotic drugs.

In this study, we developed an instant freeze-dried kelp and egg soup cube by optimizing raw material selection, formulation parameters, and freeze-drying conditions, thus establishing an optimal preparation process. Tender kelp exhibited significantly lower fracture property and hardness than mature kelp (p < 0.05) and contained significantly higher levels of key aroma compounds (beta-ionone and geranyl acetone) and lower levels of the key fishy odor compound 1-octen-3-one. Therefore, tender kelp was selected as the preferred raw material. The optimal formulation was determined as: 800 g water, 1.4 g carboxymethylcellulose sodium (CMC-Na), 0.05 g tender kelp powder, 64 g tender kelp, 2.6 g salt, 10 g ginger, 56 g egg, 1.2 g starch, 1.2 g monosodium glutamate (MSG), and 1.6 g scallion. The optimal freeze-drying conditions included a pre-freezing temperature of -20 degrees C, a sublimation temperature of -5 degrees C, and a desorption temperature of 60 degrees C. The resulting soup cubes exhibited excellent sensory quality, good rehydration properties, and high freeze-drying efficiency. These findings provide novel insights and a technical basis for future research and innovation in kelp pre-made dishes.

Nannochloropsis gaditana (N. gaditana) is a promising novel food ingredient enriched with eicosapentaenoic acid (EPA), yet its nutritional value, lipid composition, and flavor characteristics haven’t been elucidated systematically. In this study, N. gaditana was characterised with 55.57

This study aimed to investigate the effects of sodium hypochlorite (NaClO) bleaching on the quality of Basa (Pangasius bocourti) fish maw (BFM) and the formation of semicarbazide (SEM). Production of SEM increased (p < 0.05) when NaClO concentration, soaking temperature, or duration were increased. Notably, increasing NaClO solution pH also enhanced SEM formation. Soaking BFM in NaClO with available chlorine concentrations of 500, 700, and 1000 mg/L generated 0.05, 0.07, and 0.09 μg/kg SEM at pH 3 compared to 0.70, 1.19, and 2.34 μg/kg SEM at pH 11, respectively. NaClO improved BFM texture by creating a tight, fibrous structure, but also damaged the secondary structure and α-chains of collagen. Untargeted metabolomics showed that NaClO treatment significantly upregulated lipid metabolism pathways (biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and glycerophospholipid metabolism) and elevated degradation of arginine, proline, and urocanic acid. This was associated with the accumulation of nitrogen-containing precursors in the urea cycle, which then reacted with NaClO, generating substantial SEM. Controlled SEM-generating reactions experiments confirmed that SEM was produced from reaction of urea and NaClO. This study elucidates the mechanism of SEM formation and identifies key factors influencing SEM levels, thereby providing a theoretical foundation for safe processing and quality control of fish maw.

Semicarbazide (SEM) is widely monitored as a metabolite of the nitrofuran antibiotic nitrofurazone (NFZ). In recent years, frequent occurrences of excessive SEM residues in aquatic products have seriously hindered the export trade and sustainable development of the Chinese aquaculture industry. Studies have shown that SEM derives from both exogenous and endogenous sources. Exogenous sources include illegal drug use, contamination from water, feed, and algae, and chemical reactions during processing. Endogenous formation, conversely, occurs through pathways such as amino acid metabolism, the urea cycle, and chitin metabolism. This review systematically examines the sources, formation mechanisms, and metabolic behavior of SEM in aquatic products with a focus on advanced detection methods, including metabolomics, transcriptomics, and high performance liquid chromatography. Furthermore, targeted control strategies are proposed, encompassing aquaculture environmental management, optimization of processing procedures, and regulation of key metabolites. This review aims to provide a scientific foundation for the effective prevention and control of SEM contamination in aquatic products in China.

Takifugu bimaculatus, a pufferfish species farmed in Fujian Province, is known for its non-toxic flesh and collagen- rich skin. We identified a novel collagen-derived matrix metalloproteinase 1 (MMP-1) inhibitory peptide, from T. bimaculatus skin with potent anti-photoaging properties. Using multistage membrane and gel filtration chromatography, we purified low-molecular-weight collagen peptides from T. bimaculatus skin (TBSCH-L). NanoHPLC-MS/MS and virtual molecular docking screening were employed to identify peptides targeting MMP-1. Four anti-photoaging peptide sequences, GDRGFPGE, GPAGPRGA, FPGGPGAK, and RGFPGGDGAA, were identified by assessing the viability of UVB-induced L929 cells. GPAGPRGA (GP8) exhibited the highest MMP-1 inhibitory activity and cellular photoprotection. Surface plasmon resonance confirmed high-affinity binding between MMP-1 and GP8. GP8 significantly reduced intracellular reactive oxygen species (ROS) levels and enhanced superoxide dismutase activity at concentrations of 100-200 mu M in UVB-exposed L929 cells. At 200 mu M, GP8 significantly decreased malondialdehyde content. GP8 also accelerated migration of L929 cells, demonstrating its wound-healing potential, markedly reduced intracellular beta-galactosidase levels, and downregulated phosphorylation levels of extracellular signal-regulated kinases, c-Jun N-terminal kinases, p38 proteins, and cJun protein expression within the MAPK/AP-1 signaling pathway, thereby lowering MMP expression in L929 cells. Exposure of zebrafish to 25-100 mu M GP8 effectively mitigated UVB-induced damage, restoring up to 31.2 % of caudal fin integrity, while significantly reducing ROS levels, lipid peroxidation, and cellular apoptosis. GP8, a novel marine-derived anti-photoaging peptide, holds promise for applications in cosmetic and functional food sectors.

As a culturally iconic Chinese delicacy, pufferfish lacks systematic research on thermal processing optimization and pre-cooked meal development, limiting its industrial standardization and quality preservation. This study aimed to bridge this gap by evaluating steaming effects on Takifugu flavidus quality. This study systematically evaluated its physicochemical properties and flavor profiles under different steaming durations by determining the water loss rate, mass loss rate, water distribution status, textural properties, color, and free amino acid content using an electronic nose, electronic tongue, and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS). The results indicated that the core temperature of the fish meat reached 70 °C after 9 min of steaming. With higher steaming time, its mass loss rate and water loss rate generally increased, though the water loss rate temporarily decreased at 10 min. The mass loss rate stabilized after 12.5 min. The hardness and chewiness of the fish meat increased significantly when steamed for 12.5 min or longer. After 5 min of steaming, the brightness value and yellow-blue value of the fish meat significantly increased, whereas the red-green value significantly decreased. The total free amino acid content showed a fluctuating upward trend and electronic tongue analysis revealed an increase in umami and richness after steaming. Electronic nose and HS-GC-IMS analyses demonstrated that the variety and content of volatile flavor compounds significantly increased with prolonged steaming. Sensory evaluation showed that the 10 min steaming group exhibited better texture and color, while the 15 min steaming group had the best odor. Therefore, the optimal steaming time for T. flavidus was determined to be 10–15 min. For home cooking, a 15 min steaming process achieves the peak abundance of flavor compounds and the highest sensory evaluation score. For the industrial production of pre-cooked meals, a 10 min steaming process can meet the doneness requirements while maintaining suitable textural properties and color stability. The findings of this study not only advance the scientific understanding of thermal processing effects on pufferfish quality attributes, but also establish a critical technological foundation for developing standardized industrial processing protocols and high-quality pre-prepared pufferfish products.

This study analyzed the basic nutritional components and amino acid, fatty acid, and mineral composition of hybrid abalone Haliotis discus hannai ♀ × H. fulgens ♂ adductor (AM), transition (TM), and skirt (SM) muscles. The taste characteristics of the muscles were measured via electronic tongue, and the volatile compounds were identified by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis. Compared to SM, AM and TM exhibited relatively similar basic nutritional compositions. Although SM exhibited the highest moisture content (84.67%), its protein content (only 11.83%) and total carbohydrate content (only 0.19%) were significantly lower than those of AM (20.42% and 4.14%) and TM (19.10% and 4.48%). The ash and fat contents were similar across the three muscle parts. The amino acid composition was consistent across three parts, and AM showed the highest total amino acid content, ratio of essential amino acids, and essential amino acid index. All three muscle parts were rich in polyunsaturated fatty acids, but the content was higher in AM and TM than in SM. The mineral elements were rich in variety, with high K, P, Mg, and Zn contents. Bitterness intensities were lower and umami and richness intensities were higher in AM and TM than in SM. The contents of volatile compounds related to fishy odor were higher in TM and SM than in AM. The results provided a scientific basis for the intensive processing and comprehensive utilization of Haliotis discus hannai ♀ × H. fulgens ♂.

To develop highly nutritious Bangia fusco-purpurea (BFP) vegan sausages, we investigated the effects of BFP, gluten, and xanthan gum–konjac gum–carrageenan complex gel (CG) on the gel strength and sensory quality of the sausages. The formulation process was optimized through single-factor and orthogonal tests, whereas the gel formation mechanism of the key factors was explored. The orthogonal test results showed that the optimal addition levels of BFP, gluten, and CG were 5%, 56%, and 37%, respectively. Variance analysis revealed that both gluten and CG significantly affected gel strength (p < 0.05), with gluten notably influencing the overall sensory quality (p < 0.05). Texture profile analysis (TPA) and rheological properties demonstrated that as gluten (33–37%) and CG (52–56%) concentrations increased, the gel strength and elastic modulus exhibited concentration-dependent enhancement. Further analysis of the sulfhydryl content, disulfide bonds, surface hydrophobicity, and microstructure revealed that higher gluten content promoted intermolecular disulfide crosslinking and hydrophobic group exposure, whereas CG contributed to physical filling via hydrogen and ionic bonds, resulting in a uniform and dense gel network structure. The synergistic effects of gluten and CG enhanced the gel properties of BFP vegan sausages, providing a theoretical foundation for the development of high-quality plant protein-based meat alternatives.

Skin sensitivity is increasingly prevalent, necessitating new therapeutic agents. This study screened multifunctional peptides from Takifugu fasciatus skin for transient receptor potential vanilloid 1 (TRPV1)-inhibitory and anti-inflammatory activities and investigated their mechanisms in alleviating sensitive skin (SS). A low-molecular-weight hydrolysate was prepared through enzymatic hydrolysis of T. fasciatus skin, followed by ultrafiltration, with subsequent peptide identification performed using nano-HPLC-MS/MS and molecular docking-based virtual screening. Among 20 TRPV1-antagonistic peptides (TFTIPs), QFF (T10), LDIF (T14), and FFR (T18) exhibited potent anti-inflammatory effects in (lipopolysaccharide) LPS-induced RAW 264.7 macrophages. T14 showed the strongest TRPV1 inhibition; T14 (200 μM) inhibited Ca2⁺ in capsaicin-stimulated HaCaT cells by 73.1% and showed stable binding in molecular docking, warranting further analysis. Mechanistic studies revealed that T14 suppressed NF-κB signaling by downregulating p65 protein expression, thereby reducing pro-inflammatory cytokine secretion (G-CSF, GM-CSF, ICAM-1, IL-6, TNF-α) in RAW 264.7 cells. Additionally, T14 (400 μM) inhibited ET-1 in LPS-stimulated endothelial cells by 75.0%; ICAM-1 reached 49.0%. Network pharmacology predicted STAT3, MAPK3, SPHK1, and CTSB as key targets mediating T14’s effects. These study findings suggest that T14 may be a promising candidate for skincare applications targeting SS.

This study investigated the effect of the water content of large yellow croaker fillets on their quality characteristics after roasting. The large yellow croaker fillets were randomly divided into groups, namely, the fresh group (BMC-77), the 3% salt-cured group (BMC-70), and groups cured with 3% salt followed by hot air drying to obtain different moisture contents (BMC-65, BMC-60, and BMC-55). Then, the fillets were roasted at 220 °C for 20 min. There were four replicates for each group. Various indicators, including color, texture, thiobarbituric acid-reactive substance (TBARS) content, total volatile basic nitrogen (TVB-N) content, water distribution, volatile components, and myofibrillar proteins were determined, and a sensory evaluation was carried out. The results showed that as the water content decreased, the lightness (L*) of the roasted fillets significantly decreased (p < 0.05), while the redness (a*) and yellowness (b*) increased. The hardness, shear force, TBARS, and TVB-N values all increased significantly (p < 0.05). The proportion of immobile water decreased, while the proportions of tightly bound water, free water, and loosely bound water increased. The electronic nose, electronic tongue, and GC-MS analyses revealed that there were significant differences in odor, taste, and volatile components among fillets with different water contents. A comprehensive analysis of all the indicators demonstrated that the fillets with an initial water content of 65% (BMC-65) achieved the best sensory qualities after roasting in terms of taste and flavor. An appropriate reduction in the initial water content helped to improve the texture and appearance of the fillets while delaying the degradation of proteins and lipids. This study provides a theoretical foundation for optimizing the roasting process of large yellow croaker fillets. Future research could explore the synergistic effects of the roasting conditions and water content to achieve more accurate quality control.

In this study, we aimed to explore the hypoglycemic effects of a hydrolysate on Takifugu bimaculatus skin (TBSH). The effect of the dipeptidyl peptidase-IV (DPP-IV) inhibitory activities from different TBSH fractions was investigated on basic indexes, gut hormones, blood lipid indexes, viscera, and the gut microbiota and its metabolites in rats with type 2 diabetes mellitus (T2DM). The results showed that the <1 kDa peptide fraction from TBSH (TBP) exhibited a more potent DPP-IV inhibitory effect (IC50 = 0.45 ± 0.01 mg/mL). T2DM rats were induced with streptozocin, followed by the administration of TBP. The 200 mg/kg TBP mitigated weight loss, lowered fasting blood glucose levels, and increased insulin secretion by 20.47%, 25.23%, and 34.55%, respectively, rectified irregular hormonal fluctuations, lipid metabolism, and tissue injuries, and effectively remedied gut microbiota imbalance. In conclusion, TBP exerts a hypoglycemic effect in rats with T2DM. This study offers the potential to develop nutritional supplements to treat T2DM and further promote the high-value utilization of processing byproducts from T. bimaculatus. It will provide information for developing nutritional supplements to treat T2DM and further promote the high-value utilization of processing byproducts from T. bimaculatus.

Protamine is a cationic peptide derived from fish sperm and has several important functional properties: antibacterial properties, acting as a carrier for injectable insulin and as a heparin antagonist, combatting fatigue, etc. Thus, it has been widely used in medicinal applications and food products. Cultured Takifugu flavidus is a type of pufferfish with a delicious taste that is popular in China, and its production is increasing significantly. Therefore, protamine was extracted via acid extraction from the sperm of Takifugu flavidus and further isolated and purified via sephadex gel chromatography, ion exchange chromatography, and desalination chromatography. Furthermore, the physicochemical properties of protamine were investigated. The results showed that the sperm of the cultured T. flavidus were non-toxic, and the extracted and purified protamine had high contents of arginine (36.90%) and lysine (27.02%), respectively. The secondary structure of protamine was mainly β-folded and irregularly curled. Additionally, protamine exhibited high thermal stability with a denaturation temperature of 176 °C. This study would provide a theoretical basis for the structural analysis, bioactivity, and resource development of pufferfish protamine and help to promote the development of the pufferfish industry.

Marine-derived foods, often called blue foods, are promising sustainable alternatives to conventional food sources owing to their abundant amino acids and high protein content. Current treatments for hyperuricemia, a chronic condition attributed to purine metabolism disorders, are associated with various side effects. Novel peptide xanthine oxidase inhibitors have been discovered in the hydrolyzed products of marine fish and invertebrate proteins, which have demonstrated promising therapeutic potential by reducing uric acid levels in vitro and in vivo. This review explores the potential therapeutic effects of xanthine oxidase inhibitors derived from marine fish and invertebrates, summarizes the methods for extracting bioactive peptides from marine organisms, and emphasizes the impact of different proteases on the structure–activity relationship of bioactive peptides. The hypouricemic effects of these bioactive peptides warrant further verification. There is consensus on the in vitro chemical methods used to verify the xanthine oxidase inhibitory effects of these peptides. Considering several cell and animal model development strategies, this review summarizes several highly recognized modeling methods, proposes strategies to improve the bioavailability of bioactive peptides, and advocates for a diversified evaluation system. Although the screening and evaluation methods for antihyperuricemic peptides have been shown to be feasible across numerous studies, they are not optimal. This review examines the deficiencies in bioavailability, synthesis efficiency, and evaluation mechanisms in terms of their future development and proposes potential solutions to address these issues. This review provides a novel perspective for the exploration and application of marine-derived hypouricemic bioactive peptides.

The Nrf2/ARE pathway is considered the most important endogenous antioxidant signaling pathway in mammals, playing a crucial role in defending against external damage. This study investigated the functional characteristics of Nrf2 in the abalone, Haliotis discus hannai. The full-length cDNA sequence of the HdhNrf2 gene was cloned using rapid amplification of cDNA ends (RACE) technology and consists of 4568 base pairs encoding a protein of 694 amino acids. The predicted theoretical molecular weight was 77 kDa, with an isoelectric point of 4.72. Multiple sequence alignment analysis revealed the relative conservation of the HdhNrf2 amino acid sequence in H. discus hannai. The tissue expression pattern of the HdhNrf2 gene was analyzed using real-time fluorescence quantitative PCR, which showed the highest expression in the gills, followed by hemocytes, with the lowest levels in the foot and mantle. The inducible expression of HdhNrf2 and antioxidant genes in abalone under H2O2 stress was investigated at various time points. Furthermore, an expression vector, pET-28a(+)-rHdhNrf2, was constructed, and the recombinant protein rHdhNrf2 was obtained through induced expression and purification. These findings indicated that HdhNrf2 plays a crucial role in the defense of abalones against oxidative stress.

Background: Melanin overproduction leads to pigmented skin diseases. Brown algae polyphenols, non-toxic secondary metabolites, exhibit potential bioactivities. Sargassum fusiforme, an edible seaweed, has been underexplored in the field of beauty despite its polyphenol richness. Methods: Polyphenols from S. fusiforme were extracted using macroporous resin (SFRP) and ethyl acetate (SFEP). Their antioxidant and anti-aging properties, tyrosinase inhibitory activities, and mechanisms were assessed. The melanogenesis inhibition effect and mechanism by SFRP was examined in B16F10 melanoma cells. Results: Both SFRP and SFEP demonstrated scavenging activities against DPPH, superoxide anion, and hydroxyl radicals. SFRP showed stronger anti-collagenase and anti-elastase effects. They dose-dependently inhibited mushroom tyrosinase, with IC50 values of 9.89 μg/mL for SFRP and 0.99 μg/mL for SFEP. SFRP reversibly inhibited tyrosinase, while SFEP showed irreversible inhibition. SFRP also suppressed melanin content and intracellular tyrosinase activity in B16F10 cells, downregulating the expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 1 and 2 expression through the PI3K/Akt and MAPK/ERK signal pathways. Conclusions: S. fusiforme polyphenols, especially SFRP, exhibit promising antioxidant, anti-aging, and melanogenesis inhibitory properties, highlighting their potential application as novel anti-melanogenic agents in cosmetics and the food industry.

Amphioctopus neglectus is a species of octopus that is favored by consumers due to its rich nutrient profile. To investigate the influence of different thawing methods on the quality of octopus meat, we employed four distinct thawing methods: air thawing (AT), hydrostatic thawing (HT), flowing water thawing (FWT), and microwave thawing (MT). We then explored the differences in texture, color, water retention, pH, total volatile basic nitrogen (TVB–N), total sulfhydryl content, Ca2+–ATPase activity, and myofibrillar protein, among other quality indicators in response to these methods, and used a low-field nuclear magnetic resonance analyzer to assess the water migration that occurred during the thawing process. The results revealed that AT had the longest thawing time, leading to oxidation-induced protein denaturation, myofibrillar protein damage, and a significant decrease in water retention. Additionally, when this method was utilized, the content of TVB–N was significantly higher than in the other three groups. HT, to a certain extent, isolated the oxygen in the meat and thus alleviated protein oxidation, allowing higher levels of Ca2+–ATPase activity, sulfhydryl content, and springiness to be maintained. However, HT had a longer duration: 2.95 times that of FWT, resulting in a 9.84% higher cooking loss and a 28.21% higher TVB–N content compared to FWT. MT had the shortest thawing time, yielding the lowest content of TVB–N. However, uneven heating and in some cases overcooking occurred, severely damaging the protein structure, with a concurrent increase in thawing loss, W value, hardness, and shear force. Meanwhile, FWT improved the L*, W* and b* values of octopus meat, enhancing its color and water retention. The myofibrillar protein (MP) concentration was also the highest after FWT, with clearer subunit bands in SDS-PAGE electrophoresis, indicating that less degradation occurred and allowing greater springiness, increased Ca2+–ATPase activity, and a higher sulfhydryl content to be maintained. This suggests that FWT has an inhibitory effect on oxidation, alleviating protein oxidation degradation and preserving the quality of the meat. In conclusion, FWT outperformed the other three thawing methods, effectively minimizing adverse changes during thawing and successfully maintaining the quality of octopus meat.

Abnormal melanogenesis can lead to hyperpigmentation. Tyrosinase (TYR), a key rate-limiting enzyme in melanin production, is an important therapeutic target for these disorders. We investigated the TYR inhibitory activity of hydrolysates extracted from the muscle tissue of Takifugu flavidus (TFMH). We used computer-aided virtual screening to identify a novel peptide that potently inhibited melanin synthesis, simulated its binding mode to TYR, and evaluated functional efficacy in vitro and in vivo. TFMH inhibited the diphenolase activities of mTYR, reducing TYR substrate binding activity and effectively inhibiting melanin synthesis. TFMH indirectly reduced cAMP response element-binding protein phosphorylation in vitro by downregulating melanocortin 1 receptor expression, thereby inhibiting expression of the microphthalmia-associated transcription factor, further decreasing TYR, tyrosinase related protein 1, and dopachrome tautomerase expression and ultimately impeding melanin synthesis. In zebrafish, TFMH significantly reduced black spot formation. TFMH (200 μg/mL) decreased zebrafish TYR activity by 43% and melanin content by 52%. Molecular dynamics simulations over 100 ns revealed that the FGFRSP (T-6) peptide stably binds mushroom TYR via hydrogen bonds and ionic interactions. T-6 (400 μmol/L) reduced melanin content in B16F10 melanoma cells by 71% and TYR activity by 79%. In zebrafish, T-6 (200 μmol/L) inhibited melanin production by 64%. TFMH and T-6 exhibit good potential for the development of natural skin-whitening cosmetic products.

With the rapid emergence of pufferfish aquaculture and processing industries, fish skin is underutilized as a byproduct of processing, leading to resource waste. In this study, Takifugu bimaculatus skin collagen (TBSC) was extracted by acetic acid solubilization and its physicochemical properties were analyzed. The effects of TBSC and the TBSC hydrolysate (TBSCH) on ultraviolet (UV) irradiation-induced photoaging were investigated using a mouse model. The purity of TBSC was 90.02%. Electrophoresis and Fourier infrared spectroscopy characterization of TBSC showed that the type of collagen in TBSC was typical standard type I. The degree of hydrolysis was selected to optimize the hydrolysis conditions for TBSC. The papain enzyme dosage, temperature, pH, and hydrolysis duration of 51,000 U/g, 48.03°C, 5.35, and 4 h have been demonstrated to be the optimum hydrolysis conditions for TBSCH. Oral administration of either TBSC or TBSCH ameliorated UV-induced skin erythema and hyperkeratosis. TBSC and TBSCH treatment increased collagen content and had an inhibitory effect on matrix metalloproteinase (MMP)-2 and MMP-3 expression, whereas MMP-9 expression was significantly reversed only in the TBSCH-treated groups. The expression of the c-Jun protein was much lower in these groups, suggesting that TBSCH had a greater alleviating effect on collagen degradation and extracellular matrix breakdown. Therefore, it is proposed that TBSCH has the potential to be used as a nutricosmetic agent with protective attributes against UV-induced skin damage and concurrent collagen depletion.

In this paper,the active parts of sea cucumber(Apostichopus japonicus)with high antihypertensive activity were screened and the preparation process of active peptides was optimized.Different parts(body wall,intestine,and ovum)of A.japonicus were hydrolyzed by enzymolysis,and the ACE inhibition rate was used as an indicator to screen the optimal protease.The optimal active site for inhibition was selected by comparative screening of the half maximal inhibitory concentration(IC50)determination of ACE inhibitory rate of each lysate.Single factor and response surface tests were used to determine the optimum enzymatic hydrolysis conditions of the active peptides.The relative molecular weight of the protease hydrolysates was determined to determine its distribution range.The ACE inhibition activity of different components was analyzed after separation by ultrafiltration membrane.Search results,alkaline protease was selected as the optimal hydrolytic enzyme,and the IC50 values of ACE inhibition of each protease lysate from body wall,intestine and ovum were 1.11,4.02,0.65 mg/mL,respectively,so that A.japonicus ovum had a better ACE inhibition effect and were the optimal active site for inhibition.Its optimal preparation process parameters for enzymatic hydrolysis were as follows:5 h enzymatic hydrolysis time,3.5 U/mg enzyme added,65.26 °C enzymatic hydrolysis temperature,3.51%substrate concentration,pH9.02 enzymatic hydrolysis,and ACE inhibition rate of A.japonicusr ovum was 80.65%±0.52%under these conditions,which was close to the predicted value.The molecular weight of proteolytic products was concentrated under 3000 Da,accounting for 98.37%of the total content,of which 1000～3000 Da accounted for 9.50%,and less than 1000 Da accounted for 88.87%.The ACE inhibitory activity of oligopeptide components(IC50=0.30 mg/mL)isolated by ultrafiltration membrane was significantly higher than that of hydrolysates and trapped liquid components after process optimization.The results of this study would provide a theoretical basis for high-quality utilization of the by-products of A.japonicus,which could be used as high-quality resources for the isolation and purification of antihypertensive peptides.