Potential of Thermolysin-like Protease A69 in Preparation of Bovine Collagen Peptides with Moisture-Retention Ability and Antioxidative Activity

Bovine bone is rich in collagen and is a good material for collagen peptide preparation. Although thermolysin-like proteases (TLPs) have been applied in different fields, the potential of TLPs in preparing bioactive collagen peptides has rarely been evaluated. Here, we characterized a thermophilic TLP, A69, from a hydrothermal bacterium Anoxybacillus caldiproteolyticus 1A02591, and evaluated its potential in preparing bioactive collagen peptides. A69 showed the highest activity at 60 °C and pH 7.0. We optimized the conditions for bovine bone collagen hydrolysis and set up a process with high hydrolysis efficiency (99.4%) to prepare bovine bone collagen peptides, in which bovine bone collagen was hydrolyzed at 60 °C for 2 h with an enzyme–substrate ratio of 25 U/g. The hydrolysate contained 96.5% peptides that have a broad molecular weight distribution below 10000 Da. The hydrolysate showed good moisture-retention ability and a high hydroxyl radical (•OH) scavenging ratio of 73.2%, suggesting that the prepared collagen peptides have good antioxidative activity. Altogether, these results indicate that the thermophilic TLP A69 has promising potential in the preparation of bioactive collagen peptides, which may have potentials in cosmetics, food and pharmaceutical industries. This study lays a foundation for the high-valued utilization of bovine bone collagen.     

Purification of Antioxidant Peptides by High Resolution Mass Spectrometry from Simulated Gastrointestinal Digestion Hydrolysates of Alaska Pollock (Theragra chalcogramma) Skin Collagen

In this study, the stable collagen hydrolysate was prepared by alcalase hydrolysis and twice simulated gastrointestinal digestion from Alaska pollock skin. The characteristics of hydrolysates and antioxidant activities in vitro, including 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS^•+) scavenging activity, ferric-reducing antioxidant power (FRAP) and hydroxyl radical (OH·) scavenging activity, were determined. After twice simulated gastrointestinal digestion of skin collagen (SGI-2), the degree of hydrolysis (DH) reached 26.17%. The main molecular weight fractions of SGI-2 were 1026.26 and 640.53 Da, accounting for 59.49% and 18.34%, respectively. Amino acid composition analysis showed that SGI-2 had high content of total hydrophobic amino acid (307.98/1000). With the simulated gastrointestinal digestion progressing, the antioxidant activities increased significantly (p < 0.05). SGI-2 was further purified by gel filtration chromatography, ion exchange chromatography and high performance liquid chromatography, and the A_1a3c–p fraction with high hydroxyl radical scavenging activity (IC50 = 7.63 μg/mL) was obtained. The molecular weights and amino acid sequences of key peptides of A_1a3c–p were analyzed using high resolution mass spectrometry (LC-ESI-LTQ-Orbitrap-MS) combined with de novo software and UniProt of MaxQuant software. Four peptides were identified from A_1a3c–p, including YGCC (444.1137 Da) and DSSCSG (554.1642 Da) identified by de novo software and NNAEYYK (900.3978 Da) and PAGNVR (612.3344 Da) identified by UniProt of MaxQuant software. The molecular weights and amino acid sequences of four peptides were in accordance with the features of antioxidant peptides. The results indicated that different peptides were identified by different data analysis software according to spectrometry mass data. Considering the complexity of LC-ESI-LTQ-Orbitrap-MS, it was necessary to use the different methods to identify the key peptides from protein hydrolysates.     

Jellyfish Collagen: A Biocompatible Collagen Source for 3D Scaffold Fabrication and Enhanced Chondrogenicity

Osteoarthritis (OA) is a multifactorial disease leading to degeneration of articular cartilage, causing morbidity in approximately 8.5 million of the UK population. As the dense extracellular matrix of articular cartilage is primarily composed of collagen, cartilage repair strategies have exploited the biocompatibility and mechanical strength of bovine and porcine collagen to produce robust scaffolds for procedures such as matrix-induced chondrocyte implantation (MACI). However, mammalian sourced collagens pose safety risks such as bovine spongiform encephalopathy, transmissible spongiform encephalopathy and possible transmission of viral vectors. This study characterised a non-mammalian jellyfish (Rhizostoma pulmo) collagen as an alternative, safer source in scaffold production for clinical use. Jellyfish collagen demonstrated comparable scaffold structural properties and stability when compared to mammalian collagen. Jellyfish collagen also displayed comparable immunogenic responses (platelet and leukocyte activation/cell death) and cytokine release profile in comparison to mammalian collagen in vitro. Further histological analysis of jellyfish collagen revealed bovine chondroprogenitor cell invasion and proliferation in the scaffold structures, where the scaffold supported enhanced chondrogenesis in the presence of TGFβ1. This study highlights the potential of jellyfish collagen as a safe and biocompatible biomaterial for both OA repair and further regenerative medicine applications.     

Isolation, characterization and biological evaluation of jellyfish collagen for use in biomedical applications

Fibrillar collagens are the more abundant extracellular proteins. They form a metazoan-specific family, and are highly conserved from sponge to human. Their structural and physiological properties have been successfully used in the food, cosmetic, and pharmaceutical industries. On the other hand, the increase of jellyfish has led us to consider this marine animal as a natural product for food and medicine. Here, we have tested different Mediterranean jellyfish species in order to investigate the economic potential of their collagens. We have studied different methods of collagen purification (tissues and experimental procedures). The best collagen yield was obtained using Rhizostoma pulmo oral arms and the pepsin extraction method (2-10 mg collagen/g of wet tissue). Although a significant yield was obtained with Cotylorhiza tuberculata (0.45 mg/g), R. pulmo was used for further experiments, this jellyfish being considered as harmless to humans and being an abundant source of material. Then, we compared the biological properties of R. pulmo collagen with mammalian fibrillar collagens in cell cytotoxicity assays and cell adhesion. There was no statistical difference in cytotoxicity (p > 0.05) between R. pulmo collagen and rat type I collagen. However, since heparin inhibits cell adhesion to jellyfish-native collagen by 55%, the main difference is that heparan sulfate proteoglycans could be preferentially involved in fibroblast and osteoblast adhesion to jellyfish collagens. Our data confirm the broad harmlessness of jellyfish collagens, and their biological effect on human cells that are similar to that of mammalian type I collagen. Given the bioavailability of jellyfish collagen and its biological properties, this marine material is thus a good candidate for replacing bovine or human collagens in selected biomedical applications.     

Toxicity of several δ-endotoxins of Bacillus thuringiensis against the cotton pest Earias insulana (Lepidoptera: Noctuidae)

The toxicity of nine Bacillus thuringiensis Cry proteins against neonate Earias insulana larvae was tested using a mixture of crystals and spores. The mean lethal concentration (LC₅₀) of Cry1Ac was 1.99 μg/ml. Cry1Fa, Cry1Ca, Cry1Ja and Cry2Aa were more active than Cry1Ac, with LC₅₀ values of 0.22, 0.24, 0.29, 0.43 μg/ml, respectively. Cry1Da and Cry1Aa were considerably less active than Cry1Ac. The remaining proteins, Cry1Ba and Cry1Ab, displayed no activity. Relative potencies were also calculated. Cry1Ja and Cry1Fa were significantly more active (7.72 and 5.71 times, respectively) than Cry1Ac, while Cry1Ca was significantly (1.95 times) more active than Cry2Aa.     

Two Novel Antioxidant Nonapeptides from Protein Hydrolysate of Skate (Raja porosa) Muscle

In the current study, the preparation conditions of neutrase hydrolysate (SMH) from skate (Raja porosa) muscle protein were optimized using orthogonal L₉(3)⁴ tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S) 2%, and enzymolysis time 5 h, EC₅₀ of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B) were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A) and NWDMEKIWD (SP-B) with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC₅₀ 0.390 and 0.176 mg/mL), DPPH· (EC₅₀ 0.614 and 0.289 mg/mL), and O₂⁻· (EC₅₀ 0.215 and 0.132 mg/mL) in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp), acidic (2Asp and Glu), and basic (Lys) amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs.     

Changes in the Molecular Characteristics of Bovine and Marine Collagen in the Presence of Proteolytic Enzymes as a Stage Used in Scaffold Formation

Biopolymers, in particular collagen and fibrinogen, are the leading materials for use in tissue engineering. When developing technology for scaffold formation, it is important to understand the properties of the source materials as well as the mechanisms that determine the formation of the scaffold structures. Both factors influence the properties of scaffolds to a great extent. Our present work aimed to identify the features of the molecular characteristics of collagens of different species origin and the changes they undergo during the enzymatic hydrolysis used for the process of scaffold formation. For this study, we used the methods of gel-penetrating chromatography, dynamic light scattering, reading IR spectra, and scanning electron microscopy. It was found that cod collagen (CC) and bovine collagen (BC) have different initial molecular weight parameters, and that, during hydrolysis, the majority of either type of protein is hydrolyzed by the proteolytic enzymes within the first minute. The differently sourced collagen samples were also hydrolyzed with the formation of two low molecular fractions: Mw ~ 10 kDa and ~20 kDa. In the case of CC, the microstructure of the final scaffolds contained denser, closely spaced fibrillar areas, while the BC-sourced scaffolds had narrow, short fibrils composed of unbound fibers of hydrolyzed collagen in their structure.     

Antioxidant Activities of Hydrolysates of Arca Subcrenata Prepared with Three Proteases

In order to get products with antioxidant activity from Arca subcrenata Lischke, the optimal hydrolase and hydrolysis conditions were investigated in the paper. Three proteases (neutrase, alcalase and papain) were applied to hydrolyze the homogenate of A. subcrenata. An orthogonal design was used to optimize hydrolysis conditions, and the pH-stat methods was used to determine the degree of hydrolysis. Viewed from the angle of reducing power, such as scavenging activities against α,α-diphenyl-β-picrylhydrazyl (DPPH) radical and hydrogen peroxide, the antioxidant activities of the alcalase hydrolysate (AH) were superior to neutrase hydrolysate (NH) and papain hydrolysate (PH), and its EC₅₀ values in DPPH radical and hydrogen peroxide scavenging effect were 6.23 mg/ml and 19.09 mg/ml, respectively. Moreover, compared with products hydrolyzed by neutrase and papain, the molecular mass of AH was lower and its content of amino acid of peptides was higher. Therefore, alcalase was selected as the optimal enzyme to produce active ingredients since its hydrolysate exhibited the best antioxidant activity among them and possessed large amount of potential active peptides.     

Antioxidant Capacity of Flaxseed Products: The Effect of In vitro Digestion

This study evaluated the effect of in vitro digestion of flaxseed products on Folin-Ciocalteu reagent reducing substances (FCRRS), its antioxidant capacity and prevention of oxidative DNA damage in human monocyte cell line U937. Flaxseed protein isolate was obtained from defatted flaxseed meal and the protein hydrolysate with high antioxidant capacity was obtained from hydrolysis of the protein isolate with Alcalase in a two factor central composite rotatable design (pH 8.5 and enzyme: substrate 1:90, w/w). The FCRRS content and antioxidant capacity measured by FRAP and ORAC in aqueous and 70 % methanol extracts were the highest in protein hydrolysate, followed by protein isolate, while the defatted meal showed the lowest values. After in vitro gastrointestinal digestion, the FCRRS content of protein isolate and hydrolysate reached similar values, however the hydrolysate had the highest antioxidant capacity, measured by FRAP while the isolate had the highest ORAC values. The defatted meal showed the lowest capacity in all assays (p?<?0.05). The hydrolysate did not protect against DNA damage induced by H₂O₂ in U937 cells under the conditions of the present study. The results suggest that flaxseed protein isolate and hydrolysate are potential functional food ingredients with antioxidant capacity.     

Type II Collagen and Gelatin from Silvertip Shark (Carcharhinus albimarginatus) Cartilage: Isolation,Purification, Physicochemical and Antioxidant Properties

Type II acid soluble collagen (CIIA), pepsin soluble collagen (CIIP) and type II gelatin (GII) were isolated from silvertip shark (Carcharhinus albimarginatus) cartilage and examined for their physicochemical and antioxidant properties. GII had a higher hydroxyproline content (173 mg/g) than the collagens and cartilage. CIIA, CIIP and GII were composed of two identical α₁ and β chains and were characterized as type II. Amino acid analysis of CIIA, CIIP and GII indicated imino acid contents of 150, 156 and 153 amino acid residues per 1000 residues, respectively. Differing Fourier transform infrared (FTIR) spectra of CIIA, CIIP and GII were observed, which suggested that the isolation process affected the secondary structure and molecular order of collagen, particularly the triple-helical structure. The denaturation temperature of GII (32.5 °C) was higher than that of CIIA and CIIP. The antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl radicals and the reducing power of CIIP was greater than that of CIIA and GII. SEM microstructure of the collagens depicted a porous, fibrillary and multi-layered structure. Accordingly, the physicochemical and antioxidant properties of type II collagens (CIIA, CIIP) and GII isolated from shark cartilage were found to be suitable for biomedical applications.     

Thermal transition properties of hoki (Macruronus novaezelandiae) and ling (Genypterus blacodes) skin collagens: implications for processing

Hoki (Macruronus novaezelandiae) and ling (Genypterus blacodes) are cold-water fish caught in New Zealand waters. Their skins are a major component of the post-processing waste stream. Valuable products could be developed from the skins, as they are primarily composed of collagen, which has many commercial applications. We prepared acid soluble collagens (ASC) from hoki and ling skins, and analyzed their thermal denaturation properties using a Rapid Visco™ Analyzer. At slower heating rates the denaturation temperature (TD) of hoki and ling collagens decreased. This result is consistent with the model of irreversible rate kinetics for the denaturation of collagen. We determined the effects of solvents that disrupt hydrogen bonding on ASC stability. Increasing concentrations of urea from 0.1 M to 1.0 M and acetic acid from 0.1 M to 0.5 M decreased TD. This resulted from the effects of these reagents on the hydrogen bonds that stabilize the collagen triple helix.     

Functional dominance of different aged larvae of Bt-resistant Spodoptera frugiperda (Lepidoptera: Noctuidae) on transgenic maize expressing Vip3Aa20 protein

Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is the main target pest of transgenic maize expressing insecticidal proteins from Bacillus thuringiensis Berliner (Bt) in Brazil. To optimize resistance management strategies, we evaluated the functional dominance of different aged larvae of Bt-resistant FAW on Vip3Aa20 maize. We measured the survival and development of Vip3Aa20-resistant, -heterozygote, and -susceptible strains on MIR162 (expressing Vip3Aa20) and Bt11 × MIR162 × GA21 (expressing Vip3Aa20 and Cry1Ab) maize. The resistant strain, from neonate to sixth instar, showed more than 72% survival on Vip3Aa20 maize. From surviving larvae, more than 64 and 54% developed to pupae and adults, respectively. In contrast, heterozygote and susceptible strains showed no larval survival up to fourth instar, and less than 25% larval survival in the fifth and sixth instar on Vip3Aa20 maize. These larvae produced less than 21% of pupae and adults. The development time of FAW strains from neonate-to-adult exposed to Vip3Aa20 maize was similar; however, the resistant strain showed an increase of ∼ 2 d when compared to those fed only non-Bt maize. In summary, the resistance of S. frugiperda to Vip3Aa20 maize is functionally recessive from neonate up to fourth instar larvae. However, high larval survival of resistant strain and some survival of heterozygote larvae in advanced instars on Vip3Aa20 maize were observed. These results will be important for designing insect resistance management to Bt maize plants expressing Vip3Aa20 protein in Brazil.     

酶解法制备大豆小肽的工艺研究

以豆粕为发酵原料,利用复合酶酶解方法制备大豆小肽,筛选碱性、中性蛋白酶和胰蛋白酶进行复配酶解豆粕。结果表明:复合酶的最佳配比为碱性蛋白酶∶中性蛋白酶∶胰蛋白酶为3∶2∶1;酶解条件:p H8.5,反应温度50℃,反应时间4.5 h,水解度为94.55%,苦味值为3;小肽显示分子量分布范围:≤1 000 Da可达74.67%以上,其中≤500 Da占55.61%以上。综上试验结果可知,对比单酶、双酶及3种酶酶解豆粕的水解度和苦味值两项指标,3种酶组合使用更适合于制备水解度高、苦味低的大豆小肽。     

Anticancer Activity of a Hexapeptide from Skate (Raja porosa) Cartilage Protein Hydrolysate in HeLa Cells

In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY), which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa) cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay indicated that FIMGPY exhibited high, dose-dependent anti-proliferation activities in HeLa cells with an IC₅₀ of 4.81 mg/mL. Acridine orange/ethidium bromide (AO/EB) fluorescence staining and flow cytometry methods confirmed that FIMGPY could inhibit HeLa cell proliferation by inducing apoptosis. Western blot assay revealed that the Bax/Bcl-2 ratio and relative intensity of caspase-3 in HeLa cells treated with 7-mg/mL FIMGPY were 2.63 and 1.83, respectively, significantly higher than those of the blank control (p < 0.01). Thus, FIMGPY could induce apoptosis by upregulating the Bax/Bcl-2 ratio and caspase-3 activation. Using a DNA ladder method further confirmed that the anti-proliferation activity of FIMGPY was attributable to its role in inducing apoptosis. These results suggest that FIMGPY from skate cartilage protein hydrolysate may have applications as functional foods and nutraceuticals for the treatment and prevention of cancer.     

Potential Prebiotic Oligosaccharide Mixtures from Acidic Hydrolysis of Rice Bran and Cassava Pulp

Two agricultural wastes, rice bran and cassava pulp were subjected to acidic hydrolysis by 2 M sulfuric acid which resulted in hemicellulosic oligosaccharide mixtures. Monosaccharide component analysis of these mixtures revealed that the oligosaccharides of rice bran acid hydrolysate (RAHF) composed of glucose and arabinose while cassava pulp acid hydrolysate (CAHF) was found to be comprised of glucose, galactose and arabinose. Both RAHF and CAHF were able to fuel all of the tested three Lactobacillus, five Bifidobacterium and three Bacteroides strains indicating the prebiotic potential of these oligosaccharide mixtures. Moreover, Lb. gasseri grew significantly better on RAHF than on inulin, a benchmark prebiotic oligo- and polysaccharide mixture. When the digestibility of RAHF and CAHF were tested it was found that these oligosaccharide mixtures were only slightly hydrolyzed upon exposure to simulated human gastric (by less than 8%) and pancreatic juices (by less than 3%). Additionally, most sensory attributes of the above obtained oligosaccharide mixtures supplemented two model cereal drink formulations were generally not different from those of the control, while the overall acceptance was not affected significantly in one cereal drink formulation.     

Identification and Biological Characterization of Angiogenic and Tumor Growth Inhibitors derived from Sinica cetorhinus maximum Cartilage

Shark (Sinica cetorhinus maximum) cartilage was extracted in 1 mol/L Gu- HCl guanidine. Two purified active proteins with apparent molecular weights of 15.2×10³ Da and 8.0×10³ Da (designated as Sp15 and Sp8, respectively) were obtained through ultrafiltration and Superdex 75 chromatography. The activities of the samples were studied in terms of their potential inhibition of vascular endothelial cell growth in vitro, of angiogenesis both in rabbit cornea and chick embryo chorioallantoic membrane (CAM) assay models in vivo, and of growth of transplanted S180 sarcoma in mice in vivo. The results showed that Sp15 expressed a typical lysozymatic activity up to 223,000 U/mg and its N-terminus was highly homologous to lysozymes of various mammalian origins. Sp15 exhibited a strong anti-angiogenic activity only in vitro, whereas Sp8 shared this effect both in vitro and in vivo. Both Sp15 and Sp8 provided an effective anti-tumor activity in mice bearing transplanted S180 sarcoma. These results suggest that Sp15 is a shark cartilage-derived lysozyme that participates in the defense to bacterial invasion to the body, while Sp8 is an angiogenic inhibitor that mediates at least part of the anti-tumor activity associated with shark cartilage probably through the inhibition of tumor-induced angiogenesis.     

Marine Origin Collagens and Its Potential Applications

Collagens are the most abundant high molecular weight proteins in both invertebrate and vertebrate organisms, including mammals, and possess mainly a structural role, existing different types according with their specific organization in distinct tissues. From this, they have been elected as one of the key biological materials in tissue regeneration approaches. Also, industry is constantly searching for new natural sources of collagen and upgraded methodologies for their production. The most common sources are from bovine and porcine origin, but other ways are making their route, such as recombinant production, but also extraction from marine organisms like fish. Different organisms have been proposed and explored for collagen extraction, allowing the sustainable production of different types of collagens, with properties depending on the kind of organism (and their natural environment) and extraction methodology. Such variety of collagen properties has been further investigated in different ways to render a wide range of applications. The present review aims to shed some light on the contribution of marine collagens for the scientific and technological development of this sector, stressing the opportunities and challenges that they are and most probably will be facing to assume a role as an alternative source for industrial exploitation.     

Effect of Salicornia herbacea on Osteoblastogenesis and Adipogenesis in Vitro

Bone-related complications are among the highest concerning metabolic diseases in the modern world. Bone fragility and susceptibility to fracture increase with age and diseases like osteoporosis. Elevated adipogenesis in bone results in osteoporosis and loss of bone mass when coupled with lack of osteoblastogenesis. In this study the potential effect of Salicornia herbacea extract against osteoporotic conditions was evaluated. Adipogenesis inhibitory effect of S. herbacea has been evidenced by decreased lipid accumulation of differentiating cells and expression levels of crucial adipogenesis markers in 3T3-L1 pre-adipocytes. S. herbacea treatment reduced the lipid accumulation by 25% of the control. In addition, mRNA expression of peroxisome proliferator-activated receptor (PPAR)γ, CCAAT/enhancer-binding protein (C/EBP)α and sterol regulatory element binding protein (SREBP)1c were inhibited by the presence of S. herbacea. Bone formation enhancement effect of S. herbacea was also confirmed in MC3T3-E1 pre-osteoblasts. The presence of S. herbacea significantly elevated the alkaline phosphatase (ALP) activity by 120% at a concentration of 100 μg/mL in differentiating osteoblasts. S. herbacea also significantly increased the expression of osteoblastogenesis indicators, ALP, bone morphogenetic protein (BMP)-2, osteocalcin and collagen type I (collagen-I). In conclusion, S. herbacea possess potential to be utilized as a source of anti-osteoporotic agent that can inhibit adipogenesis while promoting osteoblastogenesis.     

Cosmetic,Biomedical and Pharmaceutical Applications of Fish Gelatin/Hydrolysates

There are several reviews that separately cover different aspects of fish gelatin including its preparation, characteristics, modifications, and applications. Its packaging application in food industry is extensively covered but other applications are not covered or covered alongside with those of collagen. This review is comprehensive, specific to fish gelatin/hydrolysate and cites recent research. It covers cosmetic applications, intrinsic activities, and biomedical applications in wound dressing and wound healing, gene therapy, tissue engineering, implants, and bone substitutes. It also covers its pharmaceutical applications including manufacturing of capsules, coating of microparticles/oils, coating of tablets, stabilization of emulsions and drug delivery (microspheres, nanospheres, scaffolds, microneedles, and hydrogels). The main outcomes are that fish gelatin is immunologically safe, protects from the possibility of transmission of bovine spongiform encephalopathy and foot and mouth diseases, has an economic and environmental benefits, and may be suitable for those that practice religious-based food restrictions, i.e., people of Muslim, Jewish and Hindu faiths. It has unique rheological properties, making it more suitable for certain applications than mammalian gelatins. It can be easily modified to enhance its mechanical properties. However, extensive research is still needed to characterize gelatin hydrolysates, elucidate the Structure Activity Relationship (SAR), and formulate them into dosage forms. Additionally, expansion into cosmetic applications and drug delivery is needed.     

Amino Acid Profiles and Biopotentiality of Hydrolysates Obtained from Comb Penshell (Atrina pectinata) Viscera Using Subcritical Water Hydrolysis

The recovery of amino acids and other important bioactive compounds from the comb penshell (Atrina pectinata) using subcritical water hydrolysis was performed. A wide range of extraction temperatures from 140 to 290 °C was used to evaluate the release of proteins and amino acids. The amount of crude protein was the highest (36.14 ± 1.39 mg bovine serum albumin/g) at 200 °C, whereas a further increase in temperature showed the degradation of the crude protein content. The highest amount of amino acids (74.80 mg/g) was at 230 °C, indicating that the temperature range of 170–230 °C is suitable for the extraction of protein-rich compounds using subcritical water hydrolysis. Molecular weights of the peptides obtained from comb penshell viscera decreased with the increasing temperature. SDS-PAGE revealed that the molecular weight of peptides present in the hydrolysates above the 200 °C extraction temperature was ≤ 1000 Da. Radical scavenging activities were analyzed to evaluate the antioxidant activities of the hydrolysates. A. pectinata hydrolysates also showed a particularly good antihypertensive activity, proving that this raw material can be an effective source of amino acids and marine bioactive peptides.