Polysaccharides in CO2 enriched Arthrospira platensis: Structure, physico-chemical properties, antioxidant and cytotoxicity activities and laser burn wound healing in rats.

This work was undertaken to determine the structural characteristics of polysaccharides extracted from CO2-enriched Arthrospiraplatensis (Spirulina Water Soluble Polysaccharide: SWSP), as well as its antioxidant activities, cytotoxic effects and laser burn wound healing in rats. This SWSP was structurally characterized by Scanning Electron Microscopy (SEM), Fourier-transformed infrared (FT-IR), X-ray diffraction (XRD), high-performance liquid chromatography (HPLC), and thin layer chromatography (TLC). This novel polysaccharide was found to have an average molecular weight of 6.21 kDa. It is a hetero-polysaccharide composed of rhamnose, xylose, glucose and mannose. According to XRD and FT-IR spectra, the SWSP showed a semi-crystalline structure. It is composed of 100 to 500 µm geometric shaped units with flat surfaces and it was found to inhibit the proliferation of human colon (HCT-116) and breast (MCF-7) cancers. This polysaccharide display potential antioxidant activities determined through three different assays: scavenging activity against 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) scavenging assay and ferric reducing antioxidant power assay (FRAP). Results strongly support the beneficial effects of the SWSP to accelerate wound healing in rats. Indeed, its application significantly increased tissue re-epithelization and remodeling phases, after 8 days of the experiment. Findings herein demonstrated that SWSP could be a novel auspicious source of natural wound healing closure and/or cytotoxic remedy.

Efficacy of Essential Trace Elements Supplementation on Mineral Composition, Sperm Characteristics, Antioxidant Status, and Genotoxicity in Testis of Tebuconazole-treated Rats.

OBJECTIVE: This research was performed to evaluate the effect of tebuconazole (TBZ) on reproductive organs of male rats and to assess the protective role of combined essential trace elements in alleviating the detrimental effect of TBZ on male reproductive function. METHODS: For this purpose, 48 rats were exposed to 100 mg/kg TBZ, TBZ supplemented with zinc (Zn), selenium (Se), copper (Cu), and iron (Fe), TBZ + (Se + Zn); TBZ + Cu; or TBZ + Fe. The experiment was conducted for 30 consecutive days. RESULTS: TBZ caused a significant perturbation in mineral levels and reduction in reproductive organs weights, plasma testosterone level, and testicular antioxidant enzyme activities. The TBZ-treated group also showed a significant increase in sperm abnormalities (count, motility, and viability percent), plasma follicle-stimulating hormone and luteinizing hormone concentrations, lipid peroxidation, protein oxidation, and severe DNA degradation in comparison with the controls. Histopathologically, TBZ caused testis impairments. Conversely, treatment with trace elements, in combination or alone, improved the reproductive organ weights, sperm characteristics, TBZ-induced toxicity, and histopathological modifications in testis. CONCLUSION: TBZ exerts significant harmful effects on male reproductive system. The concurrent administration of trace elements reduces testis dysfunction, fertility, and toxicity induced by TBZ.

Hetero-exopolysaccharide from the extremely halophilic Halomonas smyrnensis K2: production, characterization and functional properties in vitro.

In this study, we firstly reported the production and the structural characterization of a novel hetero-exopolysaccharide namely EPS-K2 from the extremely halophilc Halomonas smyrnensis K2. Results revealed that EPS-K2 was mainly composed of three monosaccharides including mannose (66.69%), glucose (19.54%) and galactose (13.77%). EPS-K2 showed high thermostability with a degradation temperature around 260 °C, which could make it a suitable candidate for application in thermal processes. Moreover, EPS-K2 showed attractive functional properties. In fact, it exhibited potent antioxidant activity in a dose-dependent manner as assessed in analyses of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, iron chelating and DNA protection ability. Furthermore, EPS-K2 showed strong adhesion inhibition activity against Enterococcus faecalis (75.52 ± 3.35%) and Escherichia coli (61.95 ± 2.48%) at 1 g/l concentration, as well as a high biofilm disruption activity especially against E. coli (70.73 ± 2.78%), at 2 g/l concentration. According to its biotechnological properties, EPS-K2 could be exploited as functional ingredient in food, biomedicine, and pharmaceutical industries.

Structural characterization and functional properties of novel exopolysaccharide from the extremely halotolerant Halomonas elongata S6.

Production of extracellular polysaccharides by halophilic Archaea and Bacteria has been widely reported and the members of the genus Halomonas have been identified as the most potential producers. In the present work, a novel exopolysaccharide (EPS-S6) produced by the extremely halotolerant newly isolated Halomonas elongata strain S6, was characterized. According to the HPAE-PAD results, EPS-S6 was mainly composed of glucosamine, mannose, rhamnose and glucose (1:0.9:0.7:0.3). EPS-S6 was highly negatively charged and its molecular weight was about 270 kDa. Studies on its functional properties showed that EPS-S6 had several potential features. It has noticeable antioxidant activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH•) inhibition and DNA protection, good ability to inhibit and to disrupt pathogenic biofilms, excellent flocculation of kaolin suspension and interesting emulsifying properties at acidic, neutral and basic pH. Therefore, EPS-S6 could have potential biotechnological concern in several fields such as in food, cosmetic and environmental industries.

Synthesis, intermolecular interactions and biological activities of two new organic-inorganic hybrids C6H10N2,2Br and C6H10N2,2Cl·H2O.

A slow evaporation method has permitted the crystallization of two novel crystals of (2-aminomethyl)pyridindiumdihalide C6H10N2,2Br (1) and C6H10N2,2Cl·H2O (2). The structures of the prepared compounds (1) and (2) were elucidated by single-crystal X-ray diffraction which revealed that they crystallize, respectively, with triclinic and monoclinic symmetries. Their crystal packing was stabilized by non-covalent interactions, including N-H⋯Br, C-H⋯Br, N-H⋯Cl, O-H⋯Cl and N-H⋯O hydrogen bonds. 3-D Hirshfeld surface analysis followed by 2-D fingerprint schemes gives insights into the intermolecular interactions in the crystalline structure. Furthermore, the FT-IR spectroscopy of these two compounds was carried out. The synthesized products were also screened for in vitro antioxidant and antimicrobial activities, which reveals their favourable antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as the discolouration of ß-carotene.

Structure and biological activities of polysaccharide purified from Senegrain seed.

A polysaccharide named Senegrain Water-Soluble Polysaccharide (SWSP) was extracted and purified from Senegrain seeds. The physicochemical properties of SWSP were evaluated by Thin-layer chromatography (TLC), High Performance Liquid Chromatography (HPLC), Scanning Electron Microscopy (SEM), and Differential Scanning Colorimeter (DSC). TLC results showed that SWSP is a gluconic acid polymer. It had a network with a large number of cavities. This polysaccharide with a semi-crystalline structure has an average molecular weight of 47.42 kDa. On other trend, obtained data exhibited potent antidiabetic and antibacterial activities of SWSP. Additionally, the antioxidant activities of SWSP were studied in vitro, and demonstrated that this polymer displayed an interesting ABTS radical scavenging activity as well as a protective effect on the hydroxyl radical-induced DNA damage. The effects of SWSP on oxidative processes in minced raw beef during refrigerated (4 °C) storage were investigated. The results proved that SWSP decreased the TBARS value and inhibited the MetMb accumulation during the period of refrigeration storage. Overall, the finding demonstrated the potential applications of SWSP in food industries.

Cardiotoxicity and myocardial infarction-associated DNA damage induced by thiamethoxam in vitro and in vivo: Protective role of Trigonella foenum-graecum seed-derived polysaccharide.

The risk of pesticides on the human health and environment has drawn increasing attention. Today, new tools are developed to reduce pesticide adverse effects. This study aimed to evaluate the toxicity induced by, thiamethoxam (TMX), and the cytoprotective effect of a novel polysaccharide, named fenugreek seed water polysaccharide (FWEP) in vitro using H9c2 cardiomyoblastes and in vivo using Wistar rat model. Animals were assigned into four groups per eight rats each: group 1 served as a control group, group 2 received TMX, group 3, and group 4 received both FWEP and TMX tested at two doses (100 and 200 mg/kg, respectively). Regarding the in vitro study, our results demonstrated that TMX induced a decrease in H9c2 cell viability up to 70% with the highest concentration. In vivo, TMX injection induced marked heart damage noted by a significant increase in plasma lactate dehydrogenase, creatine phosphokinase, troponin-T, aspartate amino transferase activities, cholesterol, and triglyceride levels. Concomitant alterations in cardiac antioxidant defense system revealed depletion in the levels of glutathione and non-protein thiol and an increase in the activity of superoxide dismutase, catalase, and glutathione peroxidase. Similarly, a significant increase in heart lipid, malondialdehyde, advanced oxidation protein product and in protein carbonyls levels was also noted. In addition, heart tissues histo-architecture displayed major presence of apoptosis and necrosis as confirmed by DNA degradation. However, supplementation with FWEP alleviated heart oxidative damage and genotoxicity. In this manner, ABTS radical-scavenging activity, linoleic acid oxidation tests and heart genomic and DNA nicking assay had proved FWEP strong antioxidant potential. In conclusion, FWEP provided significant protection against TMX-induced heart injury, and could be a useful and efficient agent against cardiotoxicity and atherosclerosis.

In vitro and in vivo anti-diabetic and anti-hyperlipidemic effects of protein hydrolysates from Octopus vulgaris in alloxanic rats.

This study aims to examine the effects of non-hydrolyzed octopus (Octopus vulgaris) muscle proteins (NHOPs) and their hydrolysates (OPHs) on alloxan induced diabetes in Wistar rats (AIDR). Animals were allocated into seven groups of six rats each: control group (C), diabetic group (D) and diabetic rats treated with acarbose (D + Acar), non-hydrolyzed octopus proteins (D + NHOPs) and octopus proteins hydrolysates (D + OPHs) groups. The diabetic rats presented a significant increase in glycemic status such as α-amylase activity (in plasma, pancreas and intestine), hepatic glycogen, blood glucose and glycated hemoglobin (HbA1c) levels, as well as a significant decrease in the levels of plasma insulin and total hemoglobin compared to control group. In addition, plasma and liver contents in total cholesterol, triglycerides and LDL-cholesterol significantly increased in AIDR compared to control group. However, the daily administration of OPHs for 30 days improved the glucose tolerance test, the glycemic status of diabetic rats and corrected the lipid profiles. Further, a significant increase in the activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and gamma-glutamyl transpeptidase as well as in the level of plasma bilirubin on diabetic status was observed, indicating considerable hepatocellular injury. OPHs treatment was found to attenuate the increased activities of the plasma enzymes produced by diabetes and caused a subsequent recovery towards normalization compared to the control group. By contrast, the NHOPs treatment was found to increase the glucose metabolic disorders in AIDR. These beneficial effects of OPHs were confirmed by histological findings in the hepatic and pancreatic tissues of diabetic treated rats. Indeed, they avoid lipid accumulation in the hepatocytes and protect the pancreatic ß-cells from degeneration. Our results thus suggest that OPHs may be helpful in the preventing from diabetic complications by reversing hepatotoxicity.

Physicochemical, techno-functional, and antioxidant properties of a novel bacterial exopolysaccharide in cooked beef sausage.

This work investigates the effects of partial replacement of vitamin C (Vit C) with a purified exopolysaccharide (EPS-Ca6) produced by Lactobacillus sp. Ca6, on the antioxidant activities of cooked beef sausages during refrigerated storage. The physicochemical, techno-functional and viscosity properties of EPS-Ca6 were also studied. Functional properties of EPS-Ca6 were determined based on Water Holding Capacity (WHC), Oil Holding Capacity (OHC), emulsification activity, and foaming ability. EPS-Ca6 demonstrated excellent emulsifying and emulsion stabilizing properties. It was able to emulsify several food-grade oils and hydrophobic compounds, particularly corn oil and diesel with emulsification indexes of 90 and 100%, respectively at a concentration of 0.5%. The effect of EPS-Ca6 on oxidative processes in cooked beef sausages during storage up to 12days at 4°C was evaluated. The obtained results showed a high rate (p<0.05) of oxymyoglobin (OxyMb) and low lipid oxidation. Overall, our findings provided evidence that EPS-Ca6 could be used as a natural additive for maintaining storage stability of cooked beef sausages, and could replace synthetic polymer in several industrial applications.

Cytoprotective Effects of the Red Marine Alga Chondrus canaliculatus Against Maneb-Induced Hematotoxicity and Bone Oxidative Damages in Adult Rats.

The current study aimed at evaluating the ability of a mineral and antioxidant-rich extract from Chondrus canaliculatus to improve maneb (MB)-induced toxicity in adult rat. The animals were divided into four groups: group 1 used as a control group, group 2 received MB, group 3 received MB + C. canaliculatus extract, and group 4 received only the algal extract. MB, a Mn-containing ethylene-bis-dithiocarbamate fungicide, induced oxidative stress damages, mineral perturbations in the plasma, urine, and bone, and genotoxicity in rats. Hematological analysis revealed in the MB-treated group a disruption in the number of red blood cells, platelets, and white blood cells associated with a striking genotoxicity. Interestingly, a significant increase in malondialdehyde and advanced oxidation protein product levels in erythrocytes and bones were found. On the other hand, an impairment of the antioxidant status in both tissues was occurred. Along, our results revealed that MB injection caused a striking drop and disruption in bone's mineral rates, especially calcium and phosphorus. These biochemical results were in accordance with the histological and molecular changes. However, co-treatment with C. canaliculatus extract showed, for the first time, that this alga was effective against MB-induced hematotoxicity, genotoxicity, and oxidative stress in the blood and bone and maintained osteomineral metabolism and bone histo-architecture. Such observations might be explained by the strong in vitro antioxidant and antibacterial activities exhibited by the alga, as well as by its high levels in several minerals: calcium, phosphorus, sodium, potassium, magnesium, iron, and zinc.

Bioactive properties: enhancement of hepatoprotective, antioxidant and DNA damage protective effects of golden grey mullet protein hydrolysates against paracetamol toxicity.

This study was undertaken to examine the hepatoprotective, antioxidant, and DNA damage protective effects of protein hydrolysates from Liza aurata, against paracetamol overdose induced liver injury in Wistar rats. L. aurata protein hydrolysates (LAPHs) were mainly constituted by glutamic acid (Glu) and glutamine (Gln) and lysine (Lys). In addition, they contained high amounts of proline (Pro), leucine (Leu) and glycine (Gly). The molecular weight distribution of the hydrolysates was determined by size exclusion chromatography, which analyzed a representative hydrolysate type with a weight range of 3-20 kDa. The hepatoprotective effect of LAPHs against paracetamol liver toxicity was investigated by in vivo assay. Rats received LAPHs daily by gavage, for 45 days. Paracetamol was administrated to rats during the last five days of treatment by intraperitoneal injection. Paracetamol overdose induced marked liver damage in rats was noted by a significant increase in the activities of serum aspartate amino transferase (AST) and alanine amino transferase (ALT), and oxidative stress which was evident from decreased activity of the enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), and level of glutathione (GSH), and increased concentration of lipid peroxidation products (MDA). Furthermore, paracetamol increased the DNA damage with liver histopathological changes. LAPH pretreatment significantly attenuated paracetamol-induced hepatotoxic effects, including oxidative damage, histopathological lesions, and apoptotic changes in the liver tissue. Interestingly, LAPHs restored the activities of antioxidant enzymes and the level of GSH, ameliorated histological and molecular aspects of liver cells. The present data suggest that paracetamol high-dose plays a crucial role in the oxidative damage and genotoxicity of the liver and therefore, some antioxidants such us LAPHs might be safe as hepatoprotectors. Altogether, our studies provide consistent evidence of the beneficial effect of LAPHs on animals treated with a toxic dose of paracetamol and might encourage clinical trials.

Zebra blenny protein hydrolysates as a source of bioactive peptides with prevention effect against oxidative dysfunctions and DNA damage in heart tissues of rats fed a cholesterol-rich diet.

High-cholesterol diet (HCD) is suspected to produce in excess free radicals having adverse effects on human health and causing atherosclerosis damage in heart tissues. In our study, the effects of zebra blenny protein hydrolysates (ZBPHs) were investigated on cardiac oxidant/antioxidant status as well as DNA damage and histopathological disorders in rats, fed with a hypercholesterolemic diet. The molecular weight distribution of the hydrolysates was determined by size exclusion chromatography, which analyzed a representative hydrolysate type with a weight range of 3-20kDa. ZBPHs effectively protected heart genomic DNA against oxidative damage induced by Fenton's reagent. HCD promoted oxidative stress with a rise in serum aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activities and thiobarbituric acid reactive substance (TBARS), advanced oxidation protein product (AOPP) and hydrogen peroxide (H2O2) levels in heart tissues. An increase in glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities as well as a fall in ATPase activities and glutathione (GSH) level was also noted in heart of hypercholesterolemic rats. Treatment with ZBPHs ameliorated the biochemical parameters cited above. In addition, pre-treatment with ZBPHs prevented DNA fragmentation. The histopathological findings confirmed the biochemical results and the potential antioxidant activities of ZBPHs which can help the cure and management of cardiovascular diseases induced by high-cholesterol levels.

Potential protective effects of polysaccharide extracted from Ulva lactuca against male reprotoxicity induced by thiacloprid.

CONTEXT: Polysaccharides (PSs) from seaweeds have been reported to possess biological activity of potential medicinal values. OBJECTIVE: The current study was conducted to establish the protective effects of PS extracted from Ulva lactuca against oxidative stress induced by Thiacloprid (THC) in the rat reproductive system. MATERIALS AND METHODS: Rats were exposed either to THC, THC + PS (100 mg/kg), or THC + PS (200 mg/kg). RESULTS: Our study showed that THC induced severe disorders in the functional sperm parameters. A decrease in antioxidant activities and their genes expression were observed in the same group, compared to the controls. Our molecular data showing also a severe DNA breakdown in the testis of THC treated group. Moreover, THC treated group showed severe histopathological changes. CONCLUSIONS: Our results revealed that PS extracted from Ulva lactuca alleviated the THC induced reprotoxicity and reduced oxidative stress damages, DNA breakdown and histological injuries in the testis.

Protective effect of Sargussum vulgare sulfated polysaccharide against molecular, biochemical and histopathological damage caused by alloxan in experimental diabetic rats.

Diabetes is a serious condition that is linked to the development of oxidative stress. In the context of enhancing the biodiversity of Tunisia's flora, this study aimed to evaluate the effect of Sargussum vulgare sulfated polysaccharide (SVSP) on hyperglycemia and diabetes complications in the alloxan-induced diabetic rats. Our results showed a disturbance of carbohydrate, lipid, hematological and histopathological parameters, an increase in the α-amylase enzyme activity and damage to the pancreatic, hepatic and renal tissues in rats rendered diabetic by alloxan. In contrast, treatment with SVSP resulted in a correction of fasting and postprandial blood glucose and HbA1c through inhibition of pancreatic α-amylase. We also noticed an improvement in hemogram parameters and an attenuation of the pancreatic oxidative stress markers as well as histological protections. On the other hand, the administration of SVSP to diabetic rats caused, besides the correction of glycemic and lipid parameters, a good defense against hepatotoxicity and nephrotoxicity of diabetes as well as good antioxidant status and histological protections.

Octopus vulgaris protein hydrolysates: characterization, antioxidant and functional properties.

Composition, functional properties and in vitro antioxidant activities of octopus (Octopus vulgaris) protein hydrolysates (OPHs) were evaluated. OPHs were prepared by treatment with commercial Esperase (OPH-Esp), alkaline protease extract from Zebra blenny (Salaria basilica) (OPH-ZB) and enzyme preparation from Bacillus subtilis A26 (OPH-A26). OPHs showed different degrees of hydrolysis (DH from 17.6 to 21%), and hydrophobic/hydrophilic peptide ratio. The amino acid profiles of OPHs showed a high level of essential amino acids, and Lys was the most abundant amino acid. Enzymatic hydrolysis improved solubility significantly as well as emulsifying and foaming properties of octopus proteins. The emulsifying activity index of OPHs decreased with increasing concentrations. Conversely, the foaming abilities increased as the hydrolysate concentrations increased. For the antioxidant activities, five different in vitro assay systems were investigated. All hydrolysates displayed various degrees and dose dependant antioxidant activities. The highest DPPH scavenging activity and reducing power were achieved by OPH-A26. OPH-Esp displayed the highest ability to prevent the bleaching of ß-carotene, whereas OPH-ZB exhibited the highest protection against hydroxyl radical induced DNA breakage. The results suggested that OPHs could be used, as a promising source of functional peptides with antioxidant activities, to formulate functional foods.

Evaluation of the biotechnological potential of a novel purified protease BS1 from Bacillus safensis S406 on the chitin extraction and detergent formulation.

An extracellular alkaline stable protease BS1 from a new bacteria strain, Bacillus safensis S406, isolated from the Sfax solar saltern, was purified and characterized. The enzyme was purified to homogeneity by ammonium sulfate precipitation, Sephadex G-75 gel filtration, Mono-Q anion-exchange chromatography and ultrafiltration, with a 12.70-fold increase in specific activity and 20.29% recovery. The enzyme has a molecular weight of 29kDa and appeared as a single band on native-PAGE. The optimum pH and temperature values of its proteolytic activity were pH 11.0 and 60°C, respectively. BS1 was tested for the deproteinization of shrimp wastes to extract chitin. An enzyme-protein ratio of 10U/mg of proteins allows to eliminate 93% of protein linked to the chitin after 3h hydrolysis at 45°C. Being very active in alkaline conditions, the potential application of BS1 in laundry formulation was investigated. The enzyme showed high stability in the presence of non-ionic surfactants and some commercial liquid and solid detergents, suggesting its eventual use in detergent formulations.

Increasing maneb doses induces reactive oxygen species overproduction and nephrotoxicity in adult mice.

BACKGROUND AND PURPOSE: The aim of this study was to elucidate the biochemical, molecular and histopathological aspects of the kidney injuries as well as the hematological perturbations induced after adult mice exposure to increasing doses of maneb (MB). MATERIAL AND METHOD: Adult mice were intraperitoneally treated for seven days with four graded doses of MB, corresponding to 1/8, 1/6, 1/4 and 1/2 of its lethal dose (LD50=1500 mg/kg body weight). RESULTS: Hematological analysis revealed a significant disruption in total white blood cells and platelets and a significant decrease in the plasmatic levels of ferrozine in mice treated with 1/8, 1/6 and 1/4 of MB LD50. However, the ferrozine levels increased significantly in the group treated with 1/2 of MB LD50. Evenly, our results showed a significant increase in the levels of malondialdehyde, lipid hydroperoxides, hydrogen peroxide and advanced oxidation protein products in all treated groups. The activities of catalase and glutathione peroxidase decreased significantly in all MB treated mice. Additionally, all treated groups exhibited strong nephrotoxicity signs, including increases in plasma urea, creatinine and albumin levels and lactate dehydrogenase activity, as well as a significant decrease in uric acid levels. Electrophoresis analysis revealed nucleic acid degradation, testifying the genotoxicity of MB. Moreover, the histopathological observations showed severe renal injuries, which could be related to the above mentioned data. CONCLUSIONS: Our data showed, for the first time, that the MB tested doses led to oxidative stress installation causing renal cell damages and lowering all defense systems capacities.

Antioxidant and hemolytic activities, and effects in rat cutaneous wound healing of a novel polysaccharide from fenugreek (Trigonella foenum-graecum) seeds.

The aim of this work was to evaluate the antioxidant and hemolytic activities as well as the in vivo wound healing performance of a novel polysaccharide (FWEP) extracted from fenugreek (Trigonella foenum-graecum) seeds. The antioxidant activity was evaluated in vivo and in vitro using various assays. Results showed that FWEP exhibited strong antioxidant activities but no hemolytic activity was observed towards bovine erythrocytes. The application of FWEP hydrogel on the wound site in a rat model enhanced significantly wound healing activity and accelerated the wound closure after 14days of wound induction. Histological examination also demonstrated fully re-epithelialized wound with a complete epidermal regeneration. Altogether, these evidences demonstrated that FWEP had strong wound healing potential presumably achieved through its antioxidant activities.

In-vitro antioxidant and functional properties of protein hydrolysates from golden grey mullet prepared by commercial, microbial and visceral proteases.

Bioactive Liza aurata protein hydrolysates (LAPHs) were prepared by treatment with Trypsine (PH-TR), Esperase (PH-ES), enzyme preparations from Pseudomonas aeruginosa A2 (PH-A2), Bacillus subtilis A26 (PH-A26) and Liza aurata (PH-LA). Their functional properties and antioxidant activities were evaluated. The hydrolysates had degree of hydrolysis (DH) values ranging from 8.15 % to 13.05 %. Reverse-phase HPLC analyses of the LAPHs showed considerable variation in peptide composition. All hydrolysates had high protein content (83.14 %-86.43 %). Glutamic acid, Glutamine (Glx) and Lysine (Lys) were the most abundant amino acids. All protein hydrolysates had a good solubility emulsifying and foam properties were found to be considerably improved by enzymatic hydrolysis. In addition, all hydrolysates showed varying degrees of antioxidant activities evaluated by various in vitro tests. Further, all LAPHs did not show hemolytic activity towards human erythrocytes. The results thus revealed that protein hydrolysates from golden grey mullet could be used as food additives possessing both antioxidant activity and functional properties.

New acidic proteases from Liza aurata viscera: Characterization and application in gelatin production.

The present study reports the extraction and characterisation of acidic protease from the viscera of golden grey mullet (LACAP), and its use in gelatin preparation. The optimum pH for the crude extract activity was 3.0, with high stability over a pH range from 3.0 to 7.0. The enzymatic extract lost about 79% of its activity by pepstatin A. Due to its high activity under acidic conditions, gelatin was extracted from the skin of L. aurata using different levels of LACAP (0, 5 and 10U/g of skin, named GGSG0, GGSG5 and GGSG10). The extraction yield of GGSG0 was only 3.3% and the addition of acidic proteases increased the yields, which reached 5% and 8.2% at 5 and 10U/g of skin, respectively. In addition, Fourier transform infrared (FT-IR) and SDS-page profiles of gelatins indicated that the structure was affected by enzymatic pre-treatment. The results of functional properties showed that the emulsion stability and activity indexes (ESI and EAI) of GGSG0 were higher than those of GGSG5 and GGSG10. Furthermore, foam expansion (FE) and foam stability (FS) increased as the concentration of gelatin increased. The results showed that L. aurata by-products can be a potential source of gelatin and protease.