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In this study, the effects of different temperatures, incubation times and types of reducing sugars, including glucose and different low molecular weight (Mw) chito-oligosaccharides (COS) with varying acetylation degree (AD), on the extent of Maillard reaction (MR) on chitosan-based films were studied. Interestingly, an improvement of structural and functional properties of all MR-crosslinked films was noted, which is more pronounced by heating at higher temperature and exposure time. These findings were proved through Fourier-transform infrared and X-ray diffraction analyses. In addition, color change and Ultraviolet spectra demonstrate that glucose addition provides the high extent of MR, followed by COS1 (Mw < 4.4 kDa; AD, 18.20%) and COS2 (Mw < 4.4 kDa; AD, 10.63%). These results were confirmed by enhanced water resistance and thermal properties. Moreover, MR-chitosan/COS films showed the highest mechanical properties, whereas, glucose-loaded films were brittle, as demonstrated by scanning electron microscopy micrographs. Furthermore, MR-chitosan/COS1 films exhibited the better antioxidant behavior followed by chitosan/glucose and chitosan/COS2 films, mainly at higher heating-conditions. Thereby, MR-crosslinked chitosan/COS based films were attractive to be applied as functional and active coating-materials in various fields.

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A fucoidan, sulfated polysaccharide, was extracted from the brown seaweed Cystoseira schiffneri during 4 harvest periods (December, April, July, and September) and studied for its structural and chemical properties. The Cystoseira schiffneri fucoidan (CSF) showed important variation in sulfate content ranging from 7.8% in December to 34.8% in July. This was confirmed by Fourier transform infrared and nuclear magnetic resonance spectroscopies showing characteristic signals of sulfated polysaccharides. Molecular mass of the CSF varied as a function of season from 3,745 in December to 26,390 Da in July. Gas chromatography-mass spectroscopy showed that CSF fractions were "mannogalactofucans" composed mainly of mannose, fucose, and galactose with low levels of other monosaccharides. Moreover, interesting in vitro antioxidant activities that depend on the harvest season were noted for CSF. Thus, the present work might contribute to establish criteria for extracting bioactive fucoidans from an endemic Tunisian seaweed C. schiffneri.

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The current work aimed to prepare emulsion gels based on European eel skin gelatin (ESG). The results revealed that the ESG exhibited interesting antioxidant and functional properties in a dose-dependent manner. The ESG has a gel strength of 354.86 g and high gelling and melting temperatures of about 33 and 43 °C, respectively. Hence, based on its interesting gelling ability, the ESG-based gel was employed to stabilize European eel oil (EO) emulsions. In this context, two emulsions were prepared by homogenization or homogenization followed by sonication at EO:ESG weight ratios of 1:2 and 1:4. The physicochemical, textural, structural and thermal properties of emulsion gelatin-based gels (EGGs) were evaluated. The EGGs had a rigid and a cohesive gel network, according to the textural and microstructural analysis. Structural and thermogravimetric analyses showed the effective entrapment of EO in the ESG gel network.

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This work focused on studying the physicochemical and antioxidant properties changes of varying molecular weight (Mw) chitosan-depolymerization products (CDP)-based films occurring after crosslinking by heat-treatment and Maillard reaction (MR). Based on color properties and browning index, an enhancement of films properties was observed after treatment at 90 °C with a reduction in their water content, solubility and contact angle. Brown MR products were developed in heated films containing glucose thus improving their barrier properties. This effect was more pronounced in lower Mw-CDP based films. In addition, according to TGA, EAB and TS analyses an improvement in heat-treated films thermal stability and mechanical properties was detected and further confirmed through FTIR, X-ray and SEM analyses. The evaluation of the antioxidant potential through four different assays allowed to conclude that glucose addition, thermal treatment and the use of low Mw-CDP highly enhanced the MR-modified films antioxidant capacity. Consequently, MR crosslinked chitosan-based films could be potentially used as an alternative for bioactive and functional packaging effective in food oxidation inhibition, especially using low Mw chitosan derivatives.

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The present work aims to encapsulate goby fish protein hydrolysate (GPH), endowed with antioxidant activity, through ionic gelation process using blue crab chitosan (CH) and tripolyphosphate anions and to evaluate the structural, thermal and antioxidant properties of the elaborated microparticles (MPs). The GPH-loaded MPs present spherical shape as seen by scanning electron microscopy (SEM) images and positive zeta potential. The increase of loaded GPH concentration led to the increase of encapsulation efficiency (EE) and to the reduction of the particle size. In fact, MPs, loaded with 2 and 5 mg/ml GPH, had EE values of 44 and 58% and mean particles size of 4.81 and 3.78 µm, respectively. Furthermore, thermogravimetric analysis (TGA) profiles revealed the enhanced thermal stability of encapsulated biopeptides compared to the free ones. Release kinetic data showed a Fickian diffusion behavior which follows swelling and a diffusion-controlled mechanism for peptides liberation. Finally, as opposed to unloaded MPs, an improvement of the antioxidant activity of the loaded MPs with biopeptides was observed.

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The present study investigates the potential of sardinelle protein isolate (SrPI) combined to maltodextrin (MD), at different ratios (1:0, 1:1, 1:2, 1:3 and 1:4, w/w), as wall matrix to stabilize and encapsulate corn oil (1:2, oil/ wall material ratio). Emulsions were prepared by homogenization followed by sonication treatment and then dried by the spray-drying process. The obtained microcapsules were characterized regarding the encapsulation efficiency (EE), scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and thermodynamic analyses (thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC)). Data revealed that the combination of SrPI and MD resulted in very high EE compared to SrPI used alone as wall material, and the EE increased with the amount of MD incorporated to the SrPI solution. SEM images showed the production of irregular and larger particles with the increase of MD concentration. Moreover, TGA showed that microparticles obtained by 1:4 w/w ratio (SrPI/MD) displayed the highest protection of corn oil. Thus, these findings revealed the effectiveness of SrPI and MD mixture to encapsulate and protect corn oil, which offered a promote application for food and pharmaceutical industries.

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The present study was undertaken to establish a distinct relationship between blue crab chitosan (Cs) acetylation degree (AD) and molecular weight (Mw) and its structural features, thermal properties and bioactivity. Therefore, chitosans with different AD were prepared and Cellulase was used to produce Cs derivatives with decreasing Mw. Results clearly display a decrease of the ordered structure of Cs, with the increase of AD and the decrease of Mw. Thermal stability/degradation screening disclose a greater thermal resistance for Cs with lower AD and higher Mw. The anti-adhesive potential of Cs was, additionally, studied, as function of AD and Mw. The effectiveness of Cs in preventing biofilm adhesion was strongly influenced by its AD and Mw, with the lowest inhibition values for higher AD and lower Mw. Interestingly, the effectiveness of Cs in disrupting pre-formed biofilms increased with decreasing Mw. Moreover, Cs derivatives were found to be advantageously efficient in prolonging human blood clotting times, based on data of activated partial thromboplastin time, Quick time and thrombin time assays, typically for the intrinsic coagulation pathway. Accordingly, depending on the predicted application of Cs, either in food, biomedical and pharmaceutical industries, AD and Mw are critical traits to be inevitably reflected on.

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This work aimed to modify blue crab chitosan-based films through the Maillard reaction (MR) as a novel alternative to improve their functional and biological properties. To this end, different saccharides (glucose (aldohexose), fructose (ketohexose), xylose (aldopentose) and arabinose (aldopentose)), at different weight ratios 0.5, 1.0 and 2.0 % (g/100 g polymer), were studied, and films were heated at 90 °C for 24 h. Based on color changes and browning index measurements, the extent of MR was the highest with aldopentoses, whereas hexoses and particularly ketohexoses, exhibited a relative crosslinking rate. These findings were further reflected with an improvement in treated films mechanical properties and thermal degradation temperatures, and advantageously, barrier properties against UV light and water. In addition, the MR-modified Cs-based films antioxidant activity was interestingly enhanced with mainly aldopentoses. Consequently, MR crosslinked chitosan-based films are promising alternative for active and functional packaging able of food oxidation hindering, especially using aldopentoses.

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This work aimed to the development of chitosan and protein isolate composite hydrogels, for carotenoids-controlled delivery and wound healing. By increasing the concentration of the protein isolate, chitosan hydrogels were more elastic at a protein isolate concentration not exceeding 15% (w/w). Chitosan-protein isolate composite hydrogels revealed low cytotoxicity towards MG-63 osteosarcoma cells. Thanks to its appropriate structural, swelling and mechanical resistance properties, chitosan hydrogel (3%; w/v), reinforced with 15% (w/w) of protein isolate, was selected for the carotenoids in vitro release study. Release profiles, show delivery patterns, where carotenoids were more barely released at a pH 7.4 medium (p < .05), compared to more acidic microenvironments (pH 4.0 and pH 2.0). Thus, developed hydrogels could be applied as pH-sensitive intelligent carriers, for drugs-controlled release, with interesting antioxidant abilities. The in vivo healing potential of hydrogels in rats' models was further studied. Topical application of hydrogel-based patches allowed the acceleration of wound healing and the complete healing, for composite hydrogel enriched with carotenoids.

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In this study, carotenoproteins (CPs) were encapsulated in blue crab chitosan-tripolyphosphate and chitosan-protein isolate nanoparticles by ionotropic gelation and complex coacervation, respectively. The success of CPs encapsulation was confirmed by FT-IR spectroscopy, TGA and XRD techniques. Particles size and thermal stability of nanoparticles depend on the encapsulation method. Indeed, a regular distribution and spherical shape, with size range of about 300 nm (ionotropic gelation) - 600 nm (complex coacervation), were observed by SEM analysis. The encapsulation efficiency and loading capacity of CPs were about 74% and 31% for the complex coacervation and 89% and 47% for the ionotropic gelation approaches, respectively. In vitro release studies showed a fast initial release effect, followed by a slow CPs release. The highest amount of released CPs in a shorter time was observed with the ionotropic gelation method. Further, in vitro release kinetics of CPs were found to be medium dependent, where nanoparticles incubated in ethanol displayed higher released CPs amount in a longer release time, compared to nanoparticles immerged in PBS (pH ~ 6.8). These findings suggest that the encapsulation technique obviously affected the particles structure, and the glass transition temperature, and the mass loss of encapsulated materials. The better CPs thermal stabilization was obtained for the ionotropic gelation nanoparticles.

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Recently, the application of natural biocompatible polymeric hydrogels for the conception of drug delivery matrices has attracted widespread interest. Thus, in the present study, riboflavin pH-sensitive drug delivery hydrogels were developed based on blue crab chitosan (Cs), via direct dissolution in alkali/urea aqueous solution at low temperatures. First, the effect of Cs characteristics in terms of acetylation degree (AD) and molecular weight (Mw) on the structural, mechanical, thermal, swelling and in vitro biodegradation of Cs-based hydrogels were studied. Data from overall analysis revealed that Cs with low AD and high Mw exhibited improved mechanical properties, as evidenced by the compressive and rheological behaviors tests, thermal resistance, swelling behavior and in vitro degradation kinetics. However, hydrogels pore sizes were reduced with the AD decrease and Mw increase. Additionally, hydrogels in PBS (pH 5.5) underwent quicker degradation, compared to those immersed in PBS (pH 7.4). In the drug delivery model, the kinetics of Riboflavin release, through the Cs-based hydrogels were monitored. The Riboflavin release exhibited typical deliverance patterns, with significantly higher released amounts in more acidic systems. Therefore, drug encapsulation within the conceived pH-sensitive Cs-based hydrogels could provide suitable and promoting microenvironment for drugs delivery.

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Carotenoids, natural pigments, are a group of chemically heterogeneous molecules, present in numerous taxonomical clusters. Because of their various bioactivities, carotenoids are day-by-day applied in numerous fields. The present work aimed to investigate an efficient extraction process of carotenoids from blue crab shells and their identification by HR-ESI-MS technique. In this context, different methods (enzymatic, maceration, Soxhlet, etc.) and solvents (variable polarity index) were tested. Maceration using the binary system hexane/isopropanol (50/50) was found to be the most efficient process, producing high carotenoids content and low total phenolic and soluble protein amounts (p < 0.05). When combined with an enzymatic pretreatment, this procedure was found to be remarkably (p < 0.05) more efficient and selective especially towards astaxanthin (p < 0.05). The HR-ESI-MS identified 23 compounds, depending on the adopted extraction approach. The compounds identified may have potential for applications in food or pharmaceutical industries.

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The objective of this study was to prepare European eel oil (EO) microcapsules using European eel protein isolate (EPI) as a wall material and investigate its oxidative stability. The EPI emulsions were obtained at different EO: EPI ratios (1:1, 1:2 and 1:4, w/w) and using two emulsification procedures: Homogenization (H) and homogenization followed by ultrasonication (HU) treatments. The microcapsules prepared by combining the two emulsification processes (HU) and at core and wall ratio of was 1:4 presented the smallest particles size and the greatest encapsulation efficiency (68.50%) and oxidative stability. Scanning electron microscopy (SEM) images proved the spherical shape of all microcapsules without fissure on the surface. The capsules exhibited an interesting antioxidant activity depending on the EO:EPI ratio, especially for the metal chelating potential. Thus, the effect of ultrasonication process and the EPI concentration on the characteristic, the stability and the antioxidant activity of the encapsulated EO has been proved.

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In this study, the antihypertensive activity of Purafect®-smooth hound viscera protein hydrolysate (VPH) and its peptide fraction with molecular weight (MW) below 1 kDa (VPH-I) was investigated. In addition, the lipase inhibitory activity, as well the anticoagulant potential, in vitro, were assessed. The antihypertensive effects of VPH and VPH-I were studied during 24 h (short-term effect) and 30 days (long-term effect) using high-salt (18% NaCl) and -fructose (10%) diet (HSFD)-induced hypertension. Data showed that, 4 h post-administration of VPH and VPH-I (200 mg/kg BW), the systolic blood pressure of rats was reduced by about 6 and 9 mmHg, respectively. These effects were similar to that obtained with Captopril (~9 mmHg at t = 4 h). On the other hand, exposing the rats to daily to HSFD, coupled to the administration of viscera peptides, was found to attenuate hypertension. In addition, the proteins' treatments were able to correct lipid and glycemic disorders, by reducing the total cholesterol and triglyceride contents and resorting to the plasma glucose level, compared to the HSFD group. Overall, the present findings demonstrated the preventive effect of VPH-peptides from hypertension complications, as a result of their biological properties.

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In this study, novel polysaccharides extracted from cuttlefish skin (CSP) and muscle (CMP), by precipitation with cetylpyridinium, were characterized and their antioxidant and antibacterial activities were investigated. CMP showed the highest amounts of sulfated groups (6.6%), uronic acids (9.2%) and proteins (3.7%). Infrared spectroscopic analysis indicated the presence of sulfonyl (OSO) and acetyl (CH3CO-) groups for both CSP and CMP. In addition, CSP showed the presence of glucuronic acid (GlcA) and galacturonic acid (GalA) as major components, while CMP showed highest amount of GalA in its monosaccharide composition. Sulfated polysaccharides were found to display important antibacterial activity against several Gram+ and Gram- bacteria. In addition, they exhibited strong antioxidant activities as showed by various in vitro tests. Fractionation of cuttlefish polysaccharides, by DEAE-cellulose column showed one peak during the buffer elution phase and three major fractions for CMP and two peaks for CSP during the linear gradient of NaCl. The last eluting sulfated fraction from each sample, characterized by the highest negative charge, was found to exhibit the best antioxidant and antibacterial activities. The obtained results demonstrated that cuttlefish polysaccharides and their fractions could serve as natural antioxidant and antibacterial agents.

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The present study deals with the isolation of sulfated polysaccharides (Ps) from the Bullet tuna by-products (head, skin and bones). Results of chemical characterization revealed that Ps-bones showed the highest total sugar, uronic acid and sulfate group contents. Tuna extracted-Ps contained a mixture of neutral sugars, with high amounts of glucuronic and galacturonic acids and presented different molecular weights. The presence of sulfate groups in different Ps was confirmed by FTIR analysis. Interestingly, Ps-bones showed the highest antioxidant activity among all the extracted Ps. Moreover, results revealed that all polysaccharides displayed varying degrees of antibacterial activity. Ps-bones exhibited high and wide spectrum of activities, inhibiting the growth of all bacteria tested. Ps-bones incorporated during fillet cooking offered an excellent protection of fish fillet by avoiding pH change, color loss, lipid oxidation and spoilage. Overall, the results demonstrated that Ps could be potentially used as natural antioxidant and antibacterial agents.

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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.

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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.

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This study was carried out to investigate the hypolipidemic, cardioprotective and anticoagulant properties of fish goby protein hydrolysates (GPHs) in rats fed a high fat and fructose diet (HFFD). Wistar rats were fed with HFFD for 2 months, coupled with the oral administration of GPHs and undigested goby protein (UGP). Compared with the standard diet, HFFD induced dyslipidemia and liver structure alterations, and increased pancreatic lipase activity. In addition, HFFD caused a significant increase in body weight. Interestingly, administration of UGP and GPHs to HFFD fed rats was efficacious in lowering serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-c) as well as hepatic TC and TG, and increased the serum high density lipoprotein cholesterol (HDL-c) content. Moreover, all treatments significantly decreased the atherogenic index and coagulant factor levels (thrombin and prothrombin). UGP and GPH administration also significantly decreased pancreatic lipase activity, which mitigates lipid accumulation. Similarly, UGP and its hydrolysates showed cardioprotective potential revealed by decreasing the risk of atherogenic and coronary artery disease and improving the liver architecture. The ex vivo plasma clotting test showed that GPHs exert a great therapeutic anticoagulant potential. The overall results demonstrated that GPH supplementation can counteract high-fat/fructose diet-induced obesity.

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Smooth-hound viscera hydrolysates (SHVHs) were prepared by treatment with Neutrase (SHVH-N) and Purafect (SHVH-P). Hydrolysates were then separated according to their molecular weight, using the ultra-filtration membrane system, into 5 fractions (≥50, 50-5, 5-3, 3-1 and ≤1kDa). Fractions showed different amino acid compositions and angiotensin I-converting enzyme (ACE) inhibitory potentials. The SHVH-P-FV (≤1kDa) and SHVH-N-FIV (3-1kDa) fractions showed the best ACE-inhibitory activities with IC50 values of 53.31 and 75.05µg/ml, respectively. According to their high ACE-inhibitory potential, FIV and FV were fractionated by RP-HPLC and then analyzed by LC-MS/MS to identify peptide sequences. A systematic peptidomic study resulted in the identification of numerous novel sequences. Furthermore, in silico data, based on the molecular docking simulation, showed that GPAGPRGPAG, AVVPPSDKM, TTMYPGIA, and VKPLPQSG could bind ACE active site with low interaction scores. Indeed, they share hydrogen bonds and Van der Waals and electrostatic interactions with ACE catalytic pockets.

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