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Sila A.,University of Sfax | Sila A.,CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute | Bougatef A.,University of Sfax
Journal of Functional Foods | Year: 2016

In recent years, several attempts have been made for the utilisation of the protein rich fish processing by-product discards and underutilised fish proteins for the production of commercially valuable food ingredients. There has been an increasing interest in the utilisation of marine products, and novel bioprocessing technologies are developing for isolation of some bioactive substances. Antioxidant peptides isolated from marine food products have been used as functional foods and nutraceuticals. Peptides obtained by enzymatic hydrolysis of fish proteins exhibit not only nutritional but also biological properties for use in diet or in therapeutic purposes. In this review, we have focused on the enzymatic process for generating antioxidant peptides from marine by-products as well as on the isolation procedures of selected antioxidant peptides. © 2015 Elsevier Ltd.


PubMed | CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute, Laboratory of Oral Health and Orofacial Rehabilitation LR, University of Monastir, BioImaging Center Lille 3642 and Lille University Hospital Center
Type: | Journal: Microbial pathogenesis | Year: 2016

Staphylococcus aureus (S.aureus) is one of several opportunistic microbial pathogens associated with many healthcare problems. In the present study, S. aureus was assessed for its biofilm-forming ability on materials routinely used in dental offices, including stainless steel (SS), polyethylene (PE), and polyvinyl chloride (PVC). Materials that were tested were characterized for roughness (Ra) and surface free energy (SFE). The adhesion forces exerted by S. aureus to each substratum were investigated using atomic force microscopy (AFM), and biofilm formation was quantitatively assessed by crystal violet staining assay. AFM measurements demonstrated that the strongest adhesion forces (20nN) were exerted on the PE surfaces (P<0.05) and depended more on Ra. In addition, the results of biofilm formation capability indicated that S. aureus exhibited more affinity to SS materials when compared to the other materials (P<0.05). This ability of biofilm formation seems to be more correlated to SFE (R=0.65). Hence, control of the surface properties of materials used in dental practices is of crucial importance for preventing biofilm formation on dental materials to be used for patients dental care.


PubMed | CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute and CNRS Lille Research Center in Informatics, Signal and Automatic control
Type: Journal Article | Journal: Nucleic acids research | Year: 2016

Since its creation in 2006, Norine remains the unique knowledgebase dedicated to non-ribosomal peptides (NRPs). These secondary metabolites, produced by bacteria and fungi, harbor diverse interesting biological activities (such as antibiotic, antitumor, siderophore or surfactant) directly related to the diversity of their structures. The Norine team goal is to collect the NRPs and provide tools to analyze them efficiently. We have developed a user-friendly interface and dedicated tools to provide a complete bioinformatics platform. The knowledgebase gathers abundant and valuable annotations on more than 1100 NRPs. To increase the quantity of described NRPs and improve the quality of associated annotations, we are now opening Norine to crowdsourcing. We believe that contributors from the scientific community are the best experts to annotate the NRPs they work on. We have developed MyNorine to facilitate the submission of new NRPs or modifications of stored ones. This article presents MyNorine and other novelties of Norine interface released since the first publication. Norine is freely accessible from the following URL: http://bioinfo.lifl.fr/NRP.


PubMed | CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute, University of Artois and Lille University of Science and Technology
Type: | Journal: International journal of food microbiology | Year: 2016

In this study we identified the culturable population of mesophilic lactic acid bacteria (LAB) from a French cheese Maroilles made either with raw or pasteurized milk using MALDI-TOF mass spectrometry (MS). Samples from rind and heart of Maroilles cheese were used, the LAB were selected on MRS agar at 30C and 197 Gram-positive and catalase-negative strains were subjected to identification by MALDI-TOF MS profiling. All strains were unambiguously identified: 105 strains from Maroilles made with raw milk (38 on the rind and 67 in the heart) and 92 strains from Maroilles made with pasteurized milk (39 on the rind and 53 in the heart). MALDI-TOF MS identification allowed identification of three genera belonging to LAB including Lactobacillus, Enterococcus and Leuconostoc. Lactobacillus was the most represented genus with seven species: Lactobacillus plantarum (L. plantarum), L. paracasei, L. curvatus, L. rhamnosus, L. fructivorans, L. parabuchneri, L. brevis found in Maroilles made with both kind of milk. The correlation between the 16S rDNA-based identification performed on selected strains and those obtained by MALDI-TOF-MS demonstrates that this fast, economically affordable, robust and reliable method for bacteria characterisation stands as an attractive alternative to the commonly-used methods and its application in food industry is discussed.


PubMed | CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute and University of Monastir
Type: | Journal: Microbial pathogenesis | Year: 2017

Biosurfactants also called bioemulsifiers are amphipathic compounds produced by many microorganisms that allow them to exhibit a wide range of biological activities. The aim of this study was to determine the antioxidant and antiproliferative potential of biosurfactants isolated from Lactobacillus casei and to assess their anti-adhesive and anti-biofilm abilities against oral opportunistic Staphylococcus aureus strains. The antioxidant activity of biosurfactant was evaluated using the in vitro scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The antiproliferative activity was determined on epithelial cell line (HEp-2) by the Methylthiazole tetrazolium (MTT) reduction assay. The anti-adhesive and antibiofilm activity against S. aureus strains were achieved using crystal violet staining. Our results revealed that the DPPH scavenging activity of biosurfactants at 5.0mg/mL concentration is between 74.6 and 77.3%. Furthermore, biosurfactants showed antiproliferative potency against studied epithelial cells as judged by IC50 and its value ranged from 109.10.84mg/mL to 129.70.52mg/mL. The results of the growth inhibition indicate that biosurfactant BS-LBl was more effective against oral S. aureus strains 9P and 29P with an IC50 of 1.920.26mg/mL and 2.160.12mg/mL respectively. Moreover, both biosurfactants displayed important antibiofilm activity with eradication percentages ranging from 80.221.33% to 86.212.94% for the BS-LBl, and from 53.381.77% to 64.422.09% for the BS-LZ9. Our findings demonstrate that biosurfactants from L. casei strains exhibited considerable antioxidant and antiproliferative potencies and were able to inhibit oral S. aureus strains with important antibiofilm efficacy. They could have a promising role in the prevention of oral diseases.


PubMed | CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute and Lille University of Science and Technology
Type: | Journal: Journal of AOAC International | Year: 2017

The objective of the present study was to evaluate the impact of rosemary and basil essential oils (EOs) on the qualityof Atlantic mackerel fillets stored at 2C up to 15 days. Atlantic mackerel (Scomber scombrus) fillets were periodically evaluated to assess their textural, color, physicochemical, and spectral characteristics. The results indicated that rosemary and basil treatments were effective for inhibiting the formation of total volatile basic nitrogen (TVB-N) and lipid oxidation products during storage. Based on TVB-N values, the shelf life of Atlantic mackerel fillets treated with rosemary and basil EOs was extended by 2 and 5 days, respectively, compared to the control group. Similar results were obtained with thiobarbituric acid-reactive substance analysis, which demonstrated an extended shelf life of Atlantic mackerel immersed with rosemary and basil EOs of 2 and 3 days, respectively, compared to the control group. The factorial discriminant analysis applied on the concatenated first five principal components corresponding to the physicochemical, textural, color, and fluorescence measurements allowed clear discrimination of the three groups, because a correct classification rate of 93.3% was obtained. Therefore, treatment with basil and rosemary EOs, as natural biopreservative compounds, could present ahigh-potential application in the seafood industry.


PubMed | CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute and Pontifical Catholic University of Campinas
Type: Journal Article | Journal: Canadian journal of microbiology | Year: 2016

Biosurfactants are important in many areas; however, costs impede large-scale production. This work aimed to develop a global sustainable strategy for the production of biosurfactants by a novel strain of Bacillus amyloliquefaciens. Initially, Bacillus sp. strain 0G was renamed B. amyloliquefaciens subsp. plantarum (syn. Bacillus velezensis) after analysis of the gyrA and gyrB DNA sequences. Growth in modified Landys medium produced 3 main recoverable metabolites: surfactin, fengycin, and acetoin, which promote plant growth. Cultivation was studied in the presence of renewable carbon (as glycerol) and nitrogen (as arginine) sources. While diverse kinetics of acetoin production were observed in different media, similar yields (6-8 gL


PubMed | CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute
Type: | Journal: Food chemistry | Year: 2016

Bovine cruor, a slaughterhouse by-product, contains mainly hemoglobin, broadly described as a rich source of antimicrobial peptides. In the current context of food safety, bioactive peptides could be of interest as preservatives in the distribution of food products. The aim of this work was to study the 137-141 fragment of hemoglobin (Thr-Ser-Lys-Tyr-Arg), a small (653Da) and hydrophilic antimicrobial peptide. Its production was fast, with more 65% finally produced at 24h already produced after 30min of hydrolysis with pepsin. Moreover, increasing substrate concentration (from 1 to 8% (w/v)) resulted in a proportional augmentation of 137-141 production (to 807.9541.03mgL(-1)). The 137-141 application on meat as preservative (0.5%, w/w) reduced the lipid oxidation about 60% to delay meat rancidity. The 137-141 peptide also inhibited the microbial growths under refrigeration during 14days. These antimicrobial effects were close to those of the butylated hydroxytoluene (BHT).


Hassoun A.,CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute | Karoui R.,CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute
Food Chemistry | Year: 2016

Quality assessment of whiting (Merlangius merlangus) fillets stored in normal air (control group) and modified atmosphere packaging (MAP1: 50% N2/50% CO2 and MAP2: 80% N2/20% CO2) for up to 15 days at 4 °C was performed. The physico-chemical [pH, drip loss, moisture content, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS) and peroxide value (PV)], textural (i.e., hardness, fragility, gumminess, chewiness, springiness, cohesiveness), and color (i.e., L∗ a∗ b∗) parameters were determined. Front face fluorescence spectroscopy (FFFS) emission spectra were also scanned on the same samples with excitation set at 290 and 360 nm. The results indicated that MAP treatment, particularly MAP1 had an obvious preservative effect on fish quality by reducing pH value, TBARS and TVB-N contents, and retarding the softening of fish texture compared to control samples. Principal component analysis (PCA) applied to physico-chemical and instrumental data sets showed a clear discrimination of fish samples according to both their storage time and condition. A complete (100%) of correct classification was obtained by the concatenation of spectral, physico-chemical, and instrumental data sets. The results demonstrated that storage under MAP can be recommended to improve quality of whiting fillets, which in turn, can be evaluated by FFFS as a rapid and non-destructive technique. © 2016 Elsevier Ltd. All rights reserved.


Kamal M.,CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute | Karoui R.,CNRS Regional Laboratory of Agri-Food and Biotechnology Research: The Charles VIOLLETTE Institute
Trends in Food Science and Technology | Year: 2015

Authenticity of dairy products has become an urgent issue for producers, researchers, governments, consumers and so on due to the increase of falsification procedures inducing lost large of money as well as the confidence of consumers. The determination of the authenticity and the detection of adulteration of milk and dairy products have been determined by several analytical techniques (e.g., physico-chemical, sensory, chromatography, and so on). Although these methods are considered as the reference ones, they required sophisticated analytical equipment's and skilled operators; they are also time consuming and need both the purchase and disposal of chemical reagents. Therefore, there is a need to find cheap and fast methods for the determination of the authenticity and the detection of adulteration of these products. Thus, spectroscopic techniques such as fluorescence spectroscopy, near infrared (NIR), mid infrared (MIR), nuclear magnetic resonance (NMR), among others, in combination with multivariate data analysis methods could be considered helpful tools in this domain. The advantages and disadvantages of each technique will be also discussed in this review. © 2015.

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