Antibacterial Activity of Some Lactic Acid Bacteria Isolated from an Algerian Dairy Product

In the present study, the antibacterial effect of 20 lactic acid bacteria isolates from a traditional cheese was investigated. 6 isolates showed antibacterial effect against Gram positive bacteria. Streptococcus thermophilus T2 strain showed the wide inhibitory spectrum against the Gram positive bacteria. Growth and bacteriocin production profiles showed that the maximal bacteriocin production, by S. thermophilus T2 cells, was measured by the end of the late-log phase (90 AU ml−1) with a bacteriocine production rate of 9.3 (AU ml−1) h−1. In addition, our findings showed that the bacteriocin, produced by S. thermophilus T2, was stable over a wide pH range (4–8); this indicates that such bacteriocin may be useful in acidic as well as nonacidic food. This preliminarily work shows the potential application of autochthonous lactic acid bacteria to improve safety of traditional fermented food

Stabilisation de l'hemoglobine par les solvants organiques: etude de l'auto-oxydation et de la denaturation thermique

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 79638 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Ultrafiltration Fractionation of Bovine Hemoglobin Hydrolysates: Prediction of Separation Performances for Optimal Enrichment in Antimicrobial Peptide

International audienc

Physicochemical and biological properties of eel by-products protein hydrolysates: Potential application to meat product preservation

European eel by-products have been hydrolysed in order to produce novel bioactive peptides with antibacterial and antioxidant activity. Protein hydrolysates from Anguilla by-products obtained by treatment with Savinase® (PHAB-s) have high protein content than that produced with Protamex® (PHAB-p). Furthemore, both protein hydrolysates had a high percentage of essential amino acids. In addition, results indicated that PHAB-s and PHAB-p exhibited different degrees of antioxidant activities, evaluated by several antioxidant assays. Thus, PHAB-s displayed high antioxidant activity, in terms of DPPH-radical scavenging effect (IC50 = 5.2 mg/ml), β-carotene bleaching inhibitory effect (CI50 = 4.4 mg/ml) and metal chelating activity. At 10 mg/ml, PHAB-p showed the highest reducing power. Antibacterial activities of PHAB-s and PHAB-p were also evaluated. PHAB-s showed the most important inhibitory effects against seven bacterial species. The application of PHAB-s and PHAB-p on minced meat as preservative reduced the lipid oxidation and inhibited the microbial growth during chilled storage for 11 days.This work was funded by the Ministry of Higher Education and Scientific Research, Tunisia and the Spanish Ministry of Economy, Industry and Competitiveness under project AGL2014-52825-R.Peer reviewe

Biochemical and antioxidant properties of peptidic fraction of carotenoproteins generated from shrimp by-products by enzymatic hydrolysis

The composition, functional properties and in vitro antioxidative activity of the peptidic fraction of carotenoproteins from shrimp (Parapenaeus longirostris) by-products generated by enzymatic treatment with Alcalase® was evaluated. The peptidic fraction of carotenoproteins (PFCP) contained 80.8 ± 0.21% protein, 2.74 ± 0.3% lipid, 14.4 ± 0.14% ash, 1.13 ± 0.08% chitin and 1.08 ± 0.02 μg total carotenoid/g of sample. The amino acid profile of PFCP showed a high percentage of essential amino acids, such as arginine, lysine, histidine and leucine. Therefore, PFCP had a high nutritional value and could be used as a supplement to poorly balanced dietary proteins. PFCP showed an excellent solubility and possessed interfacial properties, which were governed by their concentrations. The antioxidant activities of PFCP at different concentrations were evaluated using various in vitro antioxidant assays, including the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power, chelating effects assay and β-carotene bleaching. The antioxidant activity of PFCP, based on their protection of supercoiled DNA strand from scission by peroxyl and hydroxyl radicals into the nicked circular form was also investigated. Results from this study suggest that the peptidic fraction of carotenoproteins is a good source of natural antioxidants and peptides with interesting functionalities.This work was funded by the Ministry of Higher Education and Scientific Research, Tunisia, and also by the Spanish Ministry of Foreign Affairs (ref. AP/038291/11).Peer Reviewe

ETUDES DE L’IMMOBILISATION ET LA SELECTIVITE DE LA PEPSINE DANS UN MICROENVIRONNEMENT HYDROPHILE CATIONIQUE

L’intérêt de ces études est de favoriser l’apparition de peptides a activités biologiques au cours de l’hy droly se de l’hémoglobine. La fixation de la pepsine sur l’alumine a permis d’observer une modification de la sélectivité de la réaction d’hy droly se de l’hémoglobine : l’accumulation d’une population peptidique intermédiaire de haute masse moléculaire est favorisée par rapport à la réaction menée en phase homogène (Figure 4,5). Avec la pepsine immobilisée sur l’alumine native et fonctionnalisée, il a été observe que la vitesse d’hy droly se de la VV-hémorphine 7 est ralentie comparée à la réaction menée en phase homogène. Enfin, après immobilisation de la pepsine sur native et fonctionnalisée, une production considérablement accélérée de la néoky otorphine a été mise en évidence

Spectral irradiance calibrations at the National Research Council of Canada (NRC)

The basis of accurate photometric evaluations of light sources is provided by accurate spectral measurements under specified geometric conditions. This accuracy is ensured by traceable, internationally recognized absolute spectroradiometric scales. National Metrology Institutes (NMIs) develop primary-level spectroradiometric facilities and verify these absolute optical measurements through international comparisons with other NMIs. This paper describes the NRC facilities, standards and the results of recent international CCPR (Consultative Committee for Photometry and Radiometry) key comparisons of spectral irradiance measurements. It concludes with a brief update on our plans for using our new high-temperature blackbody as the basis for a new spectroradiometric scale.Peer reviewed: YesNRC publication: Ye