getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.56.02.18.5561 

Time-Kill Kinetics of Lipid Fractions Isolated from Condiments against Foodborne Pathogens


Ayeza Naeem1*orcid tiny, Tanveer Abbas1orcid tiny, Tahira Mohsin Ali2orcid tiny and Abid Hasnain2orcid tiny


1Department of Microbiology, University of Karachi, Main University Road, Karachi, 75270 Sindh, Pakistan
2Department of Food Science and Technology, University of Karachi, Main University Road, 75270 Sindh, Pakistan



Article history:
Received: 12 October 2017
Accepted: 2 March 2018
cc


Key words:
time-kill kinetics, scanning electron microscopy, cell constituent release, foodborne pathogens



Summary:
Lipid fractions that are extracted from condiments have a wide array of biological potential and are commonly utilized for medicinal and culinary applications. This investigation aims at determining the antimicrobial potential of lipid fractions isolated using two different solvent systems against five foodborne pathogens. The antibacterial efficacy was tested after 0, 1, 2, 3 and 24 h of incubation with the active agent. The leakage of cellular content was assessed at 1 and 2 h of incubation. Scanning electron microscope (SEM) images were obtained after 18 h of contact time with lipid fractions at their minimum inhibitory concentration (MIC). From the results obtained from time-kill and cell constituents release tests, it could be concluded that during 3 and 1 h of incubation, the lipid fractions were more potent against Gram-negative isolates (Escherichia coli ATCC 8739). However, prolonged incubation with the active agent inhibited Gram-positive isolate, i.e. Listeria monocytogenes ATCC 13932. SEM images of treated microorganisms also confirmed the inhibitory action of selected lipid fractions against all the tested pathogens. The cellular morphology of the bacteria was completely altered after 18 h of incubation with the lipid fractions. The results of the present study corroborate significant inhibitory effects and disruption in bacterial cell integrity following prolonged incubation with these lipid fractions. The results also affirm the use of the tested lipid fractions in food systems.



*Corresponding author:  email3  ayeza.naeem@gmail.com

getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.56.02.18.5393 

Bioprospecting for Genes Encoding Hydrocarbon-Degrading Enzymes from Metagenomic Samples Isolated from Northern Adriatic Sea Sediments


Ranko Gacesa1,2,3#orcid tiny, Damir Baranasic1,4#orcid tiny, Antonio Starcevic1,5orcid tiny, Janko Diminic1,5orcid tiny, Marino Korlević6orcid tiny, Mirjana Najdek6orcid tiny, Maria Blažina6orcid tiny, Davor Oršolić1orcid tiny, Domagoj Kolesarić1orcid tiny, Paul F. Long2,3orcid tiny, John Cullum4orcid tiny, Daslav Hranueli1,5orcid tiny, Sandi Orlic7,8orcid tiny and Jurica Zucko1,5*orcid tiny


1Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia
2Institute of Pharmaceutical Science King’s College London, Franklin-Wilkins Building, Stamford Street, London SE1 9NH, UK
3Department of Chemistry, King’s College London, Franklin-Wilkins Building, Stamford Street, London SE1 9NH, UK
4Department of Genetics, University of Kaiserslautern, Postfach 3049, DE-67653 Kaiserslautern, Germany
5Centre of Research Excellence for Marine Bioprospecting - BioProCro, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
6Centre for Marine Research, Ruđer Bošković Institute, G. Paliaga 5, HR-52210 Rovinj, Croatia
7Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
8Center of Excellence for Science and Technology Integrating Mediterranean Region, Microbial Ecology, HR-10000 Zagreb, Croatia



Article history:
Received: 16 June 2017
Accepted: 12 February 2018
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Key words:
oil pollution, n-alkane degradation, database


Summary:
Three metagenomic libraries were constructed using surface sediment samples from the northern Adriatic Sea. Two of the samples were taken from a highly polluted and an unpolluted site respectively. The third sample from a polluted site had been enriched using crude oil. The results of the metagenome analyses were incorporated in the REDPET relational database (http://redpet.bioinfo.pbf.hr/REDPET), which was generated using the previously developed MEGGASENSE platform. The database includes taxonomic data to allow the assessment of the biodiversity of metagenomic libraries and a general functional analysis of genes using hidden Markov model (HMM) profiles based on the KEGG database. A set of 22 specialised HMM profiles was developed to detect putative genes for hydrocarbon-degrading enzymes. Use of these profiles showed that the metagenomic library generated after selection on crude oil had enriched genes for aerobic n-alkane degradation. The use of this system for bioprospecting was exemplified using potential alkB and almA genes from this library.


*Corresponding author:  tel3  +38514605151
                                           fax2  +38514836083
                                            email3  jzucko@pbf.hr


#These authors contributed equally to this work

getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.56.02.18.5450 

Effect of Fermentation on the Protein Digestibility and Levels of Non-Nutritive Compounds of Pea Protein Concentrate


Burcu Çabuk1orcid tiny, Matthew G. Nosworthy2orcid tiny, Andrea K. Stone1orcid tiny, Darren R. Korber1orcid tiny, Takuji Tanaka1orcid tiny, James D. House2orcid tiny and Michael T. Nickerson1*orcid tiny



1Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK, S7N 5A8, Canada
2Department of Human Nutritional Sciences, Department of Food Science, Department of Animal Science, Canadian Centre for Agri-Food Research in Health and Medicine, Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada



Article history:
Received: 30 July 2017
Accepted: 28 February 2018
cc


Key words:
pea protein concentrate, fermentation, non-nutritive compounds, protein digestibility, protein quality



Summary:
In order to determine the impact of fermentation on protein quality, pea protein concentrate (PPC) was fermented with Lactobacillus plantarum for 11 h and total phenol and tannin contents, protease inhibitor activity, amino acid composition and in vitro protein digestibility were analyzed. Phenol levels, expressed as catechin equivalents (CE), increased on dry mass basis from 2.5 at 0 h to 4.9 mg CE per 1 g of PPC at 11 h. Tannin content rose from 0.14 at 0 h to a maximum of 0.96 mg CE per 1 g of PPC after 5 h, and thereafter declined to 0.79 mg/g after 11 h. After 9 h of fermentation trypsin inhibitor activity decreased, however, at all other fermentation times similar levels to the PPC at time 0 h were produced. Chymotrypsin inhibitor activity decreased from 3.7 to 1.1 chymotrypsin inhibitory units (CIU) per mg following 11 h of fermentation. Protein digestibility reached a maximum (87.4 %) after 5 h of fermentation, however, the sulfur amino acid score was reduced from 0.84 at 0 h to 0.66 at 11 h. This reduction in sulfur content altered the in vitro protein digestibility-corrected amino acid score from 67.0 % at 0 h to 54.6 % at 11 h. These data suggest that while fermentation is a viable method of reducing certain non-nutritive compounds in pea protein concentrate, selection of an alternative bacterium which metabolises sulfur amino acids to a lesser extent than L. plantarum should be considered.




*Corresponding author:  tel3  +13069665030
                                           fax2  +13069668898
                                            email3  Michael.Nickerson@usask.ca

getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.56.02.18.5474 

The Effect of Short-Toothed and Dalmatian Sage Extracts on Platelet Aggregation


Andrea Antolić1orcid tiny, Željan Maleš2orcid tiny, Maja Tomičić3orcid tiny and Mirza Bojić4*orcid tiny



1University of Zagreb, Faculty of Science, Roosevelt Square 6, HR-10000 Zagreb, Croatia
2University of Zagreb, Faculty of Pharmacy and Biochemistry, Department of Pharmaceutical Botany, Schrottova 39, HR-10000 Zagreb, Croatia
3Croatian Institute of Transfusion Medicine, Department of Platelet and Leukocyte Immunology, Petrova 6, HR-10000 Zagreb, Croatia
4University of Zagreb, Faculty of Pharmacy and Biochemistry, Department of Medicinal Chemistry, A. Kovačića 1, HR-10000 Zagreb, Croatia



Article history:
Received: 16 August 2017
Accepted: 15 December 2017
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Key words:
sage, flavonoids, phenolic acids, platelet aggregation



Summary:
Sage (Salvia sp.) is a genus of a native Mediterranean plant used for aromatization of foods. In this study, total polyphenolic profile, antioxidant properties and antiplatelet effect of short-toothed sage (Salvia brachyodon Vandas) are analyzed and compared to most commonly used Salvia species (S. officinalis, Dalmatian sage). Content of total flavonoids was 0.08-0.23 % and of phenolic acids 0.47-3.04 %. Antioxidant DPPH assay showed higher antioxidant capacity of S. brachyodon (29-36 mg/mL of gallic acid equivalents) than of S. officinalis. In functional test of primary haemostasis, extracts of S. brachyodon have prevented platelet aggregation in nanomolar concentration (21 nM), thus showing potential in prevention of thrombus formation as functional food or dietary supplement. Antiplatelet activity was related to antioxidant capacity (r=0.7014, p=0.0352) indicating that prevention of aggregation is not caused by an individual component, but it is rather a result of synergistic effect of polyphenols. The obtained results are preliminary and a more detailed study of the possibility of applying the investigated plant species as supplements for the prevention of the problem of cardiovascular system and platelet aggregation is needed.



*Corresponding author:  tel3  +38514818304
                                           fax2  +38516394400
                                            email3  mbojic@pharma.hr

getpdf  NLM-PubMed-Logo  doi: 10.17113/ftb.56.02.18.5414 

The Tunisian Artemisia Essential Oil for Reducing Contamination of Stored Cereals by Tribolium castaneum


Ikbal Chaieb1,2orcid tiny, Amel Ben Hamouda2*orcid tiny, Wafa Tayeb3orcid tiny, Khaoula Zarrad2orcid tiny, Thameur Bouslema2orcid tiny and Asma Laarif2orcid tiny


1Laboratory of Plant Protection, University of Carthage, National Agricultural Research Institute of Tunisia, Hédi Karray Street, TN-2049 Ariana, Tunis, Tunisia
2University of Sousse, Regional Centre of Research on Horticulture and Organic Agriculture, 57, Chott Mariem, TN-4042 Sousse, Tunisia
3Biochemistry Laboratory, Nutrition-Functional Foods and Vascular Health, University of Monastir, Faculty of Medicine, Avicenne Street, TN-5019 Monastir, Tunisia



Article history:
Received: 16 July 2017
Accepted: 22 November 2017
cc


Key words:
Artemisia sp., essential oil, chemical composition, insecticidal activity, repellency



Summary:
Essential oils of three species of Artemisia genus (A. absinthium L., A. campestris L. and A. herba-alba (Asso)) were analyzed by gas chromatography–mass spectrometry (GC-MS) and their potential insecticidal and repellent activities against the stored grain insect Tribolium castaneum (Herbst) was investigated. Fumigant and repellent activity bioassays were investigated in vitro. Chemical characterisation of essential oils showed that the bicyclic monoterpenes were predominant in all Artemisia essential oils, A. absinthium essential oil having the highest content of bicyclic monoterpenes, bicycloheptanes, naphthalenes and cycloalkenes. A. campestris had the highest content of sesquiterpenoids and acyclic monoterpenoids. A. herba-alba was characterised by the highest amounts of menthane monoterpenoids, oxanes, cumenes, oxolanes, ketones, benzenoids and monocyclic monoterpenes. Fumigant bioassay demonstrated that the three types of oil applied separately caused significant insect mortality. The lowest median lethal dose, LC50=142.8 μL/L, was observed with A. herba-alba. In repellency test, essential oil of A. absinthium was more potent with more rapid action than all other species. The mixture of Artemisia sp. essential oils showed an antagonistic effect in all the tested combinations. This study highlighted an important potential of Artemisia sp. especially A. herba-alba and A. absinthium in the control of the pests of stored products.



*Corresponding author:  email3  ben.hamouda@yahoo.fr

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