Food Science and technology

The traditional manufacturing method of Kishk involves a daily addition of plain yoghurt to Bourghul (5:1 ratio), followed by heavy handling during the 5-day period of uncontrolled fermentation. In order to improve quality, safety and yield losses, a modified procedure with a single addition of strained yoghurt (Labneh), in a 3:1 ratio, was investigated. The physico-chemical, microbiological and sensory characteristics of both Kishk products were assessed during five days of controlled fermentation (RT: 23- 25 °C; RH: >85%). Green and dried modified-Kishk were of similar quality characteristics when compared to traditional ones. Moisture content was lower in traditional (63 %) compared to modified (66 %), whereas titratable acidity was higher in modified Kishk (1.22 against 1.02 %). Peroxidation (PV = 0; TBARS = 0.2 mg MDA/Kg), and lipolysis (AV max 3.48 %) were always in the acceptable ranges. Pathogenic bacteria (E. coli, Salmonella spp., L. monocytogenes, S. aureus) were not d...

Un merci du coeur à tous mes collègues, Lamia et Lyes, pour vos discussions intéressantes, Jad, pour ton support « chimiométrique » et ton amitié, et surtout Gisèle, pour qui je garde des souvenirs inoubliables. A tous mes amis qui ont partagé les bons et les moins bons moments, tout au long de cette thèse, je vous remercie. Un grand merci à mes parents pour m'avoir permis de réaliser mes longues études et pour tous leurs sacrifices consentis. Sans vous, je n'aurais jamais pu aller jusqu'au bout. Un merci à vous, mes chères soeurs, pour vos encouragements et votre soutien, souvent discret, mais toujours efficace. Enfin, à mon mari, Tony, pour avoir vécu au rythme de ma thèse, pour avoir été si patient, et m'avoir soutenue dans les moments de découragement, merci.

The aim of the present study was to quantify some nutritional and safety quality parameter changes that take place in nuts (roasting) and sesame seeds (dehulling, roasting, milling, and sterilization) during processing. Such evaluation was based on chemical analysis of various indicators of lipid alteration in raw and processed pistachios, almonds, peanuts, and tahina. Lipid oxidation was assessed by the evolution of lipid oxidation products including hydroperoxides, p-anisidine, and thiobarbituric acid reactive substances, as well as carboxymethyllysine (CML) and trans fatty acids (tFAs). All these parameters were significantly affected by the different processing stages, especially by roasting and sterilization (tahina). Nut roasting and sesame heat treatment increased the primary (hydroperoxides) and secondary (aldehydic compounds) lipid oxidation products, with the p-anisidine value reaching 6-11.5 and thiobarbituric acid reactive substances 3-5 mg/kg (equiv of malondialdehyde) in the different end products. In addition, roasting led to the formation of CML (between 12.7 and 17.7 ng/mg) and tFAs (between 0.6 and 0.9 g/100 g) in nuts and tahina, which were absent in the raw material. Roasting parameters appear as the critical factor to control to limit the CML and tFA formation in the final product.

Un merci du coeur à tous mes collègues, Lamia et Lyes, pour vos discussions intéressantes, Jad, pour ton support « chimiométrique » et ton amitié, et surtout Gisèle, pour qui je garde des souvenirs inoubliables. A tous mes amis qui ont partagé les bons et les moins bons moments, tout au long de cette thèse, je vous remercie. Un grand merci à mes parents pour m'avoir permis de réaliser mes longues études et pour tous leurs sacrifices consentis. Sans vous, je n'aurais jamais pu aller jusqu'au bout. Un merci à vous, mes chères soeurs, pour vos encouragements et votre soutien, souvent discret, mais toujours efficace. Enfin, à mon mari, Tony, pour avoir vécu au rythme de ma thèse, pour avoir été si patient, et m'avoir soutenue dans les moments de découragement, merci.

In order to develop a new Kishk-based ripened semi-hard cheese, two different wheat types, namely Bourghol and Semolina, were used. The process involved adding together cereal, goat strained yogurt, starter cultures and rennin enzyme. Physicochemical parameters and sensory attributes were assessed during 4 weeks of ripening at 10°C. The results showed an increase in titratable acidity, pH and solubility index in both types of cheese over ripening period reaching final levels of 1.95%, 3.75 and 85% respectively. Free amino acids were accumulating in Semolina cheese (17.75 mg Leu/g in final product), with a sharp increase after week 2 concurring with a marked decrease in residual lactose. A higher depletion rate of residual lactose was observed for Semolina cheese (49% in Semolina vs 40% in Bourghol) (p<0.05), reflecting better utilization of lactose by LAB. Both types of cheese showed limited oxidation rates (low peroxide and TBARS values) and balanced lipolysis, where FFA for...

The influence of growing-area and technological aspects on the Lebanese Soury variety is presented. The pedoclimatic conditions, quality parameters, and fatty acids of oil samples were examined using chemometric tools to demonstrate the typicality of Lebanese olive oil. Furthermore, the effect of several technological factors on olive oil quality was studied. Accordingly, olive oil samples were collected across Lebanon corresponding to two climatic zones (Zone A: Low-altitude regions; Zone B: High-altitude regions). Principal component analysis was capable of discriminating the two zones with distinct fatty acid profiles. Zone A exhibited a fatty acid profile mostly dominated by linoleic, linolenic, palmitic, and palmitoleic acid content. As for zone B, it showed a unique fatty acid profile distinguished by oleic acid. These results are mostly attributed to the climatic effect and the altitude of the growing area. Moreover, independent component analysis, coupled to one-way ANOVA, d...

The impact of harvest period on the quality parameters, polyphenols, fatty acids, sterols, and volatile compounds of Lebanese olive oil from the Soury variety was investigated in this study. Two groups of olive oil were compared, each with a specific harvest date. HD1 was harvested in October, whereas HD2 was picked in November. The analysis of both olive oil categories showed that HD2 witnessed a significant increase in all quality parameters except K270 and a decrease in total polyphenol content from 138 mg/mL to 44 mg/mL. Oleic and linoleic acids had an inverse relation, where the former decreased and the latter increased with the harvest date’s advancement. Palmitic acid in both groups was higher than the standards set for extra virgin olive oil. The relative amount of β -Sitosterol was mainly found to decrease, while those of stigmasterol, ∆5,24 -stigmastadienol, ∆7 -stigmastenol, and ∆7 -avenasterol increased with delaying harvest time. As for the volatile compounds, principle...

The potential of front-face fluorescence spectroscopy coupled with chemometric techniques, namely multiple linear regression (MLR) applied on parallel factor (PARAFAC) scores and partial least squares (PLS), was tested on Lebanese olive oil samples possessing natural variability within their chemical parameters. Ninety-six olive oil samples have been harvested at different dates and from two seasons, processed using different extraction methods, collected from different altitudes and other factors that can increase the variability of the samples' chemical composition. Fluorescence excitation-emission matrices (EEM) of the collected samples were measured, and the relationship between them and the chemical parameters was examined. Twenty-two MLR regression models based on PARAFAC scores were generated, the majority of which showed a good correlation coefficient (R > 0.7 for ten predicted variables). A second model using PLS on the unfolded EEM was also conducted to improve the regression and to assess if it can handle the variability in hand. However, similar results, with a slight improvement over the MLR model, were obtained. In a non-experimental design, such variability may hinder the potentials of front-face fluorescence; however average to good MLR and PLS models were obtained, predicting the Lebanese olive oil deterioration quality parameters and fatty acid content.

Background Coronavirus disease 2019 (COVID-19) has affected millions of lives globally. However, the disease has presented more extreme challenges for developing countries that are experiencing economic crises. Studies on COVID-19 symptoms and gut health are scarce and have not fully analyzed possible associations between gut health and disease pathophysiology. Therefore, this study aimed to demonstrate a potential association between gut health and COVID-19 severity in the Lebanese community, which has been experiencing a severe economic crisis. Methods This cross-sectional study investigated SARS-CoV-2 PCR-positive Lebanese patients. Participants were interviewed and gut health, COVID-19 symptoms, and different metrics were analyzed using simple and multiple logistic regression models. Results Analysis of the data showed that 25% of participants were asymptomatic, while an equal proportion experienced severe symptoms, including dyspnea (22.7%), oxygen need (7.5%), and hospitalizat...

This study aimed at demonstrating the antiviral activity of Lactobacillus gasseri CMUL57 (L. gasseri CMUL57), L. acidophilus CMUL67 and L. plantarum CMUL140 against herpes simplex type 2 (HSV-2) and Coxsackievirus B4E2 (CVB4E2), which are enveloped and naked viruses, respectively. These lactobacilli were non-cytotoxic and were able to reduce the cytopathic effect induced by HSV-2 in Vero cell monolayers. However, lactobacilli were not active against CVB4E2. Tested lactobacilli displayed anti-HSV-2 activity when they were co-incubated with the virus prior to inoculating the mixture to Vero cell monolayers. The detection of HSV-2 DNA by PCR in pellets of bacteria/virus mixtures let us to hypothesize that anti-HSV-2 activity of lactobacilli resulted from the viruses' entrapment. This study showed the capabilities of vaginal lactobacilli to inhibit enveloped viruses such as HSV-2. Keywords Antiviral • Interaction virus and mammalian cells • Lactobacillus • Anti-herpetic activity Communicated by Erko Stackebrandt.

doc.univ-lille1.fr Mesdames Dolla SARKIS et Berthe Marie IMBERT m'ont fait l'honneur d'être rapporteurs de ma thèse, elles ont pris le temps de m'écouter et de discuter avec moi. Leurs remarques m'ont permis d'envisager mon travail sous un autre angle. Pour tout cela je les remercie. Je remercie aussi tous les examinateurs membres de mon jury qui, à chaque étape de mon cursus de formation, m'ont prodigué d'utiles conseils qui m'ont aidé à bien structurer mon étude : il s'agit de Monsieur Jacques MOKHBATE, Ghassan MATAR et Mohamed AMICHE. Je tiens à remercier Professeur Pascal DHULSTER, directeur de l'institut Charles violette où j'ai travaillé en France, et mes sincères remerciements au Professeur Philippe Jacques, directeur adjoint de l'école doctorale SMRE. Mes remerciements vont également à M .le Prof Mohamad KHALIL, Directeur du Centre AZM de Biotechnologie-Tripoli, pour la gentillesse et la patience qu'il a manifestées à mon égard durant cette thèse, pour toutes les facilités administratives menées de son part. J'aimerais aussi remercier le doyen de l'école doctorale sciences et technologie, M. le Prof Fawaz EL OMAR, pour son support et sa gentillesse. J'aimerais adresser un remerciement particulier à professeur Fouad DABOUSSI, Professeur à l'université Libanaise, pour sa gentillesse, sa bonne humeur et son soutien tout au long de ces années et surtout les derniers mois difficiles. Je tiens à remercier mes plus proches collègues, docteurs ou futurs docteurs, pour la bonne ambiance de travail : Marwan OSMAN, Michel WEHBE, Dima EL SAFADI, Rayane RAFEI, Sara KHALIFE, Dr. Bachar ISMAIL et Dr. Adnan HALABI. Je tiens également à remercier tous les membres du "laboratoire" ProBioGEM et plus particulièrement Monsieur Max BECHET et Madame Cathy OUBLION pour leurs aides et leur gentillesse. Je passe mes remerciements avec mes sentiments d'honneurs pour mes amies et collègues au Laboratoire de Microbiologie au centre AZM, et très

the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

In recent decades, probiotics have shown benefi cial effects on animal and human health. Probiotics can protect the host against several health threats, including infectious diseases. Before 1995, researchers believed that the effect of probiotics was only on gut microbiota which can restore the gut fl ora and thus prevent pathogenic bacteria from triggering gastroenteritis. Recent studies have shown that the immunomodulatory activity is the most important mechanism of action of probiotics. From this information, researchers started to evaluate the effect of some immunobiotics, not only on pathogenic bacteria but also on viruses, including enteric and respiratory viruses. Several studies have confi rmed the potential antiviral activity of some probiotics due to the immunomodulatory effect. These studies were conducted on humans (clinical trials) and in animal models. In this chapter, probiotics with antiviral effect against respiratory and enteric viruses will be presented and discussed, as well as their mechanisms of action.

La listériose, bien qu'elle soit une zoonose, est une pathologie invasive qui peut affecter les nouveau-nés, les femmes enceintes ainsi les adultes immunodéprimés. Les manifestations cliniques se traduisent par des gastroentérites fébriles, des formes sévères invasives incluant les septicémies, méningites, rhombencéphalites, infections prénatales et avortements. Les espèces de Listeria sont des bactéries ubiquitaires, capables de s'adapter à l'environnement, chez l'animal et les aliments végétaux. Dans ce travail, notre objectif a été d'évaluer la présence de Listeria monocytogenes dans du lait cru collecté au Liban Nord. Au total, cent échantillons de lait de vache ont été analysés par la technique Grand VIDAS (Biomérieux France). Les résultats obtenus ont révélé l'absence de Listeria monocytogenes dans tous les échantillons analysés.

Illness caused by enteropathogens represents an important economic and health burden worldwide. The majority of enteropathogens causes gastrointestinal infections which have a great impact on public health both in developing and developed countries. The aim of this study is to detect and identify the main enteropathogens in Lebanese diarrheal stool from children under 15 years old. The detection was performed by using both conventional method and microarray technique CLART ® EnteroBac (Genomica-Spain). Five enteric pathogens, Salmonella spp, Shigella spp, Clostridium difficile B, Enteropathogenic E. coli, Campylobacter jejuni were detected in 80 diarrheal stools, from children under 15 years old. The results showed that CLART ® EnteroBac technique have detected enteropathogens in 19% of samples, whereas 1% returned positive using stool culture methods.

Lactic acid bacteria (LAB) are used in many fields such as fermentation agents, increasing nutritional value and improving organoleptic quality of food. Also they are used as probiotics and preservatives against pathogens and spoilage microbes by producing antimicrobial substances such as bacteriocins. Fifty cow's milk samples were collected and 175 LAB isolates were isolated and identified by using biochemical method. Fifteen isolates showed an antimicrobial activity against Listeria monocytogenes ATCC® 19115™. One strain, BL4 which showed the strongest activity, was chosen to extract and characterize its antimicrobial substance in order to evaluate its potential use as a new food protective agent. This strain was identified as Enterococcus mundtii by pyrosequencing method. The active substance was extracted using solvent method. This Bacteriocin like Inhibitory Substances "BLIS" can support a high temperature (121 ˚C) for a long time and resist pH variation. The BLIS BL4 can be considered as a peptide active against many food pathogen and food-spoilage microbes, such as Listeria monocytogenes and Penicillium spp. BLIS BL4 can be used in food application as bio-preservative to reduce food-spoilage and food-borne diseases in food products.

Enterohemorrhagic Escherichia coli O157:H7 is a pathogenic strain associated with infections caused by consumption of undercooked raw meat. Sensitive and rapid detection methods for this pathogen are essential for the meat industry to ensure a safe meat supply. This study was conducted to determine the prevalence of E. coli O157:H7 in raw minced beef. A total of 80 raw minced meat samples were collected from eighty different slaughterhouses. Samples were investigated for the presence of E. coli O157:H7 by using VIDAS system followed by culture, biochemical characterization and PCR confirmation.It was observed that 18.8% (15/80) of samples were positive for E. coli O157:H7 by VIDAS, 33.33% (5/15) were identified as E. coli by conventional biochemical tests, while toxin genes amplification by PCR showed negative results for all samples 0%.