34 research outputs found

    Grape Microbiome: Potential and Opportunities as a Source of Starter Cultures

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    Grape microbiome is the source of a vastly diverse pool of filamentous fungi, yeast and bacteria that will play a coordinated role for the quality of the produced wines. In recent times, the significance of this pool of microorganisms with a long list of studies of the microbial ecology of grape berries of different geographical origin, cultural practices, grape varieties and climatic conditions has been acknowledged. Similarly, the ongoing microbial evolution of must fermentations has been fully uncovered. All these ecology studies, along with detailed metabolic studies and sensorial characterisations of the produced wines, led to the suggestion of the microbial terroir. These new concepts are today leading worldwide research efforts to the production of unique wines, preserving their historical identity and verifying their quality and geographical origin. This chapter is a quick but thorough and up-to-date review of how autochthonous microbiota highlight the terroir in wines, a comparison of commercial and wild yeast strains and how this biodiversity has been explored. Moreover, technological, physiological and oenological selection criteria will be under consideration. At the end, the positive and negative aspects of wild vinifications, the technological problems of wild strains and some suggestions for the future in starter cultures will be presented

    Yeast Ecology of Fermented Table Olives: A Tool for Biotechnological Applications

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    The table olive is considered to be a traditional fermented vegetable in the Mediterranean countries and its production and consumption is recently spreading all around the world. The presence of yeasts is very important during olive fermentation due to their double role. On one hand, yeasts maintain desirable biochemical activities (lipase, esterase, β-glucosidase, catalase, production of killer factors, etc.) with essential technological applications in this fermented vegetable. On the other hand, spoilage activity may be shown. However, recent studies have reported that yeasts coming from table olives would be a new source of potential probiotics. Indeed, many yeast species found in table olive processing, have been reported to demonstrate such properties. Thus, starter cultures technology will play significant role, not only in olive fermentation by controlling the safety and the quality of the final product, but also in consumer’s health

    The Multiple and Versatile Roles of Aureobasidium pullulans in the Vitivinicultural Sector

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    The saprophytic yeast-like fungus Aureobasidium pullulans has been well documented for over 60 years in the microbiological literature. It is ubiquitous in distribution, being found in a variety of environments (plant surfaces, soil, water, rock surfaces and manmade surfaces), and with a worldwide distribution from cold to warm climates and wet/humid regions to arid ones. Isolates and strains of A. pullulans produce a wide range of natural products well documented in the international literature and which have been regarded as safe for biotechnological and environmental applications. Showing antagonistic activity against plant pathogens (especially post-harvest pathogens) is one of the major applications currently in agriculture of the fungus, with nutrient and space competition, production of volatile organic compounds, and production of hydrolytic enzymes and antimicrobial compounds (antibacterial and antifungal). The fungus also shows a positive role on mycotoxin biocontrol through various modes, with the most striking being that of binding and/or absorption. A. pullulans strains have been reported to produce very useful industrial enzymes, such as β-glucosidase, amylases, cellulases, lipases, proteases, xylanases and mannanases. Pullulan (poly-α-1,6-maltotriose biopolymer) is an A. pullulans trademark product with significant properties and biotechnological applications in the food, cosmetic and pharmaceutical industries. Poly (β-l-malic acid), or PMA, which is a natural biopolyester, and liamocins, a group of produced heavy oils and siderophores, are among other valuable compounds detected that are of possible biotechnological use. The fungus also shows a potential single-cell protein source capacity with high levels of nucleic acid components and essential amino acids, but this remains to be further explored. Last but not least, the fungus has shown very good biocontrol against aerial plant pathogens. All these properties are of major interest in the vitivinicultural sector and are thoroughly reviewed under this prism, concluding on the importance that A. pullulans may have if used at both vineyard and winery levels. This extensive array of properties provides excellent tools for the viticulturist/farmer as well as for the oenologist to combat problems in the field and create a high-quality wine

    The stability pact for Southeastern Europe 1999-2008: the post-cold war international experience on cooperation and organization in the Balkans

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    The thesis focuses on the special institutional characteristics and the role of the Stability Pact for Southeastern Europe, as well as on its work, for stabilizing post-conflict SEE during 1999-2008, by approaching the SP as a unique construct of international law and international institutions. The SP is framed within the political and institutional post-Cold War environment, as well as the within the broader process of regional and European integration. The theoretical perspective on which the thesis is based is that of pluralism, with evident elements of constructivism. Given that there has been no such analysis or approach of the SP in the past, research was based on primary resources and it included original documents of international treaties and agreements, decisions and declarations, as well as interviews with key people involved in the Stability Pact. The thesis includes an introduction, six chapters, conclusions and annexes. Chapter 1 explores various structures of international organization, focusing on international and the establishment of norms and principles, by approaching the SP as an original institution which introduced international norms to Southeast Europe. Chapter 2 discusses the post-Cold War framework of institutional structures in Europe, focusing on issues related with intervention and preventive diplomacy, and an emphasis on the role of the Organization for Security and Cooperation in Europe (OSCE). Chapter 3 provides and analysis of the particular historic and political conditions leading to the establishment of the Stability Pact for SEE as a part of the EU’s and Euro-Atlantic community’s enlargement strategy. Chapter 4 offers a detailed overview of the constituent documents of the SP and its functions, while Chapter 5 presents the broader structure of regional cooperation and organization in SEE, which the SP added to. Chapter 6 is focused on the innovative nature of the SP in terms of its legal characteristics, offering an analysis as an international organization and discussing its unique legal features, as well as its methods and modus operandi. The conclusions of the thesis discuss the effect of the work of SP on integration on the state level, a regional level and on a European level. Finally, the work of the SP is evaluated as an experience on which the international community may build further, through formalizing cooperation of already existing development mechanisms (e.g. the UN network and the World Bank), under the auspices of a permanent institution to promote stability and prevent crises using the comprehensive model introduced by the Stability Pact for SEE.Η διδακτορική διατριβή επικεντρώνεται στα ιδιαίτερα θεσμικά χαρακτηριστικά και το ρόλο του Συμφώνου Σταθερότητας για τη ΝΑ Ευρώπη, και το έργο του για τη σταθεροποίηση της ΝΑ Ευρώπης κατά την περίοδο 1999-2008, εξετάζοντας το μηχανισμό αυτό ως ιδιαίτερο μόρφωμα του διεθνούς δικαίου και της διεθνούς θεσμοποίησης, θέτοντάς τον στο πλαίσιο των πολιτικών και θεσμικών συνθηκών της μετα-Ψυχροπολεμικής περιόδου, αλλά και της διαδικασίας περιφερειακής και Ευρωπαϊκής ολοκλήρωσης. Θεωρητικά, η διατριβή είναι βασισμένη στο πλαίσιο του πλουραλισμού, με στοιχεία κονστρουκτιβισμού. Η έρευνα υπήρξε πρωτογενής, καθώς δεν έχει υπάρξει αντίστοιχη εξέταση ή ανάλυση του Συμφώνου Σταθερότητας στο παρελθόν. Περιελάμβανε αναδρομή σε πρωτότυπα κείμενα διεθνών συνθηκών, συμφωνιών, αποφάσεων και διακηρύξεων, αλλά και συνεντεύξεις με πρόσωπα που διαδραμάτισαν ρόλο σχετικά με το έργο του Συμφώνου Σταθερότητας. Η διατριβή περιλαμβάνει εισαγωγή, 6 κεφάλαια, συμπεράσματα και παραρτήματα. Στο πρώτο κεφάλαιο, εξετάζονται θέματα της διεθνούς οργάνωσης, με επίκεντρο το διεθνές δίκαιο και την καθιέρωση διεθνών κανόνων και αρχών συμπεριφοράς, προσεγγίζοντας το Σύμφωνο Σταθερότητας ως πρωτότυπο θεσμό εισαγωγής διεθνών αρχών και αξιών στη περιοχή της ΝΑ Ευρώπης. Στο δεύτερο κεφάλαιο γίνεται ανάλυση του πλαισίου θεσμικής συνεργασίας στην Ευρώπη μετά το τέλος του Ψυχρού Πολέμου, με έμφαση στα θέματα της νομιμοποιημένης παρέμβασης και της αποτρεπτικής διπλωματίας, κυρίως μέσω του Οργανισμού για την Ασφάλεια και τη Συνεργασία στην Ευρώπη. Στο τρίτο κεφάλαιο εξετάζεται το ειδικό ιστορικό και πολιτικό πλαίσιο γένεσης του Συμφώνου Σταθερότητας για τη ΝΑ Ευρώπη, με κεντρικό άξονα τη στρατηγική διεύρυνσης της Ευρωπαϊκής Ένωσης και της ευρύτερης Ευρω-Ατλαντικής κοινότητας. Στο τέταρτο κεφάλαιο αναλύεται το περιεχόμενο του Συμφώνου Σταθερότητας για την ΝΑ Ευρώπη, και ο τρόπος λειτουργίας του, ενώ στο πέμπτο κεφάλαιο παρουσιάζεται το συνολικό πλαίσιο περιφερειακής συνεργασίας και οργάνωσης στα Βαλκάνια, στο οποίο εντάχθηκε και το οποίο συμπλήρωσε το Σύμφωνο Σταθερότητας. Το έκτο κεφάλαιο επικεντρώνεται στην καινοτομία του Συμφώνου Σταθερότητας ως νομικό μόρφωμα, με ανάλυση των χαρακτηριστικών του ως διεθνούς οργανισμού - τόσο ως προς τις νομικές του διαστάσεις, όσο και ως προς τον τρόπο λειτουργίας και δράσης του. Στα συμπεράσματα της διατριβής εξετάζεται η επίδραση του Συμφώνου Σταθερότητας για τη ΝΑ Ευρώπη τόσο στο επίπεδο της εσωτερικής ολοκλήρωσης (σε επίπεδο κράτους), όσο και στο περιφερειακό επίπεδο και στο επίπεδο της Ευρω-Ατλαντικής ολοκλήρωσης. Τέλος, αξιολογείται το έργο του Συμφώνου Σταθερότητας ως μια εμπειρία πάνω στην οποία η διεθνής κοινότητα μπορεί να χτίσει περαιτέρω, μέσω της συνεργασίας ήδη υπαρχόντων μηχανισμών ανάπτυξης (π.χ. δίκτυο ΟΗΕ και Παγκόσμια Τράπεζα), δημιουργώντας ένα μόνιμο διεθνή φορέα που θα προσεγγίζει θέματα σταθεροποίησης και αποτροπής κρίσεων στα πρότυπα της ολοκληρωμένης προσέγγισης της ανάπτυξης από το Σύμφωνο Σταθερότητας για τη ΝΑ Ευρώπη

    Microbial composition and physicochemical attributes of traditional feta cheese made in different mountainous regions

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    The microbiological and compositional characteristics, as well as the volatile organic compounds (VOCs) of traditional Feta cheese produced in three mountainous areas of Greece from milk obtained by animals of local herds fed exclusively with fresh pasture, were studied. The dominant microbial group was Lactic Acid Bacteria (LAB). Their identification with the SDS-PAGE showed that Lc. lactis subsp. lactis prevailed in milk and fresh cheese samples, while Lb. plantarum in mature cheeses. A great variability in the technological properties among the different strains of all areas, was recorded. The results suggested that cheeses from the three areas differ in species composition of NSLAB and their technological properties. Thus, cheeses may mature differently and develop different flavor characteristics. The genetic diversity of NSLAB isolates was assessed by RAPD-PCR and PFGE. The data indicated intraspecies genetic heterogeneity and specificity depending on the production area. In addition, traditional Feta cheese may be the source of different NSLAB genotypes in order to make cheese with specific sensorial attributes, characteristic for each area. The dynamics and the diversity of dominant microbiota in fresh and mature Feta cheese was assessed applying the PCR-DGGE method. DGGE profiles suggested variability in the microbial composition of cheeses within the production area and distinctive differences in band profile of NSLAB in cheeses between the three areas, revealing species that were not isolated during the culturing study. The compositional characteristics, amino acids and short chain organic acids, commonly found in traditional Feta cheese, showed that the area of production influenced each parameter studied. The results suggested that the cheeses may be differentiated, according to their production area, by their compositional characteristics. The VOCs profile and content of the plants, bulk forage, raw milk samples, fresh and mature cheeses, were evaluated. The PCA applied to the 23 collected plant species, could differentiate the two areas with respect to VOCs composition. The milk obtained from the three areas, was poorer in VOCs than the plant species. Common terpenes for plants and milk may be used as bio-markers for linking traditional Feta cheese to the respective grazing pasture, as PCA suggested. Aldehydes were found in higher (P<0.05) amounts for area 1 fresh cheeses, ketones for cheeses from area 2 (P<0.05) and alcohols for cheeses from area 3 (P<0.05). Terpenes were the most dominant group of VOCs, followed by hydrocarbons. In mature cheeses, acids were the first most abundant group of VOC, followed by esters and alcohols. There were substances common for all areas and others appear as discriminants for each individual area of cheese production. There were also common terpenes in mature cheeses from all areas and others characteristic for each area of production. Overall, the VOCs composition of traditional Feta cheese made in three mountainous areas of Greece could differ depending on the production area.Μελετήθηκαν τα μικροβιολογικά και φυσικοχημικά χαρακτηριστικά καθώς επίσης τα πτητικά οργανικά συστατικά (VOCs) της παραδοσιακής Φέτας που παράγεται σε τρεις ορεινές περιοχές της Ελλάδας από γάλα ζώων ντόπιων φυλών που διατρέφονται αποκλειστικά με χλωρά βοσκή. Οι κυρίαρχες ομάδες μικροοργανισμών ήταν τα γαλακτικά βακτήρια. Η ταυτοποίησή τους με SDS-PAGE έδειξε πως στο γάλα και στα φρέσκα τυριά επικρατούσε το Lc. lactis subsp. lactis, ενώ στα ώριμα το Lb. plantarum. Η μελέτη των τεχνολογικών τους ιδιοτήτων έδειξε πως τα τυριά των τριών περιοχών διαφέρουν ως προς τη σύνθεση των NSLAB και τις τεχνολογικές ιδιότητες που διαθέτουν και συνεπώς είναι πιθανό να ωριμάζουν διαφορετικά και να αναπτύσσουν διαφορετικά οργανοληπτικά χαρακτηριστικά. Η γενετική ετερογένεια των απομονώσεων εκτιμήθηκε με την εφαρμογή των RAPD-PCR και PFGE. Τα προφίλ έδειξαν υψηλή γενοτυπική ετερογένεια μεταξύ των στελεχών που ανήκαν στο ίδιο είδος, αλλά και εξειδίκευση ανάλογα με τα τυριά της περιοχής από τα οποία είχαν απομονωθεί. Υποδεικνύεται πως η παραδοσιακή Φέτα μπορεί να αποτελέσει αξιόλογη πηγή διαφορετικών γενοτύπων NSLAB που θα μπορούσαν να αξιοποιηθούν για την παραγωγή τυριών ιδιαίτερων σε κάθε περιοχή. Η δυναμική και η ποικιλομορφία των βακτηριακών κοινοτήτων φρέσκων και ώριμων τυριών, μελετήθηκε με την εφαρμογή της PCR-DGGE. Τα βακτηριακά προφίλ έδειξαν μια μεταβλητότητα στη μικροβιακή σύνθεση των τυριών εντός της περιοχής παραγωγής, καθώς και διακριτές διαφορές στα προφίλ των NSLAB στα τυριά διαφορετικών περιοχών, αναδεικνύοντας είδη που δεν απομονώθηκαν κατά την καλλιεργητική μελέτη. Η μελέτη των φυσικοχημικών χαρακτηριστικών των τυριών, ο καθορισμός των ελεύθερων αμινοξέων και οργανικών οξέων, έδειξε πως η περιοχή παραγωγής των τυριών ασκεί επίδραση στις παραμέτρους που μελετήθηκαν. Το προφίλ και η περιεκτικότητα των φυτών, του νωπού γάλακτος, των φρέσκων και ώριμων τυριών σε VOCs έδειξε διαφορές μεταξύ των τριών περιοχών. Στα 23 φυτικά είδη που συλλέχθηκαν, έγινε ανάλυση με PCA η οποία διαφοροποίησε τις περιοχές με βάση τη σύνθεση των VOCs. Το γάλα των τριών περιοχών ήταν φτωχότερο σε VOCs φυτικής προέλευσης, ενώ κοινά τερπένια σε φυτά και γάλα θα μπορούσαν να χρησιμοποιηθούν ως δείκτες για τη σύνδεση της παραδοσιακής Φέτας με την περιοχή παραγωγής της. Στα φρέσκα τυριά, οι αλδεΰδες ήταν σημαντικά (Ρ<0,05) υψηλότερες για τα τυριά της περιοχής 1, οι κετόνες για την περιοχή 2 (Ρ<0,05), οι αλκοόλες για την περιοχή 3 (Ρ<0,05), ενώ τα τερπένια αποτελούσαν την επικρατέστερη ομάδα VOCs, ιδιαίτερα για τα τυριά των περιοχών 1 και 3. Στα ώριμα τυριά, τα οξέα ήταν η επικρατέστερη ομάδα VOCs και ακολουθούνταν από τους εστέρες και τις αλκοόλες, οι οποίες βρέθηκαν σε σημαντικά υψηλότερη (Ρ<0,05) ποσότητα στα τυριά της περιοχής 2. Βρέθηκαν ενώσεις κοινές για τα τυριά όλων των περιοχών και άλλες που χαρακτήριζαν τυριά μιας μόνο περιοχής. Παρόμοια, υπήρχαν τερπένια κοινά στα ώριμα τυριά και των τριών περιοχών και άλλα που φαίνεται να αποτελούν χαρακτηριστικές ενώσεις για τα τυριά της κάθε περιοχής. Συνεπώς, η σύνθεση των VOCs της παραδοσιακής Φέτας που παράγεται σε τρεις ορεινές περιοχές της Ελλάδας διαφέρει, ανάλογα με την περιοχή παραγωγής της, ενώ διαφορές εντοπίστηκαν και μεταξύ των τυριών της ίδιας περιοχής

    The Multiple and Versatile Roles of Aureobasidium pullulans in the Vitivinicultural Sector

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    The saprophytic yeast-like fungus Aureobasidium pullulans has been well documented for over 60 years in the microbiological literature. It is ubiquitous in distribution, being found in a variety of environments (plant surfaces, soil, water, rock surfaces and manmade surfaces), and with a worldwide distribution from cold to warm climates and wet/humid regions to arid ones. Isolates and strains of A. pullulans produce a wide range of natural products well documented in the international literature and which have been regarded as safe for biotechnological and environmental applications. Showing antagonistic activity against plant pathogens (especially post-harvest pathogens) is one of the major applications currently in agriculture of the fungus, with nutrient and space competition, production of volatile organic compounds, and production of hydrolytic enzymes and antimicrobial compounds (antibacterial and antifungal). The fungus also shows a positive role on mycotoxin biocontrol through various modes, with the most striking being that of binding and/or absorption. A. pullulans strains have been reported to produce very useful industrial enzymes, such as &beta;-glucosidase, amylases, cellulases, lipases, proteases, xylanases and mannanases. Pullulan (poly-&alpha;-1,6-maltotriose biopolymer) is an A. pullulans trademark product with significant properties and biotechnological applications in the food, cosmetic and pharmaceutical industries. Poly (&beta;-l-malic acid), or PMA, which is a natural biopolyester, and liamocins, a group of produced heavy oils and siderophores, are among other valuable compounds detected that are of possible biotechnological use. The fungus also shows a potential single-cell protein source capacity with high levels of nucleic acid components and essential amino acids, but this remains to be further explored. Last but not least, the fungus has shown very good biocontrol against aerial plant pathogens. All these properties are of major interest in the vitivinicultural sector and are thoroughly reviewed under this prism, concluding on the importance that A. pullulans may have if used at both vineyard and winery levels. This extensive array of properties provides excellent tools for the viticulturist/farmer as well as for the oenologist to combat problems in the field and create a high-quality wine

    Enterococci Isolated from Cypriot Green Table Olives as a New Source of Technological and Probiotic Properties

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    &Tau;able olive is one of the main fermented vegetable worldwide and can be processed as treated or natural product. Lactic Acid Bacteria (LAB) are responsible for the fermentation of treated olives. The aim of this work was to study the technological characteristics and the potential probiotic properties of LAB isolated from Cypriot green table olives. This is the first comprehensive report on the isolation and characterization of LAB isolates retrieved from Cypriot green table olives. From a collection of 92 isolates from spontaneously fermenting green olives, 64 g positive isolates were firstly identified to genus level using biochemical tests, and secondly to species level using multiplex species specific polymerase chain reaction (PCR) amplifications of the sodA gene. Moreover, each of our isolates were tested for their technological and probiotics properties, as well as for their safety characteristics, using biochemical and molecular methods, in order to be used as starter cultures. Finally, to discriminate the most promising isolates on the base of their technological and probiotics properties, Principal component analysis was used. All the isolates were identified as Enteroccocus faecium, having interesting technological properties, while pathogenicity determinants were absent. Principal component analysis showed that some isolates had a combination of the tested parameters. These findings demonstrate that enteroccoci from Cypriot table olives should be considered as a new source of potential starter cultures for fermented products, having possibly promising technological and probiotic attributes

    Assessment of microbial diversity of the dominant microbiota in fresh and mature PDO Feta cheese made at three mountainous areas of Greece

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    The aim of the present study was to assess the dynamics and the diversity of dominant microbiota in fresh and mature traditional Feta cheese produced in three mountainous areas and for that purpose a combined approach of culture-independent examination with conventional genotypic typing of the predominant NSLAB microbiota were applied. The microbial communities were monitored by PCR-DGGE on seven fresh and nine mature Feta cheese samples made by three artisanal producers. DGGE profiles suggested variability in the microbial composition of cheeses within the production area and distinctive differences in band profile of NSLAB in cheeses between the areas. PCR-DGGE analysis showed that Lactococcus spp. were the most widespread bacteria, Streptococcus macedonicus was detected often and, among lactobacilli, Lactobacillus plantarum prevailed. The diversity of NSLAB isolates from fresh and mature cheeses was assessed by RAPD-PCR and PFGE. Typing data indicated intraspecies genetic heterogeneity and specificity to the production area. Our results point to the conclusion that the manufacturing environment influence the dynamic and the diversity of microbial groups developed in the cheese and possibly the cheese flavour. In addition, the traditional Feta cheese may be a source of different NSLAB genotypes to make cheese with sensorial peculiarities appropriate for each area
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