Application of innovative technologies in the production of probiotic foods and in vivo investigation of probiotic properties

The aim of the PhD thesis was the development of new probiotic food products with immobilized cells on natural supports. The above accomplishment include a) in vivo investigation of the probiotic properties of the strains L.plantarum 2035 and L. plantarum ACA-DC 2640, b) examination of biomass production of probiotic cells using whey, c) immobilization of probiotic cells on natural supports, d) production of dried cultures, e) investigation of the effect of temperature storage on cell viability, f) examination of the effect of immobilization and drying on the fermentation efficiency and on the aromatic profile of fermented milk products, and g) evaluation of using immobilized probiotic cells for food production.Initially, 24h after single-dose or daily administration the strains L. plantarum 2035 and L. plantarum ACA-DC 2640 were detected through multiplex PCR at levels ≥ 7 logcfu/g in feces, cecal or colon fluids or intestinal tissues.Throughout the production of L. casei ATCC 393 biomass using whey, the maximum growth rate and maximum biomass productivity were observed at pH 6.5. Higher (P 7 logcfu/g up to 396 days of storage at 4˚C. During the storage of wet cultures, a gradual decrease (P 6 ή 7 logcfu/g), and on the metabolic activity.Σκοπός της διατριβής ήταν η ανάπτυξη νέων προβιοτικών προϊόντων με ακινητοποιημένες καλλιέργειες σε φυσικούς φορείς. Γι’ αυτό διερευνήθηκαν (α) in vivo για προβιοτικές ιδιότητες κύτταρα L. plantarum 2035 και L. plantarum ACA-DC 2640, (β) η παραγωγή προβιοτικών καλλιεργειών σε τυρόγαλα, (γ) η ακινητοποίηση προβιοτικών καλλιεργειών σε φυσικούς φορείς, (δ) η ξήρανση υγρών προβιοτικών καλλιεργειών, (ε) η επίδραση θερμοκρασίας αποθήκευσης στη βιωσιμότητα προβιοτικών καλλιεργειών, (στ) η επίδραση ακινητοποίησης και ξήρανσης στη μεταβολική δραστικότητα και στο προφίλ πτητικών ενώσεων ζυμωμένων προϊόντων γάλακτος, και (ζ) η καταλληλότητα ακινητοποιημένων προβιοτικών καλλιεργειών στην παραγωγή τροφίμων. Ειδικότερα, 24h μετά από εφάπαξ ή καθημερινή χορήγηση τα στελέχη L. plantarum 2035 και L. plantarum ACA-DC 2640 ταυτοποιήθηκαν με multiplex PCR σε ανώτατα επίπεδα ≥ 7 logcfu/g σε κόπρανα, εντερικό περιεχόμενο ή εντερικό ιστό τυφλού και κόλου. Κατά την παραγωγή κυττάρων L. casei ATCC 393 σε τυρόγαλα, ο μέγιστος ρυθμός ανάπτυξης και η μέγιστη παραγωγικότητα βιομάζας παρατηρήθηκαν σε pH 6.5. Μεγαλύτερη (P 7 logcfu/g έως και 396 ημέρες μετά την αποθήκευση στους 4˚C. Επιπλέον, στις υγρές καλλιέργειες καταγράφηκε σταδιακή μείωση (P 6 ή 7 logcfu/g), και στη μεταβολική δραστικότητα

Citrus medica and Cinnamomum zeylanicum Essential Oils as Potential Biopreservatives against Spoilage in Low Alcohol Wine Products

Low alcohol wine is a new entry in the global wine market, due to the increase in consumers’ concern for health, economic and modern lifestyle issues. As low alcohol products are prone to spoilage, the adoption of natural-derived products with antimicrobial activity as biopreservatives seems to be an intriguing alternative. Thus, the aim of the present study was to investigate the possible antimicrobial properties of Citrus medica and Cinnamomum zeylanicum essential oils (EOs) and assess their commercial prospective in the wine industry. The main constituents identified by GC/MS analysis were limonene (38.46%) and linalool (35.44%) in C. medica EO, whereas trans-cinnamic-aldehyde (63.58%) was the dominant compound in C. zeylanicum EO. The minimum inhibitory (MIC), non-inhibitory (NIC) and minimum lethal concentration (MLC) values against common wine spoilage microbes were initially determined. Subsequently, their efficiency was further validated in low alcohol (~6% vol) wines, either separately or in combination at 0.010% (v/v), as well as in wines deliberately inoculated with Gluconobacter cerinus, Oenococcus oeni, Pediococcus pentosaceus, Dekkera bruxellensis, Candida zemplinina, Hanseniaspora uvarum, Pichia guilliermondii or Zygosaccharomyces bailii. EO addition led to considerable spoilage and microbial growth delay during storage at room or refrigerated temperature, suggesting their potential use as wine biopreservatives

Preliminary Evaluation of the Use of Thermally-Dried Immobilized Kefir Cells in Low Alcohol Winemaking

Low alcohol wines (≤10.5% vol) are novel products that have gradually been gaining the consumers’ and market’s interest over the last decade. Taking into account the technological properties of immobilized cell systems alongside with the commercial need for dry cultures, the aim of the present study was to assess the suitability of thermally-dried immobilized kefir cells on DCM, apples pieces, and grape skins in low alcohol wine production. Storage of thermally-dried kefir culture in various temperatures (−18, 5, and 20 °C) resulted in high viability rates for immobilized cells (up to 93% for yeasts/molds immobilized on grape skins and stored at −18 °C for 6 months). Fermentation activity was maintained after storage in all cases, while high operational stability was confirmed in repeated batch fermentations for a period of 6 months. Principal Component Analysis (PCA) revealed that the fermentation temperature rather than the state of kefir culture affected significantly volatiles detected by Head Space Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry analysis. Notably, all new products were of high quality and approved by the sensory panel

Preliminary Evaluation of the Use of Thermally-Dried Immobilized Kefir Cells in Low Alcohol Winemaking

Low alcohol wines (≤10.5% vol) are novel products that have gradually been gaining the consumers’ and market’s interest over the last decade. Taking into account the technological properties of immobilized cell systems alongside with the commercial need for dry cultures, the aim of the present study was to assess the suitability of thermally-dried immobilized kefir cells on DCM, apples pieces, and grape skins in low alcohol wine production. Storage of thermally-dried kefir culture in various temperatures (−18, 5, and 20 °C) resulted in high viability rates for immobilized cells (up to 93% for yeasts/molds immobilized on grape skins and stored at −18 °C for 6 months). Fermentation activity was maintained after storage in all cases, while high operational stability was confirmed in repeated batch fermentations for a period of 6 months. Principal Component Analysis (PCA) revealed that the fermentation temperature rather than the state of kefir culture affected significantly volatiles detected by Head Space Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry analysis. Notably, all new products were of high quality and approved by the sensory panel

Freeze-Dried Immobilized Kefir Culture in Low Alcohol Winemaking

Low alcohol wines represent a rising trend in the global market. Since for ethanol removal, certain physicochemical methods that negatively affect wine quality are applied, the aim of this present study was to evaluate the efficiency of freeze-dried, immobilized kefir culture on natural supports (apple pieces, grape skins and delignified cellulosic material) in low alcohol winemaking at various temperatures (5–30 °C). Initially, genetic analysis of kefir culture was performed by Next Generation Sequencing. There was an immobilization of kefir culture on grape skins-enhanced cell survival during freeze-drying in most cases, even when no cryoprotectant was used. Simultaneous alcoholic and malolactic fermentations were performed in repeated batch fermentations for >12 months, using freeze-dried free or immobilized cells produced with no cryoprotectant, suggesting the high operational stability of the systems. Values of great industrial interest for daily ethanol productivity and malic acid conversion [up to 39.5 g/(Ld) and 67.3%, respectively] were recorded. Principal Component Analysis (PCA) showed that freeze-drying rather than the fermentation temperature affected significantly minor volatiles. All low alcohol wines produced were accepted during the preliminary sensory evaluation

Maintaining Digestive Health in Diabetes: The Role of the Gut Microbiome and the Challenge of Functional Foods

Over the last decades, the incidence of diabetes has increased in developed countries and beyond the genetic impact, environmental factors, which can trigger the activation of the gut immune system, seem to affect the induction of the disease process. Since the composition of the gut microbiome might disturb the normal interaction with the immune system and contribute to altered immune responses, the restoration of normal microbiota composition constitutes a new target for the prevention and treatment of diabetes. Thus, the interaction of gut microbiome and diabetes, focusing on mechanisms connecting gut microbiota with the occurrence of the disorder, is discussed in the present review. Finally, the challenge of functional food diet on maintaining intestinal health and microbial flora diversity and functionality, as a potential tool for the onset inhibition and management of the disease, is highlighted by reporting key animal studies and clinical trials. Early onset of the disease in the oral cavity is an important factor for the incorporation of a functional food diet in daily routine