28 results on '"Giavasis I"'
Search Results
2. Effect of Different Formulations of Polyphenolic Compounds Obtained from OMWW on the Growth of Several Fungal Plant and Food Borne Pathogens. Studies in vitro and in vivo
- Author
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Leontopoulos, S.V., Giavasis, I., Petrotos, K., Kokkora, M., and Makridis, Ch.
- Published
- 2015
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3. Grape pomace improves antioxidant capacity and faecal microflora of lambs
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Kafantaris, I., Kotsampasi, B., Christodoulou, V., Kokka, E., Kouka, P., Terzopoulou, Z., Gerasopoulos, K., Stagos, D., Mitsagga, C., Giavasis, I., Makri, S., Petrotos, K., and Kouretas, D.
- Published
- 2017
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4. A feed additive containing Bacillus toyonensis (Toyocerin®) protects against enteric pathogens in postweaning piglets
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Kantas, D., Papatsiros, V. G., Tassis, P. D., Giavasis, I., Bouki, P., and Tzika, E. D.
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- 2015
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5. 16 - Production of microbial polysaccharides for use in food
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Giavasis, I.
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- 2013
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6. 6 - Fermentation monitoring and control of microbial cultures for food ingredient manufacture
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McNeil, B., Harvey, L.M., Rowan, N.J., and Giavasis, I.
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- 2013
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7. Whey protein concentrate improves antioxidant capacity, faecal microbiota and fatty acid profile of growing piglets.
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Kafantaris, I., Stagos, D., Kotsampasi, B., Kantas, D., Koukoumis, V., Moschonas, N. D., Skaperda, Z., Gerasopoulos, K., Makri, S., Goutzourelas, N., Mitsagga, C., Giavasis, I., Petrotos, K., Kokkas, S., and Kouretas, D.
- Abstract
A feeding trial involving growing piglets was undertaken to establish whether feed supplemented with whey protein concentrate (WPC), exhibiting antioxidant properties, had any effects on welfare and meat quality. For that purpose, 48 weaned piglets (20-days-old) were assigned to two experimental groups receiving standard or experimental diet for 30 days. Blood and tissue collection were performed at various time-points. The following oxidative stress markers were assessed: reduced glutathione (GSH), catalase activity, total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS), protein carbonyls (CARB) and hydrogen peroxide (H
2 O2 ) decomposition activity. The effects on bacterial growth and the fatty acid profile of meat were also assessed. Results showed that piglets fed with the WPC-supplemented diet had significantly increased antioxidant mechanisms in almost all tissues tested, as indicated by increases in GSH, H2 O2 decomposition activity and TAC compared with the control group. Piglets fed with the experimental diet exhibited decreased oxidative stress-induced damage to lipids and proteins, as shown by decreases in TBARS and CARB in the WPC group compared with the control group. In addition, the experimental diet enhanced growth of facultative probiotic bacteria and lactic acid bacteria and inhibited growth of pathogen populations. In addition, WPC inclusion in piglets' diet increased n -3 fatty acids significantly and decreased n -6/ n -3 ratio significantly compared with the control group. The current study showed that WPC inclusion in the diet had a significant effect on welfare and meat quality of growing piglets. [ABSTRACT FROM AUTHOR]- Published
- 2019
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8. Stimulatory effect of novel polyphenol-based supplements from olive mill waste on the growth and acid production of lactic acid bacteria.
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Giavasis, I., Tsante, E., Goutsidis, P., Papatheodorou, K., and Petrotos, K.
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POLYPHENOLS ,LACTIC acid bacteria ,OLIVE ,FERMENTED foods ,MEAT - Published
- 2012
9. A feed additive containing Bacillus toyonensis (Toyocerin®) protects against enteric pathogens in postweaning piglets.
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Kantas, D., Papatsiros, V.G., Tassis, P.D., Giavasis, I., Bouki, P., and Tzika, E.D.
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SWINE diseases ,PIGLETS ,FEED additives ,BACILLUS (Bacteria) ,ENTEROBACTERIACEAE diseases ,BACTERIAL spores ,EXPERIMENTAL groups ,PREVENTION - Abstract
Aims This study evaluated the efficacy of a probiotic containing Bacillus toyonensis spores (Toyocerin
® ) in postweaning piglets against enteric pathogens. Methods and Results Seven hundred and ninety-two healthy weaning pigs of a commercial farrow-to-finish pig farm were used. The negative control group fed without Toyocerin® and two experimental groups fed similar to the negative control group, but supplemented with Toyocerin® at t 500 mg kg−1 diet (Toyocerin 500 group) and 1000 mg kg−1 diet (Toyocerin 1000 group), respectively. No significant difference ( P > 0·05) in morbidity and mortality rate between groups was noticed. The Toyocerin groups showed higher body weight ( P < 0·05) and lower feed conversion ratio compared to the negative control group. Diarrhoea score was less in both Toyocerin groups than negative control group ( P < 0·05). Moreover, the use of Toyocerin® at 1000 mg kg−1 diet resulted in higher average daily feed intake compared to other groups ( P < 0·05), reduction of some enteric pathogens and increase of the number of lactic acid bacteria. Conclusions The use of Toyocerin® in weaning pigs, especially at 1000 mg kg−1 diet, improved their health and growth performance. Significance and Impact of the Study This study shows that a feed additive containing B. toyonensis (Toyocerin® ) protects against enteric pathogens in postweaning piglets when fed this additive at a proper dose. The use of Toyocerin® at 1000 mg kg−1 diet resulted in higher average daily feed intake, decrease of some enteric pathogens and higher number of lactic acid bacteria. The effect of the probiotic in other age groups remains to be established. [ABSTRACT FROM AUTHOR]- Published
- 2015
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10. Contributor contact details
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McNeil, Brian, Archer, David, Giavasis, Ioannis, Lecturer, Harvey, Linda, Wood, Brian J.B., Vongsangnak, Wanwipa, Nielsen, Jens, Mapelli, Valeria, Franzén, Carl Johan, Olsson, Lisbeth, Hoskisson, Paul A, Seviour, Robert J., Harvey, L.M., Fazenda, M., Rowan, N.J., Giavasis, I., Lecturer, Stocks, Stuart M., Waché, Yves, Sanchez, S., Ruiz, B., Rodríguez-Sanoja, R., Flores-Cotera, L.B., Dvora, H., Koffas, M.A.G., Hellmuth, Karsten, van den Brink, Johannes M., Sauer, M., Mattanovich, D., Marx, H., Grattepanche, F., Lacroix, C., Burke, D.G., Cotter, P.D., Ross, R.P., Hill, C., Suzuki, Hideyuki, Granström, Tom, Leisola, Matti, Nguyen, Thu-Ha, Haltrich, Dietmar, Ratledge, Colin, Klein, Barbara, Buchholz, Rainer, and Revuelta, Jose Luis
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- 2013
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11. Combined Hurdle Effects of Process Parameters on Biochemical, Microbiological and Sensory Attributes of Trout Fillets.
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Giavasis, I., Apostolopoulou, A., Deirmentzoglou, A., and Katsanidis, E.
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TROUT , *FOOD microbiology , *CITRIC acid , *OREGANO , *FOOD pasteurization , *BIOCHEMISTRY , *PROCESS optimization - Abstract
The combined effect of brining time, citric acid, oregano oil and pasteurization temperature on the microbiological stability, pH, lipid oxidation (thiobarbituric acid reactive substance [ TBARS]), total volatile basic nitrogen ( TVBN) and sensory characteristics of trout fillets was evaluated. Sixteen treatment combinations were produced, packaged under modified atmosphere conditions and were studied for a period of 150 days. The total viable counts, phychrophiles, sulfite-reducing clostridia and lactic acid bacteria populations were present in very low numbers throughout the storage period. The addition of citric acid resulted in lower pH and TBARS values. Oregano oil had a strong antioxidant effect. Pasteurization temperatures of 95 C resulted in higher TVBN numbers at the end of the storage period, compared with pasteurization temperatures of 85 C. Brining times of 4 h improved the flavor of the trout fillets compared with 1-h brining, whereas oregano oil improved the flavor only for the fillets brined for 1 h. Practical Applications This paper describes an application of combined hurdles (citric acid, oregano oil, brining and pasteurization) in order to produce ready-to-eat trout fillets, otherwise sensitive to microbial spoilage and lipid oxidation, with improved chemical and microbiological stability during storage. Also, it intends to highlight interactions among the combined hurdles as concern product quality. Additionally, although high pasteurization (95 C) had a high bacteriocidal impact on the product, it deteriorated texture and led to increased total volatile basic nitrogen numbers. Overall, 4-h brining combined with 0.1% citric acid, a mild heating process (85 C) and a lower than 0.5% addition of oregano oil is considered the best combination for high sensorial characteristics and keeping quality. An interesting finding was the absence of detectable microflora in samples judged as unacceptable, which lead to the conclusion that enzymatic spoilage took place due to endogenous enzymes or microbial enzymes produced prior to pasteurization and processing, which is worth further investigating. [ABSTRACT FROM AUTHOR]
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- 2014
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12. Combined Dietary Supplementation of Tenebrio molitor Larvae and Chitosan in Growing Pigs: A Pilot Study.
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Zacharis C, Bonos E, Voidarou CC, Magklaras G, Fotou K, Giannenas I, Giavasis I, Mitsagga C, Athanassiou C, Antonopoulou E, Grigoriadou K, Tzora A, and Skoufos I
- Abstract
Nowadays, the global animal industry faces considerable challenges in securing sufficient feed resources. Responding to consumer demands for reduced use of antibiotics in animal nutrition, better animal welfare status, and reduced impact on the environment, there is an increased urgency to develop innovative functional feeds with a reduced environmental footprint and the ability to improve meat quality and safety. In an effort to explore innovative feed ingredients for growing pig diets, the combined dietary supplementation of Tenebrio molitor larvae and chitosan was investigated. An experimental trial was performed with 48 weaned pigs (34 days of life; mixed sex) that were randomly assigned to four treatment groups (with six males and six females each): Group A (control), Group B (supplemented with T. molitor larvae at 10%), Group C (supplemented with chitosan at 0.05%), and Group D (supplemented with both ingredients at 10% and 0.05%, respectively). On the 42nd day of the experimental trial, samples of blood, feces, and carcass parts were taken for analysis. The results indicated that the insect larvae meal significantly improved ( p < 0.05) overall performance, increased ( p < 0.05) blood red blood cell content, increased meat phenolic content ( p < 0.05), improved meat oxidative stability ( p < 0.05), and affected meat fatty acid profile ( p < 0.05). On the other hand, chitosan had no significant effect on overall performance ( p > 0.05), but it significantly increased blood lymphocyte content ( p < 0.05), affected the fecal microbiota ( p < 0.05), improved meat oxidative stability ( p < 0.05), increased meat phenolic content ( p < 0.05), and affected meat fatty acid composition ( p < 0.05) and ( p < 0.05) meat color. Finally, the combined use of both T. molitor and chitosan significantly affected some important zootechnical parameters ( p < 0.05), fecal microbial populations ( p < 0.05), meat color ( p < 0.05), and fatty acid profile ( p < 0.05). Further investigation into the potential interaction between insect larvae meals and chitosan in pig diets is advised.
- Published
- 2024
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13. Innovative Use of Olive, Winery and Cheese Waste By-Products as Novel Ingredients in Weaned Pigs Nutrition.
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Magklaras G, Skoufos I, Bonos E, Tsinas A, Zacharis C, Giavasis I, Petrotos K, Fotou K, Nikolaou K, Vasilopoulou K, Giannenas Ι, and Tzora A
- Abstract
New sustainable sources of feeds, which can enhance the health and welfare of farm animals, lower feeding costs, and lead to safer products, are of high priority in modern animal production systems. In the present study, a novel silage created from Greek olive, winery, and feta cheese waste by-products, was evaluated as a feed ingredient at different inclusion rates (0%, 5% or 10%) in 34-day-old weaned pigs. The potential beneficial effects on performance, health and intestinal digesta microflora balance of the pigs were evaluated. Additionally, chemical, microbiological and quality analysis of the meat was carried out. Results showed no detrimental effects ( p > 0.05) on the pigs' performance and no significant changes ( p > 0.05) in meat pH, color and chemical analysis. Ileum and cecum microflora populations (total anaerobes, Lactobacillaceae) were positively affected ( p ≤ 0.05) by the dietary usage of the silage. The microbial populations ( Clostridium spp.) of belly meat cuts were positively modified ( p ≤ 0.01). The concentration of total phenols in the meat cuts were increased ( p ≤ 0.05) and their resistance to oxidation was improved ( p ≤ 0.05). In addition, the fatty acid profile of the meat lipids (polyunsaturated and n-3 fatty acids) was positively modified ( p ≤ 0.001).
- Published
- 2023
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14. Innovative Use of Olive, Winery and Cheese Waste By-Products as Functional Ingredients in Broiler Nutrition.
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Bonos E, Skoufos I, Petrotos K, Giavasis I, Mitsagga C, Fotou K, Vasilopoulou K, Giannenas I, Gouva E, Tsinas A, D'Alessandro AG, Cardinali A, and Tzora A
- Abstract
The purpose of this study was to evaluate the dietary use of novel silage that was created by combining three agro-industrial wastes produced in bulk, i.e., olive mill wastewater, grape pomace, and deproteinized feta cheese whey, in the diets of broiler chickens. A total of 216 one-day-old male Ross-308 chicks were randomly allocated to three treatment groups with six replications (12 chicks per pen). Three isocaloric and isonitrogenous diets were formulated to include the examined silage at 0%, 5%, or 10%. Commercial breeding and management procedures were employed throughout the trial. At the end of the trial (day 35), tissue samples were collected for analysis. Feeding 10% silage resulted in increased (p ≤ 0.001) final body weight (p ≤ 0.001) and feed intake. Jejunum and cecum microflora, as well as breast and thigh meat microflora, were modified (p ≤ 0.05) by the dietary inclusion. Thigh meat oxidative stability was improved (p < 0.01) by the silage supplementation. In addition, breast and thigh meat fatty acid profiles were different, respectively, (p < 0.05) in the supplemented treatments compared to the control. The examined silage was successfully tested in broiler diets with potential benefits for their performance and meat quality.
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- 2022
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15. Beyond the Microbiome: Germ-ganism? An Integrative Idea for Microbial Existence, Organization, Growth, Pathogenicity, and Therapeutics.
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Kambouris ME, Goudoudaki S, Kritikou S, Milioni A, Karamperis K, Giavasis I, Patrinos GP, Velegraki A, and Manoussopoulos Y
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- Bacteria, Humans, Pandemics, Virulence, COVID-19, Microbiota
- Abstract
The advances made by microbiome research call for new vocabulary and expansion of our thinking in microbiology. For example, the life-forms presenting in both unicellular and multicellular formats invite us to rethink microbial existence, organization, growth, pathogenicity, and therapeutics in the 21st century. A view of such populations as parts of single organisms with a loose, distributed multicellular organization, introduced here as a germ-ganism, rather than communities, might open up interesting prospects for diagnostics and therapeutics innovation. This study tested and further contextualized the concept of germ-ganism using solid cultures of bacteria and fungi. Based on our findings and the literature reviewed herein, we propose that germ-ganism has synergy with a systems medicine approach by broadening host-environment interactions from cells and microorganisms to a scale of biological ecosystems. Germ-ganism also brings about the possibility of studying the multilevel impacts of novel therapeutic agents within and across networks of microbial ecosystems. The germ-ganism would lend itself, in the long term, to a veritable biocybernetics system, while in the mid-term, we anticipate it will contribute to new diagnostics and therapeutics. Biosecurity applications would be immensely affected by germ-ganism. Industrial applications of germ-ganism are of interest as a more sustainable alternative to costly solutions such as tampered strains/microorganisms. In conclusion, germ-ganism is informed by lessons from microbiome research and invites rethinking microbial existence, organization, and growth as an organism. Germ-ganism has vast ramifications for understanding pathogenicity, and clinical, biosecurity, and biotechnology applications in the current historical moment of the COVID-19 pandemic and beyond.
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- 2022
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16. Antimicrobial Properties of Lyophilized Extracts of Olive Fruit, Pomegranate and Orange Peel Extracts against Foodborne Pathogenic and Spoilage Bacteria and Fungi In Vitro and in Food Matrices.
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Mitsagga C, Petrotos K, and Giavasis I
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- Food Microbiology, Freeze Drying methods, Plant Extracts pharmacology, Anti-Infective Agents pharmacology, Bacteria drug effects, Citrus sinensis chemistry, Fruit chemistry, Fungi drug effects, Olea chemistry, Pomegranate chemistry
- Abstract
Several novel antimicrobials with different concentrations of olive, pomegranate, and orange fruit pulp extracts were produced from agricultural byproducts and, after lyophilization, their antimicrobial activity and potential synergistic effects were evaluated in vitro and in food samples against foodborne pathogenic and spoilage bacteria and fungi. The Minimum Inhibitory of the tested bacteria was 7.5% or 10%, while fungi were inhibited at a concentration of 10% or above. The optical density of bacterial and yeast cultures was reduced to a different extent with all tested antimicrobial powders, compared to a control without antimicrobials, and mycelium growth of fungi was also restricted with extracts containing at least 90% olive extract. In food samples with inoculated pathogens and spoilage bacteria and fungi, the 100% olive extract was most inhibitory against E. coli , S. typhimurium, and L. monocytogenes in fresh burger and cheese spread samples (by 0.6 to 1.8 log cfu/g), except that S. typhimurium was better inhibited by a 90% olive and 10% pomegranate extract in burgers. The latter extract was also the most effective in controlling the growth of inoculated fungi ( Aspergillus niger , Penicillium italicum , Rhodotorula mucilaginosa ) in both yogurt and tomato juice samples, where it reduced fungal growth by 1-2.2 log cfu/g at the end of storage period. The results demonstrate that these novel encapsulated extracts could serve as natural antimicrobials of wide spectrum, in order to replace synthetic preservatives in foods and cosmetics.
- Published
- 2021
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17. Corn Silage Supplemented with Pomegranate ( Punica granatum ) and Avocado ( Persea americana ) Pulp and Seed Wastes for Improvement of Meat Characteristics in Poultry Production.
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Leontopoulos S, Skenderidis P, Petrotos K, and Giavasis I
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- Animal Feed analysis, Animal Nutritional Physiological Phenomena, Animals, Chickens, Dietary Supplements, Meat analysis, Persea chemistry, Pomegranate chemistry, Seeds chemistry, Silage, Zea mays chemistry
- Abstract
In the present study, pomegranate peels, avocado peels, and seed vacuum microwave extraction solid by-products were supplemented in corn silage in order to investigate the effects on meat quality and growth rate in broiler chicken. There were 50 broilers, divided in two groups, treated with experimental or usual feed for 43 days (group A: 25 broilers fed with avocado and pomegranate by-products and group B: 25 broilers fed with corn-silage used as control). The results showed that broiler chickens fed with a diet supplemented with a mixture of pomegranate avocado by-products (group A) showed significant differences in chicken leg meat quality, significantly improving the level of proteins and fatty acids content in breast and leg meat, respectively. More specific ω3 and ω6 fatty acids content were three times higher than in group B. Moreover, a protective effect on the decomposition of polyunsaturated fatty acids, induced by free radicals and presented in chicken meat, is based on the evaluation of lipid peroxidation by measuring thiobarbituric acid reactive substances. Pomegranate peels, avocado peels, and seed by-products appeared to have a slight reduction on meat production, while it was found to improve the qualitative chicken meat characteristics. Regarding the production costs, it was calculated that the corn-silage supplementation, used in this study, lead to a 50% lower cost than the commercial corn-silage used for the breeding of broilers.
- Published
- 2021
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18. The In Vitro and In Vivo Synergistic Antimicrobial Activity Assessment of Vacuum Microwave Assisted Aqueous Extracts from Pomegranate and Avocado Fruit Peels and Avocado Seeds Based on a Mixtures Design Model.
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Skenderidis P, Leontopoulos S, Petrotos K, Mitsagga C, and Giavasis I
- Abstract
The present study aimed to assess the antimicrobial properties of encapsulated lyophilized powdered extracts of pomegranate peels (PP), avocado peels (AP) and avocado seeds (AS) in vitro and in vivo. Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) methods, optical density measurement, and well diffusion assay were used to determine antimicrobial activity against food borne bacteria (Gram- Escherichia coli, Salmonella typhimurium, Campylobacter jejuni, Pseudomonas putida ), (Gram+ Staphylococcus aureus, Listeria monocytogenes, Clostridium perfringens, Lactobacillus plantarum ), and fungi ( Penicillium expansum and Aspergillus niger ) based on a mixture design model. Additionally, the most effective powder was studied in vivo in yogurt, cream cheese, and minced meat burger. The samples that contained high polyphenol content also exhibited higher antioxidant, antimicrobial, and antifungal activity. From the results of the well diffusion, the MIC/MBC, and the cell optical density assays, the antimicrobial activity of the extracts was found to be correlated to the total phenolic content (TPC) of the samples and the type of the microorganism. The pomegranate peels extract presented the higher TPC and antioxidant activity and constitute the highest percentage in the most active antimicrobial mixture. The powders that were tested in vitro showed microbial type-dependent effects in each food model. The results presented here can be further studied in the large-scale industrial production of natural food preservatives.
- Published
- 2021
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19. Biological Properties of Bee Bread Collected from Apiaries Located across Greece.
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Didaras NA, Kafantaris I, Dimitriou TG, Mitsagga C, Karatasou K, Giavasis I, Stagos D, Amoutzias GD, Hatjina F, and Mossialos D
- Abstract
Bee bread is the only fermented product of the beehive. It constitutes the main source of proteins, lipids, vitamins, and macro- and microelements in honeybee nutrition and it exerts antioxidant and antimicrobial properties, though research on these aspects has been limited so far. In this study 18 samples of Greek bee bread, two of which were monofloral, were collected during different seasons from diverse locations such as Crete and Mount Athos and were tested for their bioactivity. Samples were analyzed for their antibacterial properties, antioxidant activity, total phenolic content (TPC), and total flavonoid content (TFC). The antimicrobial activity of each sample was tested against Staphylococcus aureus , Pseudomonas aeruginosa , Klebsiella pneumoniae , and Salmonella typhimurium . Our data demonstrate that all samples exert inhibitory and most of them bactericidal activity against at least two pathogens. Furthermore, all samples exert significant antioxidant activity, where the monofloral Castanea Sativa sample demonstrated superior antioxidant activity. Nevertheless, the antioxidant and antimicrobial activity were not strongly correlated. Furthermore, machine learning methods demonstrated that the palynological composition of the samples is a good predictor of their TPC and ABTS activity. This is the first study that focuses on the biological properties of Greek bee bread and demonstrates that bee bread can be considered a functional food and a possible source of novel antimicrobial compounds.
- Published
- 2021
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20. Optimization of the Vacuum Microwave Assisted Extraction of the Natural Polyphenols and Flavonoids from the Raw Solid Waste of the Pomegranate Juice Producing Industry at Industrial Scale.
- Author
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Petrotos K, Giavasis I, Gerasopoulos K, Mitsagga C, Papaioannou C, and Gkoutsidis P
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- Analysis of Variance, Models, Theoretical, Plant Extracts chemistry, Statistics as Topic, Flavonoids isolation & purification, Fruit and Vegetable Juices, Industrial Waste analysis, Microwaves, Polyphenols isolation & purification, Pomegranate chemistry, Solid Waste analysis, Vacuum
- Abstract
Pomegranate pomace (PP) is the solid waste produced in bulk by the pomegranate juice industry which is rich in polyphenols and flavonoids that can replace the hazardous chemical antioxidants/antimicrobials currently used in the agro-food and cosmetics sectors. In the present work, the vacuum microwave assisted extraction (VMAE) of natural antioxidants from raw pomegranate pomace was investigated and successfully optimized at an industrial scale. For the optimization of PP VMAE a novel, highly accurate response surface methodology (RSM) based on a comprehensive multi-point historical design was employed. The optimization showed that the maximum recovery of PP total polyphenols as well as total PP flavonoids were obtained at microwave power = 4961.07 W, water to pomace ratio = 29.9, extraction time = 119.53 min and microwave power = 4147.76 W, water to pomace ratio = 19.32, extraction time = 63.32 min respectively. Moreover, the optimal VMAE conditions on economic grounds were determined to be: microwave power = 2048.62 W, water to pomace ratio = 23.11, extraction time = 15.04 min and microwave power = 4008.62 W, water to pomace ratio = 18.08, extraction time = 15.29 min for PP total polyphenols and PP total flavonoids respectively. The main conclusion of this study is that the VMAE extraction can be successfully used at industrial scale to produce, in economic manner, high added value natural extracts from PP pomace.
- Published
- 2021
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21. Optimization of Vacuum-Microwave-Assisted Extraction of Natural Polyphenols and Flavonoids from Raw Solid Waste of the Orange Juice Producing Industry at Industrial Scale.
- Author
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Petrotos K, Giavasis I, Gerasopoulos K, Mitsagga C, Papaioannou C, and Gkoutsidis P
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- Chemical Fractionation methods, Food-Processing Industry, Fruit and Vegetable Juices analysis, Plant Extracts chemistry, Citrus sinensis chemistry, Flavonoids analysis, Microwaves, Plant Extracts analysis, Polyphenols analysis, Solid Waste analysis, Vacuum
- Abstract
Orange pomace (OP) is a solid waste produced in bulk as a byproduct of the orange juice industry and accounts for approximately 50% of the quantity of the fruits processed into juice. In numerous literature references there is information about diverse uses of orange pomace for the production of high-added-value products including production of natural antioxidant and antimicrobial extracts rich in polyphenols and flavonoids which can substitute the hazardous chemical antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work and for the first time, according to our knowledge, the eco-friendly aqueous vacuum microwave assisted extraction of orange pomace was investigated and optimized at real industrial scale in order to produce aqueous antioxidant/antimicrobial extracts. A Response Surface Optimization methodology with a multipoint historical data experimental design was employed to obtain the optimal values of the process parameters in order to achieve the maximum rates of extraction of OP total polyphenols and/or total flavonoids for economically optimum production at industrial scale. The three factors used for the optimization were: (a) microwave power (b) water to raw pomace ratio and (c) extraction time. Moreover, the effectiveness and statistical soundness of the derived cubic polynomial predictive models were verified by ANOVA.
- Published
- 2021
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22. Optimization of Vacuum Microwave-Assisted Extraction of Pomegranate Fruits Peels by the Evaluation of Extracts' Phenolic Content and Antioxidant Activity.
- Author
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Skenderidis P, Leontopoulos S, Petrotos K, and Giavasis I
- Abstract
The global interest in the use of plant by-product extracts as functional ingredients is continuously rising due to environmental, financial and health benefits. The latest advances in extraction technology have led to the production of aqueous extracts with high bioactive properties, which do not require the use of organic solvents. The purpose of this study was to optimize the conditions applied for the extraction of pomegranate peels (PP) via a "green" industrial type of vacuum microwave-assisted aqueous extraction (VMAAE), by assessing the potential bioactivity of the extracts (in terms of phenolic content and antioxidant activity), using a response surface methodology. The extraction conditions of temperature, microwave power, time and water/PP ratio were determined by the response surface methodology, in order to yield extracts with optimal total phenolics concentrations (TPC) and high antioxidant activity, based on the IC
50 value of the scavenging of the 2,2-diphenyl-1-picrylhydrazyl (DPPH● ) radical. The values of the optimum extraction parameters, such as extraction temperature (61.48 and 79.158 °C), time (10 and 12.17 min), microwave power (3797.24 and 3576.47 W) and ratio of water to raw material (39.92% and 38.2%), were estimated statistically for the two responses (TPC and IC50 values), respectively. Under these optimal extraction conditions, PP extracts with high TPC ((5.542 mg Gallic Acid Equivalent (GAE)/g fresh PP))/min and radical scavenging activity (100 mg/L (1.6 L/min)) could be obtained. Our results highlighted that the optimized industrial type of VMAAE could be a promising solution for the valorization of the PP by-products.- Published
- 2020
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23. The Effect of Encapsulated Powder of Goji Berry ( Lycium barbarum ) on Growth and Survival of Probiotic Bacteria.
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Skenderidis P, Mitsagga C, Lampakis D, Petrotos K, and Giavasis I
- Abstract
The aim of the present work was to investigate the potential prebiotic action of Goji berry powder on selected probiotic bacteria grown in a nutritive synthetic substrate and in simulated gastric and intestinal juices. Different probiotic strains of Bifidobacterium and Lactobacillus were grown in these substrates with or without the addition of encapsulated goji berry extracts of different polysaccharide and polyphenol contents. The results proved that the addition of the extracts promoted the proliferation of probiotic strains and, in particular, increased the number of bacterial colonies of Bifidobacterium animalis subsp. lactis (Bb 12 ), Bifidobacterium longum (Bb 46 ), and Lactobacillus casei by 2, 0.26, and 1.34 (log cfu/mL), respectively. Furthermore, the prebiotic effect seems to be correlated to Goji berry polysaccharides and/or polyphenols, higher contents of which (under the tested concentrations) could increase the stress tolerance of B. lactis and B. longum in a simulated gastrointestinal environment. According to the findings of the present research, it can be suggested that the Goji berry encapsulated extracts could be used as prebiotic additives in food or nutraceuticals, in order to stimulate growth or protect the viability of probiotic strains of Bifidobacterium and Lactobacillus .
- Published
- 2019
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24. Chemical Properties, Fatty-Acid Composition, and Antioxidant Activity of Goji Berry ( Lycium barbarum L. and Lycium chinense Mill.) Fruits.
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Skenderidis P, Lampakis D, Giavasis I, Leontopoulos S, Petrotos K, Hadjichristodoulou C, and Tsakalof A
- Abstract
In this study, the content composition and antioxidant activity of goji berry fruits from two species ( Lycium barbarum and Lycium chinense ) were assessed. The total carbohydrate and phenolic contents were evaluated using attenuated total reflection Fourier-transform infrared (ATR-FT-IR) spectroscopy, while the antioxidant activity of fruits was examined with two in vitro methods, which are based on the scavenging activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2'-azino-bis(3-ethyl-benzthiazoline-sulfonic acid) (ABTS•⁺) free radicals. The fatty-acid profile was determined using gas chromatography coupled with mass spectrometry (GC-MS). The results of this study indicate that the fruits of L. barbarum present higher concentrations in carbohydrates and phenolics than L. chinense Mill. fruits. Furthermore, the antioxidant activity based on the half maximal inhibitory concentration (IC
50 ) measurements of DPPH• and ABTS•⁺ free-radical scavenging was higher in L. barbarum than L. chinense Mill. Also, the GCMS analysis confirms the high levels of linoleic, palmitic, and oleic acids contained in the fruits of both species. Finally, the results of this study clearly show that the concentration of bioactive and antioxidant molecules is higher in L. barbarum than in L. chinense fruits, which was also confirmed by ATR-FT-IR measurements.- Published
- 2019
- Full Text
- View/download PDF
25. The Effects of an Olive Fruit Polyphenol-Enriched Yogurt on Body Composition, Blood Redox Status, Physiological and Metabolic Parameters and Yogurt Microflora.
- Author
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Georgakouli K, Mpesios A, Kouretas D, Petrotos K, Mitsagga C, Giavasis I, and Jamurtas AZ
- Subjects
- Adult, Bacteria classification, Cross-Over Studies, Female, Fungi classification, Humans, Male, Oxidation-Reduction, Polyphenols chemistry, Yogurt microbiology, Antioxidants, Body Composition drug effects, Fruit chemistry, Olea chemistry, Polyphenols pharmacology, Yogurt analysis
- Abstract
In the present study we investigated the effects of an olive polyphenol-enriched yogurt on yogurt microflora, as well as hematological, physiological and metabolic parameters, blood redox status and body composition. In a randomized double-blind, crossover design, 16 (6 men, 10 women) nonsmoking volunteers with non-declared pathology consumed either 400 g of olive fruit polyphenol-enriched yogurt with 50 mg of encapsulated olive polyphenols (experimental condition-EC) or 400 g of plain yogurt (control condition-CC) every day for two weeks. Physiological measurements and blood collection were performed before and after two weeks of each condition. The results showed that body weight, body mass index, hip circumference and systolic blood pressure decreased significantly (p < 0.05) following the two-week consumption of yogurt regardless of condition. A tendency towards significance for decreased levels of low density lipoprotein (LDL) cholesterol (p = 0.06) and thiobarbituric acid reactive substances (p < 0.05) following two weeks of polyphenol-enriched yogurt consumption was observed. The population of lactic acid bacteria (LAB) and production of lactate in yogurt were significantly enhanced after addition of olive polyphenols, contrary to the population of yeasts and molds. The results indicate that consumption of the polyphenol-enriched yogurt may help individuals with non-declared pathology reduce body weight, blood pressure, LDL cholesterol levels and lipid peroxidation, and promote growth of beneficial LAB.
- Published
- 2016
- Full Text
- View/download PDF
26. Bioactive fungal polysaccharides as potential functional ingredients in food and nutraceuticals.
- Author
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Giavasis I
- Subjects
- Agaricales chemistry, Agaricales metabolism, Anti-Infective Agents pharmacology, Anticholesteremic Agents pharmacology, Antineoplastic Agents pharmacology, Antioxidants pharmacology, Biological Products chemistry, Biological Products pharmacology, Biological Products therapeutic use, Biopolymers biosynthesis, Biopolymers chemistry, Biopolymers pharmacology, Biopolymers therapeutic use, Carbohydrate Sequence, Food Industry standards, Fungal Polysaccharides chemistry, Fungal Polysaccharides standards, Fungal Polysaccharides therapeutic use, Health, Humans, Hypoglycemic Agents pharmacology, Molecular Sequence Data, Neoplasms diet therapy, Neoplasms drug therapy, Prebiotics, Dietary Supplements standards, Functional Food standards, Fungal Polysaccharides immunology, Fungal Polysaccharides pharmacology
- Abstract
Fungal bioactive polysaccharides deriving mainly from the Basidiomycetes family (and some from the Ascomycetes) and medicinal mushrooms have been well known and widely used in far Asia as part of traditional diet and medicine, and in the last decades have been the core of intense research for the understanding and the utilization of their medicinal properties in naturally produced pharmaceuticals. In fact, some of these biopolymers (mainly β-glucans or heteropolysaccharides) have already made their way to the market as antitumor, immunostimulating or prophylactic drugs. The fact that many of these biopolymers are produced by edible mushrooms makes them also very good candidates for the formulation of novel functional foods and nutraceuticals without any serious safety concerns, in order to make use of their immunomodulating, anticancer, antimicrobial, hypocholesterolemic, hypoglycemic and health-promoting properties. This article summarizes the most important properties and applications of bioactive fungal polysaccharides and discusses the latest developments on the utilization of these biopolymers in human nutrition., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
27. Simultaneous and rapid monitoring of biomass and biopolymer production by Sphingomonas paucimobilis using Fourier transform-near infrared spectroscopy.
- Author
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Giavasis I, Robertson I, McNeil B, and Harvey LM
- Subjects
- Biomass, Bioreactors microbiology, Computer Simulation, Polysaccharides, Bacterial analysis, Quality Control, Species Specificity, Sphingomonas growth & development, Sphingomonas metabolism, Models, Biological, Polysaccharides, Bacterial biosynthesis, Spectroscopy, Fourier Transform Infrared methods, Sphingomonas isolation & purification, Sphingomonas physiology
- Abstract
The application of Fourier Transform near infrared spectroscopy (FT-NIRS) to near real-time monitoring of polysaccharide and biomass concentration was investigated using a gellan-producing strain of Sphingomonas paucimobilis grown in a stirred tank reactor. Successful models for both biomass and gellan were constructed despite the physichochemical complexity of the viscous process fluid. Modelling of biomass proved more challenging than for gellan, partly because of the low range of biomass concentration but a model with a good correlation coefficient (0.94) was formulated based on second derivative spectra. The gellan model was highly satisfactory, with an excellent correlation coefficient (0.98), again based on second derivative spectra. No sample pre-treatment was required and all spectral scanning was carried out on whole broth. Additionally, both models should be robust in practice since both were formulated using low numbers of factors. Thus, the near real time simultaneous monitoring of gellan and biomass in this highly complex matrix using FT-NIRS potentially opens the way to greatly improved process control strategies.
- Published
- 2003
- Full Text
- View/download PDF
28. Gellan gum.
- Author
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Giavasis I, Harvey LM, and McNeil B
- Subjects
- Carbohydrate Sequence, Fermentation, Molecular Sequence Data, Polysaccharides, Bacterial biosynthesis, Polysaccharides, Bacterial metabolism, Sphingomonas metabolism, Polysaccharide-Lyases metabolism, Polysaccharides, Bacterial chemistry
- Abstract
For decades microbial exopolysaccharides have been invaluable ingredients in the food industry, as well as having many attractive pharmaceutical and chemical applications. Gellan gum is a comparatively new gum elaborated by the Gram-negative bacterium Sphingomonas paucimobilis. Although its physico-chemical properties have been well characterized, the ecology and physiology of Sphingomonas, and the factors influencing the fermentation process for production of this gum have received much less attention. This review focuses on the metabolism and the enzymic activity of this bacterium, as well as the factors that influence gellan production, including process temperature, pH, stirring rate, oxygen transfer, and composition of the production medium. Potential strategies for improving the production process are discussed in the context of processes for the production of other microbial biopolymers, particularly exopolysaccharides. In addition, the importance and potential utility of gellan lyases in modification of gellan and in other applications is critically evaluated.
- Published
- 2000
- Full Text
- View/download PDF
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