Papers by Ioannis Giavasis
Veterinary Sciences, Jun 16, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
CRC Press eBooks, Jun 25, 2014
ABSTRACT Mushrooms have been used for centuries in Asian and other traditional cuisine and tradit... more ABSTRACT Mushrooms have been used for centuries in Asian and other traditional cuisine and traditional medicines due to their culinary and medicinal properties, but their properties remained unknown to the wide scientific community for a long time. In the last few decades, a large amount of research has focused on the types, sources, biosynthesis, and medicinal properties and applications of many mushrooms, mainly members of the Basidiomycetes family. The most common active ingredients in these higher fungi are their extracellular, intracellular, or cell wall polysaccharides, which exhibit immunostimulating, antitumor, antimicrobial, anti-inflammatory, antioxidant, prebiotic, hypoglycemic, and hypocholesterolemic effects. In the last few years, some of these mushrooms or their biopolymers have been commercialized in pharmaceutical applications, but their application in food and nutraceuticals is still at an early stage. However, the fact that many of these mushrooms are edible (and thus nontoxic) as well as tasty makes them, or their polysaccharides, potentially ideal ingredients for the formulation of novel functional foods and nutraceuticals. However, their biological properties might be affected after addition to food, due to food processing and/or interaction with food ingredients. This chapter describes the most important and studied types and sources of bioactive mushroom polysaccharides, the biosynthesis and bioprocess conditions used for the production/cultivation in solid or liquid media, the relation between molecular/structural characteristics and bioactivity, their medicinal properties, and their existing or potential applications in human nutrition. View full chapter at : http://books.google.gr/books?id=e-fMAwAAQBAJ&pg=PA171&lpg=PA171&dq=Polysaccharides+from+medicinal+mushrooms+for+potential+use+as+nutraceuticals&source=bl&ots=JWa2W2b8U1&sig=YnOX59kTgwi4rrrKmxN42hxKAxg&hl=el&sa=X&ei=4o0AVPiwEvP07Aaq6IGICQ&ved=0CCkQ6AEwAQ#v=onepage&q=Polysaccharides%20from%20medicinal%20mushrooms%20for%20potential%20use%20as%20nutraceuticals&f=false
Veterinary Sciences, Jun 12, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Elsevier eBooks, 2013
ABSTRACT Microbial polysaccharides comprise a large number of versatile biopolymers produced by s... more ABSTRACT Microbial polysaccharides comprise a large number of versatile biopolymers produced by several bacteria, yeast and fungi. Microbial fermentation has enabled the use of these ingredients in modern food and delivered polysaccharides with controlled and modifiable properties, which can be utilized as thickeners/viscosifiers, gelling agents, encapsulation and film-making agents or stabilizers. Recently, some of these biopolymers have gained special interest owing to their immunostimulating/therapeutic properties and may lead to the formation of novel functional foods and nutraceuticals. This chapter describes the origin and chemical identity, the biosynthesis and production process, and the properties and applications of the most important microbial polysaccharides.
Molecules, Nov 21, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Applied Microbiology, Jan 20, 2015
This study evaluated the efficacy of a probiotic containing Bacillus toyonensis spores (Toyocerin... more This study evaluated the efficacy of a probiotic containing Bacillus toyonensis spores (Toyocerin(®) ) in postweaning piglets against enteric pathogens. 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. The use of Toyocerin(®) in weaning pigs, especially at 1000 mg kg(-1) diet, improved their health and growth performance. 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 Fermentation allows production of healthy, preservable, and nutritious foodstuff and bev... more Abstract Fermentation allows production of healthy, preservable, and nutritious foodstuff and beverages, such as respective dairy and meat products, vegetables (pickles) and olives, beer, and wine, where a wide array of microbiota, both prokaryotes and eukaryotes, participate simultaneously or successively, creating distinct though multiple growth and developmental dynamics in terms of succession and prevalence of different genders of cellular microbiota, during and after fermentation. Genomic methodology reveals and elucidates the diversity of similar populations in different localities, enabling a more qualitative marketing of products. Simultaneously, spoilage and pathogenic microbial taxa contaminate and degrade fermented foodstuff, adversely affecting quality, shelf-life, and safety of the final product, which can be stratified by genomic and metabolomic approaches to further detail than hitherto. The positive or negative interactions of productive and counterproductive taxa within these microbiomes and their cumulative effect define the success of the process in terms of marketing efficiency, thus establishing practices of using either indigenous microbiota or added starter cultures, each with different effects on quality, sensory characteristics, storability, and safety.
Journal of Applied Microbiology, 2015
Journal of Applied Microbiology, 2015
Abstract The concept of “bacteriome” was recast to apply to microbiomics in the late 2000s as the... more Abstract The concept of “bacteriome” was recast to apply to microbiomics in the late 2000s as the major (in cell population and gene context) but residual part of individual microbiomes, once mycobiome and virome were detached. Following the genomic aspect of the microbiome of the era, the bacteriome abided to the three-domain concept, thus inaugurating the archaeome as well. Both prokaryotic biomes are characterized by diverse and massive horizontal gene transfer. The sum of antagonistic and cooperative interactions among the different participant prokaryota and their respective alterations over time, either spontaneously or due to a multitude of effectors, defines their attitude toward their surroundings, environmental, industrial, or health-associated (medicinal, veterinary, and phytopathological) contexts. Diverse in functional and spatiotemporal terms, the infinite bacteriomes are focal for process-based microbiomic studies, contrary to conventional, cell-based bacteriology, revealing novel traits as the development of multicellular, possibly chimeric prokaryota, as insinuated by multispecies biofilms. They are thus bound to attract major research effort and resources in near future.
Animal, 2018
In the present study, grape pomace (GP) was used as feed additive in the diet of weaned piglets i... more In the present study, grape pomace (GP) was used as feed additive in the diet of weaned piglets in order to develop innovative feedstuffs and to investigate their potential beneficial effects on welfare, productivity and meat quality. For examining the antioxidant capacity of the experimental feeds, 24 piglets of 20 days old were assigned to two experimental groups receiving standard or experimental diet for 30 days. Blood and tissues collections were performed at four different time-points, 2, 20, 35 and 50 days post birth. The collected tissues were brain, heart, kidney, liver, lung, quadriceps muscle, pancreas, spleen and stomach. 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 H 2 O 2 decomposition activity. The effect on bacterial growth was assessed by examining microbial populations in piglets' fecal microbiota. Furthermore, the average daily gain (ADG) was calculated and the fatty acid profile of quadriceps muscle was assessed. The results showed that piglets fed with the diet supplemented with GP, had significantly increased antioxidants mechanisms in almost all the tissues as shown by increases in GSH, H 2 O 2 decomposition activity and TAC compared with 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 GP group compared with control. In addition, the experimental diet increased significantly ADG (by 23.65%) (P < 0.05) and enhanced the growth of facultative probiotic bacteria (by up to 1.2 log colony forming units (CFU)/g) (P < 0.05) and lactic acid bacteria (by up to 2.0 log CFU/g) (P < 0.05) in GP group compared with the control group. GP supplementation inhibited the growth of pathogen populations such as Enterobacteriacae (by up to 1.8 log CFU/g) (P < 0.05) and Campylobacter jejuni (by up to 1.0 log CFU/g) (P < 0.05). Regarding fatty acid composition of meat, GP inclusion in piglets' diet increased significantly n-3 fatty acids (EPA; C20 : 5n-3, DHA; C22 : 6n-3, α-linolenic acid; C18 : 3n-3) and decreased significantly n-6/n-3 ratio compared with control (P < 0.05). The results suggested that dietary GP supplementation may have a beneficial impact on piglets' welfare and may improve productivity as well as meat quality.
Journal of Food Science and Engineering, Sep 28, 2020
Orange pomace is the solid waste of the orange juice industry which accounts for approximately 50... more Orange pomace is the solid waste of the orange juice industry which accounts for approximately 50% of the quantity of the fruits processed into juice and is a good raw material for production of high added value products with diverse uses. Orange pomace is rich in polyphenols and flavonoids which can substitute the potentially hazardous or less desirable chemical antioxidants/antimicrobials used in agro-food and cosmetics industry. In this work, an eco-friendly aqueous microwave assisted extraction of orange pomace was investigated and optimized in order to produce aqueous bioactive antioxidant/antimicrobial extracts. A three factorial Response Surface Optimization methodology with centered Box & Behnken experimental design was used to obtain optimum values of total polyphenols and total flavonoids and build predictive models for their optimal extraction conditions. The three optimization factors in terms of applied process parameters were (a) water/solid ratio, (b) extraction temperature and (c) extraction time. The effectiveness and statistical soundness of the two corresponding models regarding optimal total polyphenols and flavonoids were verified by Analysis of Variance (ANOVA).
British Biotechnology Journal, Jan 10, 2016
The Journal of Agricultural Science, 2019
A feeding trial involving growing piglets was undertaken to establish whether feed supplemented w... more 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 (H2O2) 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, H2O2 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.
Current Opinion in Biotechnology, Apr 1, 2014
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights Author's personal copy Bioactive fungal polysaccharides as potential functional ingredients in food and nutraceuticals Ioannis Giavasis 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 b-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.
DOAJ (DOAJ: Directory of Open Access Journals), Jun 1, 2003
This paper introduces the application of an agent-based software system for monitoring the proces... more This paper introduces the application of an agent-based software system for monitoring the process of gellan gum production. Gellan gum (biopolymer) is produced in industrial scale in bioreactors (sealed vessels) where the microbial culture is grown in a liquid fermentation medium under controlled environmental conditions (temperature, pH, aeration and agitation). The multi agent system will view the monitoring problem as the interaction of simple independent software entities, for effective use of the available data. The outcome of this agent-based solution will include the automatic on-line data acquisition and correlation of the most important parameters. Within such a dynamic process, like the gellan gum production, certan parameters (such as biomass, gellan and glucose concentration) change continuously and have to be measured and controlled. Also automatic knowledge derivation from past cases through the multi agent software system can be of future benefit.
Omics A Journal of Integrative Biology, Mar 7, 2022
The advances made by microbiome research call for new vocabulary and expansion of our thinking in... more 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.
Available from British Library Document Supply Centre- DSC:DXN064253 / BLDSC - British Library Do... more Available from British Library Document Supply Centre- DSC:DXN064253 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Journal of Food Science and Engineering, Jun 28, 2020
Pomegranate pomace is the solid waste of the pomegranate juice industry which accounts for approx... more Pomegranate pomace is the solid waste of the pomegranate juice industry which accounts for approximately 50% of the quantity of the fruits, which is processed into juice and is a good raw material for production of high added value products with diverse uses. Pomegranate pomace is rich in polyphenols and flavonoids which could substitute the potentially hazardous synthetic antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work, eco-friendly aqueous microwave assisted extraction of pomegranate pomace was investigated and optimized in order to produce effectively novel natural antioxidant/antimicrobial extracts. A three-factorial response surface optimization methodology with centered Box & Behnken experimental design was used to obtain the predictive models and the maximum values of total polyphenols, total flavonoids and total antioxidant capacity (TAC). The three optimization factors involved were: (a) water/solid ratio; (b) extraction temperature; (c) extraction time and the effectiveness and robustness of the three models were statistically verified by ANOVA.
Zenodo (CERN European Organization for Nuclear Research), Apr 24, 2012
In the course of the present work, plain (nonencapsulated) and microencapsulated polyphenols were... more In the course of the present work, plain (nonencapsulated) and microencapsulated polyphenols were produced using olive mill wastewater (OMW) as raw material, in order to be used for enrichment of yogurt and dairy products. The OMW was first clarified by using membrane technology and subsequently the contained poly-phenols were isolated by adsorption-desorption technique using selective macro-porous resins and finally recovered in dry form after been processed by RO membrane technique followed by freeze drying. Moreover, the polyphenols were encapsulated in modified starch by freeze drying in order to mask the color and bitterness effect and improve their functionality. The two products were used successfully as additives in yogurt preparations and the produced products were acceptable by the consumers and presented with certain advantage to the plain yogurt. For the herein proposed production scheme a patent application was already submitted.
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Papers by Ioannis Giavasis