Argyro Bekatorou

University of Patras | UP · Department of Chemistry

(1) Objectives: Traditional kombucha (K) is a fermented beverage obtained from black or green tea infusion. Besides traditional substrates, the possibility of using alternative ingredients resulted in changes in metabolic profile and biological activity. The aim of this work was to study an alternative kombucha (KJ) prepared by the addition of juju...

The aim(目的) of this study was to create(创建) various formulations of yogurt enriched with freeze(冻结)-dried adjuncts, namely(即) (i) probiotic Lactobacillus plantarum ATCC 14917 culture(文化), and (ii) L. plantarum ATCC 14917 fermented black chokeberry juice, along with a commercial(商业) starter culture(文化). The goal was to enhance(提高) functionality and...

The objective of this study was to create yogurts enriched with freeze-dried probiotic culture and freeze-dried fermented black chokeberry juice, in conjunction with a commercial starter culture. This approach was adopted to boost functionality and optimize the nutritional content of the yogurt. The study specifically investigated the impact of sup...

We report the production of BC gels by Komagataeibacter sucrofermentans in synthetic (Hestrin and Schramm; HS) and natural media (raisin finishing side-stream extracts; RFSE), and their in situ modification by natural zeolite (Zt) and activated carbon (AC) nanostructures (NSs) carrying thyme oil (Th). The NS content for optimum BC yield was 0.64 g/...

In the frame of efforts to add value to the Mediterranean currant cultivation and processing sectors, which is essential for their sustainability, sweet wine production is proposed from the finishing side-stream (FSS) of premium quality Corinthian currants, involving complete fermentation using an alcohol-tolerant yeast followed by (i) the addition...

New types of sourdough breads are proposed, made with freeze-dried sourdough adjuncts based on: (i) Lactiplantibacillus plantarum subsp. plantarum ATCC 14917, a potential probiotic (LP) alone or (ii) with the addition of unfermented pomegranate juice (LPPO) and (iii) pomegranate juice fermented by the same strain (POLP). Physicochemical, microbiolo...

The industrial finishing side-stream (FSS) of premium-quality Corinthian currants was used to produce syrups with/without pigment- and tartrate-reduction treatments. The chemical composition, total titratable acidity (TTA; % w/w as tartaric acid), volatile acidity (VA; % w/w as acetic acid), total phenolic content (TPC; as gallic acid, GA), antioxi...

The present study describes the application of an acid tolerant and potentially probiotic L. paracasei SP3 strain, recently isolated from kefir grains, in the production of a novel functional beverage based on the fermentation of pomegranate juice. The fermentation ability of the novel strain was assessed during pomegranate juice fermentations at 3...

Fruit wastes and side-streams can be used for vinegar production to create added value for the agri-food sector and enhance farmer incomes and local economies. In this study, methods for vinegar production by wild and selected acetic acid bacteria (the quick starter Acetobacter aceti and the acid-resistant Komagataeibacter europaeus), free (FC) and...

Response surface methodology was used to derive a prediction model for organic acids production by anaerobic acidogenic fermentation of cellobiose, using a mixed culture immobilized on γ-alumina. Three parameters (substrate concentration, temperature, and initial pH) were evaluated. In order to determine the limits of the parameters, preliminary ex...

Agro-industrial wastes can be valorized as biorefinery raw materials through innovative, environmentally friendly bioprocessing for added value products. In this study, a process for citrus waste valorization within the biorefinery concept is proposed, including the development of an effective biocatalyst, based on immobilized cells, for aromatic b...

Nowadays, there is a growing consumer demand for non-dairy functional foods due to several health issues related to milk and dairy consumption and increasing vegetarianism. Following that trend, in the present study emmer-based beverages were developed after flour gelatinization, fortification with fruit juices (blueberry, aronia, and grape) and fe...

Vinegar has been used for its health promoting properties since antiquity. Nowadays, these properties are investigated, scientifically documented, and highlighted. The health benefits of vinegar have been associated with the presence of a variety of bioactive components such as acetic acid and other organic acids, phenolic compounds, amino acids, c...

The industrial currants finishing generates a considerable amount of side-stream (FSS) with great potential for biotechnological exploitation. The chemical composition of FSS generated from the premium quality Vostitsa currants was studied. Its use for wine making (at low temperatures, using both free and immobilized yeast) combined with baker’s ye...

In the present study, a novel Pediococcus pentosaceus SP2 strain, recently isolated from kefir grains, was evaluated as a starter culture in sourdough bread making. The novel starter was applied in fresh, freeze-dried, and freeze-dried immobilized (on wheat bran) form. The type of culture (fresh, freeze-dried, immobilized cells) influenced the brea...

The recently isolated Lactobacillus paracasei K5 (a potential probiotic) was immobilized on 28 delignified wheat bran (DWB) and was used to produce a functional pomegranate beverage. 29 Fermentations were carried out for 24 h at different pH values (3.3, 3.6, and 3.9), and the 30 fermented juices were stored for 4 weeks at 4oC. In all cases, the im...

Balsamic vinegars have a long history of production in Italy and are mainly categorized in two types, namely the traditional and industrial types. They are both obtained from the alcoholic and acetous fermentation of cooked and concentrated grape musts, which is the main characteristic that distinguishes balsamic vinegars from other vinegars. Speci...

The aim of this study was to develop a bioprocess for low temperature fruit wine making from ready-to-use freeze-dried raw materials: sour cherry (Prunus cerasus) juice and the psychrotolerant and alcohol resistant yeast strain Saccharomyces cerevisiae AXAZ-1 immobilized on porous delignified cellulose. The effect of storage time of the freeze-drie...

The aim of this work was to develop bioprocesses to produce a high-value microbial product, bacterial cellulose (BC), utilizing the industrial side-stream of Corinthian currants finishing (CFS), with/without the addition of N-sources and cheese whey, and at various process conditions (temperature, pH level, and sugar concentration). For the optimiz...

In the present study, a novel potentially probiotic Lactobacillus paracasei strain, previously isolated from dairy products, was evaluated as a starter culture of Feta-type cheese production. Targeting industrial applications, the starter culture was applied as a ready-to-use freeze-dried culture that was either free or immobilized. The immobilized...

In this research survey the application of probiotic strain Lactobacillus plantarum ATCC 14917 in pomegranate juice fermentation is sought. Pomegranate juice was fermented for 24 h and then it was stored 4 for 4 weeks. Cell viability retained in high levels after the 24 h of fermentation and storage for 4 weeks (above 8.8 log cfu/mL), while ferment...

The aim of this study was the production of a novel, potentially synbiotic beverage by fermentation of Cornelian cherry juice using Lactobacillus paracasei K5 cells, free or immobilized on wheat bran. Fermentations were carried out for 24 h followed by cold storage of the juices for 4 weeks. The fermentation performance of the free or immobilized L...

In the present study 38 lactic acid bacteria strains were isolated from kefir grains and were monitored regarding probiotic properties in a series of established in vitro tests, including resistance to low pH, resistance to pepsin and pancreatin, and tolerance to bile salts, as well as susceptibility against common antibiotics. Among them, the stra...

Nowadays, an increasing worldwide interest in the use of renewable energy sources and the production of biofuels through the use of agro-industrial waste biomass as substrate for biofuels has become a necessity. Therefore several studies have reported the use of wastes for biofuel production including ethanol, methane and hydrogen. Another biorefin...

The novel Lactobacillus paracasei K5 strain, recently isolated from Greek cheese, was evaluated as potential sourdough bread starter. Breads were made using different amounts of L. paracasei sourdoughs as well as traditional sourdough for comparison. Quality characteristics of the breads (acidity and rising) were examined, as well as rope spoilage...

In the frame of efforts to exploit agroindustrial side-streams and wastes (AISS) for added-value products that are based on single cell protein (SCP), mixed substrates consisting of brewer’s spent grains (BSG), malt spent rootlets (MSR), cheese whey, molasses, orange, and potato pulps, were used for growth of the edible mushroom Pleurotus ostreatus...

The anaerobic acidogenic fermentation of wheat straw was studied, after various chemical and microbial pretreatments, namely (a) chemical delignification, (b) hydrolytic pretreatment with T. viride of the chemically delignified straw to enhance the organic acid (OAs) yields in the subsequent acidogenic fermentations, and (c) microbial delignificati...

Practical application: The launch on market of novel foods developed by the incorporation of functional ingredients provides potential benefits to consumers' diet and new business opportunities for producers. Probiotic food products are one significant category of functional foods. Thus, this study focused on the development of a novel ready-to-us...

A novel process development is described in this study, based on a low volume bioreactor containing enzyme (rennin) encapsulated in a nano/micro porous cellulose (or tubular cellulose; TC) and starch gel matrix (TC/SG composite), for use in continuous coagulation of milk in cheese production. To validate the process, experiments were carried out in...

Wheat bran, a common cereal processing by-product, was used as immobilisation carrier for a probiotic Lactobacillus casei strain (L. casei ATCC 393). The immobilised synbiotic biocatalyst was freeze-dried without cryoprotectants and was used as adjunct in industrial Feta cheese making (a). For comparison reasons cheeses were also made by addition o...

Development of a novel directly marketable beer brewed at low temperature in a domestic refrigerator combined with yeast immobilization technology is presented in this study. Separately, freeze-dried wort and immobilized cells of the cryotolerant yeast strain Saccharomyces cerevisiae AXAZ-1 on tubular cellulose were used in low-temperature fermenta...

Enhanced single cell oil (SCO) production by the oleaginous yeast Lipomyces starkeyi DSM 70296, immobilised on delignified porous cellulose, is reported. Pure glucose media were initially used. The effects of substrate pH and treatment temperature were evaluated, showing that 30 °C and pH 5.0 were the optimum conditions for SCO production by the im...

Delignified wheat straw was fermented by a mixed bacterial anaerobic culture obtained from a UASB reactor to produce organic acids (OAs). Kissiris was used as immobilization carrier in a 2-compartment 82 L bioreactor filled with 17 L of fermentation broth for the first 7 fermentation batches and up to 40 L or the subsequent batches. The amount of s...

Cheese whey exploitation in a biorefinery manner is proposed involving anaerobic acidogenesis by a UASB mixed anaerobic culture and alcoholic fermentation by kefir. Both cultures were immobilized on γ-alumina. The produced organic acids (OAs) and ethanol could be esterified to obtain a novel ester-based biofuel similar to biodiesel. During acidogen...

The effect of wheat bran (Triticum aestivum) as a cell immobilization carrier for probiotic yogurt production on cell viability, composition of volatile compounds and sensory characteristics, was studied. Wheat bran was delignified and separately used as a carrier for the immobilization of Lactobacillus casei ATCC393 and Lactobacillus bulgaricus DS...

Topics related to the production, properties, composition, and analysis of alcohol are highlighted and discussed in this article. The basic biochemistry, microbiology, and external factors that affect the alcoholic fermentation process are described, and its historical and economic significance to humanity is emphasized. The main types of alcoholic...

Wine is an agricultural product with very high commerce price variation, which is highly affected by quality ratings. Therefore, quality rating is particularly important for both industry and consumers. However, absence of clear concepts on what constitutes wine quality makes the perception of quality highly subjective, and it is usual for tasters...

In the present study, probiotic sour milk was produced by freeze-dried L. casei ATCC 393 cells, free or immobilized on wheat bran. Wheat bran was used with and without lignin removal. The aim was to evaluate the possibility to produce sour milk using immobilized probiotic biocatalysts that could be removed after the end of fermentation and be used...

The extent to which selected ethanol and lactic acid production bioprocesses contribute to whey waste abatement was examined. Alcoholic fermentation of whey was carried out by kefir cells immobilized on grape stalks, delignified cellulosic materials, or brewer's spent grains. Lactic acid fermentation was also performed by free kefir cells with or w...

This article presents a comprehensive review on hydrolysis and acidogenesis of lignocellulosic waste biomass and makes clear new perspectives in biofuel research. Specifically, the acidogenesis of lignocellulosics and liquid effluent have been discussed extensively with potential goal the production of a new generation biofuel. This new biofuel can...

The present study focused on organic acids (OAs) recovery from an acidogenic fermentation broth, which is the main problem regarding the use of OAs for production of ester-based new generation biofuels or other applications. Specifically, 10 solvents were evaluated for OAs recovery from aqueous media and fermentation broths. The effects of pH, solv...

The object of the current study was to develop a new process for continuous Feta-type cheese production using a biocatalyst consisting of immobilized rennin on a tubular cellulose/starch gel (TC/SG) composite, which has been proven to be an appropriate carrier for enzyme immobilization. Different methodologies were used in order to prepare four bio...

Fermentation of pomegranate juice as single or mixed substrate with orange juice, without addition of extra nutrients, using kefir grains is proposed. Sugar consumption and ethanol production were monitored during fermentation, while the formation of lactic acid and the survival of lactic acid bacteria were determined during storage at 4 °C for 4 w...

In this study, tubular cellulose (TC), a porous cellulosic material produced by delignification of sawdust, was treated with a Trichoderma reesei cellulase in order to increase the proportion of nano-tubes. The effect of enzyme concentration and treatment duration on surface characteristics was studied and the samples were analyzed with BET, SEM an...

Nowadays there has been an increased interest in the development of new functional foods and their incorporation in a healthy diet. Such products and especially probiotics exert a beneficial effect on host gut microbiota after consumption and may be capable to prevent several diseases. Fermented beverages are traditional products that act as vehicl...

An economic evaluation of an integrated technology for industrial scale new generation biofuel production using whey, vinasse, and lignocellulosic biomass as raw materials is reported. Anaerobic packed-bed bioreactors were used for organic acids production using initially synthetic media and then wastes. Butyric, lactic and acetic acid were predomi...

The aim of this investigation was to study the use of nano/micro-porous cellulosic materials (tubular cellulose, TC) produced by delignification of mango (Magnifera indica L.), sal (Shorea robusta G.) sawdust and rice husk (Oryza sativa L.) in various food bioprocesses. Specifically, the porous structure of TC renders it suitable for use as filter...

One of the major concerns in food industry is food preservation and microbial spoilage. The most commonly used technique for this purpose is pasteurization, a heat-transferring process. Pasteurization, however, alters the organoleptic characteristics, specifically in heat-sensitive foods. In this study, a novel cold pasteurization technique is prop...

A novel continuous preservation process of apple juice using a nano/micro-porous cellulosic material (or "tubular cellulose", abrrev. TC), is presented in this study. This investigation aims to the development of a non-thermal system for microbial stabilization, avoiding the degradation of food quality caused by heat. TC was used as filter in a pac...

Recent research efforts in upgrading brewery solid wastes (brewer?s spent grains, spent rootlets, spent hops and spent yeasts) by biotechnological conversion into added-value products, such as single cell protein, functional food and feed ingredients, microbial extracts, organic acids, bioplastics, biosorbent materials and immobilized cell biocatal...

Recent advances in sourdough bread biotechnology are discussed in this chapter. Implementation of sourdough methods is an important trend in bread production during the last years, mainly due to consumer‘s demands for bread of superior quality and free of chemical additives. The main advantages of sourdough application are: (1) lower bread deterior...

Α low-cost and environmentally friendly clean-up technique is evaluated in this study, based on the use of a brewery by-product, malt spent rootlets, as potential biosorbent for U(VI) sequestration from aquatic systems. Uranium uptake was rapid (2.5 h at 25 °C), and MSR exhibited capability of removing U(VI) from effluents of high acidity (pH 1.5)...

Background This investigation comprises a contribution on the production of a new generation biofuel using the industrial liquid waste of bioethanol distilleries, known as vinasse. This study focuses on the exploitation of vinasse as an acidogenesis substrate for volatile fatty acids and simultaneous ethanol production. These products can be used f...

An industrial process for black table olives fermentation was followed in order to study the effect of immobilized halophile culture and the initial halophile culture concentration in combination with temperature for a period of 30 days. For comparison, three types of batch fermentation were investigated: (a) fermentation with the indigenous microb...

The objective of this study was to produce a composite biocatalyst, based on porous cellulosic material, produced after wood sawdust delignification (tubular cellulose; TC) and starch gel (SG), for the development of bioprocesses related to enzyme applications. The composite biocatalyst was studied by Scanning Electron Microscopy to observe the SG...

The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of sucrose, raffinose and vinasse is reported. Initially, the effect of pH (4-8) and fermentation temperature (18-52°C) on the accumulation of low molecular weight organic acids (OAs) during sucrose acidogenesis, was evaluated. The promoting effect of kissiri...

The effect of γ-alumina as a fermentation advancing tool and as carrier for culture immobilisation, regarding VFAs and ethanol production during acidogenic fermentation of glucose, was examined at various process conditions (sugar concentration, pH) and operation modes (continuous with and without effluent recirculation and batch). The results show...

The authenticity of some mixed drinks like vodka or rum was correlated to the conductivity of the dilution water. Authentic drinks demonstrated low conductivity suggesting the use of treated water whereas fraud drinks were mixed with regular tap water. The objective of the present study was to test if this criterion is valid for distilled anis or i...

Porous delignified cellulose (or tubular cellulose, abbr. TC) from Indian Mango (Mangifera indica) and Sal (Shorea robusta) wood and Rice husk, and TC/Ca-alginate/polylactic acid composites, were used as Lactobacillus bulgaricus immobilisation carriers leading to improvements in lactic acid fermentation of cheese whey and synthetic lactose media, c...

This investigation describes the development of a continuous “cold pasteurisation” process for wine, using a nano/micro-porous cellulosic material (tubular cellulose, TC), produced after delignification of wood sawdust, as filter in a packed column. The packed-bed bioreactor was supplied with white or red wine contaminated with Saccharomyces cerevi...

Recently, low-temperature fermentation has been recognized as a valuable tool to improve the flavor of fermented foods such as alcoholic beverages, e.g., in terms of improved ratios of off-flavor compounds to desirable compounds on total volatiles produced during fermentation. Extremely low-temperature fermentation processes can be made feasible us...

The exploitation of various agro-industrial wastes for microbial cell mass production of Kluyveromyces marxianus, kefir, and Saccharomyces cerevisiae is reported in the present investigation. Specifically, the promotional effect of whole orange pulp on cell growth in mixtures consisting of cheese whey, molasses, and potato pulp in submerged ferment...

The production of volatile fatty acids (VFAs) in a continuous process using a synthetic glucose medium as model substrate in the presence of γ-alumina as promoter is described. The results showed formation of acetic, propionic, isobutyric, butyric, isovaleric and valeric acids, with acetic acid being more than 90% of the total VFAs produced. It is...

  The natural mixed culture kefir was immobilized on boiled corn grains to produce an efficient biocatalyst for lactic acid fermentation with direct applications in food production, such as sourdough bread making. The immobilized biocatalyst was initially evaluated for its efficiency for lactic acid production by fermentation of cheese whey at vari...

In this work an integrated cost effective system for continuous alcoholic fermentation of a cheap raw material (molasses) is described, involving yeast immobilized by a simple method on brewer's spent grains, able to ferment in the temperature range 30–40 °C, and two types of bioreactors, a Multistage Fixed Bed Tower (MFBT) and a Packed Bed reactor...

Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, which was done by SEM, porosimetry and X-ray pow...

It is known that various microorganisms efficiently adsorb dissolved metal ions and this capability was recognized as an alternative way for cheap removal of toxic or precious metals from aqueous solutions. Lactobacillus casei is a probiotic bacterium. Probiotics are live microorganisms, which "when administered in adequate amounts confer a health...

Preservation, risk of contamination, transportation and storage costs (e.g. refrigeration) are the main problems associated with wet, active starter cultures such as yeast. To deal with these aspects, drying of commercial cultures is required. A thermally dried biocat-alyst has been prepared by immobilization of the psychrotolerant yeast strain Sac...

The dependence of U(VI) uptake on the temperature of cell culture, the air flow during the cultivation process and the age of cells were studied. Saccharomyces cerevisiae, Kluyveromyces marxianus and Debaromyces hansenii were chosen as typical yeasts, which are widely used, in food industries. Our results revealed that the highest metal uptake was...

The aroma volatile compositions of sourdough breads containing kefir grains were monitored by SPME GC–MS analysis during a 5-day storage. Breads were made with (A) 20% w/w and (B) 10% w/w (on flour basis) kefir sourdough, and were compared with breads made with 20% w/w commercial sourdough (C) and sourdough prepared in the laboratory (D) without ad...

A new biocatalyst was prepared by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on whole wheat grains. This biocatalyst was subjected to freeze-drying and the effects of several protective agents and storage at 5 °C on viability and fermentative activity of yeasts cells were studied. Glycerol was the best protective agent that prese...

The commercial Saccharomyces cerevisiae Uvaferme 299 wine yeast was immobilized on cork pieces to produce a biocatalyst for use in dry red wine making. The immobilized biocatalyst was suitable for clarified and non-clarified grape must fermentation at ambient and low temperatures (0-25 degrees C). Fermentation times were low and very low amounts of...

Lactobacillus bulgaricus grown on whey was dried by a simple thermal drying method at the range 35-55 degrees C and its efficiency for lactic acid fermentation of whey was evaluated. Drying of cells in whey suspension in the examined temperature range did not affect significantly their viability (82-87% survival), indicating a protective effect of...

A new biocatalyst was prepared by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on whole wheat grains. This biocatalyst was used for 30 repeated batch fermentations of glucose and grape must at various temperatures. The biocatalyst retained its operational stability for a long period and it was proved capable to produce dry wines of...

Low-cost dried yeasts immobilized on delignified brewers' spent grains for use in wine making and brewing were produced by simple thermal drying techniques. To optimize the thermal drying process, vacuum and air stream conditions were examined. Drying of thin layers of the biocatalysts was performed at low (30-38 degrees C) and high temperatures (4...

Different types of red and white wines were prepared by fermentation of the juice which was naturally separated from uncrushed frozen grapes during thawing (A) and from the residual juice by fermentation inside the berries (B). Yeast penetrated the skin of uncrushed grapes and fermented the content completely. The new types of wines were compared w...

This paper concerns the effect of thermal-drying methodology on the investment cost for dried kefir cells production in order to be used as starter culture in cheese manufacturing. Kefir cells were produced at pilot plant scale using a 250-L bioreactor and whey as the main substrate. Kefir cells were subsequently dried in a thermal dryer at 38 degr...

Whey is the major by-product of the dairy industry, produced in large quantities and usually disposed off causing major environmental pollution, due to its high organic load that makes treatment cost prohibitive. This paper comprises a contribution on the valorisation of this high polluting liquid waste of the dairy industry, based on research for...

Two mixed starter cultures were used for sourdough bread making to evaluate their ability to improve quality and increase bread shelf-life: Lactobacillus delbrueckii ssp. bulgaricus or Lactobacillus helveticus mixed with the lactose fermenting yeast Kluyveromyces marxianus as alternative baker’s yeast. Control sourdough breads (K. marxianus) withou...

A biocatalyst, prepared by immobilization of the psychrotolerant yeast strain Saccharomyces cerevisiae AXAZ-1 on delignified brewer’s spent grains, was used for brewing at very low temperatures, resulting in beers with fine clarity, excellent quality and mature character after the end of primary fermentation. Fermentation times were low (only 20 da...

New types of bread were produced employing baker’s yeast, kefir or Lactobacillus casei immobilized on brewer’s spent grains. Bread was produced either by the straight-dough or the sourdough method. All the studied biocatalysts and their corresponding sourdoughs were found efficient for breadmaking. Good rising was achieved and the produced breads h...

Repeated batch wine fermentations were conducted using immobilized yeast cells on brewer’s spent grains as well as free cells, at 25, 20, 15 and 10°C. The operational stability of the biocatalyst was good and no decrease of its activity was observed, even at 10°C. Ethanol and wine productivities were high, showing the suitability of the biocatalyst...

Industrial scale-up of whey fermentation, promoted by raisin extracts, using free kefir-yeast cells is reported. The fermented whey would be exploited as raw material to produce kefir-like whey-based drinks, potable and fuel alcohol, as well as kefir-yeast biomass for use as baker's yeast. The scale-up process involved the development of a technolo...