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Galanakis C.M.,Chemical Analytical Laboratories Galanakis | Markouli E.,Cyprus University of Technology | Gekas V.,Cyprus University of Technology
Separation and Purification Technology | Year: 2013

The purpose of the current study is to investigate the possibility of utilizing ultrafiltration (UF) for the fractionation of phenolic compounds recovered from winery sludge (WS) and their separation from other co-extracted components. Thereby, two hydro-ethanolic extracts (a diluted and a concentrated) were prepared, using WS as an initial material, and assayed in a cross-flow apparatus against three membrane types (100 kDa- and 20 kDa-polysulfone, 1 kDa-fluoropolymer). Monitoring of the process was carried out by determining performance parameters and retention coefficients of pectin, sugars, phenolic and anthocyanins classes. Results indicated that solutes retention was affected mainly by severe fouling phenomena due to polar solutes adsorption on membrane surface instead of size exclusion. Indeed, polysulfone membranes were not able to fractionate phenolic classes except for the separation obtained between polymeric and monomeric anthocyanins. Both membranes and especially the one of 20 kDa retained high percentages (i.e. >60%) of polar solutes (phenolic compounds and sugars), whereas the one of 100 kDa allowed their separation from pectin and hydrolyzed derivatives. As far as polarity is concerned, fluoropolymer membrane separated successfully hydroxycinnamic acid derivatives from anthocyanins and flavonols in the diluted and concentrated extract, respectively, as acids possessed almost 2-fold higher retention coefficients compared to the other assayed classes. © 2013 Published by Elsevier B.V.

Patsioura A.,Technical University of Crete | Galanakis C.M.,Technical University of Crete | Galanakis C.M.,Chemical Analytical Laboratories Galanakis | Gekas V.,Cyprus University of Technology
Journal of Membrane Science | Year: 2011

The scope of the current study is to investigate the ultrafiltration process of high molecular weight β-glucan molecules with a final purpose to optimize their recovery from oat mill waste. Therefore, standard β-glucan solutions were processed in a dead-end cell using three types of membranes (regenerated cellulose, polyethersulfone and polysulfone) under several transmembrane pressures. Optimization was conducted by monitoring performance parameters and retention coefficients for each experimental combination. In terms of membrane type, polysulfone was selected as the most appropriate membrane material since it obtained satisfactory retention coefficient and performance parameter values when the β-glucan concentration was less than 600. mg/L. Thereafter, the polysulfone membrane was applied in a pilot cross-flow module instead of a dead-end cell. The retention of β-glucan as well as the flux recovery was markedly improved with no important reduction of the permeate flux. Finally, polysulfone membrane was applied in the pilot cross-flow module for the ultrafiltration of β-glucan containing feeds (<600. mg/L) recovered from the industrial oat mill waste. Results indicated that the optimized ultrafiltration process (polysulfone in cross-flow module, with transmembrane pressure ≤2. bar and β-glucan concentrations < 600. mg/L) could be utilized in order to recover β-glucan from the oat mill waste feeds and clarify them from smaller organic and inorganic compounds. A disadvantage of the latter application was the small degree of separation between β-glucan and proteins. © 2011 Elsevier B.V.

Galanakis C.M.,Chemical Analytical Laboratories Galanakis | Chasiotis S.,Cyprus University of Technology | Botsaris G.,Cyprus University of Technology | Gekas V.,Cyprus University of Technology
Food Research International | Year: 2014

Halloumi is the traditional cheese of Cyprus that is produced using typically two processes: milk coagulation and pressed curd cooking. Both processes generate two whey substrates rich in proteins and sugars. The scope of the current study is to investigate the separation and recovery of these compounds by processing samples with a cross-flow ultrafiltration module and five membranes in two sequential steps. Three membranes (100, 50 and 20. kDa) were tested in the first scenario and 20. kDa-permeates were assayed in the second using the two materials with narrower pores of 2 and 1. kDa. Experiments were conducted under constant temperature, circulation flux and several transmembrane pressures, while recovery monitoring was performed by determining operation parameters and retention of proteins, reducing and non-reducing sugars. Results indicated that ultrafiltration is able to separate the target compounds optimally upon two different approaches: using a 100. kDa-polysulphone barrier or by combining 20. kDa-polysulphone and 2. kDa-polyethersulphone membranes. The recovery of proteins in the first approach was high for both samples (69-76%), while the retention of non-reducing sugars (herein expressed mainly lactose) was negligible (2-7%). Using the combined treatment, the recovery of proteins and non-reducing sugars was almost quantitative (87-90%) and rather low (39-32%), respectively. © 2014 Elsevier Ltd.

Rahmanian N.,Gorgan University of Agricultural Sciences and Natural Resources | Jafari S.M.,Gorgan University of Agricultural Sciences and Natural Resources | Galanakis C.M.,Chemical Analytical Laboratories Galanakis
JAOCS, Journal of the American Oil Chemists' Society | Year: 2014

Food wastes are today considered as a cheap source of valuable components since the existent technologies allow the recovery of target compounds and their recycling inside the food chain as functional additives in different products. Olive mill wastewater (OMW) is generated from olive oil extraction systems. It has high addedvalue compounds namely phenolics, recalcitrants, pectin, and some important enzymes. It causes a certain amount of toxicity/phytotoxicity because of its phenolic compounds. OMW also has significant impacts when discharged directly into surface waters. Therefore, the treatment of olive mill wastewater is very much needed. Several types of techniques have been investigated for OMW treatment along with recovery and removal of its phenolic compounds. Among these techniques, physical ones are utilized for extraction purposes, while chemical and biological methods are applied in order to diminish organic load. In this review, current status and recent developments in the recovery and removal of phenolic compounds from OMW have been critically examined. © AOCS 2013.

Galanakis C.M.,Technical University of Crete | Galanakis C.M.,Chemical Analytical Laboratories Galanakis
Trends in Food Science and Technology | Year: 2011

Dietary fiber is related to the biochemical changes of cell wall polysaccharides during olive fruit ripening and post harvest processing. Besides, the recovery of dietary fibers from underutilized olive by-products has raised the interest of scientific community over the last decade. The goal of the current review is to discuss the compositional and structural characterization of olive dietary fiber, the modifications that dietary fiber undergone during olive fruit ripening and processing, the recovery and potential applications of dietary fiber from olive by-products. Finally, new research propositions have been introduced with regard to the discussed aspects. © 2010 Elsevier Ltd.

Galanakis C.M.,Chemical Analytical Laboratories Galanakis
Food and Bioproducts Processing | Year: 2013

Agricultural by-products were considered for many years as undervalued substrates due to their removal from food production line and the complicated problems arise from their treatment and disposal in the environment. Nowadays, the urgent demands for sustainability in the food and agricultural sectors led to their valorization as a source of nutraceuticals. The latest are typically produced using conventional technologies with well-known technological and scale-up boundaries, which reduce their efficacy and production yield. Emerging technologies promise to overcome these problems, but is this truth? The current viewpoint is trying to answer this question by exploring the possibility of adapting the latest technologies in the recovery downstream processing. Opportunities and challenges in the field are also discussed with a final aim of inspiring researchers to investigate the critical parameters that prevent for the moment the broad commercial implementation of emerging technologies in the particular application. © 2013 The Institution of Chemical Engineers.

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