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The present study aimed at assessing the antimicrobial properties of a water and ethanol ultrasound-assisted extraction (UAE) of dry goji berries and of lyophilised powdered pomegranate peel in vitro. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) methods, turbidity (cell density) measurement, and well diffusion assay were used to determine the antimicrobial activity against several species of foodborne bacteria (Gram – , Escherichia coli, Salmonella typhimurium, Campylobacter jejuni), (Gram + Staphylococcus aureus, Listeria monocytogenes, Clostridium perfringens), yeasts (Yarrowia lipolytica, Metschnikowia fructicola, and Rhodotorula mucilaginosa), and fungi (Penicillium expansum, Aspergillus niger, Fusarium oxysporum, and Rhizoctonia solani). Carbohydrate and phenolic contents were measured, and DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2΄-Azino-bis-(3-ethyl-benzthiazoline-sulphonic acid)) radical scavenging assays were used for the assessment of antioxidant activity. Fourier transform infrared (FTIR) spectrums of all samples were also evaluated in order to determine their chemical profiles. The lyophilised pomegranate peel exhibited the highest antioxidant, antimicrobial, and antifungal activity among all samples, while among the goji berry samples-who had only antibacterial and very little or no antifungal activity—the lyophilised aqueous extract with the lowest content of maltodextrin (2%) and highest phenolic content, had also the highest antioxidant, antimicrobial, and antifungal activity. The antioxidant and antimicrobial bioactivities seemed to be related to the content of polyphenols, the low concentration of maltodextrin in the encapsulated lyophilised samples and the use of optimised ultrasound assisted extraction. Minimum inhibitory concentration or zones of inhibition were in many (but not all) cases lower for the aqueous extracts compared to the ethanol or ethanol/hexane extracts of goji berries. In conclusion, the lyophilized powder of pomegranate peels and the aqueous extracts of goji berries encapsulated with minimal maltodextrin content and high polyphenol content exhibited high antioxidant and antimicrobial activity which could be utilized in food preservation or plant protection.

AbstractOlive mill wastewater (OMWW) is the result of the production of olive oil causing severe water pollution. In recent years, distinguished growing interest in isolation, testing, and utilization of agricultural waste or other sources of plant tissues rich in polyphenols has been arised. In this study, the evaluation of liquid polyphenols obtained from OMWW as natural bio-chemicals against several fungal pathogens on tomato plants was examined. Different concentrations of liquid formed polyphenol (LFP) at 5, 10, 20, and 30% were tested against 10 fungal pathogens causing plant diseases on tomato plants. After 40 d of application, tomato plants were harvested and plant height, number of flowers, plant fresh weight, root fresh weight, dry plant weight and dry root weight were calculated and LFP has presented encouraging results in protecting plants. Furthermore, the encapsulation of a polyphenol in encapsulating agent may help to slow down the degradation and protection from the frequent watering and runoff due to this action. Therefore, in order of major protection resulting from the use of polyphenol against major diseases classified the following phytopathogenic fungi: Botrytis cinerea, Sclerotinia sclerotiorum,and Ascochyta lentis.

AbstractOlive mill wastewater (OMWW) is a byproduct of the olive oil extraction process, characterized by high polluting load and polyphenols content. The treatment of OMWW, using microfiltration and XAD4 resin, results in recovery of polyphenols, and also in an effluent (treated OMWW) with decreased organic load and phytotoxic properties, compared to the initial OMWW. The effects of the treated OMWW (T-OMWW) application on maize kernel yield and quality, and soil quality were investigated through a two-year field experiment. T-OMWW was applied by drip irrigation to maize cultivation using two rates of 25–50 t ha−1 year−1, with the addition of mineral fertilization. Furthermore, a treatment of only T-OMWW applied at the rate of 50 t ha−1 year−1and an only mineral fertilization treatment were used. Maize kernel yield and quality were not significantly different between mineral fertilization and T-OMWW application, hence indicating that T-OMWW could fully substitute mineral fertilization under the conditions of our study. Based on the experimental results, an economic analysis was undertaken in order to evaluate the economic implications of T-OMWW application by drip irrigation to maize production. Three scenarios were investigated: (a) mineral fertilization only, (b) T-OMWW application at the rate of 50 t ha−1 year−1only, and (c) T-OMWW application at the rate of 25 t ha−1 year−1combined with reduced mineral fertilization. The cost analysis showed that T-OMWW application at the rate of 50 t ha−1 year−1was the least expensive of the three scenarios investigated, irrespective of the distance between the olive mill and the farm. The use of the farm tractor and tanker for the T-OMWW transportation was more cost effective than hiring a liquid transport company, for distance up to approximately 20 km. For greater distance, hiring a liquid transport company was more economical.

AbstractThe commercially available macroporous resin Amberlite FPX66 was evaluated for its capacity to adsorb the polyphenols contained in olive mill wastewater (OMWW). The adsorption was performed in the mode of fixed packed-bed contactor. The effects of OMWW flow rate, temperature, dilution and pH on the resin adsorption capacity were investigated. Polyphenols concentration decreased with time. The pattern of the total polyphenols concentration dependence on time was found to be similar in all cases. The pattern included a very steep section for roughly the first hour of the operation, followed by a second section of decreasing gradient down to a final asymptotic equilibrium limit. Regarding the time required for approaching the equilibrium, this was found to be unaffected by the temperature. On the contrary, the magnitude of the equilibrium concentration was substantially affected by the OMWW temperature presenting an optimum at 40°C. The increase in the OMWW flow rate affected markedly the speed of approaching the equilibrium but not its position. The variation of the total polyphenols concentration with time showed that higher concentrations yielded more rapid kinetics at the initial section, but there was no apparent differentiation of the time required to approach the equilibrium. Acidic pH appeared to be favourable for the adsorption. Finally, a novel modelling approach was developed to simulate the adsorption process kinetics.

AbstractA novel concept for olive mill wastewater (OMWW) concentration, involving the combination of open and tight reverse osmosis (RO) membranes in tubular configuration, was studied. The OMWW, prior to RO concentration, was clarified in two successive steps: passing through a coarse rotating finisher and by ceramic microfiltration, in order to remove suspended matter and facilitate the RO concentration. The clarified raw material was then concentrated using the tubular PCI UK AFC40 RO membrane. A parametric study was conducted to investigate the effect of main process parameters on permeation flux. The permeation flux of AFC40 RO membrane was found to reach consistently high values without substantial membrane fouling problems. Furthermore, the parametric study proved that the flux was linearly increased by increasing the transmembrane pressure, and exponentially decreased by increasing the OMWW mass concentration factor. In most cases, the permeation flux increased with increasing flow velocity. The effect of temperature on permeation flux was depended on both transmembrane pressure and flow velocity. The AFC40 permeate content of total dissolved solids (TDS) was approximately 0.6%, which accounts for roughly 15% of the TDS in the initial OMWW solution. The AFC40 permeate was, therefore, further concentrated using the AFC99 PCI UK tight RO membrane, aiming to obtain a permeate suitable for disposal to natural resources, whilst simultaneously reclaiming valuable antioxidants by mixing the two retentates of AFC40 and AFC99 membranes. The results of this study show that the proposed two-stage RO scheme may be potentially applied in a commercial scale and contribute towards processing of OMWW to produce liquid antioxidant and water suitable for disposal to natural resources.

Olive mill wastewater (OMWW) is the result of the production of olive oil causing severe water pollution. In recent years, distinguished growing interest in isolation, testing, and utilization of agricultural waste or other sources of plant tissues rich in polyphenols has been arised. In this study, the evaluation of liquid polyphenols obtained from OMWW as natural bio-chemicals against several fungal pathogens on tomato plants was examined. Different concentrations of liquid formed polyphenol (LFP) at 5, 10, 20, and 30% were tested against 10 fungal pathogens causing plant diseases on tomato plants. After 40 d of application, tomato plants were harvested and plant height, number of flowers, plant fresh weight, root fresh weight, dry plant weight and dry root weight were calculated and LFP has presented encouraging results in protecting plants. Furthermore, the encapsulation of a polyphenol in encapsulating agent may help to slow down the degradation and protection from the frequent watering and runoff due to this action. Therefore, in order of major protection resulting from the use of polyphenol against major diseases classified the following phytopathogenic fungi: Botrytis cinerea, Sclerotinia sclerotiorum,and Ascochyta lentis.

Olive mill wastewater (OMWW) is a byproduct of the olive oil extraction process, characterized by high polluting load and polyphenols content. The treatment of OMWW, using microfiltration and XAD4 resin, results in recovery of polyphenols, and also in an effluent (treated OMWW) with decreased organic load and phytotoxic properties, compared to the initial OMWW. The effects of the treated OMWW (T-OMWW) application on maize kernel yield and quality, and soil quality were investigated through a two-year field experiment. T-OMWW was applied by drip irrigation to maize cultivation using two rates of 25–50 t ha−1 year−1, with the addition of mineral fertilization. Furthermore, a treatment of only T-OMWW applied at the rate of 50 t ha−1 year−1and an only mineral fertilization treatment were used. Maize kernel yield and quality were not significantly different between mineral fertilization and T-OMWW application, hence indicating that T-OMWW could fully substitute mineral fertilization under the conditions of our study. Based on the experimental results, an economic analysis was undertaken in order to evaluate the economic implications of T-OMWW application by drip irrigation to maize production. Three scenarios were investigated: (a) mineral fertilization only, (b) T-OMWW application at the rate of 50 t ha−1 year−1only, and (c) T-OMWW application at the rate of 25 t ha−1 year−1combined with reduced mineral fertilization. The cost analysis showed that T-OMWW application at the rate of 50 t ha−1 year−1was the least expensive of the three scenarios investigated, irrespective of the distance between the olive mill and the farm. The use of the farm tractor and tanker for the T-OMWW transportation was more cost effective than hiring a liquid transport company, for distance up to approximately 20 km. For greater distance, hiring a liquid transport company was more economical.

The commercially available macroporous resin Amberlite FPX66 was evaluated for its capacity to adsorb the polyphenols contained in olive mill wastewater (OMWW). The adsorption was performed in the mode of fixed packed-bed contactor. The effects of OMWW flow rate, temperature, dilution and pH on the resin adsorption capacity were investigated. Polyphenols concentration decreased with time. The pattern of the total polyphenols concentration dependence on time was found to be similar in all cases. The pattern included a very steep section for roughly the first hour of the operation, followed by a second section of decreasing gradient down to a final asymptotic equilibrium limit. Regarding the time required for approaching the equilibrium, this was found to be unaffected by the temperature. On the contrary, the magnitude of the equilibrium concentration was substantially affected by the OMWW temperature presenting an optimum at 40°C. The increase in the OMWW flow rate affected markedly the speed of approaching the equilibrium but not its position. The variation of the total polyphenols concentration with time showed that higher concentrations yielded more rapid kinetics at the initial section, but there was no apparent differentiation of the time required to approach the equilibrium. Acidic pH appeared to be favourable for the adsorption. Finally, a novel modelling approach was developed to simulate the adsorption process kinetics.

A novel concept for olive mill wastewater (OMWW) concentration, involving the combination of open and tight reverse osmosis (RO) membranes in tubular configuration, was studied. The OMWW, prior to RO concentration, was clarified in two successive steps: passing through a coarse rotating finisher and by ceramic microfiltration, in order to remove suspended matter and facilitate the RO concentration. The clarified raw material was then concentrated using the tubular PCI UK AFC40 RO membrane. A parametric study was conducted to investigate the effect of main process parameters on permeation flux. The permeation flux of AFC40 RO membrane was found to reach consistently high values without substantial membrane fouling problems. Furthermore, the parametric study proved that the flux was linearly increased by increasing the transmembrane pressure, and exponentially decreased by increasing the OMWW mass concentration factor. In most cases, the permeation flux increased with increasing flow velocity. The effect of temperature on permeation flux was depended on both transmembrane pressure and flow velocity. The AFC40 permeate content of total dissolved solids (TDS) was approximately 0.6%, which accounts for roughly 15% of the TDS in the initial OMWW solution. The AFC40 permeate was, therefore, further concentrated using the AFC99 PCI UK tight RO membrane, aiming to obtain a permeate suitable for disposal to natural resources, whilst simultaneously reclaiming valuable antioxidants by mixing the two retentates of AFC40 and AFC99 membranes. The results of this study show that the proposed two-stage RO scheme may be potentially applied in a commercial scale and contribute towards processing of OMWW to produce liquid antioxidant and water suitable for disposal to natural resources.

AbstractThe commercially available macroporous resin XAD4 was evaluated for its capacity to adsorb the polyphenols contained in olive mill wastewater (OMWW). The adsorption was performed in the mode of fixed packed bed contactor. The effects of OMWW flow rate, temperature, dilution and pH on the resin adsorption capacity were investigated. Polyphenols concentration decreased with time. The pattern of the total polyphenols concentration dependence on time was found similar in all cases. The pattern included a very steep section for roughly the first 2 h of the operation, followed by a second section of decreasing gradient down to a final asymptotic equilibrium limit. Neither the time required for approaching the equilibrium nor the magnitude of the equilibrium concentration was substantially affected by the OMWW temperature. The increase of OMWW flow rate affected markedly the speed of approaching the equilibrium but not its position. The variation of the total polyphenols concentration showed that higher concentrations yielded more rapid kinetics at the initial section, but no apparent differentiation of the time was required to approach equilibrium. Acidic pH appeared to be favourable for the adsorption. Finally, a novel modelling approach was developed to simulate the adsorption process kinetics.

The commercially available macroporous resin XAD4 was evaluated for its capacity to adsorb the polyphenols contained in olive mill wastewater (OMWW). The adsorption was performed in the mode of fixed packed bed contactor. The effects of OMWW flow rate, temperature, dilution and pH on the resin adsorption capacity were investigated. Polyphenols concentration decreased with time. The pattern of the total polyphenols concentration dependence on time was found similar in all cases. The pattern included a very steep section for roughly the first 2 h of the operation, followed by a second section of decreasing gradient down to a final asymptotic equilibrium limit. Neither the time required for approaching the equilibrium nor the magnitude of the equilibrium concentration was substantially affected by the OMWW temperature. The increase of OMWW flow rate affected markedly the speed of approaching the equilibrium but not its position. The variation of the total polyphenols concentration showed that higher concentrations yielded more rapid kinetics at the initial section, but no apparent differentiation of the time was required to approach equilibrium. Acidic pH appeared to be favourable for the adsorption. Finally, a novel modelling approach was developed to simulate the adsorption process kinetics.

The present work studied the feasibility of diafiltration for processing olive mill waste water (OMWW). An experimental apparatus, consisted of a tubular membrane accommodation module, a controlled temperature raw material stock tank and a positive displacement pump, was developed to investigate the effects of transmembrane pressure, temperature, membrane type and OMWW dilution on diafiltraion flux. Three tubular Ultrafiltration membranes were used, with Molecular Weight Cut Off (MWCO) 8,000, 25,000 and 100,000 Da, respectively. The performance of each one of the three membranes, in terms of UF permeation flux, was studied by using four OMWW:water dilutions (1:2, 1:3, 1:5 and 1:10), at three temperature settings (30, 40 and 60°C). For each one of the 12 respective combination of temperature and dilution setting, six flux measurements at transmembrane pressure values adjusted within the range of 1–6 bars were taken. The experimental results showed that the overall OMWW diafiltration flux, especially in the case of the membranes withMWCO(Daltons) 25,000 and 100,000, was of high magnitude. This fact creates optimism for the commercial follow-up of the process itself by its use as the main component of a promising hybridic scheme for total handling the OMWW pollution problem in an environmentally friendly and sustainable way, according to the EU adopted environmental principle of zero discharge.

The present work studied the feasibility of diafiltration for processing olive mill waste water (OMWW). An experimental apparatus, consisted of a tubular membrane accommodation module, a controlled temperature raw material stock tank and a positive displacement pump, was developed to investigate the effects of transmembrane pressure, temperature, membrane type and OMWW dilution on diafiltraion flux. Three tubular Ultrafiltration membranes were used, with Molecular Weight Cut Off (MWCO) 8,000, 25,000 and 100,000 Da, respectively. The performance of each one of the three membranes, in terms of UF permeation flux, was studied by using four OMWW:water dilutions (1:2, 1:3, 1:5 and 1:10), at three temperature settings (30, 40 and 60°C). For each one of the 12 respective combination of temperature and dilution setting, six flux measurements at transmembrane pressure values adjusted within the range of 1–6 bars were taken. The experimental results showed that the overall OMWW diafiltration flux, especially in the case of the membranes withMWCO(Daltons) 25,000 and 100,000, was of high magnitude. This fact creates optimism for the commercial follow-up of the process itself by its use as the main component of a promising hybridic scheme for total handling the OMWW pollution problem in an environmentally friendly and sustainable way, according to the EU adopted environmental principle of zero discharge.

Low inputs in nitrogen may affect canola (Brassica napusL.) competitiveness and allelopathic potential as well as grain and oil yields. A 2‐yr study was conducted to assess nitrogen supply effect on the ability of four canola hybrids to compete with corn poppy (Papaver rhoeasL.) as well as its effect on canola seed and oil yields. Phytotoxic potential of canola hybrids on germination and growth of winter wild oat (Avena sterilisspp. ludovicianaL.), corn poppy, and wild mustard (Sinapis arvensisL.) was also determined using a perlite‐based bioassay. At canola blossom, corn poppy plant number in nitrogen‐treated plots was 23% less than that in the nitrogen‐untreated ones. Canola seed and oil yield was reduced 18.6 and 23.7%, respectively, by the competition of 100 corn poppy plants m−2, with ‘Elan’ and ‘Titan’ the most productive hybrids. Nitrogen supply did not increase in all cases the competitive ability or the seed and oil yields. In the laboratory, germination of the winter weeds was completely inhibited by the greatest extract concentration (5 g 100 mL−1) of all hybrids. Nitrogen supply did not affect, in most cases, the phytotoxicity of canola hybrids, while phytotoxicity did not significantly differ among hybrids. Conclusively, the hybrids Elan and Titan, cultivated without any herbicide or nitrogen fertilizer, could be viable as a short‐term alternative crop system for canola seed and oil production, especially in organic or low‐input fields infested by corn poppy.