Search

p-Coumaroyl-6́-secologanoside (comselogoside) is a secoiridoid identified in large amounts in olive fruits, although no studies in vitro or in vivo of comselogoside have been reported. This work focuses on the recovery and purification of this compound from olive mill waste (alperujo). The successive isolation on Amberlite XAD-16 and Sephadex LH-20 resins, allowed a comselogoside extract with 80–85% of purity. A photoisomerization of the vinyl-double bond in the p-coumaroyl moiety occurred when the extract was exposed to ultraviolet radiation and a mixture of the trans and cis-isomers was obtained. Both isomers were characterized using NMR, mass spectroscopy, and UV spectrometry. The J (coupling constant) of the protons on the C7 and C8 on the unsaturated chain were found to be the difference between cis (12.8 Hz) and trans- (15.9 Hz) comselogoside. Cis-isomer exhibited lower radical-scavenging activity than trans, although a synergistic effect occurred when the cis-isomer was supplement by the trans-isomer.

p-Coumaroyl-6́-secologanoside (comselogoside) is a secoiridoid identified in large amounts in olive fruits, although no studies in vitro or in vivo of comselogoside have been reported. This work focuses on the recovery and purification of this compound from olive mill waste (alperujo). The successive isolation on Amberlite XAD-16 and Sephadex LH-20 resins, allowed a comselogoside extract with 80-85% of purity. A photoisomerization of the vinyl-double bond in the p-coumaroyl moiety occurred when the extract was exposed to ultraviolet radiation and a mixture of the trans and cis-isomers was obtained. Both isomers were characterized using NMR, mass spectroscopy, and UV spectrometry. The J (coupling constant) of the protons on the C7 and C8 on the unsaturated chain were found to be the difference between cis (12.8 Hz) and trans- (15.9 Hz) comselogoside. Cis-isomer exhibited lower radical-scavenging activity than trans, although a synergistic effect occurred when the cis-isomer was supplement by the trans-isomer.

Olive oil production using the two-phase extraction system generates large amounts of biomass named alperujo, which has high percentage of water, slightly acidic pH, and high concentration of salts, organic matter, and phenolic compounds. Due to the presence of these components, alperujo is a significant source of environmental pollution, hindering the disposal of this waste. Nevertheless, some phenolic compounds such as tyrosol and hydroxytyrosol, have high nutraceutical and antioxidant power and could have potential applications in the food, pharmaceutical and cosmetic industries. This work aimed to evaluate the ability of different alperujo-derived media, with different levels of phenolic compounds, to sustain the growth and carotenoid production by yeasts from Rhodotorula genera (R. mucilaginosa LPSC 638, R. glutinis Y54, and R. graminis Y52), as well as to prospect the biotechnological production of carotenoids in these media. The yeasts grew and produced carotenoids in all media, although growth was better in dephenolized media. The highest amount of carotenoids (43.0 ± 3.1 mg/g dry yeast) was obtained with R. glutinis Y54 grown in a thermally treated and dephenolized medium. Our study represents a novel approach to valorize alperujo with a dual benefit, the recovery of valuable compounds, i. e. phenolic compounds, and the bioproduction of new ones, i.e. carotenoids.

This work assesses the in vitro antimicrobial activity of an aqueous olive mill waste extract (AE-2) on the growth of diverse cocktails of foodborne pathogens species (Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella Enterica). The effects were evaluated by Response Surface Methodology, using a two-block (D-optimal and full factorial) sequential design, with two independent variables (hydroxytyrosol concentration 0–3000 ppm and pH 3.5–6.5) and the percentage of inhibition (%I) as the dependent variable. S. Enterica and E. coli behaviours were similar but different from L. monocytogenes and S. aureus. The models predicted the complete inhibition of the four foodborne pathogen cocktails in the region defined by 3.80–3.87 pH and 1200–1314 ppm hydroxytyrosol. Within the experimental region, the model showed the best predictions for L. monocytogenes and the worst for S. Enterica, but the errors never exceeded 46%. This study could promote the use of olive by-products as natural preservatives in the food industry, especially in acidic matrices.

Thermal treatments are the latest developments in the olive oil biorefinery industry to extract bioactive compounds from its by-products, mainly the alperujo. To reach these goals and reduce energy consumption the utilization of deep eutectic solvents has been studied. An initial screening led to define a eutectic mix of choline chloride, glycolic and oxalic acid (DES9) as one of the adequate solvents to increase the solubilization of phenols and sugars, with a temperature reduction from 180 °C to 120 °C. DES9 increased the concentration of acid sugars by six times and the concentration of hydroxytyrosol by 30 times, to up to 85.81 mg/g of dry matter. The activity of DES9 is not due to the activity of each component separately or to the mixture of the two acids, but to the eutectic mixture of all of them. In the future, these solvents could improve the extraction, stability and bioavailability of bioactive compounds and the biorefinery of alperujo.

Extracts rich in pectic polysaccharides associated to polyphenols were obtained from alperujo, the by-product of olive oil extraction, by different thermal treatments and subsequent chemical treatments. The resulting “Pectoliv” extracts exhibited strong antioxidant activities and a high antiproliferative capacities in vitro against colon carcinoma Caco-2 and leukemia monocytic THP-1 cell lines. Bleaching of the extracts with sodium chlorite removed the phenolic compounds and significantly reduced antiproliferative and antioxidant activities, confirming that these were due mainly to the associated polyphenols present in Pectoliv. However, even after bleaching, these activities remained very similar to that of a commercial citrus modified pectin obtained by chemical treatment from citrus pectin, which has been implicated in cancer treatment and prevention. Thus Pectolivs have a high potential as antiproliferative or antioxidant agents.

The development of thermal treatments is helping to optimize the management of waste generated by the two-phase olive oil extraction system. A new treatment reactor, based on the steam explosion system, has been scaled up to the industrial level and offers several physical and chemical advantages. The reactor has been adapted to work into the pomace oil extractors. Chemical advantages include the efficient solubilization of simple phenols, like hydroxytyrosol, and sugars in the liquid fraction, and a significant reduction of humidity and toxicity of the residual solid fraction, in which cellulose and oil are concentrated, making the solid residual waste more suitable for subsequent bioprocess applications. All of these parameters will lead to the widespread use of steam treatment in the near future to improve the management and obtain the maximum exploitation of this byproduct.

The application of a novel industrial process based on the hydrothermal treatment of olive oil waste (alperujo) led to a final liquid phase that contained a high concentration of simple phenolic compounds. In this study the effect of pH on phenol extraction with ethyl acetate from the aqueous phase of hydrothermally treated alperujo at 160 °C/60 min (without modification, pH 4.5, and adjusted to pH 2.5) was evaluated, beside the increase of hydroxytyrosol during the storage. The variation of the concentration of phenolic compounds in each extract was analyzed by HPLC. The phenolic extract obtained at pH 4.5 presented a higher proportion of total and individual phenols and better antioxidant capacity in vitro than the extract obtained at pH 2.5. The use of lower pH values enhances the concentration of hydroxytyrosol in the liquid diminishing the storage times.

© 2014 Elsevier Ltd. The pectin fraction released from steam-treated alperujo at 160°C for 30, 45, and 60min was purified and characterized. Differences were observed in the composition, and physical and biological activities of the pectin extracts, depending on the length of the thermal treatment. The extracts presented a low molecular weight in the range of 2-40KDa, a high content of neutral sugars, and a high percentage of acetylation. In comparison with commercial pectins, the extracts had low water and high oil holding capacities, a normal emulsifying activity and a similar emulsion stability to that of apple pectin. For the three pectin extracts studied, the invitro analyses showed considerable bile-acid binding activity and a glucose retardation index similar to the values obtained for citrus pectins. Thus, the pectins isolated from olive oil waste have suitable physical and biological properties for commercial use. Pectin extraction from alperujo, a sizeable by-product of the olive oil manufacturing process, would facilitate the use and subsequent reduction of this environmentally damaging organic waste.

Recently interest has been revived in the use of plant-derived waste oils as renewable replacements for fossil diesel fuel. Olive–pomace oil (OPO) extracted from alperujo (by-product of processed olives for olive oil extraction), and produced it in considerable quantities throughout the Mediterranean countries, can be used for biodiesel production. A steam treatment of alperujo is being implemented in OPO extraction industry. This steam treatment improves the solid–liquid separation by centrifugation and facilitates the drying for further extraction of OPO. It has been verified that the steam treatment of this by-product also increases the concentration of OPO in the resulting treated solid, a key factor from an economic point of view. In the present work, crude OPO from steam-treated alperujo was found to be good source for producing biodiesel. Oil enrichment, acidity, biodiesel yield and fatty acid methyl ester composition were evaluated and compared with the results of the untreated samples. Yields and some general physicochemical properties of the quality of biodiesel were also compared to those obtained with other oils commonly used in biodiesel production. As for biodiesel yield no differences were observed. A transesterification process which included two steps was used (acid esterification followed by alkali transesterification). The maximum biodiesel yield was obtained using molar ratio methanol/triglycerides 6:1 in presence of sodium hydroxide at a concentration of 1% (w/w), reaction temperature 60 °C and reaction time 80 min. Under these conditions the process gave yields of about 95%, of the same order as other feedstock using similar production conditions.

Polymeric phenolic fraction (PPF) was isolated by ethyl acetate extraction from hydrolyzed liquids from steam-treated alperujo and characterized. PPF is composed mainly of phenolic compounds with small amounts of carbohydrates, protein and ash. Phenols such as hydroxytyrosol (HT) and tyrosol were bound to PPF during the ethyl acetate extraction. Acid hydrolysis (3. N HCl for 10. min at 100. °C) was used to liberate HT from the PPF. The properties of both sorption and desorption of the PPF were studied to enhance the purification of HT, up to 100%. The antioxidant activities of the PPF were evaluated in vitro using ferric reducing power and DPPH radical scavenging, showing activity but lower than HT and TROLOX. The inhibition of primary oxidation of PPF was similar to both HT and vitamin E. These antioxidant activities of the PPF were not a result of the presence of HT or similar phenols. © 2013 Elsevier Ltd.

Alperujo or olive oil waste was hydrothermally treated at 160°C for 60min to increase the phenols in the liquid phase. The extract obtained from the liquid using ethyl acetate extraction was divided into 27 phenolic fractions using adsorbent and polyamide resins. Phenolic alcohols and acids, secoiridoid molecules, elenolic acid derivatives, flavonoids, verbascoside, degradation products of sugar and a polymeric phenolic fraction (PPF) were characterized using HPLC-ESI-MS. The antiradical activity, ferric reducing power and the inhibition of primary and secondary oxidation were examined for each fraction. Hydroxytyrosol was the most abundant phenol in the ethyl acetate extract and possibly the main component responsible for the invitro antioxidant activity of the entire phenol extract. However, other phenolic and secoiridoid molecules with interesting biological properties were also identified, and the crude extract could be considered a potential source of natural antioxidants. © 2013 Elsevier Ltd.

Alperujo was pre-treated in a hydrothermal reactor to solubilize the oligosaccharides. The liquid was extracted with ethyl acetate to remove the phenols, and then its sugar content was sequentially precipitated with ethanol:water solutions and ultrafiltered, obtaining oligosaccharide fractions in the range of 3000 to 1000Da that represent 23% of the total. One of the two major fractions was rich in pectic polymers, and the composition of the other fraction indicated the possible presence of xyloglucans and xylo-oligosaccharides. Hydrolysis was used to decrease the molecular weight of oligosaccharides by means of TFA or HCl for the neutral or enzymes for the pectic oligosaccharides. They were isolated by adsorption and size exclusion chromatography and identified by HPLC, GC, ESI-MS and MS/MS. The presence of tetra-, tri- and di-galacturonic acids was confirmed, and different structures for neutral and acidic xylo-oligosaccharides and oligosaccharides of xyloglucan with low molecular weight have been proposed. © 2011 Elsevier Ltd.

Olive-mill wastes and by-products from the edible olive oil industry contain a high non-stabilised organic load, including organic acids, phenolic compounds and fats with antimicrobial and phytotoxic properties, which make them unsuitable for direct agricultural application. The most abundant olive-mill by-product in Spain is “alperujo” (AL), a solid material with a lack of consistency and low porosity due to its high water content and small particle size, which can be suitably composted by adding bulking agents. Six piles were prepared by mixing AL with cotton waste, grape stalk, olive leaf and fresh cow bedding, then successively composted, five of them managed by forced ventilation assisted by mechanical turning and the sixth only turned. After monitoring the process, the relationship between the germination index (GI) and the presence of some potentially phytotoxic compounds, as well as several maturity and stability indices, was assessed. As composting advanced, the GI increased and both the fat and water-soluble phenol contents decreased, indicating a gradual detoxification as the composts matured. The values of the maturity and stability indices were frequently different from the values reported for other composts.

A pollutant solid material called “alperujo” (AL), which is the main by-product from the Spanish olive oil industry, was composted with a cotton waste as bulking agent, and the compost obtained (ALC) was compared with a cattle manure (CM) and a sewage sludge compost (SSC) for use as organic amendment on a calcareous soil. The experiment was conducted with a commercial pepper crop in a greenhouse using fertigation. Composting AL involved a relatively low level of organic matter biodegradation, an increase in pH and clear decreases in the C/N and the fat, water-soluble organic carbon and phenol contents. The resulting compost, which was rich in organic matter and free of phytotoxicity, had a high potassium and organic nitrogen content but was low in phosphorus and micronutrients. The marketable yields of pepper obtained with all three organic amendments were similar, thus confirming the composting performance of the raw AL. When CM and SSC were used for soil amendment, the soil organic matter content was significantly reduced after cultivation, while it remained almost unchanged in the ALC-amended plots.

The evaluation of the most suitable aeration technology for olive-mill by-product “alperujo” (AL) composting was carried out by using two identical piles prepared by mixing AL with a bulking agent (fresh cow bedding) and a mature compost (as inoculant). Forced ventilation was employed in conjunction with mechanical turning in one of the piles, whereas only mechanical turning was used in the other pile. These two treatment methods were evaluated by assessing process efficiency and end-product quality. The results show that the composting process was completed in less time when forced ventilation was coupled with mechanical turning. A slight delay in the evolution of pH, C/N ratio, and biodegradation of fats and organic matter was observed when only turning was employed. However, the recommended method for composting AL was mechanical turning without forced ventilation since the composition of the end-product in this case was comparable to the composted AL using forced ventilation coupled with mechanical turning. Furthermore, there were substantial economic savings by selecting mechanical turning alone, which included capital costs for equipment.

A pollutant solid material known as “alperujo”, which is the main by-product of the Spanish olive oil extraction industry, was composted with either grape stalk (GS) or olive leaf (OL) as bulking agents. The experiment consisted of two piles which were composted for 34 weeks using forced ventilation (Rutgers strategy) assisted by mechanical turning. Then, substrates were allowed to mature during 16 weeks. Temperature, pH, total organic matter, total nitrogen, C/N ratio, water-soluble organic carbon, carbohydrates and phenols, fats, as well as the phytoxicity of the substrates were evaluated in order to monitor the composting progress. The composting performance was influenced by the characteristics of the bulking agents added, GS contributing more than OL to improve the advance of the process. However, both mature composts were equally free of phytotoxicity and showed a similar composition.

Introduction of the two-phase centrifugation system for olive oil extraction during the early nineties in Spain has led to the generation of approximately four million tons per year of a solid olive-mill by-product called “alperujo” (AL). Agrochemical characterisation showed that AL has a high moisture content, slightly acidic pH values and a very high content of organic matter, mainly composed by lignin, hemicellulose and cellulose. It also has a considerable proportion of fats, proteins, water-soluble carbohydrates and a small but active fraction of hydrosoluble phenolic substances. Amongst plant nutrients, AL is rich in potassium, less so in (mainly organic) nitrogen and poor in phosphorus and micronutrients. Some of those properties are not compatible with agricultural requirements, for which reason composting may be considered a suitable alternative for its disposal. AL needs to be characterised before composting, and so an attempt was made to correlate the easily determined ash content with other parameters; the regression models thus obtained are discussed.