Olive By-products Research Articles

A sustainable approach for the extraction of cholesterol-lowering compounds from an olive by-product based on CO2-expanded ethyl acetate

Olive (Olea europaea) processing results in large amounts of by-products that contain valuable molecules such as phenolic compounds and phytosterols. These molecules have demonstrated to reduce blood cholesterol levels. This work proposes the development of a method to obtain simultaneously phenolic compounds and phytosterols from the olive stone using CO2-expanded liquid extraction. Hansen solubility parameters were employed for the theoretical prediction of the most suitable bio-based solvent to extract target compounds. The Box–Behnken experimental design was employed to select the optimal conditions of pressure (8–25 MPa), the molar fraction of CO2 in ethyl acetate (0.15–0.55), and the temperature (40–80 °C). Extracts showing the highest and the lowest reductions of micellar cholesterol solubility capacity were analyzed by gas chromatography coupled to mass spectrometry to find out the compounds responsible for this activity. Different phenolic compounds, free fatty acids, and phytosterols were identified in the extracts. β-Sitosterol and, especially, tyrosol and hydroxytyrosol were the compounds that primarily contributed to the reduction of micellar cholesterol solubility capacity.

Valorization of Olive By-Products as Substrates for the Cultivation of Ganoderma lucidum and Pleurotus ostreatus Mushrooms with Enhanced Functional and Prebiotic Properties

The successful management of olive by-products constitutes a major challenge due to their huge volume, high organic content, and toxicity. Olive-mill wastes (TPOMW) and olive pruning residues (OLPR) were evaluated as substrates for the cultivation of Ganoderma lucidum and Pleurotus ostreatus. Chemical composition, glucans, total phenolic content, and antioxidant activity were measured in mushrooms, and their prebiotic potential was assessed by examining their effect on the growth of four intestinal bacteria. Several substrates based on olive by-products had a positive impact on P. ostreatus mushroom production, whereas only one performed adequately for G. lucidum. Increased ratios of OLPR to wheat-straw resulted in an increase of crude protein content in P. ostreatus fruit-bodies by up to 42%, while G. lucidum mushrooms from OLPR-based substrates exhibited an up to three-fold increase in α-glucan, or a significant enhancement of β-glucan content, when compared to beech sawdust (control). The mushrooms’ FTIR spectra confirmed the qualitative/quantitative differentiation detected by standard assays. In regard to prebiotic properties, mushrooms powder supported or even enhanced growth of both Lactobacillus acidophilus and L. gasseri after 24/48 h of incubation. In contrast, a strain-specific pattern was observed in bifidobacteria; mushrooms hindered Bifidobacterium bifidum growth, whereas they supported a similar-to-glucose growth for B. longum.

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Heat shock and UV-B episodes modulate olive leaves lipophilic and phenolic metabolite profiles

Olea europaea L. is the basis of the olive oil chain value. Olive by-products remain economically underexplored despite their richness in polyphenols and fatty acids. Heat waves and raised UV-B radiation episodes (that increasingly affect Mediterranean orchards) may influence these compounds. Herein we characterize the most relevant leaf lipophilic and phenolic compounds of an important Portuguese cultivar Cobrançosa, immediately and 30 days after exposure to high UV-B radiation or heat shock (HS). Plants were exposed to either UV-B (12 kJ m−2 d-1) or HS (40 °C for 2 h) for two consecutive days. Hydroxycinnamic acids, triterpenes, sterols and fatty acids are less influenced by UV-B and HS, while the amounts of flavonoids, secoiridoids and monoterpenes increased. In particular, after both treatments, quercetin-3-O-glucoside levels increased in leaves, and UV-B stimulated oleuropein levels. HS reduced the amounts of verbascoside, oleuropein and luteolin-7-O-glucoside, while UV-B only decrease apigenin-7-O-rutinoside levels. Thirty days after UV-B and HS relief, these compounds showed different profiles. Whereas UV-B recovering plants showed increased amounts of thymol-β-d-glucopyranoside, in HS recovering plants, the increase was more relevant for oleuropein, chrysoeriol-7-O-glucoside and luteolin-7-O-glucoside. Data evidence that Cobrançosa leaves are particularly rich in luteolin-7-O-glucoside, oleuropein, and oleic and palmitic acids, and that their levels may be stimulated by climate-change related conditions, contributing to the economical valorisation of leaves.

β-Cyclodextrin Does not Alter the Bioaccessibility and the Uptake by Caco-2 Cells of Olive By-Product Phenolic Compounds.

Alperujo—a two-phase olive mill waste that is composed of olive vegetation water and solid skin, pulp, and seed fragments - is a highly valuable olive by-product due to its high content in phenolic compounds. In this study, we assessed whether β-cyclodextrin (β-CD), which is used to extract and protect alpejuro phenolic compounds (hydroxytyrosol-O-glucoside, tyrosol, caffeic, and p-coumaric acids) could impact on their bioaccessibility (i.e., the percentage of molecule found in the aqueous phase of the digesta) and uptake by intestinal cells, by using an in vitro digestion model and Caco-2 TC7 cells in culture, respectively. Our results showed that β-CD did not change the bioaccessibility of the selected phenols. Hydroxytyrosol-O-glucoside and caffeic did not cross Caco-2 cell monolayers. Conversely ferulic acid, identified as the main caffeic acid intestinal metabolite, was absorbed through intestinal cell monolayers (~20%). Interestingly, β-CD moderately but significantly improved the local absorption of tyrosol and p-coumaric acid (2.3 + 1.4% and 8.5 ± 4.2%, respectively, p < 0.05), even if their final bioavailability (expressed as bioaccessibility × absorption by Caco-2 cells) was not modified (16.2 ± 0.6% vs. 16.8 ± 0.5% for tyrosol and 32.0 ± 3.2% vs. 37.2 ± 3.2% for p-coumaric acid, from pure alperujo and alperujo complexed with β-CD, respectively). Overall, our results show that β-CD is an interesting extraction and storage agent for phenolic compounds that does not alter their in vitro bioavailability.

Performance of Barki Lambs Fed on Rations Containing Olive Cake with or Without Polyethylene Glycol.

Olive by-products could be a suitable alternative feedstuffs ingredient in ruminants rations. This study was carried out to evaluate effects of replacing clover hay by olive cake with or without addition of poly ethylene glycol in growing lambs ration. Thirty five Barki lambs averaged 34 kg body weight and 5 months old were divided into 5 groups (7 animals of each) according to live weight for 90 days feeding trial. Olive cake was treated mechanically by hummer mill, screened to produce screening olive cake (treated olive cake, TOC). Data of dry matter and organic matter digestibility were decreased with ration containing 20% TOC from ration or 67% from clover hay comparing with others. No significant differences were observed among groups in crude protein digestibility. Total digestible nutrients (TDN) as an energy measurement for the experimental rations cleared that replacing process of clover hay by TOC up to 20% of DM intake or 67% of clover hay, given lower values (65.32 and 66.80%). The rumen pH values were not affected by the different experimental rations including control. The highest rumen NH3 was recorded with lambs fed ration containing 33% TOC without PEG instead of clover hay, while the lowest values was recorded with that group fed ration containing 33% TOC with PEG. No significant differences were detected in total gain, ADG as well as feed efficiency among the experimental rations. Dry matter intake slightly increased with feeding growing lambs on TOC containing rations except R5 compared to the control group. Summing up partially de-stoned olive cake by screening could be used in replacing clover hay for growing lamb rations, at inclusion levels up to 33 and 67% with or without poly ethylene glycol, with no adverse on performance of growing lambs.

Assessment and valorization of treated and non-treated olive mill wastewater (OMW) in the dry region

PurposeThe quantity of Olive by-products does not stop increasing and a water shortage that threatens the olive tree culture; require a serious valuation of these by-products. A comparative and valorization study of two kinds of OMW; Fresh OMW (FOMW), directly issue from three-phase continuous extraction factory and Disposal Evaporation Ponds OMW (DOMW) were done.MethodsPhysico-chemical and biological parameters of OMWs and soil irrigated with OMWs, respectively, were determined. An antibacterial activity test of FOMW against Clinic Standard Bacteria was determined. A statistical analysis was performed for all defined parameters.ResultsA significant increase of pH value of 6 and a lower failure of the EC in 8.94 (mS/cm−1) were registered after OMW disposal in evaporation ponds. We registered a fall of BOD5 and COD from 61.05–116.37 (g/L) to 55.67–103.82 (g/L), respectively. A significant increment of phenol compound removal was observed after OMW disposal. However, a switch of fatty acids distribution and content was observed, which several fermentation pathways could explain took place. This result suggested by a clear shift in biomass composition. An important soil fertility after DOMW soil irrigated was traduced by an important value of the germination index (170.55%) and efficient organic matter increment of 2.3%. A CMI rate of 32.76 (μg mL−1) was determined by FOMW against different clinic standard bacteria.ConclusionA spectacular soil fertility effect was obtained from DOMW soil spreading, that efficiently evaluate the OMW biological treatment. In addition, the FOMW was valorized as its powerful antibacterial.

Preliminary Characterization of the Composition and Phenolic Fragmentation of Olive Byproducts by Gas Chromatography–Mass Spectrometry and High-Performance Liquid Chromatography–Tandem Mass Spectrometry

ABSTRACTOlive waste is a potential resource due to its rich variety of biologically active compounds. To investigate chemical components of olive waste, the selected samples were extracted using ultrasound assisted enzyme hydrolysis and petroleum ether, ethyl acetate and n-butyl alcohol were used to obtain a series of solvent extracts. Gas chromatography–mass spectrometry analysis showed hydrocarbons, esters, acids, alcohols, and ketones present in the extracts. Some fatty acids were considered to be predominant; it is noteworthy that phenolic compounds were detected in the ethyl acetate extract fraction. Furthermore, the primary phenolic compounds were also determined by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The possible fragmentation patterns have been proposed in positive and negative ion modes; the main fragment ions were observed from the loss of methyl, hydroxyl, or carboxyl groups. The compounds showed different fragmentation ions types in both positive and negative ionization modes and gave structural information on the main phenolic compounds in olive waste. The results of this study may be used to identify valuable active compounds and guide commercial applications of olive waste.

Review and Analysis of Alternatives for the Valorisation of Agro-Industrial Olive Oil By-Products

By-products and waste from olive production (agriculture) and the olive oil industry (mills and refineries) are an important environmental issue in Mediterranean areas. Industrial waste and by-products contain highly valuable components that can also be phytotoxic. This article reviews recent research on the valorisation of olive by-products under the bioeconomy strategy. The alternatives are classified according to the ‘bioeconomy value pyramid’, which prioritises higher value uses over the current energy and compost valorisation. Special attention is paid to the use of these by-products for animal feed that can be improved by reducing the content of saturated fatty acids (SFAs) and increase the polyunsaturated fatty acids amount considered beneficial in response to their use; this makes the food healthier for humans while simultaneously reducing feeding costs and the environmental impact of livestock.

Thermal Behaviour and Reactivity of Swine Sludge and Olive By-Products During Co-pyrolysis and Co-combustion

The thermal behaviour of swine sludge/olive by-product blends was studied during pyrolysis and combustion processes and the compatibility of each component in the blend was evaluated. The experiments were conducted in a thermogravimetric analysis system, up to 900 °C. A modified independent parallel reactions model and a power law model were developed for pyrolysis and combustion, respectively and their validity was assessed against experimental data. The effect of inorganic constituents of the fuels on slagging and fouling propensities and environmental pollution was examined, through mineralogical, physico-chemical and fusibility analyses. The swine sludge decomposed over a broader temperature range than the woody residues and its combustibility was lower. Olive kernel and swine sludge showed an additive behaviour upon blending, for both pyrolysis and combustion processes. Olive pruning and swine sludge mixtures presented additivity during pyrolysis, while synergy during combustion. The kinetic models fitted the experimental results with great accuracy. The slagging/fouling potential of swine sludge was significant, while toxic metals in ashes were below legislative limits.

Nutritive evaluation and milk quality of including of tomato or olive by-products silages with sunflower oil in the diet of dairy goats

There are worldwide a number of by-products with a strong potential for use in animal feeding to cover purposes as farm economic profitability enhancement or searching of functional food ingredients. Probably fruit and vegetable industry (i.e. olive milling wastes) are amongst the most representative sectors. Two experiments were performed with lactating Murciano-Granadina goats. In Experiment 1 the objective was to assess the effect of the partial replacement of the forage in the diet with olive by-products or tomato silages supplemented with sunflower oil (SFO, 20g/kg DM) on the nutrient utilization, rumen fermentation parameters and microbial abundances, methane production and milk yield and composition. Eighteen goats were distributed in three experimental groups and fed control diet (CD) against diets containing olive by-products silage (OBSD) or tomato surplus silage (TSD). Both OBSD and TSD resulted in higher fat intake and apparent digestibility, higher digestible and metabolizable energy and total purine derivatives excretion. The rest of measured parameters remained unaffected. Diets OBSD and TSD promoted higher milk content in C18:1 trans-11, C20:2 and CLA. Milk fat of goats consuming TSD had the lowest content in C4:0, C6:0 and C8:0, while OBSD produced more total saturated FA (SFA) and less C18:1 n-9 cis and both total mono- and polyunsaturated FA. The acetate concentration was lower in the rumen of animals fed silages, while the butyrate and protozoa concentrations were higher in OBSD. The CH4 production (L/kg DMI) tended to be lower in goats consuming TSD. Experiment 2 was conducted to test the persistence (over 90 days) and in a larger number of animals (n=24) of the effects observed with TSD diet in experiment 1. The TS diet promoted higher DM intake and body weight and lower acetate:propionate ratio than CD, whereas milk yield and composition were not affected. The FA profile was modified by increases in SFA and reducing monounsaturated FA and CLA. It may be concluded that the strategy of partial replacement of conventional forage by local by-products silage combined with SFO supplementation is valuable nutritional strategy in dairy goats since it may improve the animal energy balance while ruminal fermentation, nutrients utilization and milk yield are not compromised.

Evaluation of Meat and Bone Meal as a Secondary Fuel with Olive Byproducts in a Fluidized Bed Unit. Performance and Environmental Impact of Ashes

Cocombustion of olive byproducts with meat and bone meal (MBM) was investigated in a fluidized bed system. The performance of the blends in terms of efficiency and emissions as a function of operating conditions was examined. Fly and bottom ashes were characterized and their potential uses and environmental impact were assessed through leaching tests on alkaline and acidic soils. All fuels burned mostly within the bed with a high efficiency. CO emissions were low, and SO2 emissions were negligible, while NOx emissions were below legislation limits, except those of olive kernel/MBM 80:20. The optimum performance for the blends was achieved when the MBM percentage in the mixture was 10%, reactor loading was 0.6 kg/h, and excess air was 30%. Fly ashes were rich in Ca, P, K, and Si minerals and Cu, Zn, and Sr trace elements. MBM ash consisted of high melting point calcium phosphates. Heavy metal values leached through both soils were below legislation limits for ash disposal. Ash materials could be used for s...

Bioactivity Improvement of Olea europaea Leaf Extract Biotransformed by Wickerhamomyces anomalus Enzymes.

Olive leaves represent a quantitatively significant by-product of agroindustry. They are rich in phenols, mainly oleuropein, which can be hydrolyzed into several bioactive compounds, including hydroxytyrosol. In this study, water extract from olive leaves 'Biancolilla' was analyzed for polyphenol profile, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and protective effect on differentiated Caco-2 cells. The efficacy of two enzymatic treatments in promoting the release of bioactive phenols was investigated: a) enzymatic extract from Wickerhamomyces anomalus, characterized by β-glucosidase and esterase activities; b) commercial β-glucosidase. Composition and bioactivity of the resulting extracts were compared. The results showed that the yeast-treated extract presented hydroxytyrosol content and DPPH radical scavenging activity comparable to those obtained using commercial β-glucosidase; however, it was showed the additional presence of hydroxycinnamic acids. In experiments on Caco-2 cells, the leaf extracts promoted the recovery of cell membrane barrier at different minimum effective concentrations. The high specificity of W. anomalus enzymatic extract may represent an effective tool for the release of bioactive phenols from olive by-products.

Comparison of ashes from fixed/fluidized bed combustion of swine sludge and olive by-products. Properties, environmental impact and potential uses

Residues from agriculture and processing industries or from the livestock sector play an important role for the power generation sector. However, ash materials produced during combustion may create several technical and environmental problems. In this work, bottom and fly ashes obtained from lab-scale fixed/fluidized bed combustion of swine sludge, olive by-products and their mixtures, from the island of Crete, were characterized by mineralogical, chemical, particle size distribution and fusibility analyses, as well as by standard leaching tests. Slagging and fouling propensities were determined and their environmental impact and potential uses were assessed. The results showed that the ashes were rich in Ca, Si, Mg, P, K, Cu, Zn and Sr minerals. Slagging/fouling potential of swine manure was significant. Heavy metals showed less preference for fly ashes. Toxic metal ions were released in low quantities through the soil, below the legislative limit values. The low leachability of the elements was attributed to the higher alkalinity of the extracts, as well as the mineralogical and chemical composition of the solids involved. All ashes could be used as secondary building materials, or for road construction. Alternatively, they could be used in mixtures with other byproducts as liming agents and fertilizers on acidic soils.

Evaluation of bioactive compounds, chemical and technological properties of fruits byproducts powder.

Millions of tons of fruit byproducts are discarded globally every day by food processing industries, which represents a considerable loss in terms of nutrients. The goal of this work was to evaluate the physico-chemical, technological, antioxidant properties and characterization of carotenoids for papaya, pineapple, olive byproducts and anthocyanins for blueberry byproducts. The results indicated that these byproducts are good sources of total dietary fiber, especially olive byproducts (53.68%). The powder from papaya byproducts showed the highest values for the technological characteristics of water holding capacity (8.93g water/g powder) and solubility (59.91%). All of the powders exhibited a good ability to reduce Folin Ciocalteu reagent and a high DPPH radical scavenging capacity, especially the powder from blueberry byproducts, which also exhibited a high level of anthocyanins (2063.4mg/100g). The carotenoid content was highest in the papaya powder sample, followed by the pineapple and olive powders. The results of this study indicate the high potential application of these powder byproducts as functional ingredients in food products because they can be considered a good source of antioxidant compounds.

Integrated biovalorization of wine and olive mill by-products to produce enzymes of industrial interest and soil amendments

An integral and affordable strategy for the simultaneous production of lignin-modifying and carbohydrate active enzymes and organic amendment, with the aid of a saprobe fungus was developed by using olive oil and wine extraction by-products. The polyporal fungus Trametes versicolor was cultivated in soy or barley media supplemented with dry olive mill residue (DOR) as well as with grape pomace and stalks (GPS) in solid state fermentation (SSF). This strategy led to a 4-fold increase in the activity of laccase, the principal enzyme produced by SFF, in DOR-soy media as compared to controls. T. versicolor managed to secrete lignin-modifying enzymes in GPS, although no stimulative effect was observed. GPS-barley media turned out to be the appropriate medium to elicit most of the carbohydrate active enzymes. The reuse of exhausted solid by-products as amendments after fermentation was also investigated. The water soluble compound polymerization profile of fermented residues was found to correlate with the effect of phytotoxic depletion. The incubation of DOR and GPS with T. versicolor not only reduced its phytotoxicity but also stimulated the plant growth. This study provides a basis for understanding the stimulation and repression of two groups of enzymes of industrial interest in the presence of different carbon and nitrogen sources from by-products, possible enzyme recovery and the final reuse as soil amendments.

Quantification of bioactive compounds in Picual and Arbequina olive leaves and fruit

Olive leaves and fruit possess bioactive substances such as phenolic compounds and triterpenic acids that can be obtained from olive by-products generated during olive oil extraction. The aim of the present study was the characterization and quantification of these compounds in Picual and Arbequina cultivars from different locations and throughout two seasons in both olive leaves and fruit. The major phenolic compound identified in the leaves was oleuropein, and the total content of phenolic compounds in this material reached 70 g kg-1 fresh weight. The leaves were also rich in triterpenic acids (20 g kg-1 fresh weight), with oleanolic acid being the most concentrated among them. With regard to olives, oleuropein and demethyloleuropein were the main phenolic compounds in the pulp of Picual and Arbequina cultivars, and the total concentration of these phenolic compounds reached 3.5% fresh weight. Olives can also be an important source of triterpenic acids, although this is mainly the skin part, where the maslinic and oleanolic acids are concentrated. Olive leaves can contain up to 70 g kg-1 phenolic compounds and 20 g kg-1 triterpenic acids, and olive fruit can contain up to 35 g kg-1 of the former and 3 g kg-1 of the latter. It must also be noted that this level was constant both between seasons and orchard locations. © 2016 Society of Chemical Industry.

Dietary Administration of Olive Mill Wastewater Extract Reduces Campylobacter spp. Prevalence in Broiler Chickens

Food wastes are sources of compounds that can be used as natural additives in the food and feed industry. The olive oil industry produces two main wastes: aqueous waste (olive mill wastewater) and solid waste (pomace or olive cake). These by-products are rich in phenols, which are antioxidant and antimicrobial compounds able to inhibit or delay the growth of several bacteria in vitro. The dietary effect of both olive mill wastewater polyphenolic extract (OMWPE) and dehydrated olive cake (DOC) on the prevalence of Campylobacter spp. in broiler chickens was investigated. A commercial basal diet was supplemented with either OMWPE- or DOC-enriched maize at two dosages (low: 16%; high: 33%). The prevalence of Campylobacter spp. shedding was evaluated at 21, 35, and 49 days of age. The prevalence of Campylobacter spp. differed among groups only at 49 days of age. Both OMWPE groups showed a lower (p &lt; 0.05) prevalence compared to the control group. The odds ratio evaluation showed that the higher dose of OMWPE reduced the possibility of shedding 11-fold compared to the control group (p &lt; 0.001). These results highlight the potential use of olive by-products against Campylobacter spp. in poultry.

Fish spoilage bacterial growth and their biogenic amine accumulation: Inhibitory effects of olive by-products

ABSTRACTThe antimicrobial effects of olive by-products (olive leaf extract, olive cake, and black water) on foodborne pathogens and fish spoilage bacteria isolated from anchovy, mackerel, and sardine were investigated. Total polyphenol contents in olive by-products were determined by the Folin–Ciocalteu procedure and their chemical composition was also evaluated by gas chromatography-mass spectrometry. The minimum inhibitory concentrations of olive by-product were performed using the broth microdilution method. Their impact on bacterial growth and biogenic amine production were also monitored in anchovy infusion decarboxylase broth. The total phenol content of olive cake and black water were 14.9 and 20.9 mg gallic acid/g extract, respectively. The major compounds were ethyl oleate (52.3%) and squalene (22.8%) in olive cake and palmitic acid (12.2%), phenanthrene (11.9%), and linoleic acid (11.4%) in olive leaf, while black water consisted of 51.1% squalene and 17.5% oleic acid ethyl ester. The minimum inhibitory concentration of olive leaf ranged from 0.78 to 25 mg/mL. Bacterial strains were more sensitive to olive leaf than other olive by-products. Bacterial load in anchovy infusion decarboxylase broth did not always correlate well with biogenic amine production. The effect of olive leaf, olive cake, and black water on biogenic amine accumulation varied depending on specific bacterial strains and biogenic amine. Olive cake and olive leaf generally had a stronger effect on reducing histamine accumulation by bacteria. Therefore, the results showed the potential effect of olive by-products in preventing or reducing the accumulation of histamine, which may beneficially affect human health.

Phenolic content and antioxidant activity of olive by-products and antioxidant film containing olive leaf extract

The antioxidant activity of olive leaf (OL) and cake (OC) extracts with different solvents was evaluated. 70% of aqueous ethanol extract of OL was chosen as the most antioxidant extract based on antiradical activity (DPPH) (95.4±0.3%) and oxygen radical absorbance capacity (ORAC) (0.82±0.07g equivalent Trolox per g of solution) assays. This OL extract was incorporated in two multilayer materials consisting of (i) polyethylene/polyethylene (PE/PE) film and (ii) polyethylene/paper (PE/P). These multilayers were exposed to a gas stream enriched in free radicals to evaluate the scavenging capacity of both materials. PE/PE film exhibited the highest scavenging activity of free radicals (78.8%). Migration of the phenolic compounds from olive by-products into two simulants was performed and demonstrated a non-migrating behavior. The limits of detection and quantification for oleuropein were 0.5μgkg−1 and 1.7μgkg−1 and for Luteolin-7-O-glucoside 1.3μgkg−1 and 4.3μg kg−1 respectively.