Crude Olive Oil Research Articles

Application of Doehlert Experimental Design for Optimization of a New-Based Hydrophilic Interaction Solid-Phase Extraction of Phenolic Acids from Olive Oils.

In this work, a rapid, precise, and cost-valuable method has been established to quantify phenolic compounds in olive oil using new-based hydrophilic interaction solid-phase extraction (SPE). Boehlert's experimental design applied the determination of the optimal operating conditions. An investigation into the effects of the methanol composition (50-100%), the volume of eluent (1-12 mL), and pH (1-3) on the extraction of phenols acids and total phenols from Tunisian olive oils was performed. The results showed that the extraction conditions had a significant effect on the extraction efficiency. The experiment showed that the greatest conditions for the SPE of phenolic acids were the methanol composition at 90.3%, pH at 2.9, and volume at 7.5 mL, respectively. The optimal conditions were applied to different types of olive oils, and it could be concluded that larger concentrations of polyphenols were found in extra virgin olive oil (89.15-218), whereas the lowest levels of these compounds (66.8 and 5.1) were found in cold-pressed crude olive oil and olive pomace oil, respectively.

Effect of dietary olive oil and palm oil on rumen bacterial composition in dairy cows

The rumen bacteria play a major role in lipid metabolism. Bacteria remove the double bonds of unsaturated fatty acids resulting in the production of saturated fatty acids, which are incorporated in milk. Crude olive oil (rich in unsaturated fatty acids) represents a potentially valuable feed source for dairy cows that might enhance the human-health beneficial composition of milk and dairy products. This project studied the effect of supplementing dairy cow diets with olive oil (OO) and palm oil (HVO) on rumen microbiota. For 63 days the animals were fed a control diet (basal diet) with no added lipid and two fat-supplemented diets (30 g kg−1 DM). Rumen sampling were performed at the onset of the experiment and every 21 days for 63 days using a rumen scoop. Total microbial DNA was extracted from ruminal samples for high-throughput sequencing of the 16S rRNA gene through Illumina MiSeq platform. Results revealed the dominance of phyla Firmicutes and Bacteroidetes. Firmicutes was the most prevalent phyla in diet control (75.2 %), OO (71.1 %) and HVO (75.2 %). At genus level Succiniclasticum and Prevotella were the dominant genera, belonging to Firmicutes and Bacteroidetes respectively. Succiniclasticum decrease significantly their relative abundance during OO supplementation (p)

Exploitation of olive oil mill wastewaters and molasses for ethanol production using immobilized cells of Saccharomyces cerevisiae.

An alcoholic fermentation process is described, involving molasses, the main by-product of the sugar industry, blended with crude olive oil mill wastewaters (OOMWs) and immobilized Saccharomyces cerevisiae cells on delignified cellulosic material (DCM). For comparison, fermentations with free cells were also carried out. Initially, the optimum blending mixture for molasses dilution was sought after, while at a second step repeated batch fermentations at a temperature range 5-30°C were performed to monitor the operational stability of the system. A 1/1 ratio of OOMWs/tapwater blending mixture and cell immobilization resulted in higher fermentation parameters. Ethanol concentration and daily productivity values recorded at temperatures ≥ 20°C (up to 67.8gL-1 and 67.6gL-1d-1, respectively) could be adopted by the industrial sector, although the decline in fermentation efficiency observed, probably due to the toxicity effects of OOMWs. Finally, the potential of OOMWs treatment for ethanol production is highlighted and assessed.

Chemical Composition of Amurca Generated from Jordanian Olive Oil

Amurca (olive oil lees) is one of olive oil byproducts which is a watery bitter tasting and dark colored sediment that settles at the bottom of crude olive oil containers over time. In this study, gross composition, total phenolic compounds, antioxidant activity, HPLC profile of phenolic compounds, lipid peroxidation inhibitory activity, free fatty acid and peroxide values of amurca were determined. The gross composition of Jordanian amurca was as follows: carbohydrates 0.74 ± 0.02%, proteins 0.7 ± 0.02%, fats 49.43 ± 0.29%, moisture 47.33 ± 0.30%, ash 0.89 ± 0.05% and fiber 0. 92 ± 0.03%. Total phenolic compounds content was 289 mg GAE/100 g of amurca and antioxidant activity was 22.3 ± 0.21 mg vitamin E equivalent/100 g. Peroxide value was 1.78 ± 0.03 meqO2/kg amurca, free fatty acid value was 1.62 ± 0.029 (oleic acid%) and LPO inhibition was 95.7%. The most abundant phenolic compounds detected by HPLC were oleuropen, gallic acid, 3-hydroxyphenol, sinapic acid, kaempherol, isopropyl-5-methyl phenol and luteolin.

Deacidification of olive oil by countercurrent supercritical carbon dioxide extraction: Experimental and thermodynamic modeling

Supercritical carbon dioxide was used as an extractive solvent to remove free fatty acids from cold-pressed olive oil. Crude oil of different acidity content (from 0.5 to 4.0 wt%) was extracted in a packed column at 313 K and pressures of 180, 234 and 250 bar. The group contribution equation of state was employed to simulate the separation process, representing the oil as a simple pseudo-binary oleic acid + triolein mixture. Despite the simple representation of oil composition to simulate the deacidification process, a satisfactory agreement between the experimental and calculated yields and acidity of raffinates was obtained. The thermodynamic model was employed to study a continuous countercurrent multistage extraction process which yielded a raffinate having acidity lower than 0.7 wt%, when crude olive oil with different FFA content was processed.

The removal of colour, carotene and acidity from crude olive oil by using sepiolite

SummaryThe capacity of sepiolite to adsorb colouring matters in olive oil was studied. The effects of adsorption time, temperature and solid:liquid ratio were selected as parameters. The effect of bleaching of olive oil was evaluated for determining the % free fatty acid (FFA), % bleachability and residual carotene by using both thermally activated sepiolite (AS) and acid‐activated sepiolite (AAS). Results reveal that thermally acid‐activated sepiolite was more efficient than thermally activated sepiolite. The adsorption equilibriums of carotene and FFA on AS and AAS were described by the Freundlich models. A higher adsorption coefficient (K) was observed for AAS (Kcarotene = 2.73 × 10−3mgg−1, KFFA = 0.98mgg−1) compared to AS (Kcarotene = 2.63 × 10−7mgg−1, KFFA = 0.21mgg−1). Moreover, the rate constants obtained for carotene and colour by using AAS (kcolor = 0.0241 min−1, kcarotene = 0.0217min−1) were higher than that of AS (kcolor = 0.01min−1, kcarotene = 0.0165min−1).

Effect of refining on the phenolic composition of crude olive oils

AbstractBy definition, virgin olive oil is consumed unrefined, although a great proportion of the olive oil produced has to be refined to render it edible. Phenolic compounds are among the substances eliminated during the refining process; in the present work these were characterized by HPLC, and their evolution during the different refining steps was studied. The complete refining process removed most polyphenols from oils, but the behavior of individual compounds at each step also was observed. o‐Diphenols (hydroxytyrosol, catechol, and hydroxytyrosol acetate) and flavonoids (luteolin and apigenin) were eliminated first during the alkaline treatment. Tyrosol and 4‐ethylphenol remained in the oil until the deodorization step. A large amount of phenolic compounds was discovered in the refining by‐products such as soapstocks and deodorization distillates. In the latter streams, the concentrations of tyrosol and 4‐ethylphenol reached up to 149 and 3720 mg/kg by‐product, respectively. This high level of 4‐ethylphenol and its well‐known strong off‐odor can interfere during further processing of the deodorization distillates, and this must be taken into account when deciding what is to become of them. Similarly, the results of this work open the possibility of recovering phenolic compounds from the “second centrifugation olive oils” by adding a new washing step prior to the refining process. By including this new step, the most polar polyphenols, hydroxytyrosol and tyrosol, will diffuse from oil to water and a concentration of up to 1400 mg/L of hydroxytyrosol may be achieved.

Cleaner production implementation through process modifications for selected SMEs in Turkish olive oil production

Turkey as a Mediterranean country has suitable conditions for olive oil production. However, by-products of olive oil production (pomace and vegetation water) require specific management with the goal of pollution prevention. This paper explores the applicability of Cleaner Production (CP) methodology for fifteen crude olive oil extraction Small and Medium sized Enterprises (SMEs), one olive oil refining plant and one pomace oil extraction plant operating on the Aegean Sea coast of Turkey. It has been deducted that; if the recommended CP options comprising water, energy saving issues, and pomace management options regarding energy production and raw material recovery via thermal conversion processes will be implemented, the need for end-of-pipe treatment (EOP) facilities will decline and power generation from pomace will be environmentally, technically and economically feasible.

Potent fungi for decolourisation of olive oil mill wastewaters

A broad screening of 58 fungi including 46 white rot strains on solid media resulted in the selection of 13 white rot fungi, which were active in decolourising the poly R-478 lignin model and were capable of growing on crude olive oil mill wastewaters (OOMW) with a COD of 100 g l −1. Decolourisation of the dye in liquid media in static as well as agitated conditions was studied in relation with ligninolytic enzymes production. Tests on OOMW-based media diluted at different COD concentrations and without any additional carbon source, showed that Pycnoporus coccineus, Pleurotus sajor caju, Coriolopsis polyzona and Lentinus tigrinus were very active in decolourisation and COD removal of OOMW at 50 and 75 g l −1 COD. At 100 g l −1 COD only the first two fungi were effective. In particular, P. sajor caju and C. polyzona showed levels of decolourisation as high as 75% when COD of the effluent was 50 g l −1. Both mono and polyaromatics were considerably reduced after 20 days incubation with C. polyzona as confirmed by gel filtration analysis. Marked differences in enzyme activity of individual strains suggest that different mechanisms are possible for OOMW decolourisation.

Rapid evaluation of phenolic component profile and analysis of oleuropein aglycon in olive oil by atmospheric pressure chemical ionization-mass spectrometry (APCI-MS).

Epidemiological studies have linked the Mediterranean diet with a low incidence of cardiovascular diseases. Olive oil, the major fat component of this diet, is characterized by antioxidant properties related to their content in catecholic components, particularly oleuropein aglycon. Therefore quantification of these components in edible oils may be important in determining the quality, and consequently its commercial value. The present method allows us to obtain the profile of the phenolic components of the oil from the methanolic extracts of the crude olive oil. In particular tyrosol, hydroxytyrosol, elenolic acid, deacetoxyligstroside and deacetoxyoleuropein aglycons, ligstroside and oleuropein aglycons, and 10-hydroxy-oleuropein are clearly identified by atmospheric pressure chemical ionization-mass spectrometry (APCI-MS). Moreover, oleuropein and its isomers present in the oil are quantified by APCI-MS/MS analysis of the extracts without preliminary separation from other phenolic compounds.

Oxidative stability of avocado oil

AbstractThis study is concerned with the extent of oxidative deterioration and oil stability as determined by measuring peroxide and conjugable oxidation products (COP) values and AOM time of refined bleached avocado oil in comparison with refined soybean and olive oil. The formation of peroxides in avocado oil exposed to daylight at room temperature is similar to that of soybean oil but greater than that of olive oil. No differences were found in peroxide formation, oxodiene values and COP values between the tested oil stored in the dark, at 60 C and at room temperature. The COP ratio in oils stored at 60 C is similar for avocado and olive oil, but differs from that of soybean oil.The AOM stability time both for refined avocado and soybean oil was approximately 14 hr, and for refined olive oil was 15 hr.The extent of oxidative stability of crude avocado oil was determined by measuring peroxide value compared with crude olive oil. Crude avocado oil is very sensitive to oxidation when exposed to daylight and fluorescent light, in contrast to its stability in the dark at room temperature. The chlorophyll content in crude avocado oil is reduced rapidly on exposure to daylight and fluorescent light.

Comparative Nutritional Value of Corn Oil and Olive Oil for Growing Chickens

EFFECTS OF supplementing chick rations with corn oil and soybean oil have been studied by a number of workers (Rand et al, 1958; Carew et al., 1959; Sibbald et al., 1961). However, little information is available on the effects of feeding olive oil to growing chickens.Olive oil is one of the most widely used vegetable oils in the countries of the Middle East. Thus more information on the nutritive value of olive oil is needed. Two forms of the oil are available: edible olive oil that is used extensively in human diets, and crude olive oil that is used mainly for local production of soap.The purpose of this investigation is to compare the effects of feeding corn oil, edible olive oil and crude olive oil on body weight gains, feed efficiency, liver weight, liver and plasma cholesterol and fatty acid composition of carcass fat of chickens.EXPERIMENTAL PROCEDURE

Acetylenic compounds. I. The dehydrohalogenation reactions by sodamide in liquid ammonia and preparation of some mono‐acetylenic substances and their derivatives

SummaryThe advantages of dehydrohalogenation by sodamide in liquid ammonia over the alcoholic potassium hydroxide method are noted. The sodamine reaction is found to be a mild and quite suitable reaction for the preparation of mono‐acetylenic acids (especially those having long and balanced alkyl groups on either side of the triple bond) by dehydrobromination of the dibromides obtained from the corresponding olefinic compounds. Dehydrobromination of tetrabromostearic acid was unsuccessful. A large laboratory scale preparation of stearolic acid has been accomplished. Stearolic acid and 9,10‐diketo‐stearic were prepared from the crude olive oil acids. A procedure for detecting oleic acid and stearolic acid in mixtures has been outlined. The sodamide dehydrohalogenation method has been successfully applied to the preparation of 6‐octadecynoic acid (for the first time from a natural source, petroselinic acid), phenyl acetylene and 10‐undecynoic acid from their parent olefinic compounds. An explanation for the low yields of the last two substances has been offered.

Interfacial tension and hydrogen-ion concentration

The predominance of hydrogen-ion concentration (1) in the colloidal chemistry of the proteins and other substances (Loeb (2)) makes imperative an investigation of those changes at the interface between two phases which are brought about by changes in hydrogen-ion concentration. Previous investigators have directed their attentions to the purely chemical aspects of the interfacial tension between soap solutions and oils, or to non-reactive chemical substances, such as benzene. Using a drop-weight method of measuring interfacial tension, Donnan (3) showed that crude rape oil and crude olive oil showed a much smaller interfacial tension against alkaline solutions (NaOH and Na carbonate) than against distilled water. The same olive oil showed no such difference against N/1000 NaOH after a process of purification, which was intended to remove the fatty acid. He also found that a paraffin showed no difference for interfacial tension when N/100 NaOH was substituted for distilled water, whereas the same paraffin containing 0·6 per cent, stearic acid, showed a large decrease when in contact with the alkaline solution. The decrease in interfacial tension, so produced, was found to be a function both of the amount of fatty acid dissolved in the paraffin, and also of the amount of alkali. It was further shown that of the series of acids, formic, acetic, butyric, caprylic, lauric, and stearic, tried respectively in solution in the paraffin, stearic and lauric acids alone showed any appreciable lowering of surface tension when an alkaline aqueous fluid was substituted for distilled water. Harkins and Humphrey (4) extended Donnan’s work by showing that alkali (NH4OH) lowered the interfacial tension of benzene solutions of butyric and acetic acid against water. The depression of interfacial tension so produced was a function of the concentration of fatty acid, but tended to become maximal for butyric acid at a concentration of 0·5 mols. per litre. Later, Clowes (5) showed that the decrease in interfacial tension produced by alkalis, such as Na, K, Li, at the interface crude olive oilwater, was lessened by the presence of divalent salts, such as Ca and Ba.