Soxhlet System Research Articles

Trans-RESVERATROL AND ANTIOXIDANT ACTIVITY OF GRAPE (Vitis vinifera sp) BYPRODUCTS

Polyphenols from agroindustries byproducts have great potential as a source of antioxidant compounds. The present study evaluated the antioxidant activity and polyphenol content of the husks and seeds of grapes obtained from a winery of the produce wine. The hydroalcoholic extract (HAE) of the husks was obtained through an exhaustive maceration process. Seeds were extracted in a Soxhlet system, mixed with hydroalcoholic solution and the dried extract was partitioned into solvents to yield the chloroform fraction (CLF), ethyl acetate fraction (EAF), and butanol fraction (BUF). The EAF and HAE had phenolic equivalents of 200.76 and 320.64 mg of gallic acid per gram of extract, respectively. The HAE showed higher antioxidant activity than the fractions in the phosphomolybdenum method, the same in DPPH assay, with IC 50 of 16.82 mg/mL, and β -carotene/linoleate system, with antioxidant activity of 82.09%. High performance liquid chromatography (HPLC) method was developed and validated for quantifying trans -resveratrol in the HAE. The method showed linearity (2.5-7.5 µg/mL), correlation coefficient of 0.9907, precision and accuracy (resveratrol recovery = 101.02%). The HAE had a trans -resveratrol concentration of 17.33 µg/mg. The results of the validation of the HPLC method were satisfactory, which allowed analysis of the extract with precision and accuracy.

Effect of Subcritical Carbon Dioxide Extraction and Bran Stabilization Methods on Rice Bran Oil

AbstractThe extraction of rice bran oil using the conventional organic solvent‐based Soxhlet method involves hazardous chemicals, whereas supercritical fluid extraction is a costly high‐temperature operating system. The subcritical carbon dioxide Soxhlet (SCDS) system, which operates at a low temperature, was evaluated for the extraction of rice bran oil in this study. In addition, rice bran that had been subjected to steam or hot‐air stabilization were compared with unstabilized rice bran (control). The yields; contents of tocopherols, tocotrienols and oryzanol; fatty acid profiles; and the oxidative stabilities of the extracted rice bran oils were analyzed. The yields using hexane and SCDS extraction were approximately 22 and 13–14.5 %, respectively. However, oil extracted using the SCDS system contained approximately 10 times more oryzanol and tocol compounds and had lower free fatty acid levels and peroxide values compared with hexane‐extracted oil. Overall, SCDS extraction of steamed rice bran represents a promising method to produce premium‐quality rice bran oil.

Comparative Effects of Biomass Pre-Treatments for Direct and Indirect Transesterification to Enhance Microalgal Lipid Recovery

Microalgal lipid recovery for biodiesel production is currently considered suboptimal, but pre-treatment of algal biomass, the use of solvent mixtures and the positioning of transesterification can lead to increased yields. Here, the effect of various reportedly successful pre-treatments and solvent mixtures were directly compared to each other and combined with direct and indirect transesterification methods using the oleaginous microalga Tetraselmis sp. M8. Microwave and thermal pre-treatments were applied and the total lipid and fatty acid methyl ester (FAME) recoveries were investigated. The application of pre-treatments increased FAME recovery through indirect transesterification when a Soxhlet system was used but they had no significant effect for direct transesterification. Gravimetric analyses of total lipids revealed that lipid recovery was highest when utilizing the chloroform-based Bligh and Dyer extraction method; however FAME yield was the highest when applying a Soxhlet system utilizing a solvent mixture of hexane-ethanol (3:1). Total lipid recovery did not necessarily correlate with the recovery of FAMEs. The highest FAME recovery was achieved from thermal or microwave pre-treated biomass followed by indirect transesterification through Soxhlet extraction. FAME recovery could be more than doubled (increase of up to 171%) under these conditions. We conclude that a simple thermal pre-treatment (80°C for 10 min) in combination with solvent mixture extraction through indirect transesterification may present a cost-effective and scalable option for large-scale lipid extraction from microalgae.

TEMPORAL TRENDS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) IN A DATED SEDIMENT CORE OF A HIGH ATITUDE MOUNTAIN LAKE: CHUNGARA LAKE- NORTHERN CHILE (18° S)

In this study levels, fluxes and temporal trend of PAHs are reported in a sediment core from Chungara Lake (18° S) in Northern Chile. The sediments were obtained by Kayac corer and freeze dried. PAHs were extracted in SOXHLET system and measured by HPLC with diode array detector and fluorescence detection. Sedimentary record chronology was determined using 210Pb isotopes and organic carbon (%) was also measured in sediments. Concentrations (ng g-1 d.w.) of PAHs were low ranging from ~1 to 50. PAHs fingerprint was dominated by 3-ring (21%) and 4-ring. Organic carbon (%) ranged from ~17 to 24 (21±3) and no statistical significant correlation (p<0.05) was detected between OC (%) and PAHs along the sediment core. PAHs fluxes (μg m-2yr-1) fluctuated from ~0.3 (cm 1) to 35 (cm 5) in 1978. LPAHs/HPAHs ratios (0.04 to 3) indicate petrogenic and pyrolytic origin of PAHs. This results contributes with new information of PAHs deposition at high altitudinal lake in Southern Hemisphere.

Combination of a fast cleanup procedure and a DR-CALUX® bioassay for dioxin surveillance in Taiwanese soils.

Our goal was to determine dioxin levels in 800 soil samples collected from Taiwan. An in vitro DR-CALUX® assay was carried out with the help of an automated Soxhlet system and fast cleanup column. The mean dioxin level of 800 soil samples was 36.0 pg-bioanalytical equivalents (BEQs)/g dry weight (d.w.). Soil dioxin-BEQs were higher in northern Taiwan (61.8 pg-BEQ/g d.w.) than in central, southern, and eastern Taiwan (22.2, 24.9, and 7.80 pg-BEQ/g d.w., respectively). Analysis of multiple linear regression models identified four major predictors of dioxin-BEQs including soil sampling location (β = 0.097, p < 0.001), land use (β = 0.065, p < 0.001), soil brightness (β = 0.170, p < 0.001), and soil moisture (β = 0.051, p = 0.020), with adjusted R2 = 0.947 (p < 0.001) (n = 662). An univariate logistic regression analysis with the cut-off point of 33.4 pg-BEQ/g d.w. showed significant odds ratios (ORs) for soil sampling location (OR = 2.43, p < 0.001), land use (OR = 1.47, p < 0.001), and soil brightness (OR = 2.83, p = 0.009). In conclusion, four variables, including soil sampling location, land use, soil brightness, and soil moisture, may be related to soil-dioxin contamination. Soil samples collected in northern Taiwan, and especially in Bade City, soils near industrial areas, and soils with darker color may contain higher dioxin-BEQ levels.

Polyphenol composition and antioxidant and metal chelating activities of the solid residues from the essential oil industry

Essential oils of aromatic plants have numerous applications in fields like medicine, cosmetic and food industry. Nevertheless, the average yield of essential oil distilled from aromatic plants is below 5% (w/w) and consequently a considerable amount of solid residues is generated. These residues are especially rich in polyphenols that can be exploited as health-promoting compounds in food and feed or as anti-aging ingredients in cosmetic products, and thus to enhance the overall profitability of the aromatic plants. In this work, we have tentatively identified the polyphenols present in solid residues from the steam distillation of Cistus ladanifer, Lavandula×intermedia, Santolina rosmarinifolia and Thymus mastichina, and evaluated their antioxidant and chelating activities by means of several in vitro methods, such as the β-carotene/linoleate model system, reducing power, DPPH radical scavenging, and iron and copper ion chelation. A Soxhlet extraction and an ultrasound-assisted extraction have been used in terms of comparison. Most of the extracts whether they were obtained by Soxhlet system or by ultrasonic method showed good antioxidant activities. Soxhlet ethanolic extract of T. mastichina showed an antioxidant activity comparable to the standard red grape pomace. The influence of the total polyphenol content on the chelating activities was not as important as on the antioxidant activities and the predominant role of certain polyphenols and/or the presence in the extracts of other compounds with a favourable chemical structure to metal complexation can be assumed. This was the case of the ultrasound ethanolic extract of C. ladanifer, which was the most effective in iron chelating activity despite its medium-to-low content of total polyphenols. All these data point to profit from these aromatic plant solid residues as a valuable source of bioactive compounds.

The use of Crambe abyssinica seeds as adsorbent in the removal of metals from waters

This study aimed to evaluate the efficacy of crambe seeds (Crambe abyssinica Hochst) as adsorbent material in the removal of the toxic metals cadmium, lead and chromium from contaminated solutions. The byproduct was obtained from oil extraction of crambe seeds in a Soxhlet system. In kinetic tests, the adsorbent masses had varied in solutions containing the metals under pH 5.0 and 7.0. Metal concentrations were determined by flame atomic absorption spectrometry (FAAS). According to optimal conditions found, the adsorption assays were performed for obtaining the isotherms of each metal, which were linearized in agreement with the mathematical models of Langmuir and Freundlich. According to the obtained results, the adsorbent was effective in removing the assessed metals in aqueous solutions, being feasible its employment as an alternative material for the adsorption of metals, besides being a byproduct, which has undergone no prior treatment.

Evaluación preliminar de la composición química de las hojas de carica papaya l y del efecto anti protozoario de un extracto enriquecido en alcaloides a partir de la misma

El presente trabajo se ocupa del estudio de la parte foliar de las hojas de la especie Carica papaya L. debido a su uso generalizado para el tratamiento de diversos parásitos inferido a la presencia del alcaloide carpaina. Se realiza una extracción total en un equipo Soxhlet y el mismo se procesa por el sistema de cambio de fase ácido-base-solvente orgánico para tener una fracción rica en alcaloides con un 1 % de rendimiento respecto al peso de planta de partida. Este extracto se evalúa frente a una cepa de Plasmodium berghei teniendo una IC50 aceptable como positiva de 50 µg/mL, no así para una cepa de Leishmania amazonensis con una IC50 de 73,3 µg/mL. De esta fracción mediante un proceso de contracorriente con 5 intercambiadores se purifica un producto con todas las características de alcaloide que al realizar los espectros de RMN de 1H y 13C comparando con los informes de la literatura se asigna para el mismo la estructura de la carpaina. El presente trabajo permite tener una técnica sencilla para obtener este alcaloide de forma selectiva y da la posibilidad de seguir ampliando diferentes evaluaciones biológicas con el mismo.

Application of High Power Ultrasound and Microwave in Food Processing: Extraction

High power ultrasound has opportunity to be used as tool for extraction. The first Soxhlet extraction assisted by ultrasound, named Ultrasound-Assisted Soxhlet (UASE) was developed in 2004 by Luque de Castro et al. Another innovative method for ultrasound assisted extraction was developed by Chemat et al. System for oil extraction, named Sono- Soxhlet system was developed by inserting an ultrasonic probe directly into the extraction chamber, i.e. ultrasound is applied directly in the extraction reactor. The lipid extracts obtained from the Sono-Soxhlet process are qualitatively the same as conventional process, and time for extraction is significantly reduced, requiring 30 minutes vs. conventional 8h. On the other hand, there is also promising technique of using microwaves for food processing. Microwaves are largely used in food industries for drying, pasteurization, sterilization, thawing, tempering, baking and so on. Microwaves are electromagnetic waves whose frequency varies within 300 MHz to 300 GHz. Domestic microwave appliances operate generally at a frequency of 2.45 GHz, while industrial microwave systems operate at frequencies of 915 MHz and 2.45 GHz.

Quantification of the Robusta Fraction in a Coffee Blend via Raman Spectroscopy: Proof of Principle

Among the 100 different known Coffea species, Coffea arabica L. (Arabica) and Coffea canephora Pierre (Robusta) are the only two of commercial interest. They differ in a range of agronomic, genetic, and chemical properties. Due to the significant price difference between Arabica and Robusta, there is an economic incentive to illicitly replace Arabica with Robusta. Therefore, it is crucial to have accurate methods to determine the Robusta-to-Arabica-ratio in blends. This paper presents the proof of principle of a new and fast approach to determine the Robusta fraction in a blend based on Raman spectroscopy. The oils of two references (a pure Robusta and pure Arabica coffee) and six blends thereof consisting of different Robusta and Arabica fractions were extracted using a Soxhlet system. The solutes were analyzed by means of Raman spectroscopy without further workup. Using the intensity ratio between two Raman peaks, one characteristic for kahweol and one characteristic for fatty acids, allowed determinination of the Robusta content in a given mixture. The intensity ratio is linearly dependent on the Robusta content of the compound. Above a Robusta content of 75 wt %, kahweol was not detectable. The Raman data are in agreement with results obtained from the very time-consuming multistep DIN 10777 procedures based on HPLC.

Distribution of sterols in sediment cores from martel inlet, Admiralty Bay, King George Island, Antarctica

In the present study, sterols organic markers were applied to identify the sources of organic matter in Admiralty Bay. For this purpose, sediment samples were extracted using a Soxhlet system, clean up with column chromatography and injected into a gas chromatograph. Measurable levels of all sterols analyzed confirm the multiplicity of sources of sedimentary organic matter. In BTN and STH,the most abundant sterol was the colest-5-en-3β-ol (cholesterol) with 2.24 μg.g–1 and 4.12 μg.g–1, respectively, while in FER, itwas the 24-metil-colest-5-en-3β-ol (campesterol) with 1.83 μg.g–1. The saturated sterols have smaller concentrations in relation to parental unsaturated, which may indicate a low rate of bacterial and hydrogenation processes. A generic profile of the vertical distribution representing all 15 sterols studied was obtained by Principal Component Analysis (PCA). In three cores, the vertical distribution pattern of organic material presented the smallest values in the bottomdepth layers, reflecting the organic matter already immobilized while in the upper layers values showed a gradual increase towards the top, representing the recentdeposition of organic matter.

Molecular geochemical indicators of sewage input in the Antarctic coastal area (Admiralty Bay, King George Island, Antarctica)

Antarctica has been described as a pristine environment for many years. However, human presence has resulted in fossil fuel combustion, vehicular emissions, fuel spills in the marine and terrestrial environments and sewage waste discharged into the ocean. Currently, most Antarctic research stations (around 79 scientific centres) are located in coastal areas, and they release their untreated sewage containing domestic waste directly into the marine environment. A group of molecular tracers such as steroids and linear alkylbenzenes (LABs) have been successfully used to investigate domestic waste discharges and faecal contamination in different regions, including Admiralty Bay, Antarctica (Martins et al., 2002; 2005). Coprostanol (5β-cholestan3β-ol) and coprostanone (5β-cholestan-3-one) have been widely used as faecal contamination markers because they are present in human faeces (Figure 1). Additionally, epicoprostanol (5β-cholestan-3β-ol) indicates the level of treatment of the faecal matter as it is formed during the extensive anaerobic sewage treatment of wastewaters (Figure 1). Also, LABs are present at levels from 1 to 3% in surfactants and detergents with linear alkylbenzene sulphonates (LASs) due to incomplete sulfonation (Figure 2), and they are frequently discharged via sewage outfalls together with faecal matter. These compounds are usually preserved in the sediment, and can be used as molecular tracers of domestic wastes. The monitoring of environmental conditions, such as hydrocarbon levels (Martins et al., 2004; 2010) and PCBs, near the sewage discharge from the Comandante Ferraz Brazilian Research Station, located at Martel Inlet, Admiralty Bay, King George Island, has been carried out since the austral summer of 1996/97. The aim of this study is to evaluate the sewage contribution from Ferraz station to Admiralty Bay and to compare the historical trend reported in previous studies. This evaluation is based on the results of molecular geochemical indicators such as steroids and LABs from the upper layer of sediments sampled during the austral summers of 2009/10. In Antarctica, monitoring the extent of sewage pollution dispersal is essential as Antarctic Treaty signatory nations must conform to the Protocol on Environmental Protection. Admiralty Bay is the largest around King George Island. The bay area is an Antarctic Specially Managed Area (ASMA), and the Scientific Committee on Antarctic Research (SCAR) has recommended environmental studies on present-day conditions of the region. Most sampling sites were located near Ferraz station. This medium size station was established in the summer of 1984, and usually has a population of approximately 50 people during the summer. The sewage system receives intermediate primary and secondary treatment before being discharged through a short pipe (Figure 3) near the sea. The sewage treatment system has been in operation since the austral summer of 1995/96 and was designed to serve a population of 50. For analyses of steroids, sediments are extracted using a Soxhlet system for 8 hours with 70 mL of ethanol. The concentrated extract is submitted to a clean up with column chromatography with deactivated alumina and elution with 15 mL of ethanol. The extract is evaporated till completely dry and derivatized to form trimethylsilyl ethers 4

Potential oilseed crops from the semiarid region of northeastern Brazil

The caatinga semi-arid ecosystem of northeastern Brazil is characterized by a dry, spiny and predominantly deciduous shrub/forest vegetation, and many species there are potential sources of renewable resources for the oleochemical industry. The present research determined the oil content and fatty acid profiles of seeds from eight caatinga species. Seed oils were extracted in a Soxhlet system, and their fatty acid content identified by GC–MS. Oil content varied between 20.2% in Tabebuia impetiginosa (Mart.) Standl. (Bignoniaceae) and 46.4% in Barnebya harleyi (W.R. Anderson & B. Gates) Malpighiaceae. Anemopaegma laeve DC. (Bignoniaceae) had the highest oleic acid content (63.4%), while high levels of linoleic acid were found in Banisteriopsis pubipetala (Juss.) Cuatrec. (42.8%) and B. harleyi (31.9%) (both Malpighiaceae). Palmitic acid was the major fatty acid (50%) in Hippocratea volubilis (L.) (Celastraceae). High levels of linoleic and linolenic acids were found in Croton adamantinus Mull. Arg. (Euphorbiaceae), averaging 44.2% and 45.2% respectively. Gadoleic acid in was the most abundant fatty acid in the oil produced by Serjania lethalis A. St. Hill. (Sapindaceae), averaging 69.6%. B. pubipetala, B. harleyi, C. adamantinus, and H. volubilis were identified as promising species for cultivation.

Determination of eighty-one volatile organic compounds in dietary Rumexinduratus leaves by GC/IT-MS, using different extractive techniques

The volatile compounds of Rumex induratus leaves were studied for the first time. In order to achieve the most complete volatile profile four different extractive techniques (hydrodistillation, solid-phase microextraction, Soxhlet system and direct solvent extraction) were applied. The different extracts were analysed by gas chromatography/ion trap-mass spectrometry (GC/IT-MS) which allowed the identification of 81 compounds, distributed by several chemical classes: esters, terpenes, aldehydes, acids, norisoprenoids, ketones, naphthalene derivatives, steroids derivatives and alcohols, among others. The different techniques lead to different compounds' extraction. Using hexane and dichloromethane, 9 and 4 compounds were extracted, respectively. Hydrodistillation, solid-phase microextraction and Soxhlet extraction allowed the extraction of 43, 24 and 29 compounds, respectively. Hydrodistillation was revealed to be the most effective technique, allowing the extraction of a higher number of compounds, both in the hydrolat (20 compounds) and essential oil (34 compounds), having 11 compounds in common.

Fast supercritical fluid extraction of low- and high-density polyethylene additives: Comparison with conventional reflux and automatic Soxhlet extraction

The extraction of antioxidant additives, such as, Irganox 1076 and Irgafos 168, from low-density polyethylene (LDPE) and Irganox 1010 and Irgafos 168 from high-density polyethylene (HDPE) was carried out by supercritical fluid extraction (SFE) working in constant pressure, conventional reflux, and automatic Soxhlet system (Soxtec). Recoveries and repeatability of the evaluated methods, using LDPE and HDPE reference materials, showed some differences between them, but more significant differences were found with features such as sample-processing and time required, which are both crucial for the exploitation of these techniques for quantification in routine industrial quality analysis for additives. SFE was found to be the most advantageous technique in terms of simplicity, cost-effectiveness and speed in comparison to conventional reflux and Soxtec procedures.

Polychlorinated Biphenyls (PCBs) in Mussels along the Chilean Coast

Chile signed the Stockholm Convention, which establishes measures to reduce or eliminate Persistent Organic Pollutants (POPs) release into the environment, including the prohibition of their use and reduction of secondary products release, as well as management related with waste treatment. Among POPs, PCBs are a family of 209 compounds that differ in chlorine level and position. These substances present a wide variability in their physicochemical properties such as vapor pressure, water solubility and partition coefficients that determine their behavior and mobility within the different environmental compartments. In Chile, as in other countries, the use of these compounds were and continue to occur in diverse industrial applications such as dielectric fluid in transformers and condensers, with a use in Chile of approximately 550,000 L. A sampling of bivalves was performed during the years 2000-2002 in order to obtain information on the spatial distribution of the PCB levels for the length of the long Chilean coast (18 degrees-54 degrees South latitude, 4,200 km), contributing in this way to a better understanding of the PCB trend and eventual fractionation along latitudinal gradients in Chile, using as the bivalve Perumytilus purpuratus ('Chorito Maico') bioindicator. The marine bivalves Perumytilus purpuratus were collected in 16 localities in northern and southern Chile. All samples were lyophilized, and PCBs (51 congeners) were extracted in a Soxhlet system (24 h) with n-hexane. Samples were cleaned in florisil and analyzed by GC-ECD. Blanks, certified reference materials and standards were processed along with the samples. The results obtained for P. purpuratus indicate a congeneric distribution profile associated to a latitudinal gradient, and the statistical analysis of the congeneric composition of the PCBs indicated five groups in relation to the molecular weight (number of chlorines), where the lighter congeners were observed in areas corresponding to high latitudes with total PCB values of 298 ng/g dry weight. P. purpuratus turns out to be a good bioindicator of PCB levels in the coastal areas of Chile due to its wide distribution. The highest concentrations and the more volatile congeners were found in southern Chile, which could be the result of processes of long-range transport or illegal discharge occurring in such remote areas. These results confirm previous data from the International Mussel Watch project ten years ago. Future studies are needed to confirm our findings utilizing another environmental matrix such as soil/sediments and air samples.

Microwave enhanced extraction of wool wax from solid wool scour wastes

A microwave enhanced extraction method for the separation of wool wax from scour wastes has been developed. Samples analysed have been obtained from industrial wool scour processes. Microwave parameters (irradiation time and power applied), and other parameters (solvent used, number of samples per extraction, sample weight, solvent volume and effect of water addition) have been studied in order to obtain the greatest recovery in the shortest time. It was found that microwave extraction for this kind of sample gives efficiencies the same as that achieved by classical Soxhlet system. The time of analysis is reduced from 4 h to 8 min compared with the Soxhlet extraction systems and the amount of solvent decreased from 125 to 10 ml.

Extracción de naringina de Citrus paradisi L. estudio comparativo y optimización de técnicas extractivas

Se realizó el estudio comparativo de distintas técnicas extractivas de naringina utilizando cáscaras de pomelo (Citrus paradisi). Las mejores condiciones de preparación previa del material son el fragmentado de cáscara fresca y el secado en estufa con posterior fragmentado. Para cáscara fresca resulta más conveniente la extracción con etanol puro por Soxhlet (obteniéndose 26g/kg de peso fresco), mientras que para cáscara seca los mejores resultados se obtienen en la extracción con la mezcla etanol-agua en las proporciones 70:30 por maceración (20g/kg de peso fresco) y reflujo (22g/kg de peso fresco). Se observaron evidencias de la importancia del agua en el proceso de extracción. Se determinaron los valores de concentración de naringina en cáscaras de distintas variedades de Citrus paradisi de la región del Noroeste Argentino.

Analysis of pesticide residues in matrices with high lipid contents by membrane separation coupled on-line to a high-performance liquid chromatography system

Separation through membranes coupled to an HPLC system was used as a technique for the analysis of pesticide multiresidues in samples with high lipid contents. As well as the usual procedure, in the proposed system it is possible to recirculate the sample through the membrane cell, which permits the extraction system to be applied to cases in which only a very small volume of sample is available. A procedure for pesticide multiresidue analysis in egg samples was developed as a representative example of the applicability of the proposed method. To accomplish this, the analytes (dichlorvos, dimethoate, propoxur, paraoxon, pirimicarb, atrazine, ametryne, terbutryne, azinphos-methyl, folpet) were subjected to prior extraction in a Soxhlet system, after which the extract was introduced into the membrane separation device coupled to the HPLC system. This procedure afforded clean chromatograms, hence considerably facilitating determination, and at the same time was efficient in removing macromolecular compounds. For egg samples, spiked at a concentration level of 0.750 mg/kg, recoveries ranged from 60 to 98%. The detection limits varied from 0.018 mg/kg for dichlorvos to 0.002 mg/kg for atrazine.

Método rápido de obtención de aceite de oliva virgen para determinación de acidez

A rapid and simple method to obtain, from olive samples, enough quantity of oil to determine acidity grade is proposed. From paste samples of milled olives, different fraction are separated to be centrifugated during 5 minutes at 4500 r.p.m. Oil acidity results obtained from sodium sulfate anhidrous and natural microtalc added samples are compared with blank samples, and with those obtained by the Abencor extraction procedure. The correlation between the acidity of oil samples obtained by the Abencor method is also analyzed against other samples obtained by the normalized method in Spain, norm UNE 55070, Soxhlet system. Results show that in all the centrifugated samples enough amount of oil is obtained to determin the acidity grade, it also show that treatment with sodium sulfate anhidrous obtains a bigger recovery percentage, and that in all 3 cases, the acidity shows a good correlation with that of the Abencor system, doubling the number of samples analysed by the Abencor system. It also shows that the acidity grade obtained by using the UNE 55070 norm is aproximately 0,3 grades above that obtained by the Abencor system.