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Escuderos M.E.,IFAPA Centro del Llano
Critical Reviews in Analytical Chemistry

The virgin olive oil aroma evaluation has been applied as a quality and authentication control technique. Many analytical procedures have been used to identify and quantify the volatile components that characterize olive oil flavor. Among of them, gas chromatography is the main technique applied for this purpose. This study carries out an extensive and complete review of all the works published, since 30 years ago to the present, that have used gas chromatography technology for olive oil aroma analysis. Special attention has been devoted to the olive oil volatile compounds extraction and concentration techniques and separation and identification methods applied. © Taylor and Francis Group, LLC. Source

Aguilar M.J.,IFAPA Centro del Llano
Journal of Water Reuse and Desalination

The objective of this work was to determine how some wastewater acids could be used to prevent the decomposition of urea into ammonia during storage. The effect of storing human urine with olive oil mill wastewaters (OOMW) or water bubbled with CO2 (BW), was studied. Moreover, the application of two levels of urine dissolved in water OOMW, has been studied in relation to the properties of two soils (loam and silty-clay loam). Our data provide evidence that human urine dissolved in OOMW significantly reduced the release of ammonium-N. Moreover, OOMW and CO2 significantly lowered the pH. A dosage higher 10% OOMW dissolved in fresh urine in volume could inhibit the hydrolysis of the urea for more than 6 months. Moreover, urine-N dissolved in OOMW significantly reduced the emission of nitrates from soils for 3 months, increasing K and P values. The application of urine with BW raised the soil pH and lowered the EC, but had no effect on nutrient contents. Thus, urine dissolved in OOMW and applied to soils could act as NPK-fertilizer. However, the impact of fertilization with human urine-OOMW-CO2 requires further investigation with respect to crop production and pollution. © IWA Publishing 2011. Source

Aguilar M.J.,IFAPA Centro del Llano
Journal of Hazardous Materials

The aim of this work was to investigate the effect of urine on the absorption of greenhouse gases such as CO 2. Human urine diluted with olive-oil-mill wastewaters (OMW) could be used to capture CO 2 from flue gas of coal-fired power plant and convert CO 2 emissions into valuable fertilizers (mainly, NH 4HCO 3) that can enhance CO 2 sequestration into soil and subsoil layers. Thus, the CO 2 emissions could be reduced between 0.1 and 1%. The proposed strategy requires further research to increase CO 2 absorption and assess the risks associated with wastewater reuse and xenobiotics in the agroecological environment. © 2012 Elsevier B.V. Source

Colombo S.,IFAPA Centro del Llano | Christie M.,Aberystwyth University | Hanley N.,University of Stirling
Ecological Economics

This paper investigates the sensitivity of choice experiment values 3AL for ecosystem services to 'attribute non-attendance'. We consider three cases of attendance, namely that people may always, sometimes, or never pay attention to a given attribute in making their choices. This allows a series of models to be estimated which addresses the following questions: To what extent do respondents ignore attributes in choice experiments? What is the impact of alternative strategies for dealing with attribute non-attendance? Can respondents reliably self-report non-attendance? Do respondents partially attend to attributes, and what are the implications of this? Our results show that allowing for the instance of 'sometimes attending' to attributes in making choices offers advantages over methods employed thus far in the literature. © 2013 Elsevier B.V. Source

Guzman E.,IFAPA Centro del Llano | Baeten V.,Walloon Agricultural Research Center | Pierna J.A.F.,Walloon Agricultural Research Center | Garcia-Mesa J.A.,IFAPA Centro del Llano

In the real marketplace, providing high-quality olive oil is important from the perspective of both consumers and producers. Quality control should meet all requirements in the production process, from farm to packaging. The quality of olive oil can be affected by several factors, including agricultural techniques, seasonal conditions, farming systems, maturity, method and duration of storage, and process technology. The quality of oil produced also depends largely on the quality of the olives. In an enterprise aimed at producing high-quality oils, olives with defects ('ground'; i.e., fallen to the ground) should be separated from healthy fruit ('sound'; i.e., collected directly from the tree), because a very small portion of low-quality fruit can ruin the whole batch. The fruit falls partly because of its maturation process, but also because of pest and disease attack or weather conditions (strong wind). Fruit that has fallen to the ground can suffer a rapid deterioration in quality. Currently, the separation of fruits is based mainly on visual inspection or information provided by the farmer. These are not very reliable procedures. Methods using analytical parameters to characterize the oil, such as acidity and peroxide value, can be applied, but they require a lot of time and materials. Alternative techniques are therefore needed for the rapid and inexpensive discrimination of olives as part of a quality control strategy. The work described here aims to determine the potential of low-resolution Raman spectroscopy for the discrimination of olives before the oil processing stage in order to detect whether they have been collected directly from the tree (i.e., healthy fruit) or not. Low-resolution Raman spectroscopy was applied together with multivariate procedures to achieve this aim. PCA was used to find natural clusters in the data. Supervised classification methods were then applied: Soft Independent Modeling of Class Analogy (SIMCA), PLS Discriminate Analysis (PLS-DA) and K-nearest neighbors (KNN). The best results were obtained using the KNN method, with prediction abilities of 100% for 'sound' and 97% for 'ground' in an independent validation set. These results demonstrated the potential of a portable Raman instrument for detecting good quality olives before the oil processing stage, by developing models that could be applied before this stage, thus contributing to an overall improvement in quality control. © 2012 Elsevier B.V. All rights reserved. Source

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