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Salguero-Chaparro L.,IFAPA Alameda del Obispo | Baeten V.,Walloon Agricultural Research Center | Fernandez-Pierna J.A.,Walloon Agricultural Research Center | Pena-Rodriguez F.,IFAPA Alameda del Obispo
Food Chemistry | Year: 2013

The acidity, moisture and fat content in intact olive fruits were determined on-line using a NIR diode array instrument, operating on a conveyor belt. Four sets of calibrations models were obtained by means of different combinations from samples collected during 2009-2010 and 2010-2011, using full-cross and external validation. Several preprocessing treatments such as derivatives and scatter correction were investigated by using the root mean square error of cross-validation (RMSECV) and prediction (RMSEP), as control parameters. The results obtained showed RMSECV values of 2.54-3.26 for moisture, 2.35-2.71 for fat content and 2.50-3.26 for acidity parameters, depending on the calibration model developed. Calibrations for moisture, fat content and acidity gave residual predictive deviation (RPD) values of 2.76, 2.37 and 1.60, respectively. Although, it is concluded that the on-line NIRS prediction results were acceptable for the three parameters measured in intact olive samples in movement, the models developed must be improved in order to increase their accuracy before final NIRS implementation at mills. © 2013 Elsevier Ltd. All rights reserved.

Salguero-Chaparro L.,IFAPA Alameda del Obispo | Pena-Rodriguez F.,IFAPA Alameda del Obispo
LWT - Food Science and Technology | Year: 2014

Visible/near-infrared calibrations were developed for the determination of the quality parameters (fat content, moisture and free acidity) of intact olive fruits. The reflectance spectra were acquired in two different instruments (diode-array versus grating monochromator based instruments). The grating monochromator based instrument was used at the laboratory (off-line analysis), whereas the portable diode-array based device was placed on top of a conveyor belt set to simulate measurements in an olive oil mill plant (on-line analysis). Partial least squares (PLS) regression and least squares support vector machine (LS-SVM) were used for the development of the calibration models. A total of 174 samples were prepared for the calibration (N=122) and validation (N=52) sets. The root mean square error of prediction (RMSEP) and the residual predictive deviation (RPD) values were better using the diode-array instrument and applying the PLS regression method for the fat content parameter while for the free acidity and moisture content, the LS-SVM algorithm gave the best results. The results obtained seems to suggest the viability of the on-line system, instead of the off-line analysis, for the determination of physicochemical composition in intact olives. © 2013 Elsevier Ltd.

Salguero-Chaparro L.,IFAPA Alameda del Obispo | Baeten V.,Walloon Agricultural Research Center | Abbas O.,Walloon Agricultural Research Center | Pena-Rodriguez F.,IFAPA Alameda del Obispo
Journal of Food Engineering | Year: 2012

In the last years, the potential of NIRS for quantitative and qualitative analysis of olives fruits and oils has been investigated. However, limited work has been published about the on-line implementation of NIR spectroscopy in this sector. NIRS application at factory level (olive mills) is desirable. However, prior its implementation, many parameters related to the on-line spectrum acquisition, must be studied and optimised. In this paper, the influence of parameters such as focal distance and integration time has been studied. On-line spectral measurements were performed on intact olives in the spectral range of 380-1690 nm using a diode array spectrometer located on the top of a conveyor belt. The statistical criteria used to evaluate the spectral repeatability for each level of parameters considered were the standard deviation (SD) of the log (1/R) values and the root mean square statistics (RMS). Results demonstrated that for on-line control of olives in movement, spectra acquisition process was more affected by the focal distance chosen than by the integration time used. A focal distance of 13 mm and an integration time of 5 s have been defined as the optimal operational conditions. © 2012 Elsevier Ltd. All rights reserved.

Campos-Fernandez J.,University of Cordoba, Spain | Arnal J.M.,IFAPA Alameda del Obispo | Gomez J.,IFAPA Alameda del Obispo | Lacalle N.,University of Cordoba, Spain | Dorado M.P.,University of Cordoba, Spain
Fuel | Year: 2013

The use of straight (in modified engines) or blended alcohols with fossil fuel provides an attractive alternative fuel for internal combustion engines. Moreover, alcohol can be produced by biorefineries, thus reducing the use of fossil resources. However, main achievements in this field correspond to the use of short-chain alcohols, like ethanol, while there is little experience with higher alcohols. In this work, the performance of a direct-injection diesel engine, without any modifications, fueled with 1-pentanol/diesel fuel blends has been evaluated. Blends with 10% pentanol/90% diesel fuel, 15% pentanol/85% diesel fuel, 20% pentanol/80% diesel fuel and 25% pentanol/75% diesel fuel (v/v) were tested and engine performance results were compared with those provided by neat diesel fuel. Experimental results showed insignificant engine power, brake thermal efficiency and brake-specific fuel consumption variations when the engine was fueled with the majority of the blends instead of straight diesel fuel. Moreover, statistical analysis showed no significant differences between the blends and diesel fuel (EN 590) tests. During engine starting, no difficulties were experienced and the engine performed satisfactorily on the blends throughout the entire test. On the basis of this study, pentanol/diesel fuel blends can be considered acceptable diesel fuel alternatives if exhaust emissions and long-term engine tests show acceptable results. © 2013 Elsevier Ltd. All rights reserved.

Salguero-Chaparro L.,IFAPA Alameda del Obispo | Palagos B.,IRSTEA | Pena-Rodriguez F.,IFAPA Alameda del Obispo | Roger J.M.,IRSTEA
Computers and Electronics in Agriculture | Year: 2013

The recent development of new portable devices enables the establishment of NIRS technology at industrial setting (on-line). However, the numerous existing NIRS databases based on a particular parameter, have been constructed with laboratory instruments (off-line), which have required a considerably effort in terms of time, labor and costs. For this reason, the transfer of calibrations between devices of different characteristics is a clearly crucial step. In this study, three different standardization algorithms: Slope/Bias Correction (SBC), Piecewise Direct Standardization (PDS) and Transfer by Orthogonal Projection (TOP) were tested and evaluated for transferring olives quality databases between an off-line NIRS monochromator (FOSS NIRSystem 6500) and a portable NIRS diode-array spectrometer (CORONA 45 visNIR). The results obtained showed that the use of TOP yielded the best Standard Error of Prediction (SEP) values for the fat content (1.97%) and free acidity (2.52%) parameters, while PDS for moisture content (2.24%). These results suggest that good calibration models for quality evaluation in intact olives can be obtained, based on spectral databases transferred between diverses NIRS spectrometers. © 2013 Elsevier B.V.

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