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Jimenez A.,University of Extremadura | Rufo M.M.,University of Extremadura | Paniagua J.M.,University of Extremadura | Pachon F.T.,University of Extremadura | Crespo A.,Centro Tecnologico Agroalimentario Extremadura CTAEX
19th International Congress on Sound and Vibration 2012, ICSV 2012

Nowadays, non-destructive testing is being used to assess the quality of many foods. Non-invasive ultrasound provides a non-destructive method for determining physical properties in a wide range of them (vegetables, fruits, meats, oils, dairy, etc.). The aim of this work is to describe and show some results obtained in the non-invasive ultrasonic method to study the change in mechanical properties of organic cheese (P.O.D. Torta del Casar) made from the milk of sheep. Specifically, we show those related to the use of shear wave transducers in the test of the pieces of cheese. The results show that this type of transducer is perfectly valid to evaluate simultaneously the values of the ultrasound propagation velocities of the longitudinal and shear waves. This is because the emitted shear waves undergo a mode conversion at their incidence on the crust, with a partial transformation into longitudinal waves. Source

Ordiales E.,Centro Tecnologico Agroalimentario Extremadura CTAEX | Fernandez M.,University of Extremadura | Benito M.J.,University of Extremadura | Hernandez A.,University of Extremadura | And 2 more authors.
Food Analytical Methods

The purpose of this work was to develop a PCR method for the identification of Cynara cardunculus used in the elaboration of “Torta del Casar” cheese. One hundred five specimens were collected from different parts of the Extremadura region (Spain). Morphological characterisation was performed in situ at the time of sampling. Comparison of the morphological data was by genotypic characterisation. Different genetic profiles were obtained using seven random primers with the random amplified polymorphic DNA (RAPD) technique obtaining better results with the primer OPAE10. For the simple sequence repeat (SSR) technique, ten microsatellites were used, the best genetic profiles being obtained with the microsatellite CMAFLP-24. All the specimens were analysed with both primers, showing that the method provided a fast and accurate characterisation of C. cardunculus that could be used for the Protected Designation of Origin “Torta del Casar” as a tool for traceability and control in the process of elaboration of the cheese. Thistles with different genetic profiles were used in cheese-making finding that this is a good tool to monitorisation for quality control of cheese texture characteristics elaborated with these rennets. © 2014, Springer Science+Business Media New York. Source

Ordiales E.,Centro Tecnologico Agroalimentario Extremadura CTAEX | Benito M.J.,University of Extremadura | Martin A.,University of Extremadura | Fernandez M.,University of Extremadura | And 2 more authors.
Journal of Dairy Research

The purpose of this work was to analyse the influence of rennet from different Cynara cardunculus plants, selected for its clotting and proteolytic activity on caseins, on the characteristics of manufactured 'Torta del Casar' cheeses. After classifying the cardoon according to proteolytic activity into five groups of greater or lesser activity, 16 batches of cheeses were made with rennet derived from different wild cardoon plants. We observed a major development of the proteolysis during ripening leading to the generation of non-protein nitrogen compounds. Especially noteworthy was the relationship of amino acid nitrogen (AN) generation with rennet clotting activity after 24 h of maceration, and the fact that the production of biogenic amines was not related to the proteolytic activity of the rennet. The activities of the rennet observed 'in vitro' were also developed 'in vivo' in the cheeses, with the different rennets used affecting the final sensory characteristics of cheeses. The rennet with high clotting activity after 24 h of maceration was positively correlated with the creaminess, viscosity, and acceptability of the cheese. However, the high proteolytic activity rennet negatively influenced the acidity, bitterness, and creaminess parameters. Therefore the most appropriate cardoons for making this cheese are those with higher clotting activities and moderate proteolytic activities especially on β-casein. The use of controlled and characterised cardoons in the manufacturing process of Torta del Casar is fundamental to obtaining the homogeneous product demanded by the Torta del Casar Registry of the Protected Designation of Origin. © 2013 Proprietors of Journal of Dairy Research. Source

Ordiales E.,Centro Tecnologico Agroalimentario Extremadura CTAEX | Martin A.,University of Extremadura | Benito M.J.,University of Extremadura | Hernandez A.,University of Extremadura | And 2 more authors.
Food Chemistry

The purpose of this work was to develop a procedure based on protein analysis by free zone capillary electrophoresis (FZCE) that can be used as an alternative to other methods in the determination of the technological quality of vegetable rennet to use in "Torta del Casar" cheese-making. Samples of cardoon flowers (Cynara cardunculus) grouped according to location, harvest year, and ripening stages were used in the study. For the FZCE, a protocol for extracting the methanol-soluble proteins was tested. This method was found to give good repeatability of the corrected migration time (CMT), and showed higher effectiveness in discriminating the technological properties (milk-clotting and casein degradation activities) of vegetal rennets than the SDS-PAGE technique. In addition, three peaks found in the FZCE electropherograms were examined as a good tool to predict the impact of vegetable rennet on the creaminess and overall acceptability of the "Torta del Casar" cheese. © 2011 Elsevier Ltd. All rights reserved. Source

Ordiales E.,Centro Tecnologico Agroalimentario Extremadura CTAEX | Benito M.J.,University of Extremadura | Martin A.,University of Extremadura | Casquete R.,University of Extremadura | And 2 more authors.
Food Control

The objective of this work was to study the growth and development of fortuitous flora and food pathogens in the traditional Spanish cheese "Torta del Casar". Sixteen batches of "Torta del Casar" were manufactured from the same unpasteurized Merino ewe's milk, using Cynara cardunculus L. rennets, corresponding to 16 plants, one for each batch. The cheeses were classified based on their texture spreadability analysis data (TSA) into four clusters, from very creamy to not creamy cheeses.Although there were no differences between the counts of different microbial groups in the different clusters of cheese, the microorganism isolated did differ between clusters, especially between the Group 1 cluster (less creamy cheese) and Group 4 (creamiest cheese), with the most notable isolates in the latter being a LAB Lactococcus lactis subsp. cremoris, and the enterobacteria Serratia proteamaculans and Enterococcus devriesei. Pathogen development was similar in all four groups of cheeses. Small differences were found for some pathogens (Listeria spp. and Salmonella spp.) which may have been due to interference with the different autochthonous microbiota. Indeed, the different autochthonous microbiota appears to influence the texture of the cheeses and the development of pathogens in them. © 2013 Elsevier Ltd. Source

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