Friday, 20 September 2013

Os queixos galegos actuais difiren amplamente dos tradicionais



Catro variedades con Denominación de Orixe Protexida, unha produción aproximada de 5,5 millóns de quilos ao ano e un valor bruto duns 15 millóns de euros. Estas son as cifras dos queixos galegos (Arzúa-Ulloa, Tetilla, San Simón da Costa e Cebreiro), produtos hoxe en día fabricados maioritariamente de xeito industrial ou semi-industrial que pouco teñen que ver nos seus perfís sensoriais cos que se elaboraban de forma artesanal con leite cru, algún deles incluso en perigo de desaparición. Unha idea que expoñen e argumentan os profesores da Universidade de Vigo Juan Antonio Centeno e Francisco Javier Carballo e os investigadores do Centro de Investigacións Agrarias de Mabegondo (CIAM) Patricia Rodríguez e José Ignacio Garabal, que recollen as diferenzas entre ambos tipos de producións na monografía Os queixos galegos: perfís sensoriais dos queixos artesanais tradicionais e dos queixos industriais actuais.

A publicación compendia a análise descritiva dos perfís sensoriais dos queixos industriais actuais destas catro variedades en función de datos tomados dos regulamentos das diferentes Denominacións de Orixe e de estudos posteriores a 1995, así como as características organolépticas (perceptibles a través dos sentidos) dos produtos tradicionais obtidas de traballos publicados ata 1990 e da realización de catas de 60 queixos de leite cru entre os anos 2004 e 2007 no CIAM.

A clave está no leite

Os investigadores atribúen a diferenza de aromas e sabores entre ambos tipos de producións basicamente ao leite e aos seus tratamentos. Por un lado, o leite actual é diferente na súa composición do que se empregaba tradicionalmente, procedente na súa meirande parte de vacas da raza rubia galega “alimentadas e manexadas de maneira máis extensiva, con menor aporte de concentrados”.

Por outra banda, a aplicación dun “muxido en condicións hixiénicas estritas e a conservación polo frío” fan que o leite actual destinado a queixería teña unha carga microbiana moi por debaixo da de hai 20-30 anos, cando no leite había “un maior contido en bacterias lácticas e outros microorganismos beneficiosos para a calidade sensorial do queixo”. Adicionalmente, a entrada en escena do proceso de pasteurización “destrúe os poucos microorganismos beneficiosos para a calidade sensorial do queixo que poida conter o leite, e inactiva a enzima lipoproteín lipasa que degrada as graxas orixinando diferentes sustancias aromáticas”, comenta o profesor Juan Antonio Centeno.

Se a estas modificacións se lle engade o emprego de fermentos microbianos ou cultivos iniciadores comerciais inespecíficos, o resultado é un queixo que non ten o sabor e aroma típicos ou tradicionais. “Estes fermentos, responsables da formación de aromas non diferenciados, como manteiga, froitos secos… proceden doutras producións de países do norte de Europa, non son autóctonos, conferíndolle aos produtos características sensorias propias de queixos como por exemplo os Gouda ou os Edam holandeses”, salienta o investigador.

A solución: recuperar e empregar cepas de microorganismos autóctonos

Para paliar esta perda de tipicidade, os investigadores propoñen dúas medidas concretas. Por unha banda, fabricar os queixos con leite cru, sen tratamento térmico; pola outra, empregar cultivos específicos tanto iniciadores como adxuntos de microorganismos autóctonos “previamente illados de queixos tradicionais e seleccionados mediante ensaios de laboratorio e como resultado de elaboracións experimentais en planta piloto”.

Trataríase de potenciar a recuperación e o emprego de cepas microbianas autóctonas, garantindo unha maior singularidade e diferenciación dos queixos. Os Laboratorios de Tecnoloxía de Produtos Lácteos do CIAM, na actualidade sen dotación de persoal, e de Tecnoloxía de Alimentos da Universidade de Vigo dispoñen de microorganismos autóctonos que foron ensaiados con éxito en elaboracións experimentais de queixos Arzúa-Ulloa, Tetilla e Cebreiro, tendo igualmente illado nos últimos anos novos microorganismos de interese tecnolóxico.

Sen embargo, e a pesar de que os Consellos Reguladores das Denominacións de Orixe amosaron o seu interese na protección destes microorganismos con vistas á preparación de cultivos iniciadores e adxuntos específicos para empregar a nivel industrial ou semi-industrial, aínda non se ten financiado e desenvolvido ningún proxecto con esta finalidade. Motivos? “Podemos pensar inicialmente en dous: a imposición dun estrito sentido comercial, debido ao escaso volume de negocio que xera a venda de fermentos para queixería, especialmente para denominacións cunha produción reducida como San Simón da Costa ou Cebreiro; e a probable diminución da produción e o previsible aumento da demanda de leite nos vindeiros anos como materia prima para a fabricación de produtos lácteos estandarizados e ben situados nos mercados”, conclúe Centeno.

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