EFFECT OF CARBON DIOXIDE (CO2) USE IN THE MICROSTRUCTURE OF MINAS FRESCAL AND MINAS PADRÃO CHEESES

Abstract

The preacidification of cheese milk with CO₂ can brings technological and economics benefits. Unlike other acids, great part of the carbonic acid formed by the CO₂ solubilization is lost during the cheese-making, which can prevent functional and technological cheese problems. The objective of this work was to evaluate the effects of industrial use of dissolved CO₂, in pasteurized cheese milk, in the microstructure of Minas Frescal and Minas Padrão cheeses. The experiments were carried out with two methods of incorporating CO₂ into pasteurized cheese milk: CO₂ injection, under pressure in the milk at 32°C until to reach pH 6.30 and addition of 5% of carbonated water to the cheese milk in the cheese vat, besides the control treatment. Microscopic analyses were performed by scanning electron microscopy (SEM) of cheeses subjected to different treatments at 7 and 29 days of storage. Under the conditions employed in the experiment and the results, we can conclude that the Minas Frescal and Minas Padrão cheeses treated with CO₂ injection presented visually the more compact and more porous microstructure in comparison to other treatments. This behavior was attributed to the decrease in pH that provided the formation of protein matrix composed of smaller sizes casein molecules, interfering with the interactions between the caseins and favoring the formation of a highly porous and compact protein structure.