Mechanical properties have been widely correlated with textural characteristics to determine the interactions during the process formation of dairy gel. These interactions are strongly affected by process conditions and system composition. In the present study, the rheological of acid-induced protein dairy gels with (2(7-3)) and without (2(6-2)) sucrose and subjected to small and large deformations were studied using an experimental design. The independent variables were the sodium caseinate, whey protein concentrate (WPC), carrageenan and sucrose concentrations as well as stirring speed and heat treatment time and temperature. Mechanical deformation tests were performed at 0.1, 1, 5, and 9 mm/s up to 80% of initial height. A heavy dependence of rupture stress on increasing crosshead speed and the formation of harder gels with the addition of sucrose were observed. Moreover the elastic and viscous moduli, obtained by fitting the Maxwell model to stress relaxation data, increased with increasing addition of sucrose. These results can be explained by preferential hydration of the casein with sucrose, causing an induction of casein-polysaccharide and casein-casein interactions.

Carne salgada desidratada é um produto largamente usado no Brasil, como fonte de proteína animal. O principal objetivo deste tipo de processamento é a remoção de água, inicialmente por mudanças de pressão osmótica e, a seguir por secagem, levando a um produto com umidade intermediária, como o charque e o "jerked beef". O processo de desidratação osmótica, pela penetração do sal e saída de água, causa redução nos níveis de atividade de água. Alterações de cor também ocorrem durante o processamento. Neste trabalho, estas duas variáveis são avaliadas, em pedaços de carne submetidos à salga seca e úmida. Os valores de atividade de água iniciais foram reduzidos em ambas as etapas, sendo mais acentuado para salga seca, obtendo ao término desse experimento 0,79 unidades a 10ºC e 0,75 a 20ºC. Os efeitos do sal também alteraram os parâmetros de cor, afetando os valores de L* a* b*, e direta e diferentemente o valor de DE das salgas. O estudo dos parâmetros de cor e da atividade de água é útil para um melhor conhecimento e controle do processo de carne salgada desidratada.

Dehydrated salted meat is a product largely used in Brazil and it is a very important animal protein source. The main objective of this kind of processing is to remove water. Initially by osmotic pressure changes and in a second step, by drying, which results in an intermediate moisture level product. The osmotic dehydration process, with salt uptake and water loss, causes the reduction of the water activity level in beef. Also a change of color occurs during the processing. In this work, these variables were studied in meat pieces submitted to wet and dry salting. The values of water activity were reduced in both treatments, but in dry salting the effect was greater than in wet salting. The value at 10ºC was 0.79 and 20ºC 0.75 after finishing the experiment. The effect of salt into salted meat changed the values L* a* b*, decreased then directly and differently in relation to DE. This study is important to understand and to control the process of salted dehydrated meat production.