Effects of fungal growth on the firmness of a cheese analogue formulated with different casein-to-fat ratios

The growth rates of nine fungal species inoculated on a cheese analogue formulated with different casein-to-fat ratios (0.6, 0.8, 1.0 and 1.2) and incubated at 10 and 20 °C was evaluated. The species belonged to the genera Penicillium, Aspergillus, Mucor and Cladosporium. It was found that, in general, the species tended to grow faster at 20 °C, and at casein-to-fat ratios of 1.0 and 1.2. In order to determine the impact of fungal presence on loss in firmness, the texture of cheese analogues was analyzed with a penetrometer ball probe. When incubation was done at 20 °C, loss in firmness was higher (17.56-64.85%) than at 10 °C (11.12-58.03%), but it was not affected by the casein-to fat ratio. The species differed on their ability to reduce the firmness of the cheese analogues, although this was not strictly correlated with their growth rate. Thus, our results indicate that whereas fungal growth in cheese is affected by temperature and casein-to-fat ratio, the amount of visible mycelium on the rind would not be a good parameter to predict the extent of textural modifications, which would be mostly influenced by the temperature of ripening and the species involved.