Effect of selected mould strains on proteolysis in dry fermented sausages

In order to contribute to the knowledge of the actual role played by moulds in the proteolytic process occurring during the ripening of dry fermented sausages, a total of six different species of Penicillium and Mucor genera, previously isolated from Spanish dry fermented sausages and selected because of their proteolytic activity against meat proteins, were inoculated on the surface of dry sausages (manufactured in a local factory) with natural and artificial casings. In all batches, water-soluble nitrogen, non-protein nitrogen, phosphotungstic-acid-soluble nitrogen, free amino acids and total volatile nitrogen were studied. The results indicated that the greater difference between control and inoculated batches corresponded to water-soluble and non-protein nitrogen fractions in those inoculated with Penicillium spp. The batch inoculated with Mucor showed an increase in low-molecular-weight-fractions. The proteolytic processes were more intense in batches prepared with natural casings due to the most intense colonization by moulds. It was concluded that the influence of moulds depends on the mould strain and on the type of casing used.