2. Universidad Cardenal Herrera-CEU

During the processing of dry-cured meat products, sarcoplasmic and myofibrillar proteins undergo proteolysis, which has a marked effect on product flavor. Microbial proteolytic activity is due to the action of mostly lactic acid bacteria (LAB) and to a lesser extent micrococci. The proteolytic capacity of molds in various meat products is of interest to meat processors in the Mediterranean area. Eleven LAB and mold strains from different commercial origins were tested for proteolytic activity against pork myosin, with a view to possible use of these strains as starter cultures for Iberian dry-cured ham. Proteolytic activity was tested by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The LAB strains with the highest proteolytic activity were Lactobacillus plantarum (L115), Pediococcus pentosaceus (Saga P TM), and Lactobacillus acidophilus (FARGO 606 TM). The best fungal candidate was Penicillium nalgiovense LEM 50I followed by Penicillium digitatum, Debaryomyces hansenii, and Penicillium chrysogenum.

The behaviour of two combined starter cultures and their influence on the microbiological and physicochemical characteristics of dry-cured ham have been evaluated. Three lots of dry-cured hams were tested during processing (0, 9, 48, 74, 112, 142, 166 and 211 days). Lot 1 had no added starter culture. Lot 2 contained a starter culture of Penicillium chrysogenum, Penicillium digitatum, Penicillium nalgiovense, Debaryomyces hansenii, Lactobacillus plantarum, Lactobacillus acidophilus, Pediococcus pentosaceus and Micrococcus varians was and lot 3 had L. plantarum, L. acidophilus, P. pentosaceus and M. varians. The use of a selected starter culture based on a combination of lactic acid bacteria (LAB) and fungal strains with a demonstrated proteolytic activity such as P. chrysogenum and D. hansenii (lot 2) did not affect the main characteristics of dry-cured ham processing, even enhancing some desirable aspects, like its non-protein nitrogen contents. LAB strains were not significantly affected by combining them with fungal starter, and better counts were found with respect to control. A higher thiobarbituric acid reactive substances content was described in lot inoculated only with LAB (lot 3). Potentially pathogenic microorganisms were not detected in any of the lots studied. The starter culture used in lot 2 showed a potential interest for use in dry-cured ham production.