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Evaluation of proteolytic activity of micro-organisms isolated from dry cured ham
M Rodríguez1, F Núñez, J J Córdoba
1Higiene y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad de Extremadura, Cáceres, Spain. marrodri@unex.es
Abstract:
In order to determine the possible contribution of micro-organisms to the ripening of meat products, 48 cocci, 18 moulds and 20 yeasts isolated from dry-cured Iberian ham were evaluated for proteolytic activity. Two specific methods were used: the ability to hydrolyse myosin in broth and, for those strains showing high activities, hydrolysis on both myofibrillar and sarcoplasmic proteins on pork slices. Moulds and cocci showed the highest proteolytic activity for myosin in broth. Both myofibrillar and sarcoplasmic proteins were recovered at lower rates from inoculated than from sterile incubated pork. The deepest changes in myofibrillar and sarcoplasmic proteins were originated by one strain each of Penicillium chrysogenum and Staphylococcus xylosus, respectively. Only small changes were observed in the concentrations of free amino acids from inoculated pork slices, except for the samples with P. chrysogenum, where there were increases in all free amino acids. Thus, P. chrysogenum makes a significant contribution to proteolysis during the ripening of dry-cured meat products.
Insights
Micro-organisms contribute to dry-cured meat ripening. Penicillium chrysogenum significantly enhances proteolysis by increasing free amino acids in Iberian ham during ripening.
Area of Science:
- Food Microbiology
- Meat Science
- Biochemistry
Background:
- Microbial activity is crucial for the complex biochemical changes during meat product ripening.
- Understanding the specific roles of different microorganisms, including cocci, molds, and yeasts, is key to optimizing dry-cured meat quality.
Purpose of the Study:
- To evaluate the proteolytic activity of microorganisms isolated from dry-cured Iberian ham.
- To determine the contribution of specific microbial strains to protein hydrolysis during meat ripening.
Main Methods:
- Isolated 48 cocci, 18 molds, and 20 yeasts from dry-cured Iberian ham.
- Assessed proteolytic activity using myosin hydrolysis in broth and protein hydrolysis on pork slices.
- Analyzed changes in myofibrillar, sarcoplasmic, and free amino acid content.
Main Results:
- Molds and cocci exhibited the highest myosin hydrolysis activity in broth.
- Inoculated pork slices showed lower recovery rates of myofibrillar and sarcoplasmic proteins compared to sterile controls.
- Penicillium chrysogenum and Staphylococcus xylosus demonstrated significant protein degradation.
- P. chrysogenum inoculation led to increased free amino acids.
Conclusions:
- Penicillium chrysogenum significantly contributes to proteolysis in dry-cured meat products.
- Specific microbial strains play distinct roles in the complex ripening process of dry-cured Iberian ham.