Proteolytic activity of lactic acid bacteria strains and fungal biota for potential use as starter cultures in dry-cured ham

Palatability and physicochemical properties of sausages prepared via lactic acid fermentation and drying at low temperature

The present study aimed to assess the palatability of sausages undergoing low-temperature fermentation and drying process. Lactobacillus sakei D-1001 or Lactobacillus salivarius A001 were used as starter cultures for fermentation, and the following properties of the sausages were investigated: colony-forming units of lactic acid bacteria; concentrations of lactic acid, protein, peptides, and free amino acids; distribution of protein; composition of free amino acids; and physical properties and taste. Alterations in the composition of proteins, peptides, and free amino acids as well as in various physical properties were caused by fermentation by lactic acid bacteria. A sensory test indicated that the palatability of the fermented sausages was greater than that of the non-fermented sausages, particularly in terms of hardness and juiciness. This was considered to be due to protein degeneration and changes in the physical properties of the sausages as a result of fermentation by lactic acid bacteria. However, the taste of the fermented sausages was sourer than that of the non-fermented sausages, and therefore, inferior. Our study revealed that the palatability of the sausages in terms of hardness and juiciness were increased by low-temperature fermentation by lactic acid bacteria and the drying process.

Behavior and effect of combined starter cultures on microbiological and physicochemical characteristics of dry-cured ham

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.

Recent advances in cured raw ham manufacture

Cured raw hams are a valuable and popular group of meat products. The consumption and international trade have increased during the last years, therefore new technologies to accelerate the production process and to increase product quality and safety are needed. In the current review, an overview of European protected cured raw hams is presented. Furthermore, traditional methods for cured raw ham production together with recent advantages in the techniques for pretreatment (trimming, blade tenderization, and freeze-thawing), curing/salting (tumbling, vacuum impregnation, pulsed pressure, ultrasound, pulsed electric fields, simultaneous thawing/salting), drying/ripening (Quick-Dry-Slice-process, oil drop application, high temperature short time process) and postprocessing (vacuum and modified atmosphere packaging, high hydrostatic pressure, high pressure carbon dioxide, high pressure carbon dioxide with ultrasound) are described. Moreover, application techniques and effects of protective cultures and starter cultures, such as molds, yeasts, coagulase-negative staphylococci and lactic acid bacteria, on cured raw ham quality and safety are reviewed.

Determination of lipolytic and proteolytic activities of mycoflora isolated from dry-cured teruel ham

Fungi play a key role in dry-cured ham production because of their lipolytic and proteolytic activities. In the present study, 74 fungal strains from dry-cured Teruel hams and air chambers were tested for proteolytic and lipolytic activities, with a view to their possible use as starter cultures. Lipolytic activity of fungi was studied against lauric, palmitic, stearic and oleic acids, whereas proteolytic activity was studied against casein and myosin. Of the 74 fungal strains tested, most of them demonstrated lipolytic activity (94.59 %). Lipolytic activity against lauric and oleic acids was stronger than against palmitic and stearic acids. 39 strains (52.70 %) demonstrated proteolytic activity against casein and the 6 highest proteolytic strains were also tested for pork myosin proteolysis. Some strains belonging to Penicillium commune, Penicillium chrysogenum, Penicillium nalgiovense and Cladosporium cladosporioides were selected because of their significant proteolytic and lipolytic activities and could be suitable to use as starters in dry-cured ham.

Lactobacillus sakei CRL1862 improves safety and protein hydrolysis in meat systems

AIMS

The capacity of Lactobacillus sakei CRL1862 to prevent the growth of pathogens and its ability to degrade sarcoplasmic and myofibrillar proteins in pork meat systems was evaluated. In addition, basic safety aspects of Lact. sakei CRL1862 such as production of biogenic amines and antibiotic susceptibility were addressed.

METHODS AND RESULTS

The bacteriocin-producing Lact. sakei CRL1862 showed respectively bactericide and bacteriostatic effect against Listeria monocytogenes and Staphylococcus aureus in beaker sausage assay during 9 days of storage at 22 °C. The hydrolytic effect of Lact. sakei CRL1862 on protein extracts was evaluated by SDS-PAGE and reverse phase HPLC. A more pronounced proteolysis was evidenced in inoculated sarcoplasmic proteins compared with myofibrillar extracts with the generation of predominantly hydrophilic peptides and increase of total free amino acids concentration. Lactobacillus sakei CRL1862 produced neither histamine nor tyrosine and exhibited no resistance to the antibiotics assayed.

CONCLUSIONS

Lactobacillus sakei CRL1862 effectively controlled the growth of L. monocytogenes and Staph. aureus; moreover, it was able to hydrolyse pork meat extracts generating peptides and amino acids, which may improve hygienic and sensorial attributes of fermented meat products.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of an integrated approach to evaluate the major traits of Lact. sakei CRL1862 showed it can be applied as an autochthonous functional starter in meat fermentation.