Evaluación de la diversidad y dinámica bacteriana del chorizo tipo español durante su proceso de maduración, mediante DGGE y secuenciación masiva
Spanish-type chorizo is ripening meat product that is highly appreciated by consumers for its excellent sensory characteristics. This meat product was analyzed at different ripening stages (0, 10, 20 and 3 days). The proximal analysis was carried out, in addition to the physicochemical properties pH...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | México |
| Institución: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:1j92g751p |
| Acceso en línea: | https://doi.org/10.24275/uami.1j92g751p |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/LEM/Food Typesetting info:eu-repo/classification/LEM/Biotechnology info:eu-repo/classification/LEM/Food Analysis info:eu-repo/classification/LEM/Chorizo tipo español info:eu-repo/classification/LEM/Alimentos info:eu-repo/classification/LEM/Biotecnología info:eu-repo/classification/LEM/Sausages info:eu-repo/classification/LEM/Embutidos info:eu-repo/classification/cti/6 |
| Sumario: | Spanish-type chorizo is ripening meat product that is highly appreciated by consumers for its excellent sensory characteristics. This meat product was analyzed at different ripening stages (0, 10, 20 and 3 days). The proximal analysis was carried out, in addition to the physicochemical properties pH, water activity (aw), total acidity (AT) and malonaldehyde content (MDA). The population of total aerobic mesophilic, lactic acid bacteria (LAB) and enterobacteria were determined by traditional microbiological methods. The colonies isolated during the ripening process were identified by the 16S rRNA gene sequencing; also, their antagonistic (against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Listeria monocytogenes, Lactobacillus curvatus and Pediococcus acidilactici, lipolytic and proteolytic activity were evaluated; as well as their resistance to pH, NaCl, temperature and bile salts, in order to know the biotechnological potential of the identified strains. On the other hand, the diversity and bacterial dynamics associated with the maturation process were analyzed by means of the molecular electrophoresis technique with denaturing gradient gel (DGGE) and by massive sequencing of each of the samples, which was carried out with technology of MiSeq Illumina high-throughput sequencing technology. The proximal chemical analysis showed an increase in the content of ashes, fat and protein, and a decrease in humidity by approximately 50%. The values obtained from the physicochemical parameters analyzed were as expected, in accordance with the commercial stability and microbiological safety of the product. The pH and the aw decreased during the ripening process, while the content of AT and MDA increased significantly in accordance to the quality and characteristics of the meat product. These data are correlated with changes in the bacterial population, a decrease in the CFU of the enterobacteria and an increase in the LAB were observed. Some of the bacteria that were identified by sequencing the 16S rRNA gene were: Lactobacillus sakei, Weissella thailandensis and Pediococcus acidilactici, the latter being the only strain that presented positive antagonistic activity against a greater number of the altered microorganisms tested (Lactobacillus curvatus, Salmonella typhimurium, Staphylococcus aureus y Listeria monocytogenes), and the highest lipolytic and proteolytic activity, which is why it was considered the strain with the greatest biotechnological potential. The diversity obtained by the DGGE technique shows the genera Pseudomonas and Lactobacillus as the most abundant at the beginning and end of the ripening process, respectively, and the strains Pseudomonas fragi, Lactobacillus sakei and Lactobacillus curvatus were identified as the most predominant with this analysis. These two genera are also reported in the metagenomic analysis. However, with the massive sequencing it was possible to visualize in greater detail the changes within the bacterial diversity of each of the analyzed times. Between 679,000 and 868,000 paired sequences were obtained from each ripening stage. The total bacterial diversity in the initial sample was represented by phyla Proteobacteria (44%) and Firmicutes (55%), where Pseudomonas (23%), Streptococcus (21%), Acinetobacter (14%), Bacillus (13%) and Brochothrix (11%) were the most abundant genera, in contrast, Firmicutes phyla increased up to 89%, Lactobacillus and Streptococcus being the most representative genera during the ripening process, and within the possible dominant and subdominant species, Lactobacillus sakei, Streptococcus salivarius, Acinetobacter sp., Bacillus subtilis, Pseudomonas fragi and Lactobacillus curvatus, among others, were identified. |
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