Efecto de la mezcla de bacteriocina y extracto acuoso de semilla y cáscara de aguacate ( Persea americana ) en la estabilidad oxidante y microbiana en un sistema modelo de carne
Meat and meat products being foods rich in pro teins and lipids , they are susceptible to microbial decomposition reactions and chemical deterioration , also are ideal culture medium for the growth of pathogenic and spoilage bacteria. Deterioration reactions, such as lipid and protein oxidation occu...
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| Tipo de recurso: | tesis de maestría |
| Estado: | Versión publicada |
| Fecha de publicación: | 2016 |
| País: | México |
| Institución: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:gt54kn05f |
| Acceso en línea: | https://doi.org/10.24275/uami.gt54kn05f |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/LEM/Microbiología de la carne info:eu-repo/classification/LEM/Meat -- Preservation info:eu-repo/classification/LEM/Carne -- Preservación info:eu-repo/classification/LEM/Meat -- Microbiology info:eu-repo/classification/cti/6 |
| Sumario: | Meat and meat products being foods rich in pro teins and lipids , they are susceptible to microbial decomposition reactions and chemical deterioration , also are ideal culture medium for the growth of pathogenic and spoilage bacteria. Deterioration reactions, such as lipid and protein oxidation occurs by the interaction of food with oxygen and / or radicals and by the presence of metallic catalysts such as iron and light. The use of natural antioxidants and antimicrobials represent a good option in the prevention and reduction in the reactions of decompos ition and deterioration. A good source of antioxidants and natural antimicrobial products come from fruits and vegetables, such as peels and seeds, which have low or no added value to industrial level. In this study a strategy involving encapsulation of an extract of avocado peel as antioxidant with nisin, a natural antimicrobial, by the method of complex coacervation and antimicrobial, sensory and oxidant effect was observed to be added in developed ground beef. E xtraction , antioxidant and antimicrobial characterization of aqueous extracts of peel and seed of avocado was studied ; the total polyphenol content, flavonoids, tannins was determined , also the scavenging or sequestering capacity at different radicals and reactiv e oxygen species analyzed . S ome of the compoun ds present in the extracts were identified. The avocado peel extract showed the highest antioxidant capacity and increased free radical scavenging ability due to its content of polyphenols such as procyanidins, epicatechin and other unidentified polyphenol s. Both extracts showed no antimicrobial activity against Listeria innocua, Weissella viridescens, E. coli, Lactobacillus mesenteroides sakei and Leuconosctoc . Subseq uently, the effect of mixing two extracts byproducts avocado and nisin, in different proportions, using techniques ORAC and agar diffusion against Listeria innocua was evaluated in order to find the proportion of the three compounds that maximizes the antioxidant and antimicrobial responses. The peel extract component was responsible for the an tioxidant capacity of a mixture of nisin, seed extract and avocado peel. Extracts of peel and avocado seed, showed a synergistic effect with nisin in the antimicrobial response . The opti m ized mixture was peel extract (60%) and nisin (40%) which present t he maximum of antioxidant and antimicrobial activities. The resulting mixture of peel and nisin (60 and 40% respectively) was encapsulated by the method of complex coacervation, in which the following factors were evaluated: wall system (alginate - collagen and pectin - collagen), incorpo ration of core (in emulsion or not) and drying method (lyophilization and spray drying). In the resulting microcapsules encapsulation efficiency, loading, particle size, morphology and yield were evaluated. Factors that showed relevance in the encapsulation method were drying met hod and the core incorpora tion . High e r efficiency of encapsulation was obtained w ith the microcapsules prepared with spray drying and emulsified core . The final morphology of the microcapsules depends on the drying method employed, and the presen ce or not of an emulsion - core , the core being emulsified which presented a larger microcapsule. The microcapsules ob tained by the system pectin - collagen , emulsified core (nisin and avocado extract shell emulsion) and spray - dried had a higher entrapment efficiency of the compounds of interest. These microcapsules were added to a meat system comprised of ground beef . The presenc e of microcapsules decreased the oxidation of lipids and proteins as well as the total mesophilic , lactic bacteria and enterobacteria . On the other hand , in the sensory evaluation analysis of meat , a discriminative test A non - A was used with consumers , in order t o find differences between ground beef without the addition of preservatives and microcapsules or microcapsule in meat. The result was that consumers perceived the difference between the samples due to differences in the texture and water reten tion during cooking. The microcapsules with avocado peel extract an d nisin , offer a new option on natural preservatives , and could be an alternative to reduce the use of synthetic additives in food. |
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