Estudio de las propiedades fisicoquímicas y biológicas de microencapsulados de compuestos bioactivos de Neem en matrices de quitosano
The development of edible coatings based on biopolymers has been applied for resh fruit and vegetable products, therefore it is of great interest on the quest of materials with null toxicity, biodegradable and biocompatible, whose objective is increasing the storage life preserving the quality chara...
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| Formato: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | México |
| Recursos: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:z316q162x |
| Acesso em linha: | https://doi.org/10.24275/uami.z316q162x |
| Access Level: | acceso abierto |
| Palavra-chave: | info:eu-repo/classification/LEM/Chitosan info:eu-repo/classification/LEM/Emulsions info:eu-repo/classification/LEM/Quitosano info:eu-repo/classification/LEM/Emulsiones info:eu-repo/classification/cti/6 |
| Resumo: | The development of edible coatings based on biopolymers has been applied for resh fruit and vegetable products, therefore it is of great interest on the quest of materials with null toxicity, biodegradable and biocompatible, whose objective is increasing the storage life preserving the quality characteristics. In this regard, Chitosan (CS) is a linear heteropolysaccharide derived from chitin Ndeacetylation with antimicrobial properties that has been widely used. Therefore, in this study the application of coatings based on CS was studied to maintain quality of postharvest pitaya (Stenocereus pruinosus). S. pruinosus is an endemic fruit of Mexico and it has high nutritional value for the consumers because they reduce the chances of heart attacks and cancer, however, the main problem is its perishability with a postharvest life of only 3 days at room temperature hence it is only locally distributed. For this reason, the aim of this study was the preparation, characterization and application of coatings to extend postharvest life of pitaya. The neem (NM) extract of leaf and seed from Neem tree has been used as a biopesticide, herein NM was combined with CS and other biopolymers to improve antimicrobial characteristics of coatings. The experimental work was divided into three stages. Initially, NE and CS were obtained and characterized. NM was obtained from the leaves and seeds and compared with a commercial product, while CS was prepared by thermochemical heterogeneous deacetylation from chitin extracted with a lactic acid fermentation. The second stage consisted of the formulation of the encapsulated matrices that were cross-linked with hydroxypropyl methylcellulose (CH), and C mixed with Mezquite gum (CGM) that encapsulated commercial NM, these were obtained by oil in water emulsions. NCGM (emulsion NM-CS-GM) was the most stable emulsion, however when these coatings were applied on pitaya, only NCH (NM-CH) preserved the fruit quality for 15 days at a temperature of 10±5°C and 80±5% relative humidity. In the third stage, a mixture of leaf NM and commercial NM was also encapsulated in a matrix of C grafted with 2-hydroxyethylmethacrylate (Cg) by Pickering emulsion, which were characterized after being stabilized by chitin nanofibers as solid particles in nanoscale. The most stable emulsion could not preserve the characteristics of the fruit quality, but Cg extended 18 days at temperature of 10±5 °C and 80±5% relative humidity the postharvest life of pitaya. A plausible explanation is the presence of 2- hydroxyethylmethacrylate that can absorb water and form gels preventing water migration of water avoiding desiccation and microbial contamination. |
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