Qualidade de água de coco embalada em filmes de polietileno de baixa densidade linear incorporadas com nanopartículas de prata
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Data
2023-02-13
Autores
Brito, Sabrina da Costa
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Universidade Estadual Paulista (Unesp)
Resumo
Objetivo: Este estudo visou verificar a eficácia antimicrobiana e extensão da vida de prateleira em água de coco condicionada em filmes de polietileno de baixa densidade linear (PEBDL) aditivados com nanopartículas de prata (AgNPs) dispersas no carregador de sílica (SiO2) e hidroxiapatita (HAP), em diferentes concentrações em porcentagem (%) por filme polimérico Metodologia: Na pesquisa foram estudadas três concentrações diferentes de AgNPs (%) (0,2; 0,4 e 0,6) para ambos carregadores em filmes PEBDL, além do filme controle (sem nanopartículas). Tanto os aditivos AgNPs + SiO2 e AgNPs + HAP quanto os filmes caracterizados por: difração de raio X (DRX), espectroscopia no infravermelho com transformada de Fourier (FTIR), microscopia eletrônica de varredura (FEG-SEM), espalhamento dinâmico de luz (DLS), potencial zeta, termogravimetria (TGA) e calorimetria diferencial de varredura (DSC). A ação antimicrobiana foi pesquisada contra os seguintes microrganismos, Gram Positivo: Staphylococcus aureus, Gram Negativo: Escherichia coli e os fungos Penicillium expansum e Fusarium solani; por meio das metodologias de atividade antimicrobiana por contato e imagens bacterianas por microscopia eletrônica de varredura (MEV). Na análise de vida de prateleira de água de coco foram realizados procedimentos físico-química de pH, acidez titulável, sólidos solúveis, cor, turbidez, compostos fenólicos, açucares redutores e não redutores e minerais, e análises microbiológicas em psicrotróficos, bolores e leveduras enterobactérias e Salmonella spp. Resultados: A adição de AgNPs na matriz do PEBDL não interferiu nas propriedades químicas e térmicas dos filmes e não houve migração significante de prata para o meio externo. Em relação a atividade antimicrobiana, foi observado que a maioria das concentrações realizaram uma inibição maior de 90% em todos os microrganismos estudados, independente do carregador, entretanto uma maior ação antimicrobiana foi para bactéria Gram positiva do para que a Gram negativa e entre os carregadores, a HAP a foi mais efetiva. Com relação ao envase da água de coco em embalagens com nanotecnologia, verificou-se que, independentemente do carregador houve maior manutenção das características físico-química ao longo do período de armazenamento, correlacionando o resultado a redução da carga microbiana do produto em embalagem com AgNPs. Conclusão: Os resultados desta pesquisa demostraram que as embalagens com nanopartículas de prata, independente do carregador, e, mesmo em baixas concentrações são efetivas na manutenção e otimização da qualidade físico-química e microbiológicas da água de coco armazenada sob refrigeração acima de 5°C e em um período superior a 30 dias.
Objective: This study aimed to verify the antimicrobial efficacy and extension of shelf life in coconut water conditioned in linear low density polyethylene (LLDPE) films added with silver nanoparticles (AgNPs) dispersed in the silica carrier (SiO2) and hydroxyapatite (HAP), at different concentrations in percentage (%) per polymeric film Methodology: In the research, three different concentrations of AgNPs (%) (0.2; 0.4 and 0.6) were studied for both carriers in LLDPE films, in addition to the control film (without nanoparticles) . Both the AgNPs + SiO2 and AgNPs + HAP additives and the films characterized by: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (FEG-SEM), dynamic light scattering (DLS), zeta potential, thermogravimetry (TGA) and differential scanning calorimetry (DSC). The antimicrobial action was investigated against the following microorganisms, Gram Positive: Staphylococcus aureus, Gram Negative: Escherichia coli and the fungi Penicillium expansum and Fusarium solani; through the methodologies of antimicrobial activity by contact and bacterial images by scanning electron microscopy (SEM). In the analysis of the shelf life of coconut water, physical-chemical procedures of pH, titratable acidity, soluble solids, color, turbidity, phenolic compounds, reducing and non-reducing sugars and minerals, and microbiological analyzes on psychrotrophs, molds and enterobacterial yeasts were carried out and Salmonella spp. Results: The addition of AgNPs to the LLDPE matrix did not interfere with the chemical and thermal properties of the films and there was no significant silver migration to the external environment. Regarding antimicrobial activity, it was observed that most concentrations performed a greater than 90% inhibition in all microorganisms studied, regardless of the carrier, however a greater antimicrobial action was on Gram positive bacteria than Gram negative and between carriers, PAH was more effective. Regarding the bottling of coconut water in nanotechnology packages, it was verified that, regardless of the carrier, there was a greater maintenance of the physicochemical characteristics of this product throughout the storage period, correlating this result with the reduction of the microbial load of coconut water in packaging with AgNPs. Conclusion: The results of this research showed that packages with silver nanoparticles, regardless of the carrier and in low concentrations, are effective in maintaining and optimizing the physical-chemical and microbiological quality of water stored under refrigeration above 5°C and in a period longer than 30 days.
Objective: This study aimed to verify the antimicrobial efficacy and extension of shelf life in coconut water conditioned in linear low density polyethylene (LLDPE) films added with silver nanoparticles (AgNPs) dispersed in the silica carrier (SiO2) and hydroxyapatite (HAP), at different concentrations in percentage (%) per polymeric film Methodology: In the research, three different concentrations of AgNPs (%) (0.2; 0.4 and 0.6) were studied for both carriers in LLDPE films, in addition to the control film (without nanoparticles) . Both the AgNPs + SiO2 and AgNPs + HAP additives and the films characterized by: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (FEG-SEM), dynamic light scattering (DLS), zeta potential, thermogravimetry (TGA) and differential scanning calorimetry (DSC). The antimicrobial action was investigated against the following microorganisms, Gram Positive: Staphylococcus aureus, Gram Negative: Escherichia coli and the fungi Penicillium expansum and Fusarium solani; through the methodologies of antimicrobial activity by contact and bacterial images by scanning electron microscopy (SEM). In the analysis of the shelf life of coconut water, physical-chemical procedures of pH, titratable acidity, soluble solids, color, turbidity, phenolic compounds, reducing and non-reducing sugars and minerals, and microbiological analyzes on psychrotrophs, molds and enterobacterial yeasts were carried out and Salmonella spp. Results: The addition of AgNPs to the LLDPE matrix did not interfere with the chemical and thermal properties of the films and there was no significant silver migration to the external environment. Regarding antimicrobial activity, it was observed that most concentrations performed a greater than 90% inhibition in all microorganisms studied, regardless of the carrier, however a greater antimicrobial action was on Gram positive bacteria than Gram negative and between carriers, PAH was more effective. Regarding the bottling of coconut water in nanotechnology packages, it was verified that, regardless of the carrier, there was a greater maintenance of the physicochemical characteristics of this product throughout the storage period, correlating this result with the reduction of the microbial load of coconut water in packaging with AgNPs. Conclusion: The results of this research showed that packages with silver nanoparticles, regardless of the carrier and in low concentrations, are effective in maintaining and optimizing the physical-chemical and microbiological quality of water stored under refrigeration above 5°C and in a period longer than 30 days.
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nanotecnologia, nanopartículas de prata, antimicrobianas, embalagens ativas