RESUMO
The ultrafine fibers were produced using a polymeric blend of soy protein isolate (SPI), polyethylene oxide (PEO), and zein at a ratio of 1:1:1 (v/v/v) by electrospinning. The ginger essential oil (GEO) was encapsulated in the ultrafine fibers and the morphology, Fourier-Transform Infrared Spectroscopy (FTIR) analysis, thermal properties and relative crystallinity were evaluated. The antimicrobial activity of ginger essential oil was evaluated against five bacteria (Listeria monocytogenes, Staphylococcus aureus, Escherichia coli 0157:H7, Salmonella typhimurium, and Pseudomonas aeruginosa). Based on the preliminary tests, the concentration of GEO selected to add in the polymer solution was 12% (v/v; GEO/polymer solution). The fiber produced with 12% (v/v) GEO was used for antimicrobial analysis and in situ application (in fresh Minas cheese) against L. monocytogenes by micro-atmosphere. The ultrafine fibers produced, regardless the concentration of the essential oil, presented homogeneous morphology with cylindrical shape without the presence of beads. The application of the active fibers containing 12% GEO showed high potential to be applied in food packaging to reduce microbial contamination.
Assuntos
Microbiologia de Alimentos , Listeria monocytogenes/efeitos dos fármacos , Óleos Voláteis/química , Zingiber officinale/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Contagem de Colônia Microbiana , Escherichia coli/efeitos dos fármacos , Escherichia coli/patogenicidade , Embalagem de Alimentos , Humanos , Listeria monocytogenes/patogenicidade , Óleos Voláteis/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/patogenicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidadeRESUMO
The aim of this study was to produce and characterize inclusion complexes (IC) between ß-cyclodextrin (ß-CD) and orange essential oil (OEO) or eucalyptus essential oil (EEO), and to compare these with their pure compounds and physical mixtures. The samples were evaluated by chemical composition, morphology, thermal stability, and volatile compounds by static headspace-gas chromatography (SH-GC). Comparing the free essential oil and physical mixture with the inclusion complex, of both essential oils (OEO and EEO), it was observed differences occurred in the chemical composition, thermal stability, and morphology. These differences show that there was the formation of the inclusion complex and demonstrate the necessity of the precipitation method used to guarantee the interaction between ß-CD and essential oils. The slow loss of the volatile compounds from both essential oils, when complexed with ß-CD, showed a higher stability when compared with their physical mixtures and free essential oils. Therefore, the results showed that the chemical composition, molecular size, and structure of the essential oils influence the characteristics of the inclusion complexes. The application of the ß-CD in the formation of inclusion complexes with essential oils can expand the potential applications in foods.
Assuntos
Eucalyptus/química , Óleos Voláteis/química , Óleos de Plantas/química , beta-Ciclodextrinas/química , Cromatografia Gasosa , Citrus sinensis/química , Estabilidade de Medicamentos , Aromatizantes/análise , Frutas/química , Temperatura Alta , Compostos Orgânicos Voláteis/análiseRESUMO
BACKGROUND: Biodegradable films of native or acetylated starches with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. RESULT: The tensile strength of the acetylated starch film was lower than those of the native starch film, without fibers. The addition of fibers increased the tensile strength and decreased the elongation and the moisture of native and acetylated starches films. The acetylated starch film showed higher water solubility when compared to native starch film. The addition of cellulose fibers reduced the water solubility of the acetylated starch film. The films reinforced with cellulose fiber exhibited a higher initial decomposition temperature and thermal stability. CONCLUSION: The mechanical, barrier, solubility, and thermal properties are factors which direct the type of the film application in packaging for food products. The films elaborated with acetylated starches of low degree of substitution were not effective in a reduction of the water vapor permeability. The addition of the cellulose fiber in acetylated and native starches films can contribute to the development of more resistant films to be applied in food systems that need to maintain their integrity. © 2016 Society of Chemical Industry.