Produção de fibras ultrafinas de zeína incorporadas com complexo de inclusão de β-ciclodextrina e óleo essencial de eucalipto (Eucalyptus citriodora) com atividade antimicrobiana, pela técnica de Electrospinning

摘要

Microbial control is a constant concern in the food packaging industry. Activepackaging is capable of inhibiting microbial growth in food. In addition, the use ofbiodegradable polymers has been extensively studied. Zein is a biodegradablepolymer that has great potential in the packaging industry and can encapsulatebioactive compounds in its polymer matrix. Essential oils (EO) are naturally occurringbioactive compounds due to the secondary metabolism of some plants and havebeen studied as antimicrobial agents in active packaging. However, complexationwith some molecule is necessary in order to reduce some undesirablecharacteristics, such as high volatility. Cyclodextrins are cone-shaped moleculescapable of accommodating apolar molecules such as essential oils. An effectivetechnology capable of incorporating bioactive compounds into nanomaterials is theelectrospinning technique. The objective of this study was to produce ultrafine zeinfibers by incorporating an inclusion complex (IC) between β-Cyclodextrin (β-CD) andeucalyptus essential oil (EO) through the electrospinning technique in order toAntimicrobial membranes as active food packaging. The EEO was characterized bythe chemical composition and antimicrobial activity against 7 bacteria of importancein food. CI was evaluated for functional groups, morphology and thermal properties.Polymer solutions of pure zein at different concentrations were evaluated forapparent viscosity and electrical conductivity and the resulting membranes after theelectrospinning process were evaluated for morphology and diameter distribution.The 30% (w/v) zein solutions were added with IC at concentrations of 6, 12, 18 and24% (w/v), which were characterized for apparent viscosity and electricalconductivity. After the electrospinning process of IC solutions, these membraneswere evaluated for morphology and diameter distribution, thermal properties,functional groups and micro-atmosphere antimicrobial activity against S. aureus andL. monocytogenes. The results indicated antimicrobial activity of EEO against alltested bacteria. Through the analysis of functional groups and morphology, aneffective complexation of EEO and β-CD can be observed. The fibers obtained with30% (w/v) zein in the polymer solution showed better morphological characteristics.All membranes formed with IC reduced the microbial growth of S. aureus and L.monocytogenes. The concentration of 24% (w/v) IC was obtained with the highestpercentage of growth reduction in micro-atmosphere, with 24.3% and 28.5% for S.aureus and L. monocytogenes, respectively. The antimicrobial membranes showedcharacteristics for possible application as active food packaging.