Nanofibras poliméricas para embalagens alimentícias

Abstract

Nanotechnology has been presented as an excellent tool for the food industry, mainly for food packaging, associated with polymeric materials. This study aimed to develop nanomaterials using blowing solution (SBS), for use in food packaging, to extend the shelf life and maintenance of food quality. It was carried out in two stages: (i) the development of a bioactive nanomaterial with potential application in food as a type of active packaging, replacing toluene with orange oil (green solvent); and (ii) the obtainment of nanofibers with halocromic action for media with different pH, aqueous or gaseous levels, through the incorporation of a universal pH indicator. Besides the study of the potential use as a visual quality indicator of acid volatiles in wine. In the first step, the production of polystyrene (PS) nanofibers using orange oil as a substitute for toluene was efficient. The low solvent evaporation rate promoted to the nanofibers a residual orange oil content as identified in the infrared (IR) spectrum and thermogravimetric analysis. The presence of residual oil functionalized the nanomaterial with antimicrobial and antifungal action. In addition to promoting a plasticizing action in the obtainment of the fibers, reducing the glass transition temperature and reducing the mean diameter of the fibers, 306 ± 74 nm (orange oil) and 441 ± 110 nm (toluene). At this point, associated with the low solvent evaporation rate. In the second stage, the incorporation of bromothymol blue (BTB) to the polymer solution of PS did not interfere in the obtainment process of the nanofibers by the SBS technique. In addition, there were no differences in the mean fiber diameter with the indicator, 618 ± 277 nm, in relation to the fibers without BTB, 606 ± 242 nm. Visually, the mats presented color differences related to the indicator encapsulation. This ability promoted the identification of the 1703 cm-1 band in the IR spectrum, indicating the deprotonation of the material obtained with 0.2 wt.% of the indicator. When submitted to the acidic vapors of the wine, the mats presented a visual modification in the coloration from blue to yellow, showing variation in the colorimetric quadrants in the hue from 300° to 82°, respectively. The nanomaterials obtained from this research presented a contribution of technological innovation, aiming the application in active and intelligent food packaging, respectively.