Desenvolvimento de biofilmes poliméricos de carboximetilcelulose e extrativo do bagaço de uva, para a pulverização em cultura de maçã e proteção contra a radiação UV

Abstract

Wineries generate a large amount of solid waste, 45% of which is mainly made up of grape pomace. Studies have shown that this pomace has a significant number of phenolic compounds and antioxidants such as anthocyanins, flavonols, phenolic acids and resveratrol. In addition to their bioactive potential, these compounds have a great ability to absorb UV rays that are harmful to fruit peel and can burn them, especially in warmer regions, which have a higher incidence of sunlight. In this work, solutions, and films of the biopolymer carboxymethylcellulose (CMC) were developed with and without the addition of Vitis vinifera grape pomace extract for application on apple peels to protect against UV rays. The films and solutions were characterized using analytical techniques such as FTIR, UV-vis, contact angle and surface tension. The extractive FTIR spectrum showed the presence of –OH (3500-3200 cm-1) and C=C groups of aromatic rings (1700-1500 and 667 cm-1) evidencing the presence of polyphenols. The UV-Vis spectroscopy showed that, with the increase in thickness of the films, there was an increase in absorbance, thus, it can be inferred that higher concentrations of extractive in the biopolymer solutions can better protect apples. The analysis of contact angle of CMC 0.5% (72.0°) and CMC + Extractive (71.4°) solutions, it is observed that their value is lower than that shown by pure water (73.8°), which shows that solutions present good wettability on apples, which is further improved with addition of sodium dodecyl sulfate (DSD) surfactant, since this angle is even smaller in CMC + Extractive + DSD solution (68.5°) which contains this additive.