Preparação e caracterização de filmes de PEBD aditivados com fotoestabilizantes para a proteção de espumantes rose

Abstract

Rosé sparkling wine is a product derived from red and/or white grapes, which after being fermented and elaborated is stored in colorless glass bottles. Colorless bottles are useful to store rosé type sparkling wines because they allow the consumer to see the product, but the disadvantage is that the wine may begin to photo-oxidize causing changes in the organoleptic characteristics, especially color, and thus changes in taste. Change in the stability of the rose sparkling wine color is directly related to exposure to light. The use of light stabilizing additives in polymers, especially in low density polyethylene (LDPE) has proved an alternative to improve the protection of product packaging. Ultraviolet absorbers (AUV) and Hindered Amine Light Stabilizer (HALS) were tested alone or combined, in LDPE films, to avoid UV radiation absorption by the rosé sparkling wine. In this study, extruded LDPE films with different percentages of UV absorber (AUV) and two types of HALS (HALS1 and HALS2) were studied to protect rosé sparkling wines. The test of exposure to degradation (film and sparkling wine) was performed in a UVB accelerated aging chamber for periods of 0, 72, 168, 264, 360 and 912 h. To characterize the film and sparkling wine samples, the chemical, thermal and physical properties were evaluated with the help of techniques such as UV-Vis spectroscopy (UV-Vis), infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and water contact angle (WCA). UV-Vis analyses showed a higher consumption and loss of additive during the period of exposure polyethylene additivated only with AUV. FTIR showed the formation of carbonyl and vinylic groups in the sample of pure LDPE additivated with AUV (PEA); DSC was used to obtain lower degrees of crystallinity (Xc) for samples additivated with individually tested light stabilizers, which suggests that the additive influences the molecular structure of the polymer; and WCA analysis analyzed surfaces hydrophobic for LDPE and films containing AUV, after periods of exposure and hydrophile surfaces in the polyethylene films with higher percentages of additive concentrations. As to rosé sparkling wine, analysis of shade, total polyphenol index (IPT), colorimetric intensity (ICM) and anthocyanin index (IA) allowed the evaluation of the chromatic characteristics of the beverage, showing that among the 3 additives studied, HALS2 presented the smallest loss of red pigments, 48.3%, while LDPE had a loss of 69.8%, and the sample that allowed the best persistence of color in 912 hours of exposure in an accelerated aging chamber UVB was the PEAH2-6 sample with a loss of only 24.6% of the initial color. It may be concluded that the low density polyethylene films light stabilized used can enabled extend its ‘shelf life’ from a period of 6 to approximately 12 months of the rosé sparkling wine, 12 months of sparkling rose that has in its packaging to protect films added with the combination of two different types of light estabilizantes or HALS alone used, being that the use only of AUV is not recommended.