Composite films with UV barrier capacity to minimize flavored waters degradation

Abstract

Secondary packages for commercial flavored waters were developed from composite films to reduce beverage UV degradation. Bottle packs of orange and grapefruit flavored waters (OFW and GFW), were wrapped with films based on high density polyethylene, poly(styrene-b-butadiene-b-styrene), and thermoplastic corn starch (0 and 5% w/w bentonite). A commercial protective film (CPF) was employed as reference. Packs were placed in a UV chamber, and the effect of radiation on beverages was evaluated by colorimetry, UV–vis spectroscopy, vitamin C content (VCC), and total phenolic compounds (TPC). Wrapping films minimized OFW color variation, being this effect more evident employing composite films and comparable to CPF. Use of composite materials as secondary packages reduced the oxidative degradation of natural juices compounds, which is the main responsible of the changes observed by UV–vis spectroscopy. VCC in both flavored waters was too low, therefore after 6 days UV irradiation it could not be detected. Regarding TPC, no protective effect of all studied films was evidenced. Composite films containing 5% w/w bentonite increased UV barrier capacity of studied matrices, being the protective effect more efficient than the corresponding to CPF.