Aplicação de filmes de TPS/PBAT produzidos por extrusão reativa contendo antioxidantes naturais na conservação de castanha-do-pará

Abstract

Lipids are components found in foods and are chemically unstable as they are susceptible to oxidation reactions that cause food to taste rancid. The addition of natural antioxidants such as curcumin can prevent these reactions and reduce the risk of potential migration toxicity. The cooking water from the pine nuts also revealed significant antioxidant potential. Its direct addition to food can lead to sensory changes, which has directed research towards adding such compounds in polymeric food packaging. Thermoplastic starch (TPS) is a biodegradable polymer produced by converting native starch under heat and shear in the presence of plasticizers. When compared to common thermoplastic polymers, TPS has disadvantages that can be overcome by adding other synthetic polymers to produce packaging compatible with conventional plastic packaging. The blend of TPS and poly (butylene adipatecoterephthalate) (PBAT) is the most economically competitive. In the present work, Brazil nuts were packaged in TPS/PBAT films containing natural antioxidants (curcumin and pine nuts cooking water). The types of packaging used were: CN (control packaging without antioxidant), CCS (packaging with 0.5% w/w water-soluble curcumin) and CP (packaging with 0.5% w/w jatropha extract). The packages were conditioned at 10, 25 and 50 ºC and how they were collected at times 0, 5, 10, 15 and 30 days. Nut oil was extracted for the assessment of oxidative stability through principal component analysis (PCA). Two principal components (PCs) were able to explain more than 82% of the variation in the fusion matrix (57.8% in PC1 and 24.9% in PC2). Those along PC1 were far from day 0, but those packed in CN and CP dissipated from each other. In the region of scores along PC2 it is possible to observe that there is also a similar behavior between those packaged in CN and CP films. Analyzing the loadings of PC1 and PC2, it is assumed that the separation of scores is due to spectral domains located around 200-270 nm. Absorption in the UV-Vis region in the range of 200 to 230 nm can be conferred to primary oxidation products. It is also related to tocopherol absorption from 220 to 300 nm. The PCA achievements results that crushed nuts can be packaged in TPS/PBAT films containing the cooking water of the pine nuts and stored under 10°C. Nuts that have been packaged in films containing curcumin as an antioxidant compound can be stored at higher temperatures of up to 25ºC.