abstract
- Authors thank to CNPq (Chamada Universal– MCTI/CNPq Nº 14/ 2014, Processo 447768/2014-0), CAPES (Master's scholarship) and Fundação Araucária (Programa Universal/Pesquisa Básica e Aplicada 24/2012, protocolo 7334133700514041013) for the finantial support. Project POCI-01-0145-FEDER-006984 – Associated Laboratory LSRELCM funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through FCT - Fundação para a Ciência e a Tecnologia and to CIMO (UID/AGR/00690/2013).
- Seeds from Araucaria angustifolia (Bertol.) Kuntze are consumed after cooking and their coats discarded. Both coats and the cooking water present phenolic compounds, which may be used to improve mechanical properties and provide antioxidant characteristics to films. The objective of this work was to obtain and pinhão coat extracts and to apply these polyphenolic-rich extracts in zein films. Phenolic compounds composition, extraction yield and antioxidant activity (DPPH, ABTS and FRAP) of the extracts were determined. The most abundant molecules present in the hydroethanolic extract were (+)-catechin and an (epi)catechin dimer, whereas protocatechuic acid were predominant in the both cooking water and ethanolic extracts. Glass transition temperature of zein was not found in the extract-loaded films. Morphological changes were also caused by the presence of the extracts yielding smoother surfaces. The extracts added to zein films led to a three-fold increase in tensile strength (from 5.80 MPa to 17.65 MPa) and two-fold increase in the elongation at break (from 1.60% to 3.18%).