resumo
Chitosan has been studied as a renewable polymer to form edible films allowing the incorporation of functional compounds. The aim of this work was to evaluate the effects in the chitosan films properties of the incorporation of grape pomace extracts: 0.15% of hot water extract (mainly polysaccharides), 0.15 and 0.3% of chloroform extract (wax), and 0.3 and 0.75% of n-hexane extract (oil). The evaluation of the surface morphology revealed that the films with the aqueous extract had the most homogeneous and smoother topography. The incorporation of higher proportion of wax and oil led to changes in mechanical properties of the films, namely lower resistance and stiffness. The chitosan-based films with 0.75% oil demonstrated a 75% decrease of solubility in water, due to their hydrophobicity, as confirmed by the contact angle and surface free energy measurements. The hydrophobic films showed higher antioxidant capacity in organic medium (ABTS and DPPH assays) whereas the most hydrophilic films showed an improvement in FRAP and reducing power assays. Therefore, all the chitosan-based films prepared by incorporation of these grape pomace extracts are promising for food shelf life extension. (C) 2014 Elsevier Ltd. All rights reserved.
palavras-chave
ANTIOXIDANT ACTIVITY; MOLECULAR-WEIGHT; ESSENTIAL OIL; PHYSICOCHEMICAL CHARACTERIZATION; ANTIMICROBIAL PROPERTIES; MECHANICAL-PROPERTIES; FOOD APPLICATIONS; COMPOSITE FILMS; SEED EXTRACT; FATTY-ACIDS
categoria
Chemistry; Polymer Science
autores
Ferreira, AS; Nunes, C; Castro, A; Ferreira, P; Coimbra, MA
nossos autores
Alichandra Maria Gonçalves Castro
Estudante de doutoramento
Cláudia Nunes
Investigador Auxiliar
Paula Celeste da Silva Ferreira
Investigador CoordenadorGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G4 - Materiais Renováveis e Economia Circular
agradecimentos
Thanks are due to Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), European Union, QREN, FEDER, and COMPETE for funding the QOPNA research unit (project PEst-C/QUI/UI0062/2013; FCOMP-01-0124-FEDER-037296), CICECO (Pest-C/CTM/LA0011/2013; FCOMP-01-0124-FEDER-037271), and FCT project (PTDC/AGR-ALI/101251/2008). C. Nunes, A. Castro and P. Ferreira thank FCT for the Post-Doctoral fellowship SFRH/BPD/46584/2008, Doctoral fellowship SFRH/BD/67121/2009, and research position IF/00327/2013, respectively. The authors also thank Dao Sul-Sociedade Vitivinicola S.A (Carregal do Sal, Portugal) for providing the grape pomace.