abstract
Rice husks are a low value byproduct, even though it possesses molecules with great potential, such as arabinoxylans, proteins, and silica. These molecules can be used to improve mechanical and physicochemical properties of materials for food packaging. In this work, hydrothermal treatment was used for a sustainable extraction of the valuable molecules present in rice husks. Various extraction temperatures (180, 200, and 220 degrees C) were performed targeting to extract fractions with distinct compositions. The water extract obtained at 220 degrees C demonstrated the highest extraction yield, 3 times superior to conventional hot water extraction. These extracts exhibited high content of proteins, phenolic compounds, and carbohydrates, particularly arabinoxylans. This extract was incorporated in chitosan-based films in different ratios, 1:0.1, 1:0.3, and 1:0.5 (chitosan:extract, w:v). The film with the lowest extract ratio presented the highest flexibility (higher elongation and lower Young ' s modulus) when compared to the pristine chitosan film. The antioxidant capacity was also increased, achieving an antioxidant capacity of >10 -fold in comparison to control film. The results revealed that hydrothermal extraction emerges as an environmentally friendly and sustainable methodology for extracting valuable compounds from rice industry byproducts. This method exhibits significant potential to impart flexible and antioxidant properties to biobased materials.
keywords
ANTIOXIDANT ACTIVITY; SILICA; FILMS; ACID; COMPOSITES; CONVERSION; STABILITY; FIBERS; ASH
subject category
Biochemistry & Molecular Biology; Chemistry; Polymer Science
authors
Brites, P; Aguiar, MIS; Gonçalves, J; Ferreira, P; Nunes, C
our authors
Cláudia Nunes
Assistant Researcher
Joana Daniela Ferreira Gonçalves
Research Fellowship
Paula Celeste da Silva Ferreira
Coordinating Researcher
Paulo Brites
PhD StudentGroups
G2 - Photonic, Electronic and Magnetic Materials
G4 - Renewable Materials and Circular Economy
Projects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
Projeto de Investigação Exploratória: Paula Ferreira (IF_Paula Ferreira)
acknowledgements
This work was developed within the scope of the project CICECO- Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020) , financed by national funds through the CT/MEC (PIDDAC) . FCT is also thanked for the Investigator FCT program (PF, IF/00300/2015) and in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree -Law 57/2016, of August 29, changed by Law 57/2017, of July 19 (CN, DL 57/2016/CP1482/CT0031) . PB also thanks FCT for funding the PhD grant (UI/BD/151143/2021) .