resumo
Rheology modifiers are essential additives in numerous products in a variety of industries. Due to environmental awareness, consumer-oriented industries are interested in novel natural rheological agents that can replace synthetic chemicals. In this study, the chemical composition and rheological properties of a novel exopolysaccharide (EPS) produced by Alteromonas macleodii Mo 169 were investigated. It was mainly composed of uronic acids (50 mol%) and total carbohydrates were 17 % sulfated. The EPS viscosity increased with concentration, and a non-Newtonian shear thinning behavior was found for concentrations above 0.1 wt%. The elastic and viscous moduli indicated a weak gel-like structure above 0.4 wt%. It maintained its shear thinning behavior and viscoelastic properties in the presence of NaCl and CaCl2 for pH range 5-7 and temperatures up to 55 degrees C. Though the apparent viscosity decreased at pH 3 and 9 and temperatures above 65 degrees C, the shear thinning behavior was retained. The viscous and viscoelastic properties were recovered after heating (95 degrees C) and cooling (0 degrees C), indicating a good thermal stability and recoverability. After high shear force, the solution recovered original rheological properties within few seconds, demonstrating self-healing properties.
palavras-chave
POLYSACCHARIDE; TEMPERATURE; BEHAVIOR
categoria
Biochemistry & Molecular Biology; Chemistry; Polymer Science
autores
Concórdio-Reis, P; Ferreira, SS; Alves, VD; Moppert, X; Guézennec, J; Coimbra, MA; Reis, MAM; Freitas, F
nossos autores
Sónia dos Santos Ferreira
Bolseiro de pós-DoutoramentoProjectos
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
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)
agradecimentos
This work was supported by national funds from FCT - Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the project UIDP/ 04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences - UCIBIO, project LA/P/0140/202019 of the Associate Laboratory Institute for Health and Bioeconomy - i4HB, and CICECO (UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020), and LAQV/REQUIMTE (UIDB/50006/2020, UIDP/50006/2020), and LEAF (UID/AGR/04129/2020) through national funds and, where applicable, co-financed by the FEDER - Fundo Europeu de Desenvolvimento Regional, within the PT2020 Partnership Agreement. Patricia Concordio-Reis acknowledges FCT I.P. for PhD Grant SFRH/BD/ 131947/2017.