TY - JOUR
T1 - Effects of pH and temperature of ultrafiltration on the composition and physicochemical properties of hot-water-extracted softwood galactoglucomannans
AU - Halahlah, Abedalghani
AU - Abik, Felix
AU - Lahtinen, Maarit
AU - Kemppinen, Asmo
AU - Kaipanen, Kalle
AU - Kilpeläinen, Petri O.
AU - Granato, Daniel
AU - Ho, Minh Thao
AU - Mikkonen, Kirsi S.
PY - 2023/8
Y1 - 2023/8
N2 - The recovery of softwood galactoglucomannans (GGM) by pressurized hot water extraction and further con-centration by membrane filtration followed by spray drying yield biopolymers suitable as raw materials for renewable products. GGM are often characterized as having low viscosity in water and excellent emulsion sta-bilizing capacity, enhanced by lignin structures co-extracted with GGM. To reduce membrane fouling during filtration and subsequently to increase product yield, the pH and temperature of GGM liquor can be increased, but effects of such conditions on properties of recovered GGM have not been well understood. Herein, we sys-tematically varied the ultrafiltration pH (6-10) and temperature (30-60 degrees C) and characterized the composition and physicochemical properties of spray-dried GGM powders in comparison with freeze-dried (fGGM) and ethanol precipitated GGM (eGGM). The GGM samples ultrafiltrated at 60 degrees C and pH 10 (GGM-10/60) showed lower molar mass (2200 Da), degree of acetylation (0.09) and absolute zeta-potential (13 mV) than the other ultrafiltrated samples at pH (6-10) and temperature (30-45 degrees C) (3200-3700 Da, 0.11-0.15 and 23-32 mV, respectively). These differences could explain the unique gel formation capacity of GGM-10/60 after ultra-sonication, which opens new prospects in GGM applications such as thickening agents or in 3D printing. The present results allow the design of biorefinery processes to obtain GGM with desirable properties for specific applications.
AB - The recovery of softwood galactoglucomannans (GGM) by pressurized hot water extraction and further con-centration by membrane filtration followed by spray drying yield biopolymers suitable as raw materials for renewable products. GGM are often characterized as having low viscosity in water and excellent emulsion sta-bilizing capacity, enhanced by lignin structures co-extracted with GGM. To reduce membrane fouling during filtration and subsequently to increase product yield, the pH and temperature of GGM liquor can be increased, but effects of such conditions on properties of recovered GGM have not been well understood. Herein, we sys-tematically varied the ultrafiltration pH (6-10) and temperature (30-60 degrees C) and characterized the composition and physicochemical properties of spray-dried GGM powders in comparison with freeze-dried (fGGM) and ethanol precipitated GGM (eGGM). The GGM samples ultrafiltrated at 60 degrees C and pH 10 (GGM-10/60) showed lower molar mass (2200 Da), degree of acetylation (0.09) and absolute zeta-potential (13 mV) than the other ultrafiltrated samples at pH (6-10) and temperature (30-45 degrees C) (3200-3700 Da, 0.11-0.15 and 23-32 mV, respectively). These differences could explain the unique gel formation capacity of GGM-10/60 after ultra-sonication, which opens new prospects in GGM applications such as thickening agents or in 3D printing. The present results allow the design of biorefinery processes to obtain GGM with desirable properties for specific applications.
KW - 4111 Agronomy
KW - Acetylation degree
KW - Galactoglucomannans
KW - Membrane concentration
KW - Physicochemical characterization
KW - Ultrafiltration
U2 - 10.1016/j.indcrop.2023.116656
DO - 10.1016/j.indcrop.2023.116656
M3 - Article
SN - 0926-6690
VL - 198
JO - Industrial Crops and Products
JF - Industrial Crops and Products
M1 - 116656
ER -