Ultrasound-assisted depolymerization of kappa-carrageenan and characterization of degradation product

Abstract

Highlights First report on structural change in κ-carrageenan under ultrasonic condition. Sonication decreased the average molecular weight of κ-carrageenan. Sonication afforded minor modification in the structure of the κ-carrageenan repeating units.

Ultrasound-Assisted Water Extraction of Mastocarpus stellatus Carrageenan with Adequate Mechanical and Antiproliferative Properties

“…As the Tg is critically relevant in specific pharmaceutical, cosmetic, or food applications [ 29 ], the control of the processing conditions allowed to deliver a set of gelling hybrid carrageenans, with gelling temperatures varying from 40 to 75 °C, thus satisfying a wide application spectrum. Different features can be determinant on these properties, including the average molecular weight and polydispersity [ 30 ], and both conventional and ultrasonic processing can alter the molecular weight of carrageenan [ 6 ]. The effect of ultrasound on depolymerization is well known; an example is the work by Tecson and coauthors, who observed a decrease in molecular weight of refined κ-carrageenan, attributable to the hydrolytic cleavage and scission along the chain, especially at the O-glycosidic bond [ 6 ].…”

“…Different features can be determinant on these properties, including the average molecular weight and polydispersity [ 30 ], and both conventional and ultrasonic processing can alter the molecular weight of carrageenan [ 6 ]. The effect of ultrasound on depolymerization is well known; an example is the work by Tecson and coauthors, who observed a decrease in molecular weight of refined κ-carrageenan, attributable to the hydrolytic cleavage and scission along the chain, especially at the O-glycosidic bond [ 6 ].…”

“…These high molecular weight polymers (up to 5000 kDa, average 200–800 kDa) are approved for food applications, whereas degraded carrageenans (10–20 kDa) are not authorized [ 3 ]. However, other interesting activities of these degraded polysaccharides such as antiviral, antitumoral, antibacterial, or immunostimulant have been reported [ 4 , 5 , 6 , 7 , 8 ]. These properties depend on the carrageenan type and structure, sulfation degree and location, molecular weight, and processing methods [ 9 ].…”

“…Ultrasonic treatment is a practical method for the degradation of κ-carrageenan, leading to low-molecular-weight oligosaccharides with new functionalities and bioactivities different from those of the starting material [ 6 , 22 , 23 , 24 ]. This is an environmentally friendly scalable method that does not require the use of chemicals, saving energy and time compared with depolymerization with chemical or enzymatic methods [ 9 , 10 ].…”

“…This is an environmentally friendly scalable method that does not require the use of chemicals, saving energy and time compared with depolymerization with chemical or enzymatic methods [ 9 , 10 ]. Moreover, the degradation process is more uniform owing to improved homogeneity and agitation caused by sound waves [ 6 , 16 ]. More recently, adequate selection of the operational conditions has been proposed to modulate the mechanical features of carrageenans [ 25 ] and antitumoral properties [ 7 ].…”