Production of prebiotic gellan oligosaccharides based on the irradiation treatment and acid hydrolysis of gellan gum

• Published in: Carbohydrate polymers Vol. 279; p. 119007
• Main Authors: Gao, Minjie, Li, Hongyu, Yang, Tianyi, Li, Zhitao, Hu, Xiuyu, Wang, Zichao, Jiang, Yun, Zhu, Li, Zhan, Xiaobei
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2022
• Subjects: Acid hydrolysis; Antioxidants - chemistry; Feces; Fermentation; Gamma Rays; Gellan gum; Humans; Hydrochloric Acid - chemistry; Hydrolysis; Irradiation; Oligosaccharide; Oligosaccharides - chemistry; Polysaccharides, Bacterial - chemistry; Polysaccharides, Bacterial - radiation effects; Prebiotic activity; Prebiotics; Gellan gum; Irradiation; Acid hydrolysis; Prebiotic activity; Oligosaccharide
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2021.119007

Biologically active gellan oligosaccharides (GOSs), newly found plant elicitors and biostimulants, are produced from the hydrolysis of gellan gum. Traditional hydrolysis with concentrated acid suffers from the problems of high pollution and low functional oligosaccharide yield because the process is difficult to control. Irradiation (60Co γ-ray) with a dosage ranging from 0 kGy to 175 kGy was used to degrade gellan gum efficiently and cleanly into low molecular weight (Mw) gellan with an average Mw ranging from 449,119 Da to 72,903 Da. The low Mw gellan irradiated at 70 kGy was further hydrolyzed with low concentration acid (0.5 mol/L HCl) to produce GOSs with DPs mainly 4 and 8, indicating that the Rha-β-(1 → 3)-Glc bonds in gellan gum were easily cut to produce residues with tetrasaccharide repeat subunits. Besides antioxidant activity, GOSs were also proved with prebiotic activity by in vitro fecal fermentation in a self-designed bionic intestinal reactor. [Display omitted] •Gellan oligosaccharides were efficiently produced via coupled hydrolysis.•The structures of the hydrolysates (gellan oligosaccharides) were determined.•Specific gellan oligosaccharides (DPs 4 and 8) were isolated from the hydrolysates.•Gellan oligosaccharides were proved with prebiotic and antioxidant activities.•Biological activities of the specific oligosaccharides were compared.