Effect of γ-irradiation on some physiochemical properties of konjac glucomannan

• Published in: Carbohydrate polymers Vol. 70; no. 4; pp. 444 - 450
• Main Authors: Xu, Zhenlin, Sun, Yuanming, Yang, Youhui, Ding, Jinlong, Pang, Jie
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.2007; Elsevier Science
• Subjects: Applied sciences; chemical bonding; chemical degradation; chemical structure; color; Exact sciences and technology; gamma radiation; granules; Konjac glucomannan; konjac mannan; molecular weight; Natural polymers; Physicochemistry of polymers; Physiochemical properties; radiation dosage; Starch and polysaccharides; thermal properties; viscosity; γ-Irradiation; Physiochemical properties; Konjac glucomannan; γ-Irradiation; Konjac; Experimental study; Thermal stability; Radiation dose; Gamma radiation; Concentration effect; Radiation effect; Reaction mechanism; Oside polymer; Radiochemical degradation; Aqueous solution; Apparent viscosity; Glucomannan
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2007.05.011

Konjac glucomannan (KGM) was irradiated at 5, 20, 50 and 100 kGy and the effects of γ-irradiation on some physiochemical properties of KGM were studied by using viscosimeter, colorimeter, gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV) spectroscopy, thermal gravimetric (TG) analysis and scanning electron microscopy (SEM). γ-irradiation led to significant degradation of KGM according to the significant reduction of the weight-average molecular weight ( M w). The apparent viscosity of KGM decreased with increasing dose, while the viscosity stability was improved after irradiation. The colour of KGM became more intense brown with increasing dose up to 20 kGy. FT-IR spectra indicated that γ-irradiation introduced no significant changes into the structure but UV spectra showed a distinct absorption peak at about 265 nm, increasing with irradiation dose, which was attributed to the formation of carbonyl groups or double bond. High irradiation dose (100 kGy) caused a small decrease of thermal stability but presented no visible fissures or splitting of KGM granules according to the TG analysis and SEM microphotographs.