Effect of polysaccharide chain conformation on ultrasonic degradation of curdlan in alkaline solution

Yi-Ching Cheung; Junyi Yin; Jian-Yong Wu

doi:10.1016/j.carbpol.2018.04.118

Effect of polysaccharide chain conformation on ultrasonic degradation of curdlan in alkaline solution

Carbohydr Polym. 2018 Sep 1:195:298-302. doi: 10.1016/j.carbpol.2018.04.118. Epub 2018 Apr 30.

Authors

Yi-Ching Cheung¹, Junyi Yin², Jian-Yong Wu³

Affiliations

¹ Department of Applied Biology and Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; Department of Food and Health Science, Faculty of Science and Technology, Technological and Higher Education Institute of Hong Kong, 20A Tsing Yi Road, Tsing Yi Island, N.T., Hong Kong.
² Department of Applied Biology and Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, PR China.
³ Department of Applied Biology and Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Electronic address: jian-yong.wu@polyu.edu.hk.

PMID: 29804980
DOI: 10.1016/j.carbpol.2018.04.118

Abstract

This study was to investigate the effects of polysaccharide chain conformation on ultrasonic degradation of curdlan, a high MW β-glucan with wide applications. The ultrasonic degradation was performed in alkaline solution at 0.1 M and 0.3 M NaOH, in which the curdlan chain was mainly in triple helical conformation and random coil form, respectively. The degradation rate was represented by the kinetic model, 1/M_t - 1/M_o = kt, with the rate constant k increasing with the ultrasonic power. The degradation rate was much higher in 0.3 M NaOH than in 0.1 M NaOH, suggesting that curdlan in random coil conformation was more liable to degradation than in helical conformation. Curdlan in 0.1 M NaOH was changed from triple helices to single helices and eventually to random coils with a higher solubility. In summary, ultrasonic degradation of curdlan in alkaline solution had a close and complex relationship to the chain conformation changes.

Keywords: Chain conformation; Curdlan; Intrinsic viscosity; Kinetics; Molecular weight; Ultrasonic degradation.