Preparation of low-molecular-weight sodium alginate by ozonation

Low-molecular-weight sodium alginate (LMWSA) has been reported to possess unique physicochemical properties and bioactivities. There is little information available about degradation of sodium alginate by ozonation. Effect of ozonation on molecular weight, molecular weight distribution, color change, M/G ratio, and chemical structure of sodium alginate was investigated. The molecular weight of sodium alginate decreased from 972.3 to 76.7 kDa in the 80-min period of ozonation at 25 degrees C. Two different degradation-rate constants were calculated. Molecular weight distribution of the LMWSA changed appreciably. Ozonation cannot lead to color change of LMWSA. The M/G ratio of LMWSA was not altered significantly, compared with that of the original alginate. The FT-IR and C-13 NMR spectra indicated the chemical structure of LMWSA obtained by ozonation was not altered appreciably. New insight into the ozonation of alginate will be promisingly opened up. Ozonation of sodium alginate can be a alternative for production of LMWSA.

Automated summary

Low-molecular-weight sodium alginate (LMWSA) underwent significant molecular weight reduction and distribution changes after ozone treatment at 25 degrees Celsius for 80 minutes, while color, M/G ratio, and chemical structure remained largely unaffected. New insights into the ozone treatment of alginate were gained, highlighting its potential as an alternative method for producing LMWSA.