Abstract:

In this paper, polysaccharide selenate was prepared via the reaction between pomegranate rind polysaccharide
and sodium selenite. Four reaction conditions including ratio between the substrates, final HNO3 concentration, reaction
temperature and time were optimized based on the selenium (Se) content and yield of product using single factor
experiments and Box-Behnken experimental design. At the same time, the structure of the obtained product was analyzed.
Results showed that the optimum reaction conditions for preparing polysaccharide selenate were established as follows: ratio
between pomegranate rind polysaccharide and sodium selenite, 1:1.0 (g/g); final HNO3 concentration, 0.61%; temperature,
77.0 ℃; and time, 11.3 h. Under these conditions, the Se content and yield of polysaccharide ester selenate were 4.48 mg/g
and 41.87%, respectively. Ultraviolet spectroscopic (UV), infrared spectroscopic (IR) and thermogravimetric analyses (TGA)
fully confirmed that the polysaccharide ester selenate contained Se＝O, Se－O and Se－C. The selenization of pomegranate
rind polysaccharide under the optimized reaction conditions can create a good condition for the full development and
utilization of pomegranate rind resources.

Key words: pomegranate rind polysaccharide, sodium selenite, polysaccharide selenate, ultraviolet spectroscopy, infrared spectroscopy, thermogravimetric analysis