Study of chemical composition of Eriobotrya japonica L. and extraction of its polysaccharide as an antioxidant

The aim of this study is investigation of chemical composition of fruit and seed of loquat (Eriobotrya japonica L.), extraction of polysaccharide and evaluation of its antioxidant properties. Polysaccharide was extracted using hot water and purified by ethanol. The optimal time and temperature for the extraction of polysaccharides were 180 min and 90 ◦C, respectively. Also, the optimal ratio of water to raw materials were 6:1 and 10:1 to extract of polysaccharides from fruit and seed, respectively. The antioxidant activity of extracted polysaccharide was assessed by using DPPH (2, 2- diphenyl-1picrylhydrazyl) radical scavenging and the hydroxyl radical methods. Bands observed in the analysis by FTIR method confirmed that polysaccharides were the main compound in the extract. The results showed the total sugar of fruit polysaccharide was more than seed polysaccharide. Also, that the content of sodium, potassium, calcium, iron and zinc from fruit were higher than seed, while the amount of magnesium, manganese and copper were higher in the seed. Anti-oxidant activity in both cases and in both methods of measurement was normal. In both cases and in all concentrations, the DPPH radical scavenging activity of ascorbic acid was higher than the extracted polysaccharide. The hydroxyl radical scavenging ability of both polysaccharides was higher than ascorbic acid; while the radical scavenging ability of 100 ppm of fruit polysaccharide and ascorbic acid were about equal. Results showed the radicals scavenging activity increased with increasing concentrations, anyway anti-oxidant activity of fruit. On the basis of the results, the extracted polysaccharides from fruit and seed of Eriobotrya japonica L. can be used to improve the quality of foods, due to their acceptable antioxidant activities.