Polyphenol Compositions and Antioxidant Activity of Non-centrifugal Sugars Prepared by Ceramic Membrane Filtration Process

The polyphenol contents and ingredients of non-centrifugal sugars (NCS) obtained from juices clarified with ceramic membrane were measured and their antioxidant activities were investigated via 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, 2,2ʹ-azinobis (3-ethylbenzothiazoline-6-sulfonic acid assay (ABTS), and ferrous and cupric ion chelating assays. According to this research, the results showed that there were significant differences in the six NCSs, the contents of total phenolics and flavonoids were in range of 2846.21~4073.48 and 1999.24~2438.63 µg/g respectively and during the results of high performance liquid chromatography (HPLC), gallic acid showed the highest value. As for the antioxidant effect, DPPH, ABTS and cupric ion chelating showed better effects than control experiments, which suggested NCS had a decent antioxidant effect. In these results, D(GUC23-2) showed the best effects in the experiments of DPPH, ABTS and ferrous ion chelating. Combined with the correlation analysis, it was found that polyphenol had a high correlation with the antioxidant activity. Therefore, it could preliminarily consider that the structure and content of polyphenols had an important effect on the antioxidant activity of NCS. In summary, the sugarcane varities affect the contents of NCS and the antioxidant effect, and this study would provide some theoretical basis for the screening of sugar cane special type of sugar cane and the further study of cultivation.The difference of sugarcane varieties was the main factor that caused the difference of the kinds and contents of brown sugar polyphenols, and the difference of polyphenols content and composition was the main reason for the difference of antioxidant activity of different varieties of brown sugar.