Some Characteristics and Antioxidant Activity of Commercial Sugars Produced in Thailand

Seven commercial sugars produced in Thailand (cane sugar paste (S1), unrefined cane sugar (S2), brown cane sugar (S3), caramel crystal cane sugar (S4), refined white crystal cane sugar (S5), coconut sugar paste (S6) and palm sugar paste (S7)) were analyzed for chemical and physical properties as well as antioxidative activity. The pH values of all samples ranged from 5.17 to 5.57. S5 exhibited the highest L*value, whereas S1 showed the lowest L* value (p<0.05). Among sugars from sugar cane, S1 had the highest amount of Ca, Mg, Fe, K, and Na (p<0.05). Additionally, differences in total sugar and reducing sugar contents of all samples were observed (p<0.05). The intermediate browning products and browning intensity of all samples were also determined. S1 had the highest intermediate and browning products (p<0.05). Higher total phenolic content was observed in sample extracted with water compared with that did with 95% methanol (p<0.05). Regardless of extraction solutions, S1 extract exhibited the highest total phenolic content (p<0.05). Antioxidant activities of both extracts were evaluated. S1 exhibited the highest DPPH and ABTS radical scavenging activities and ferric reducing power, compared with other samples (p<0.05). From the results, sugar with high browning products and total phenolic content contributed to their high antioxidant activities.

Keywords: sugar, browning intensity, total phenolic content, antioxidative activity