Comparison of the concentrations of phenolic constituents in cane sugar manufacturing products with their antioxidant activities

Polyphenol content and free radical scavenging capacity of seven kinds of sugar manufacturing products (A sugars, clear juices, syrups, massecuite, and A, B, and C molasses) were studied. Seventy-two samples were collected at different stages of the process during two sugar harvests from a local sugar factory (Bois-Rouge, La Réunion). The total phenolic content of sugar products was determined according to the Folin-Ciocalteu assay. Polyphenols of sugar products were extracted with ethyl acetate and quantified by LC-UV-ESI-MS during all of the process. ABTS and DPPH assays were applied to aqueous solution of sugar products, which exhibited interesting free radical scavenging activity. Comparatively, ethyl acetate extracts exhibited higher antioxidant activity. Multivariate analyses (principal component analysis and canonical discriminant analysis) demonstrated a significant correlation between polyphenols and antioxidant activity. Moreover, it was observed that the sugar process results in an increase of the phenolic content and the free radical scavenging capacity of the different products. These products and especially molasses proved to be a rich source of natural antioxidants and may represent an interesting alternative to synthetic food antioxidants.