title: Effect of sugar on anthocyanin degradation and water mobility in a roselle anthocyanin model system using 17O NMR.
abstract: The purpose of this study was to try to elucidate the relationship between anthocyanin degradation and water mobility using (17)O NMR. A model system containing anthocyanin from roselles with different sugar concentrations (20, 40, 60%) was used to compare the effect of sugar (sucrose and honey) on the kinetics of anthocyanin degradation and water mobility after heating. Data on the anthocyanin degradation index (DI), half-life of anthocyanin, and activation energy of anthocyanin degradation showed that sucrose was a good anthocyanin protector, especially at high concentration. However, honey led to a severe anthocyanin degradation after its concentration reached 40% or it was heated to temperatures >50 degrees C. Spin-spin relaxation rates (R(2)) of water using (17)O NMR were further used to monitor the water mobility in two sugar systems to explain the differences in browning under the same concentration and water activity. R(2) in sucrose was significantly higher than that in honey after the concentration reached 40%. Apparently, increasing the ability to bind with water molecules favored the stability of anthocyanin in sucrose solution.
authors.affiliation: Department of Food Science, National Pingtung University of Science and Technology, 1 Hsueh Fu Road, Nei Pu Hsiang, 91207 Pingtung, Taiwan, Republic of China. pijen@mail.npust.edu.tw
authors.forename: Pi-Jen
authors.initials: PJ
authors.lastname: Tsai
authors.forename: Yu-Yuan
authors.initials: YY
authors.lastname: Hsieh
authors.forename: Tzou-Chi
authors.initials: TC
authors.lastname: Huang
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D003116:Color; D004355:Drug Stability; D035264:Flowers / Q000737:chemistry; D031584:Hibiscus / Q000737:chemistry*; D006722:Honey; D009682:Magnetic Resonance Spectroscopy; D012996:Solutions; D013395:Sucrose / Q000494:pharmacology*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D012996:Solutions; D014867:Water; D013395:Sucrose