Effect of Hot Water Blanching Time and Drying Temperature on The Thin Layer Drying Kinetics and Anthocyanin Degradation of Black Carrot (Daucus carota l.) Shreds

This study was conducted to investigate the eff ect of blanching treatment (98 °C for 3 and 6 min) and air drying temperature of 40, 50 and 60 °C on the thin layer drying characteristics such as drying time, drying rate constant, eff ective moisture diff usivity and activation energy, as well as on anthocyanin content of black carrot shreds.It was observed that drying temperature aff ected the drying rate but blanching did not have an eff ect on drying time.Three thin layer drying models, i.e.Page, Lewis and Henderson-Pabis were evaluated.The goodness of these models was evaluated based on the coeffi cient of determination (R 2 ), root mean square error, reduced chi square (χ 2 ) and standard error.Page model showed the best fi t to the drying data.The eff ective diff usivity ranges of 1.4•10 -9 to 2.6•10 -9 m 2 /s, 1.3•10 -9 to 2.1•10 -9 m 2 /s and 1.5•10 -9 to 2.2•10 -9 m 2 /s aft er 3 or 6 min of blanching and control samples respectively were calculated using Fick's second law.The activation energy of 37.5, 26.0 and 34.6 kJ/(mol•K) of the control samples and samples blanched for 3 or 6 min respectively was determined from the Arrhenius plot.The blanching treatment aff ected the anthocyanin content to a great extent.The anthocyanin content of (231.7±2.9) and (278.8±7.8)mg per 100 g was recorded in samples blanched for 3 and 6 min and then dried at 60 °C, and (153.0±4.3) and (247.0±5.5)mg per 100 g was recorded at 40 °C as compared to the control of (580.1±1.3) at 60 °C and (466.7±1.1)mg per 100 g at 40 °C.