Thermal Degradation Kinetics of Ascorbic Acid and Some B-Complex Vitamins in Black Mulberry (Morus nigra) Juice

Abstract

In this paper, L-ascorbic acid, thiamine (vitamin B1), riboflavin (vitamin B2) and niacin (vitamin B3)thermal degradations depending on different thermal treatment times (0, 5, 10, 15, 20, 25 and 30 min) andtemperatures (70, 80, 90 and 95°C) were investigated and results were presented. Firstly, black mulberryjuice was obtained from fresh black mulberry fruits and then thermal treatment was carried out. Lascorbic acid, thiamine, riboflavin and niacin were analyzed by using HPLC method with 25 minseparation time. L-ascorbic acid, thiamine, riboflavin and niacin thermal degradation followed first orderkinetic model during thermal treatments. Particularly, increment in temperature from 80°C to 90°Csignificantly increased rate constants of compounds. Activation energy, which indicates temperaturedependence of reaction, was calculated using Arrhenius equation. Activation energies were found to be58.5 kJ mol-1, 40.5 kJ mol-1, 45.9 kJ mol-1and 52.1 kJ mol-1 between 70°C and 95°C for ascorbic acid,thiamine, riboflavin and niacin, respectively. L-ascorbic acid, thiamine, riboflavin and niacin thermaldegradation in black mulberry juice was investigated for the first time. Thus, this study will be beneficialfor future studies.