Özet:

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) and temperatures (70, 80, 90 and 95°C) were investigated and results were presented. Firstly, black mulberry juice was obtained from fresh black mulberry fruits and then thermal treatment was carried out. L-ascorbic acid, thiamine, riboflavin and niacin were analyzed by using HPLC method with 25 min separation time. L-ascorbic acid, thiamine, riboflavin and niacin thermal degradation followed first order kinetic model during thermal treatments. Particularly, increment in temperature from 80°C to 90°C significantly increased rate constants of compounds. Activation energy, which indicates temperature dependence of reaction, was calculated Arrhenius equation. Activation energies were found to be 58.5 kJ mol-1, 40.5 kJ mol-1, 45.9 kJ mol-1 and 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 thermal degradation in black mulberry juice was investigated for the first time. Thus, this study will be beneficial for future studies.

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