Vitamin C (ascorbic acid) is one of the most important and popular vitamins, and is contained in most fruits and vegetables; the problem with vitamin C is its easy degradation during pre-treatment and storage. In this study, kinetics modeling of degradation of ascorbic acid (Vitamin C) in lettuce, cabbage and carrot commonly consumed vegetables dipped in Sodium Benzoate at temperature ranges of (26.820C 30.14)0C were investigated and samples after dipping at various temperatures and timings were prepared for analysis and High Pressure liquid chromatographic (HPLC) was used for determination of the AA of the common vegetable samples which consisted of an isocratic elution procedure with UV-Visible detection at 245nm. The rate constants and half-lives were calculated using the integrated law method. Activation energy and forecast were determined using Arrhenius equation and time series analysis. Degradation of ascorbic acid in the commonly consumed vegetables under the same pretreatment procedure followed the first-order kinetic model, as the average coefficient of determination (R2-value) was greater than 0.91. The rate constant of ascorbic acid degradation for Lettuce, Cabbage and carrot dipped in Sodium Benzoate under the same temperature condition of 26.820C were 0.046, 0.0746, 0.0746 min -1 respectively. Their half-lives were 15.06842, 9.291517 and 9.291517 mins, activation energies; 84.2009, 52.3589 and 31.0843 Kcal/mol respectively. The ln(C) forecast of the vegetables dipped in Sodium Benzoate for 60mins at 26.820C exhibited 0.3521, -0.3599 -0.1284 mg/100g for lettuce, cabbage and carrot respectively. The proposed models at 26.820C were ln(C) = ln( C0) - 0.046t, ln(C) = ln( C0) - 0.0746t, ln(C) = ln( C0) - 0.0746t.The most appropriate commonly consumed vegetable under dipped Sodium Benzoate and storage is the lettuce because its rate constant depicted from the model equations was lower, half life longer, activation energy higher, forecast longer.
Key words: HPLC, Lettuce, Cabbage, Sodium Benzoate, Ascorbic Acid, Rate Constant, Activation Energy, Forecast
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