Forecasting thermal degradation of ascorbic acid in commonly consumed vegetables dipped in sodium benzoate using computer simulation technique

Abstract

Vitamin C (ascorbic acid) is one of the most important and popular vitamins, and is con
tained 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 commonly consumed vegetables, such as lettuce, cabbage, 
and carrot, dipped in sodium benzoate at temperature ranges of 26.82°C–30.14°C were  
investigated; samples after dipping at various temperatures and timings were prepared 
for analysis; and High-Pressure Liquid Chromatography was used for the determination of 
the ascorbic acid of the common vegetable samples which consisted of an isocratic elution  
procedure with ultraviolet-visible detection at 245 nm. The rate constants and half-lives were  
calculated using the integrated law method. Activation energy and forecast were  
determined using the Arrhenius equation and time series analysis. Degradation of 
ascorbic acid in the commonly consumed vegetables under the same pretreatment pro
cedure followed the first-order kinetic model, as the average coefficient of determina
tion (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 26.82°C was 0.046, 0.0746, and 0.0746 minute−1, respectively; half-lives were 
15.06842, 9.291517, and 9.291517 minutes, respectively; and activation energies were 
84.2009, 52.3589, and 31.0843 Kcal/mol, respectively. The ln(C) forecast of the vegetables 
dipped in sodium benzoate for 60 minutes at 26.82°C exhibited 0.3521, −0.3599, and 
−0.1284 mg/100 g for lettuce, cabbage, and carrot, respectively. The proposed models at 
26.82°C were ln(C) = ln(C0
) − 0.046t, ln(C) = ln(C0
) − 0.0746t, and 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 obtained from the model equations 
was lower, half-life was longer, activation energy was higher, and forecast was longer.