Quantitative evaluation of vitamin C in industrial lemon juice by titration method

Abstract

One of the most important micronutrients of lemon juice is vitamin C. Vitamin C is a sensitive antioxidant and heat, light and oxygen are included important factors to reduce the amount of this vitamin. This study designed to evaluate vitamin C in in- dustrial lemon juice quantitatively. The present cross- sectional study was conducted on 50 bottles of different types of Shi- raz industrial lemon juice. Vitamin C levels were measured through iodine titration method. Each measurement was repeat- ed 2 times. Then Data were statistically analyzed by using SPSS software. The vitamin C of samples has been reported 18.92±6.66 (mg/100ml). Maximum and minimum vitamin C were 6.01 and 34.08 (mg/100ml) respectively. By using inde- pendent sample t-test, a comparison of the mean vitamin C of industrial lemon juice and The mean vitamin C of fresh lemon (42 mg/100ml) shown that vitamin C of industrial lemon juice is less than fresh lemon, significantly (P<0.05). By applying lin- ear regression test determined that a significant relationship exists between the amount of vitamin C in the lemon juice and duration of post-production (p-value = 0.021). This study showed that content of vitamin C in industrial lemon juice was low- er than the mean value of vitamin C in fresh lemon juice significantly and the amount of vitamin C in the lemon juice and the period after production is a significant association and with increased storage time, the amount of vitamin C reduced.