Comparison of the concentration of ascorbic acid in selected fruits (passion fruits, oranges, pineapples and mangoes)

Abstract

The present study encompasses the comparison of the concentration of ascorbic acid in selected fruits (passion fruits, oranges, Pineapples, and mangoes). Vitamin C, also known as ascorbic acid is one of the most important vitamins and is essential for human and animal life.

The vitamin C content of the selected fruits was determined by two methods which are; the titration method and the UV-spectroscopy method of analysis. In the UV-spectroscopy method, the concentration of the unknown sample was determined from the calibration graph plotted using the standard ascorbic solutions and thus having obtained the absorbance of the samples from the spectrometer, the concentration was determined.

From the titration method, the vitamin C concentration of oranges was 53.14±0.14 mg/100g while that of passion fruits was 52.41±0.03 mg/100g, and for mangos, it was 18.58±0.06 mg/100g. Pineapple had a vitamin C content of 15.35±0.06 mg/100g.

From the UV-spectroscopy method, the absorbance of ascorbic acid in the orange sample was 0.0624 which corresponded to a concentration of 41.333 mg/100g while that of mangoes was 0.0247 which corresponded to 16.2 mg/100g. The absorbance of 0.0198 for the pineapple sample which corresponding to 12.933 mg/100g and it gave an absorbance of 0.0551 for the passion fruit which corresponded to a vitamin C concentration of 36.467 mg/100g.

From this study, oranges contained the highest vitamin C(53.14±0.14 mg/100g, 41.333 mg/100g) among the test fruits followed by passion fruits(52.41±0.03 mg/100g, 36.467 mg/100g.) mangoes(18.58±0.06 mg/100g, 16.2 mg/100g.) and lastly the pineapple(15.35±0.06 mg/100g, 12.933 mg/100g) by both the titration and UV-spectroscopy methods respectively. Comparison between titration and UV-spectroscopy methods in terms of vitamin C content showed significant differences in all fruit samples. The vitamin C contents in fruits samples were higher in the titration method(53.14±0.14 mg/100g, 52.41±0.03 mg/100g 18.58±0.06 mg/100g, 15.35±0.06 mg/100g, for oranges, passion fruits, mangoes, and pineapples respectively compared with UV-spectroscopy method(41.333 mg/100g, 36.467 mg/100g, 16.2 mg/100g, 12.933 mg/100g for oranges, passion fruits, mangoes, and pineapples respectively).