Comparative determination of vitamin C on non-FDA-approved calamansi fruit juices using UV-VIS spectroscopy and HPLC and its general microbiological qualities

ABSTRACT: Vitamin C in fruit juices is essential in collagen synthesis, absorption of nonheme iron from foods, and counters high oxidative stress. The Philippine fruit juice market is growing due to urbanization and health trends. However, unregistered juices pose health risks due to lack of quality control. Accurate vitamin C quantification methods like UV-Visible spectroscopy and High-Pressure Liquid Chromatography are crucial. This research study aimed to determine the mean vitamin C concentration in non-FDA-approved calamansi fruit juices using UV-Vis spectrophotometry and High-Performance Liquid Chromatography. It also sought to assess any significant differences in vitamin C concentration among three fruit juice samples, compare the HPLC and UV- Vis methods and evaluate the microbiological quality of the juices by determining the Aerobic Plate Count, E coli, total coliform, and yeast and mold counts. The UV-Vis method used an indirect approach with potassium permanganate (KMnO4) for standard calibration and the analysis of fruit juices. The vitamin C concentration was higher with UV-Vis compared to HPLC. This difference was due to various factors affecting absorbance readings, such as reducing sugars, sample color, acids in the sample matrix, and instrumental and personal error. For HPLC, a metaphosphoric acid solution was used as the solvent for the fruit juice samples. Statistical analysis of the results from both UV-Vis and HPLC methods showed significant differences in vitamin C concentrations among the juice samples with fruit juice 2 showing no significant difference. While the HPLC method revealed significant differences among all three juices, the UV-Vis method showed no significant differences. Microbiological tests indicated that all juice samples met safety standards for consumption, confirming that they were microbiologically safe, with acceptable levels of APC, E. coli, total coliform, and yeast and mold counts.

Filipiniana