Fluorescence and UV/visible spectroscopic investigation of orange and mango fruit juice quality in case of Adama Town

Extracted Mango and Orange juices were investigated by using spectroscopic techniques such as UV/Visible and Fluorescence. Three portions of samples (fresh juice) were stored at 22 °C for eight days, stored in a water bath and heated at 40 °C, 60 °C, and 80 °C for ten minutes. The highest wavelengths (455 nm) were observed from the UV/Vis results for fresh Mango juices, while 270 nm and 460 nm were observed for stored Mango juices. Furthermore, wavelengths of 320 nm were observed in heat-treated mango juice (40 °C). No absorption peaks were observed at 60 °C and 80 °C due to temperature effects. Absorption peaks of fresh fruit were observed at 330 nm and 390 nm, while 260 nm and 320 nm reflect stored orange juices absorptions peaks. From heat-treated stored (40 °C and 60 °C) samples, 320 nm and 260 nm absorption peaks were observed, respectively. Wavelength observed (454 nm, 540 nm & 700 nm) peaks represent the fresh mango juice spectra, while 460 nm and 700 nm are for stored Mango juices. The peaks observed in the region of 400–500 nm and at 700 nm represent heat-treated mango juices at 40 °C. Heat stored Mango juices (60 °C & 80 °C) have peaks at 700 nm. Peaks observed at 700 nm, 500 nm, and 455 nm reflect fresh orange juice, while 460–500 nm and 700 nm represent the emission spectra of the samples. The stored orange juice peaks at 460–500 nm and at 700 nm, but heated-stored orange juice peaks only at 700 nm. The pH values for orange and mango juices were 3.52–3.73 and 4.02–4.72, respectively.