ABSTRACT
In this study watermelon and carrot juices were prepared and stored for one month. The effects of storage time on the physico-chemical characteristics of both juices were monitored. The physicochemical characteristics of the juices determined were pH for watermelon juice which ranged between 5.2 - 3.8, titratable acidity 0.18 - 0.65, specific gravity 1.022 - 1.003, electrical conductivity 3.38 - 3.41µS/cm, vitamin C 40.07 - 20.56 mg/100ml,reducing and total sugar 5.18 - 6.15% and 7.66 - 8.44%, respectively, UV-Vis spectrum absorption peak at 218nm and 338nm corresponding to the presence of lycopene and vitamin C respectively, calcium 13.31±0.04 to 13.29±0.09 mg/100ml, potassium 107.79±0.06 to 101.13±0.04 mg/100ml, sodium 11.80±0.04 to 10.92±0.07 mg/100ml, magnesium 11.11±0.07 to 11.08±0.05 mg/100ml. For carrot juice, pH ranged between 6.2 - 3.9, titratable acidity 0.13 - 0.86, specific gravity 1.016 - 1.010, electrical conductivity 5.19 - 5.60 µS/cm, vitamin C 31.40 - 15.72 mg/100ml, reducing sugar and total sugar 4.78 - 5.31% and 7.11 - 7.35%, respectively, UV-Vis spectrum absorption peak at wavelengths 218nm and 305nm corresponding to the presence of lycopene and β-carotene respectively, calcium 12.27±0.02 to 12.18±0.02 mg/100ml, potassium 100.70±0.07 to 98.56±0.01 mg/100ml, sodium 10.73±0.06 to 8.14±0.01 mg/100ml, magnesium 9.10±0.01 to 8.09±0.03 mg/100ml. From the results of this study, it can be concluded that some of these parameters could be used as indicators of quality loss or spoilage of the juices during storage.
