Determination of the age of Guava from the Oxalate Ion and Ascorbic Acid contents and the determination of the rate of change of Oxalate Ion and Ascorbic Acid contents with respect to the age of Guava

The oxalate ion and ascorbic acid concentrations of the matured guava fruit at different stages of ripening were determined using reported procedures. The oxalate ion content was found to increase and the ascorbic acid content was found to decrease with the aging of the fruit. From the plot of oxalate ion concentrations and ascorbic acid concentrations against number days, the approximate age of the matured guava bought from market is determined by measuring their oxalate ion t and ascorbic acid contents. The age of the guava obtained by the oxalate and ascorbic acid methods were found to be almost the same making a chance of a linear relationship between the conversion of ascorbic acid to oxalate ion. This linearity is proved by plotting the concentration of ascorbic acid against the concentration of oxalate ion. An approximate study of rate of change of oxalate ion and the ascorbic acid contents were also determined from the standard plots of oxalate ion and ascorbic acid.