L-ascorbic acid, commonly known as Vitamin C, is a potent antioxidant that the human body needs to protect against various illnesses. It is found in many fruits and vegetables, which are commonly processed into different juices for convenient consumption. Research shows that different processing techniques affect the degradation rate of L-ascorbic acid in juice. However, many of these studies are not in agreement with one another about the kinetic order of the degradation of L-ascorbic acid. In this study, a series of acid-base back titrations were performed to determine the concentration of L-ascorbic acid present in solutions stored at 30 °C, 65 °C, and 70 °C over 48 hours. At each temperature, concentrations were calculated at 0, 2, 5, 25, 28 and 48-hours. Preliminary results showed a reasonable fit for both first- and second-order kinetics. However, R<sup>2 </sup>values for the first- and second-order fits were too close to each other to conclusively determine the order of the degradation. Future work includes analyzing pH stability before running the back titration and monitoring degradation over a longer time period and wider temperature ranges. Once the kinetic order for the L-ascorbic acid standard has been determined, the activation energy will be found. These data will be used as a control in the comparison of the kinetics of various processing techniques for juices containing L-ascorbic acid.

Determining the kinetic order of the degradation of L-ascorbic acid

2019 Spring National Meeting

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