Electrochemical quantification of the levels of hydrogen peroxide in cassava using glassy carbon electrode modified with chitosan/silver nano-hybrid

Abstract

This study correlates the production of hydrogen peroxide in cassava with its rapid postharvest physiological deterioration (PPD). Chitosan/silver nanohybrid was synthesized and immobilized on glassy carbon electrode for improved detection of hydrogen peroxide in electrochemical studies. The cathodic peak current for the reduction of hydrogen peroxide to water and oxygen occurred at -550 mV and β-carotene contents of the cassava cultivars were quantified using UV-Vis spectroscopy at a wavelength of 480 nm. No significant amount of hydrogen peroxide was found in the root tubers on the first, second, third and fourth day. However, the production of hydrogen peroxide from the different cultivars on the fifth and sixth day after harvest was found to correlate with their respective β-carotene contents. The cultivar with the highest β-carotene content (Yellow roots- IBA070593: 0.0044 mg/g) was found to have the lowest level of hydrogen peroxide on day 5 and day 6: 0.096 mmol/g FW and 0.037 mmol/g respectively; while that with the least β-carotene level (White roots- IBA980505: 0.0000 mg/g) demonstrated the highest level of hydrogen peroxide content on day 5 and day 6: 0.177 mmol/g FW and 0.096 mmol/g respectively; and highest percentage increase from the fifth to the sixth day of the PPD process. It is seen from this study that an increase in the level of hydrogen peroxide indicates PPD, and that antioxidants with hydrogen peroxide scavenging properties can help increase shelf-life of cassava cultivars