Degradation of anthocyanin from litchi fruit pericarp by H 2O 2 and hydroxyl radical

• Published in: Food chemistry Vol. 116; no. 4; pp. 995 - 998
• Main Authors: Ruenroengklin, Neungnapa, Yang, Bao, Lin, Hetong, Chen, Feng, Jiang, Yueming
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2009
• Subjects: Anthocyanin; Browning; Degradation; Fruit; Hydrogen peroxide; Hydroxyl radical; Litchi; Anthocyanin; Degradation; Browning; Litchi; Hydrogen peroxide; Fruit; Hydroxyl radical
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2009.03.063

Litchi ( Litchi chinensis Sonn.) is one of the most desirable subtropical fruits with high commercial values, which is significantly affected by its skin colour due to the embedded anthocyanin pigments. This work was conducted with a view to explaining the unexpected observation that litchi polyphenol oxidase (PPO) did not oxidise directly anthocyanins. Litchi fruit were stored for 4 days at 25 °C and 80–90% relative humidity. Browning index and H 2O 2 and OH contents of pericarp tissues of litchi fruit during storage were determined. The browning index of litchi fruit rapidly increased while H 2O 2 and OH contents decreased and then increased markedly, as storage time progressed. The obvious pericarp browning was associated with the rapid increases in H 2O 2 and OH contents of litchi fruit after 4 days of storage. Furthermore, litchi anthocyanins were purified by column chromatography and then H 2O 2 and hydroxyl radical were used to examine their degradation roles in the purified anthocyanin. It was found that the purified litchi anthocyanin was degraded markedly in the presence of H 2O 2 or hydroxyl radical. Increasing concentration of H 2O 2 or hydroxyl radical enhanced the anthocyanin degradation, of which the latter exhibited a greater effect on the anthocyanin degradation although no peak of litchi anthocyanin appeared after the treatment with 0.1% H 2O 2 for 10 min. This study can account for the pericarp browning of postharvest litchi fruit during storage based on the oxidative degradation of anthocyanin caused by PPO.