Influence of blanching on the bioactive compounds of Terminalia ferdinandiana Exell fruit during storage

Abstract

Changes in quality of fruits and vegetables during processing and storage might impact on the nutritional and economical value of food products. The present study aimed to evaluate the influence of blanching on the content of vitamin C and ellagic acid (EA) as the main bioactive compounds present in Kakadu plum (KP) fruits (Terminalia ferdinandiana) during storage at 40oC to mimic typical temperature when wild harvested. Changes in the profile of fatty acids, malondialdehyde (MDA) production, as a biomarker for lipid peroxidation, and antioxidant properties of KP fruits were evaluated. The results revealed that vitamin C decreased between 25 and 52% over the storage period. Statistically significant differences in the concentration of vitamin C were associated with temperature (p < 0.05) and blanching (p < 0.05), whereas no significant differences in EA during storage were observed. DPPH radical scavenging capacity and total phenolic content of both blanched and control samples decreased by 80% and 35%, respectively, at the end of the storage period compared to day 0. In addition, the change in DPPH activity is significantly correlated (Pearson R2 = 0.829, p ˂ 0.01) with the breakdown of ellagitannins. Furthermore, KP fruit demonstrated excellent antioxidative properties by reducing MDA production. It was concluded that blanching causes significant vitamin C loss whereas neither blanching nor long-term storage at elevated temperature affect the EA content. The results also indicate that the antioxidant compounds present in the KP fruits provided considerable protection against fatty acid oxidation during storage.