Influence of different drying methods on the browning, phytochemical components and antioxidant capacity of Choerospondias axillaris fruits

Drying is an essential post-harvest processing technique used to improve the utilization efficiency of fresh fruit. The browning of Choerospondias axillaris fruits during the drying process can reduce their overall quality. In this study, we investigated the relationship between the browning degree and polyphenolics in C. axillaris fruits. Different browning samples dried by freeze (FD), microwave (MD), and hot air (HAD) methods, respectively, exhibited color differences (Delta E) ranging from 14.53 to 64.78. UPLC-Q-Exactive Orbitrap-MS analysis of the polyphenolic fractions from fresh fruit (FF), FD, MD, and HAD identified 83, 83, 83, and 56 compounds, respectively. Eight compounds were quantified by UPLC-QQQ MS-MS to evaluate the samples of different browning degrees. Correlation analysis results of HAD demonstrated the highest Delta E, while increased quantities of monomeric phenolic acids and total phenolics, attributed to enzymatic browning and oxidation degradation of flavanols. FD, led to the lowest Delta E and exhibited significantly higher levels of monomeric flavanols and total flavonoids, as well as greater antioxidant activity. It was concluded that FD could be an effective anti-browning method and suitable for the processing of C. axillaris fruits with high quality.