Abstract:
In this study, targeted screening and quantitation of phenolic acids, flavonoids and coumarins in the flavedo, albedo and pulp of six pummelo varieties were performed based on a rapid UHPLC-QqQ-MS/MS method. The contents of eight phenolic acids, twenty flavonoids and eleven coumarins were obtained, and the multi-angle analysis and difference research were carried out based on these data. Results showed that the eight phenolic acids and twenty flavonoids were all detected in the three parts of the six pummelo varieties, including 4 polymethoxylated flavonoids of nobiletin, tangeretin, sinensetin and 5-hydroxy-7,8,4′-trimethoxyflavone. The 5-hydroxy-7,8,4′-trimethoxyflavone was detected for the first time in Wendanyou, Tongxianyou, Humiyou and Chandler fruits.p-Coumaric acid and ferulic acid were the main phenolic acids in the flavedo and albedo, while sinapic acid and ferulic acid were predominant in the pulp. The total content of phenolic acids in the flavedo was higher than those in the albedo and pulp. Naringin was the flavonoid with the highest content in the three parts of the six pummelo fruits, followed by rhoifolin, and the total content of flavonoids in the albedo was higher than those in the flavedo and pulp. All the eleven coumarins could be detected in the flavedo of the pummelo fruits, and eight coumarins were detected in the albedo. In the flavedo and albedo, the contents of isoimperatorin and isomeranzin ranked the top list for coumarins. While in the pulp, only seven coumarins were detected with bergaptol and 6′,7′-epoxybergamottin showed higher contents. From the perspective of pummelo varieties, Tongxianyou contained the highest content of the detected phenolic acids, and Wendanyou was the one with the highest content of coumarins. Guanximiyou contained the highest content of the detected flavonoids, followed by Wendanyou. This study confirmed that pummelo fruits were rich in bioactive components with peel contents higher than pulp contents, and there was a big difference in types and contents of the bioactive compounds between flavedo and albedo, which is significant for pummelo processing and utilization as well as its industrial development.
