Phenolic metabolism and lignin synthesis in damaged pericarp of mangosteen fruit after impact

Firmness and lignin content increased while total phenolics decreased in damaged mangosteen pericarp following impact. The phenolic compounds associated with lignin synthesis in damaged pericarp of mangosteen fruit after impact were separated and identified by UV absorption spectra, thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) analysis. The phenolic acids unique to damaged pericarp of mangosteen fruit were identified as p- coumaric acid and sinapic acid; p-coumaric acid decreased more rapidly than sinapic acid after impact. p-Coumaric acid and sinapic acid contents in the damaged pericarp of reddish brown mangosteen fruit were greater than those of dark purple fruit, and the sinapic acid content was 20-40-fold greater than that of p-coumaric acid. The decrease in both p-coumaric acid and sinapic acid in damaged pericarp occurred more rapidly in air than under a nitrogen atmosphere. The results suggest that the incorporation of phenolic acid into lignin was greater in more mature dark purple than less mature reddish brown fruit. (C) 2002 Elsevier Science B.V. All rights reserved.