Variability of polyphenols and volatiles during fruit development of three pitanga (Eugenia uniflora L.) biotypes.

Changes in volatile constituents and phenolic compounds were investigated during fruit development of three pitanga biotypes. Constituents were submitted to multivariate analysis and fruit samples were differentiated by selina-1,3,7(11)-trien-8-one (38.2 ± 2.9%) and its epoxide (26.4 ± 7.2%) for the red-orange biotype; by curzerene (15.04 ± 2.1%) and atractylone (8.47 ± 2.1%) for the red biotype; and by spathulenol (3.7 ± 0.8%) and germacrone (54.7 ± 3.1%) for the purple biotype. Hydrolysable tannins such as mono-O-galloyl-d-glucose, 1,2,6-tri-O-galloyl-β-d-glucose, tellimagrandin II, and eugeniflorin D were identified, as well as oenothein B as the major compound (32.43 ± 7.1 mg/g dry fruit). During pitanga's maturation, anthocyanin content increased, while flavonoid and tannin contents decreased. Higher contents of the majority of phenolic compounds occurred in the red-orange biotype. Biosynthesis of phenolic compounds was influenced by biotype and degree of maturation, whereas chemovariation in essential oil constituents was mainly due to biotypes, thus confirming essential oil chemotypes of E. uniflora.