Metabolomic analysis of acerola cherry (Malpighia emarginata) fruit during ripening development via UPLC-Q-TOF and contribution to the antioxidant activity

Acerola cherry (Malpighia emarginata D.C.) is a tropical fruit of great economic and nutritional value due to its high content of vitamin C. However, there is little information available about which ripening stage of Acerola cherry can provide the best nutrients. In the current study, the chemical variation at two developmental stages (immature and mature) were investigated by metabolic profiling, and the biological properties of Acerola cherry and its antioxidant assays at four developmental stages were measured, respectively. Through comprehensive metabolites analysis via ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry system (UPLC-QTOF), 1896 annotated metabolite features were obtained, and 133 metabolites were finally identified according to the MS/MS fragments compared with these standards in in-house database. Statistically differences in the levels of amino acids, flavonoids, lipids, terpenoids and ascorbic acids were found between mature and immature fruits. Interestingly, most of differential accumulated amino acids, flavonoids, lipids, and terpenoids predominantly accumulated in the mature fruits and ascorbic acid predominantly accumulated in the immature fruits. On the other hand, their antioxidant activities were compared. The alcoholic extract of immature acerola fruit possessed better scavenging ability of DPPH and ABTS than the mature one. The well correlations were found between the antioxidant potential with its content of ascorbic acid (r = 0.9803 and 0.9897, respectively). In conclusion, Acerola cherry showed very different metabolite profile and antioxidant activities during the fruit ripening development. The maturity of Acerola cherry has to be considered when it is being used for health food products.