GC-MS study of changes in polar/mid-polar and volatile compounds in Persian lime (Citrus latifolia) during fruit growth.

BACKGROUND: Citrus fruits possess a high content of bioactive compounds whose changes during fruit maturation had not been studied in depth yet. Fruits were sampled from week 1, after the fruit onset (7 days after flowering), to week 14. Volatile compounds isolated by headspace-solid-phase microextraction and polar extracts from all samples were analyzed by gas chromatography-mass spectrometry.

RESULTS: The relative abundance of 107 identified metabolites allowed establishing differences among samples at different stages of fruit growth. Principal component analysis showed a clear discrimination among samples, and the analysis of variance revealed significant differences in 94 out of the 107 metabolites. Among total volatiles, monoterpenes increased their relative abundance from 86% to 94% during fruit growth, being d-limonene, γ-terpinene and β-pinene the most abundant; on the contrary, sesquiterpenes decreased from 11.5% to 2.8%, being β-bisabolene and α-bergamotene the most concentrated. Regarding sugars, they exhibited in general a gradual increase in abundance to reach their maximum between weeks 9 and 12. Citric and malic acids - that represent approximately 90% of the total identified carboxylic acids- reached their maximum concentration at commercial maturity (W14).

CONCLUSION: Of the 107 tentatively identified metabolites during Persian lime growth, sugars, carboxylic acids, and volatiles were those that experienced more significant changes and more clearly created differences among fruit growth stages. This article is protected by copyright. All rights reserved.