Objective  Studying the composition and dynamic changes of volatile components and free amino acids (FAAs) in the pericarp of Yellow Passion Fruit during different growth stages, and clarifying the key flavor amino acids and characteristic volatile components, can provide references for the aroma regulation, product development, and comprehensive utilization of Yellow Passion Fruit pericarp.

  Method  Using amino acid analyzer and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), the FAAs and volatile compounds in the pericarp of different growth stages (T1–T7) were detected and analyzed for differences.

  Result  A total of 15 types of FAAs were detected in the pericarp. Among the flavor amino acids, aromatic amino acids had the highest content, reaching a maximum of 98.48 mg·hg⁻¹ at T7, accounting for 39.03%. OPLS-DA and TAV analyses indicated that cystine was the key flavor amino acid that affects aroma formation. A total of 90 volatile compounds were detected in the pericarp. Aldehydes were dominant during the T1–T6 stages, while terpenes were dominant at T7. OPLS-DA and ROAV analyses showed that there were 9 types of characteristic volatile compounds with differential expression. Among them, 1-octen-3-one was the dominant compound during the T1~T5 stages, followed by benzaldehyde (T1–T4 stages) and heptanal (T5 stage). During the T6 and T7 stages, (E)-β-damascone contributed the most.

  Conclusion  Cystine was the crucial flavoring amino acid associated with the aroma formation of the pericarp. The volatile composition varied by fruit development stages, such as 1-octene 3-one was the dominant component when the pericarp was forming color in T1-T5, while (E)- β -damalenone when the fruit was maturing in T6 and T7.