Monitoring Metabolite Changes during Pineapple Ripening

Significance of the Topic

The ripening stage of pineapple (Ananas comosus) is a critical determinant of sensory quality and shelf life since it does not ripen after harvest. Metabolomic profiling offers detailed insight into biochemical transformations that underlie ripening, guiding postharvest management and improving fruit quality.

Study Objectives and Overview

This study examined metabolite dynamics in pineapple flesh, peel, and crown across five ripening stages (C0–C4) defined by UNECE color criteria. The goal was to identify ripening-related primary metabolites using gas chromatography–mass spectrometry (GC-MS) and to correlate these profiles with ripening progress via multivariate OPLS modelling.

Methodology and Instrumentation

Sample preparation involved extraction, derivatization, and GC-MS analysis as follows:

• Extraction: 10 mg sample extracted with methanol:chloroform:water (5:2:2) containing 100 µg/mL ribitol internal standard, incubation at 37 °C, centrifugation, phase separation and lyophilization.
• Derivatization: methoximation using methoxyamine hydrochloride (20 mg/mL) at 30 °C for 90 min, followed by silylation with MSTFA at 37 °C for 30 min.
• GC-MS Conditions: Shimadzu GCMS-QP2010 Ultra equipped with an InertCap 5 MS/NP column (30 m × 0.25 mm × 0.25 µm), 1 µL injection (split 25:1), helium carrier gas at 1.12 mL/min, temperature ramp from 80 °C to 330 °C, MS detection m/z 85–500.

Main Results and Discussion

• Detected peaks: 351 (crown), 297 (flesh), 359 (peel); after RSD filtering and annotation: 56 (crown), 47 (flesh), 54 (peel) metabolites.
• PCA distinguished unripe (C0–C2) and ripe (C3–C4) samples in flesh and peel; crown samples showed no clear trend.
• OPLS identified key VIP metabolites (score >1) correlating with ripening:
  • Flesh: melezitose, xylonic acid, gluconic acid (positive correlation); inositol, raffinose (negative).
  • Peel: sucrose (positive); inositol, mannose, galactose, aspartic acid (negative).

These metabolites are linked to cell wall remodeling, sugar metabolism, and stress responses, affecting fruit firmness and storage stability.

Benefits and Practical Applications

The identified biomarkers support targeted postharvest treatments such as exogenous polyamine or ascorbic acid application to modulate metabolite levels. Temperature conditioning can be tailored to adjust inositol, galactose, and raffinose concentrations, extending shelf life and maintaining quality.

Future Trends and Potential Applications

• Integration with transcriptomic and proteomic data to build comprehensive ripening models.
• Application of high-resolution and non-targeted MS methods for expanded metabolite coverage.
• Development of real-time monitoring platforms based on key metabolites for quality control.
• Incorporation of metabolomic markers into breeding programs for improved shelf life traits.

Conclusion

GC-MS metabolite profiling combined with multivariate analysis effectively characterized ripening-specific changes in pineapple. The study offers actionable biomarkers for postharvest management, enhancing fruit quality and extending shelf life.

References

• Ikram MMM, Ridwani S, Putri SP, Fukusaki E. GC-MS Based Metabolite Profiling to Monitor Ripening-Specific Metabolites in Pineapple (Ananas comosus). Metabolites. 2020;10(4):134.