Biochemical and metabolite dynamics during ripening of wood apple (Feronia limonia L.) fruits

Wood apple (Feronia limonia (L.) Swingle) is an underutilized fruit with unique consumption-linked properties of fruits at different maturity stages. This study aimed to examine the biochemical and nutritional composition and metabolite dynamics of wood apple fruits at three major stages of development to better comprehend their food and nutraceutical values at unripe mature (S1), intermediate ripe (S2), and fully ripe (S3) stages. Moisture content, total soluble solids (TSS), pectin, and carbohydrates increased from S1 to S3, while titratable acidity and ascorbic acid decreased. Phenolic content and antioxidant activity increased from the unripe mature to the fully ripe stage, while total flavonoid content did not differ remarkably. Regardless of fruit maturity stage, caffeic acid was the most abundant phenolic compound, followed by gallic acid and ellagic acid. Mineral analysis showed an increase in P and K with ripening, while Ca, Fe, and Cu decreased. Metabolite profiling identified 75 compounds that showed increasing diversity with fruit maturity, particularly in sugars, amino acids, phenolics, and lipids. Unique sugars and phenolics were stage-specific, indicating biochemical transitions contributing to flavour and nutritional value. Principal component analysis (PCA) effectively discriminated the three fruit maturity stages and identified the key biochemical attributes associated with each stage. Correlation analysis revealed strong relationships between fruit weight, pulp characteristics, moisture, TSS, and antioxidant traits. The findings of the present study provide comprehensive insights into ripening dynamics and improve the existing understanding concerning the optimal stages of harvesting for specific nutraceutical-rich value-added uses of wood apple fruits.