Changes in fruit quality parameters and volatile compounds in four wampee varieties at different ripening stages

Wampee is a nutritious fruit with an attractive taste, and its quality and flavor vary significantly at different ripening stages. Here, we comprehensively characterized the flavor quality of four wampee varieties at five ripening stages. The TSS, TSS/TA, soluble sugars, and most amino acids increased in all varieties, while TA and organic acids consistently decreased with fruit ripening. Furthermore, 57 volatiles were identified by HS-SPME-GC-MS, most of which first increased and then decreased, and fifteen aroma-active markers were screened. Overall, CIE a* value was significantly correlated with fruit sweet and sour taste and can serve as an indicator of wampee maturity. Wampee fruits at stage-4 with CIE a* of 4-8 are suitable for fresh consumption for better balance between taste and aroma, and those at stage-3 with CIE a* of 0-4 are suitable for processing. These findings provide important insights into the optimal harvest timing and quality improvement of wampee.