Comparative nutritional and metabolic analysis reveals the taste variations during yellow rambutan fruit maturation

The metabolic reasons for rambutan taste variations during maturity are unknown. Here, we obtained a unique rambutan cultivar Baoyan No.2 (BY2) with a strong yellow pericarp and excellent taste, the sugar-acid ratios of which ranged from 21.7 to 94.5 during maturation. Widely targeted metabolomics analysis was performed to reveal the metabolic reasons behind these taste variations. The results showed that 51 metabolites were identified as common different metabolites (DMs), including 16 lipids, 12 amino acids and others. Among them, the abundance level of 3,4-digalloylshikimic acid exhibited a positive correlation with the titratable acids (R2 = 0.9996) and a negative correlation with the sugar-acid ratio (R2 = 0.9999). Therefore, it could be a taste biomarker of BY2 rambutan. Moreover, all DMs were enriched in galactose metabolism, fructose and mannose metabolism and biosynthesis of amino acids pathways, which predominantly accounted for the taste variation. Our findings provided new metabolic evidence for the taste variation of rambutan.

Automated summary

Through extensive metabolomics analysis, a unique cultivar of rambutan, Baoyan No.2 (BY2), was identified to have significant taste variations during maturation. The metabolite 3,4-digalloylshikimic acid was found to be associated with the taste of BY2 rambutan and could serve as a taste biomarker. Furthermore, galactose metabolism, fructose and mannose metabolism, and amino acid biosynthesis pathways were found to be correlated with the taste variation.