Deciphering the metabolic patterns of cashew apple ripening process: A comprehensive non-targeted metabolomics analysis

Metabolite changes during the ripening process of cashew apples are crucial for their quality development. A total of 2379 metabolites were isolated and identified from fresh cashew apples at four different ripening stages using UHPLC-MS. Metabolite set enrichment analysis (MSEA) revealed that the differential metabolites in CA2_vs_CA1, CA3_vs_CA2, and CA4_vs_CA3 comparisons were mainly enriched in amino acids and peptides, steroids, pyrimidines, and fatty acids and conjugates, etc. Volcano plot analysis identified 631, 384, and 392 upregulated metabolites, and 625, 923, and 392 downregulated metabolites in CA2_vs_CA1, CA3_vs_CA2, and CA4_vs_CA3 comparisons, respectively. KEGG pathway enrichment analysis demonstrated that these differential metabolites were primarily involved in aminoacyl-tRNA biosynthesis, purine metabolism, and glycine, etc. Notably, the differential metabolites in CA4_vs_CA3 showed the highest enrichment in d-glutamine and D-glutamate metabolism, as well as phenylalanine. The metabolic profile of cashew apples revealed stage-specific patterns during ripening, offering key insights for optimizing harvest, storage, and processing.