Growth Phenology of Tubers and Accumulation of Metabolite Compounds on Two Accessions of Jicama (Pachyrhizus erosus L.)

Jicama (Pachyrhizus erosus L.) is a tropical tuber crop that has potential not only as a food source but also as a natural active ingredient in the cosmetics industry. This study aims to evaluate the phenology of tuber development and the content of primary and secondary metabolites of two jicama accessions (Bogor and Kebumen) at three tuber ages (3, 4, and 5 months). The parameters observed included tuber weight, starch yield, total soluble solids (TSS), total titratable acidity (TTA), vitamin C, total phenols, total flavonoids, and antioxidant activity (% inhibition). For data analysis, we used the T-test to compare differences between accessions. The results showed that tuber weight and starch yield increased significantly up to 5 months of age, while secondary metabolite content (phenols, flavonoids, antioxidant activity) was higher in young tubers (3–4 months). This study shows a trade-off between productivity (starch and vitamin C) and bioactive metabolite content (phenols, flavonoids, antioxidants) as the tubers age. The Bogor accession has a more stable vitamin C content, phenol levels, and antioxidant activity, while the Kebumen accession shows higher flavonoid levels in young tubers. The optimal tuber age and accession recommended to obtain a balance between productivity and secondary metabolite content is the Bogor accession at 4 months of age. This supports the potential use of jicama in the cosmetics industry as a brightening agent (vitamin C), humectant (sugar), anti-aging agent (phenols, flavonoids), and base ingredient for natural starch-based formulations. This study provides the first integrated evaluation of tuber phenology, primary metabolites, and secondary metabolite dynamics of two Indonesian jicama accessions in relation to cosmetic functionality. The results highlight a clear trade-off between productivity and bioactive compound accumulation, offering a scientific basis for selecting optimal harvest age and accession for cosmetic raw materials This study provides the first integrated evaluation of tuber phenology, primary metabolites, and secondary metabolite dynamics of two Indonesian jicama accessions in relation to cosmetic functionality. The results highlight a clear trade-off between productivity and bioactive compound accumulation, offering a scientific basis for selecting the optimal harvest age and accession for cosmetic raw materials.