Unveiling the effects of metabolites on the material properties of natural rubber by the integration of metabolomics and material characteristics

Natural rubber (NR) is an important material with excellent physical properties. Unlike synthetic rubber from petroleum, NR contains non-rubber components such as proteins, lipids, and metal ions. The non-rubber components are known to affect the properties of NR. In this study, latex samples of Hevea brasiliensis were collected for nine months and their metabolites were comprehensively analyzed by mass spectrometry. NR was made from the same latex samples used for the mass spectrometry, and their vulcanization, tensile and thermal-aging properties were assessed. By using this approach of integrating metabolite and property data, we aim to clarify the influence of metabolites on the physical properties of NR. These results suggest that the metabolite composition in the latex and the NR properties changed seasonally. Correlation analysis between the metabolites and the properties of NR indicated that different metabolites affected different properties. A regression model of NR properties using metabolites as the explanatory variables suggests that about five metabolites need to be considered when examining the relationship between properties and metabolites. This method, which combines comprehensive analysis and characterization of NR, contributes to studies aimed at elucidating how the superior properties of NR are brought about.