Natural rubber (NR) is a renewable resource collected from the tree Hevea brasiliensis with the chemical structure of cis-1,4-polyisoprene [1, 2] . NR is an important elastomeric material used to produce rubber articles such as tires, automotive parts, gloves, condoms, medical devices, and so on [2, 3] . Various outstanding properties of NR including elasticity, strength, elongation at break, and resilience make the material suitable for many flexible engineering applications. However, NR

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... ts of a small amount of non-rubber components such as proteins, lipids, carotenoids etc. [4, 5] . Polyphenol is the most important component that causes discoloration of NR [6, 7] . It is due to the presence of polyphenols that orthoquinones are generated by oxidation. These quinones react with the non-rubber constituents such as protein present in the NR latex that, changes the color 871