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CHAPTER II

Literature review

2.1 Substrates used

2.1.1 Skim latex serum

Natural rubber latex (NRL) is a white and/or slightly yellowish opaque fluid with specific
gravity range from 0.97-0.98 depending on rubber content, rubber tree species and terrain
(Veerasamy and Ismail, 2012; Rippel et al., 2003). The natural latex as it comes from the rubber
tree (Hevea brasiliensis) usually contains between 30-40% of dry rubber content and the
remaining 60-70% being mainly non-rubber materials. Non-rubber material compositions of the
natural latex rubber was containing two major compositions that consist of the first composition
of serum, its density about 1.02 g/mL and contains the compositions of carbohydrates, proteins,
sugars, carotenoids and amino acids, and the second composition of lutoids, its mostly bigger in
size than the rubber particles (Sansatsadeekul et al., 2011; Santipanusopon and Riyajan, 2009).

2.1.1.1 Compositions of non-rubber materials in the serum

Non-rubber materials in the serum from concentrated latex production process by
centrifugation method contain a wide variety of chemical species, including carbohydrates,
proteins, sugars, carotenoids, fatty acids, amino acids and lutoids.

2.1.1.1.1 Carbohydrates

Mostly carbohydrates that found in natural rubber latex were 1-methylinositol or
quebrachitol has been estimated about 1%. Moreover, minor carbohydrates were also found in
the latex include glucose, sucrose, galactose and fructose.