Table 1: Extractable protein contents of nine different dry rubber grades, as determined by the RRIM modified Lowry method.

Dry rubber sample

No of sourcesa

Mean protein level, µg/g
(against BSAb)

1.SMR CV 5 <20
2.SMR L 6 <20
3.SMR 5 1 <20
4.SMR 10 5 <20
5.SMR 20 5 <20
6.RSSc 2 <20
7.Steam coagulated 1 <20
8.DNPRd (normal) 1 22
9.DNPR (food grade) 1 <20

a Samples of the same grade obtained from different producers. b Bovine Serum Albumin protein calibration standard.
c Ribbed smoked sheets. d Deproteinized natural rubber,prepared by enzyme treatment of latex.

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