EFFECTS OF STORAGE ON THE MOLECULAR-WEIGHT OF RUBBER CONTAINED IN GUAYULE

The guayule shrub, native to the Southwestern United States, is a potential source of domestic natural rubber. Research has been involved primarily with breeding and variety selection, development of analytical methodology for determining rubber quantity, and establishing technically and economically feasible processing technology. A study was undertaken to identify parameters that influence the postharvest stability of guayule rubber. Freshly harvested, coarsely ground shrub was stored at various temperatures rnging from freezing conditions to elevated temperatures likely to be encountered where guayule is grown. These initial studies clearly establish the sensitivity of unprotected guayule rubber (no antioxidants) in respect to the rate and extent of oxidative degradation with increasing temperature.