Post-harvest stability of latex in different sizes of guayule branches

Commercial development of hypoallergenic latex from Parthenium argentatum ( Gray) for the manufacture of latex medical and household goods, is hampered by the lack of information on latex stability in the harvested shrub prior to processing. In this paper, we investigate the effect of post-harvest st orage on extractable latex content of guayule branches. We found that harve sted guayule branches can be stored at 4 degrees C for at least 2 weeks wit hout compromising latex yield, provided that dehydration does not occur. Wh en stored hydrated at 4 degrees C, latex levels declined between 2 and 5 we eks in all branch sizes with the most latex lost from the smallest branches and the least from the medium ones. The latex levels declined due to a com bination of conversion of latex into solid rubber in situ and rubber degrad ation, depending upon the branch size. Overall rubber degradation from the latex and solid rubber pools in the branches was substantial in the smalles t branches, but was not seen in the largest. Latex levels declined more qui ckly at warmer temperatures, even when the branches were hydrated, and were adversely affected by even slight dehydration. Published by Elsevier Scien ce B.V.