How pressure and filter material affect extraction of sunflower latex rubber

• We evaluated how sunflower homogenate is affected by filter material and hydraulic pressures during the filtering and pressing.
• Polypropylene fabric and Dacron® materials had significantly lower press efficiencies than cheesecloth, but in reality those efficiencies were only approximately 1% point lower than cheesecloth.
• Filter material and pressing pressure did not affect acetone, methanol, or cyclohexane extractables.
• Researchers can obtain reliable results over a wide range of pressures when using cheesecloth and possibly other filter materials.

Extraction and quantification of latex rubber in plant species requires the filtering of latex homogenate, often by applying pressure to the homogenate to separate fluids (latex) from plant matter (bagasse). The filter material used for filtering homogenate has varied. The objective of this study was to evaluate how sunflower homogenate is affected by filter material (cheesecloth, tight weave polypropylene fabric, and Dacron® loose weave material) and hydraulic pressures during the filtering and pressing phase of latex extraction and quantification. Also, we desired to know how pressing procedures (filter material and pressing pressure) affect the quantification of extractables (resin and rubber) in sunflower leaf tissue. Leaves were harvested from field-grown sunflowers during three growing seasons at the R-6 stage of maturity at the Western Colorado Research Center at Fruita, Colorado. Highest press efficiencies were obtained with cheesecloth. Polypropylene fabric and Dacron® materials had significantly lower press efficiencies than cheesecloth, but in reality those efficiencies were only approximately 1% point lower than cheesecloth. Thus, it may be possible to use other materials for pressing without a major loss in performance. Pressure had little effect on the parameters studied. Six pressures ranged from 3.4 to 17.2 MPa and did not affect press efficiency, dry matter in the homogenate, or the acetone, methanol, or cyclohexane extractables. Filter material and pressing pressure did not affect acetone, methanol, or cyclohexane extractables. These results indicate that researchers can obtain reliable results over a wide range of pressures when using cheesecloth and possibly other filter materials.