Abstract
Silphium integrifolium Michx. (Silflower) has been a promising
subject for domestication as a perennial oilseed crop. This work was
carried out to investigate the seed processing aspect of this effort.
Selected physical properties of the seed were evaluated, seed milling to
obtain enriched kernel fraction was conducted, and initial
characterization of the seed protein was performed. There was wide
variation in flat seed length (11.54 to 20.75 mm), width (4.61 to 11.76
mm), and thickness (0.92 to 1.63 mm). The thousand seed weight was 23.8
g but the tapped bulk density was only 189.58 g/L due to the presence of
wing around the seed’s periphery. The kernel accounted for 56.14% of
the seed weight and contained 31.00% oil. An enriched kernel fraction
with 79.6% purity was obtained by roller-milling, sifting, and air
classification. Linoleic (62.3%) and oleic (19.62%) acids were the
major fatty acids in the oil. The defatted enriched kernel fraction
contained 63.41% crude protein. Globulin, glutelin, albumin, and
prolamin accounted for 55.63%, 19.28%, 16.38%, and 8.71% of the
soluble proteins, respectively. At an extraction pH of 9, protein
solubility was 62%. Maximum solubility (70%) was obtained at pH 10
while minimum solubility of 9% occurred between pH 4 and 5.5. Aside
from the oil, the dehulling of silflower seeds also produced a
high-protein defatted meal, which may be used as is or as a starting
material for enriching the protein further into a protein isolate.