Abstract:
A non-edible plant, Jatropha curcas, is useful for biodiesel production due to rich oil content in the seed.
However, deoiled seed residues, seed cake, have not yet been effectively utilized so far, even though it is
rich in protein. In this study, we explored suitable strain of genus Monascus to advance anti-oxidant
capacity of the Jatropha seed cake, and investigated the chromatogram profiles to find characteristic
peaks. Sun-dried Jatropha seed cake was defatted, adjusted to 70% moisture, and used as a culture
substrate in a solid-state fermentation for Monascus fungi. Water-extract of Jatropha seed cake fermented
with M. purpureus NBRC31842 out of 30 strains of genus Monascus showed the highest anti-oxidant
activities, about 3-fold higher than those of non-inoculated control, in both oxygen radical absorbance
capacity (ORAC) assay and l,l-diphenyl-2-picryl-hydrazyl (DPPH) assay. The profiles of products
generated by M. purpureus NBRC31842 fermentation at.30D C .for 14 days were investigated using
reverse-phase C18 HPLC column chromatography. Almost all peaks detected in the water-extract of non-inoculate control were confirmed in the Monascus fermented Jatropha seed cake, and we found that some
of them were enhanced by fermentation. In addition, these peak areas increased in the water-extract of
Monascus fermented seed cake, which means that Monascus fungus degrade abundant protein in the
Jatropha seed cake during fermentation, and increase the anti-oxidant peptides. These results suggest
that the fermentation of Jatropha seed cake, by-product of biodiesel production, by Monascus fungi might
contribute to advance of anti-oxidant capacity, and it may be useful as a livestock feed.
