To develop proper processing methods for valorizing Gardenia Fructus oil press cake (GFPC), different pre-treatments were investigated to recover the phytochemicals from this industrial side stream. Chromatographic and mass spectrometric analyses were applied to assess the efficacy of the pre-treatments in releasing phytochemicals. Among the physical treatments studied, grinding enhanced the release of iridoids and crocins to the greatest extent. Geniposidic acid, crocin I and crocin II were obtained in the maximal contents as the dominant compounds in these two critical groups. Fermentation resulted in enrichment of iridoid glycoside, especially geniposide. Enzymatic treatments enhanced the release of phenolic acids from GFPC, particularly p-coumaric acid, caffeic acid, and sinapic acid by Viscozyme. Genipin, the key precursor compound for manufacturing gardenia red and blue, was enriched by treatments with cellulase and Viscozyme. The study showed that different pre-treatments can be selected for releasing target components from GFPC. The result will be helpful in providing industry with phytochemical compositional information of GFPC and creating value-added ingredients for various applications in food and health.
