Valorization of Mexican Rambutan Peel through the Recovery of Ellagic Acid via Solid-State Fermentation Using a Yeast

Rambutan (<i>Nephelium lappaceum</i> L.) is a tropical fruit that is originally from Southeast Asia and it was introduced to Mexico in the 1960s; the fruit’s peel is known to possess ellagitannins such as ellagic acid which give the peel great biological activity; solid-state fermentation has been used to obtain said compounds and rambutan peel can be used as a fermentation support/substrate; this work aims to obtain, identify and quantify ellagic acid obtained via SSF with a strain of yeast. The water-absorption index and the support’s maximum moisture were determined. To determine the ideal conditions for ellagic acid accumulation, a Box–Behnken 3^k experimental design was applied using variables such as temperature, moisture and inoculum. The maximum accumulation time of ellagic acid via solid-state fermentation was determined to be 48 h with ideal conditions of 30 °C, 60% moisture and 1.5 × 10⁷ cells/g using <i>S. cerevisiae</i>, and high-performance liquid chromatography was used to identify ellagic acid, geraniin and corilagin as the most abundant compounds. The maximum recovery of ellagic acid was 458 ± 44.6 mg/g. HPLC/ESI/MS analysis at 48 h fermentation showed biodegradation of geraniin and corilagin due to ellagic acid. Mexican rambutan peel has been demonstrated to be a suitable substrate for SSF.