Optimization of an Aqueous Enzymatic Method and Supercritical Carbon Dioxide Extraction for Paeonia suffruticosa Andr. Seed Oil Production Using Response Surface Methodology (RSM)

Abstract

Peony seed oil, a type of tree nut oil, has attracted the attention of nutritionists for its rich nutritional content. The aim of this study was to extract oil from the peony seed utilizing green and efficient methods. Specifically, aqueous enzymatic extraction was optimized using the Plackett–Burman design combined with the mixture design to extract the optimal enzyme ratio of peony seed oil. When the dosage of enzymes was 10 mg protein/g peony seed, the optimal ratios of the dosages of papain, cellulase, and pectinase were 16.15%, 31.33%, and 52.53%, respectively. Subsequently, central composite design was adopted to optimize supercritical CO2 extraction to identify the process parameters of extracting residual oil from the residue of the aqueous enzymatic extraction. Almost 6.30% of peony seed oil could be obtained from the residue using continuous extraction for 1.58 h at 49.41 °C and 59.75 Mpa. After mixing the peony seed oil extracted by the two processes, its physicochemical indices were measured. Compared with commercial peony seed oil extracted based on the organic solvent leaching method, the elative density and iodine value were higher based on our approach, whereas the other indices showed no significant differences. Thus, the two-step strategy combining the aqueous enzymatic method and supercritical CO2 extraction can be effectively applied to peony seed oil production.