Abstract: Random-Centroid Optimization (RCO) methodology were applied to optimize the extractions of polyphenols and procyanidins from the pulp and seed of Wuweizi (Schisandra chinensis). Six factors, including ethanol concentration, liquid-solid ratio, pH, temperature, heating time and extraction times were investigated. The polyphenol content (pulp) or procyanidin content (seeds), DPPH radical scavenging activity and yield were set as extraction targets. One set of optimum extraction parameters were obtained corresponding to each extraction target. The polyphenol content and yield of the pulp extracts with polyphenol content and yield as investigated targets were much higher than those with the DPPH radical scavenging activity as a target. However, no significant difference was observed on the DPPH radical scavenging activities of the three targets. Among all the seed extracts, those targeting procyanidin content showed a highest procyanidin content while those targeting DPPH scavenging activity or yield also demonstrated the highest extraction target values, respectively. The initial pH value were shown to be the most important factor in pulp polyphenol extraction, while in seed procyanidin extraction, the impact of extraction factors differed with the extraction targets.

Key words: Wuweizi (Schisandra chinensis), random-centroid optimization, polyphenols, procyanidins, extraction