Abstract: Orthogonal array design was employed to optimize the extraction of polyphenols from the seeds of pomegranate cultivar   Yushizi,, grown in Huaiyuan of Anhui province. The extraction efficiency of polyphenols was investigated with respect to ethanol concentration, temperature, extraction time, addition level of sodium hexametaphosphate as a chelating agent, pH and material/liquid ratio. The total phenol, total flavonoid, total proanthocyanidin contents of the whole seeds, kernels and husks of pomegranate and the in vitro antioxidant effects of their polyphenol extracts were compared. Better results for the extraction of polyphenols were achieved after 100 min of extraction under the conditions: pH 4.0, 60 ℃, 0.4% sodium hexametaphosphate addition, and 20:1 solid-to-liquid ratio. Pomegranate seeds were rich in proanthocyanidins as the major antioxidant components in it. Polyphenols especially proanthocyanidins were mainly present in the seed kernels of pomegranate.

Key words: pomegranate seed, pomegranate seed husk, pomegranate seed kernel, phenol, antioxidation