Abstract: Objective: To investigate the effects of temperature, time and ethanol concentration and material/liquid ratio on proanthicyanidins extraction from Amur grape seeds through single-factor and orthogonal tests and to explore the optimal extraction process. Methods: Ethanol was used for the extraction of proanthicyanidins. The total content of flavan-3-ol monomers and proanthicyanidins (both of them can be simultaneously extracted by ethanol) was determined by vanillin method, and the method used to determine the content of flavan-3-ol monomers was HPLC. Thus, the content of proanthicyanidins could be calculated as the difference between the two determined values. Results: The optimal extraction process conditions were extraction temperature of 60 ℃, ethanol concentration of 70%, extraction time of 120 min and material/liquid ratio of 1:5 (g/mL). Conclusion: Under the optimal extraction conditions, the extraction rate of proanthicyanidins from Amur grape seeds was up to 3.12%.

Key words: Amur grape seeds, proanthocyanidins, extraction, vanillin, HPLC