Effect of Different Heating Temperatures and Treatment Methods on the Active Compounds and Antioxidant Activities of Ziziphus Jujuba cv. Huizao

Five heat treatment methods including hot-air drying at 60 ℃, pasteurization at 80 ℃, four kinds of baking (110~140 ℃), steaming at 100 ℃ and boiling at 100 ℃ were used to treat Ziziphus jujuba cv. Huizao. The effect of different heating temperatures and heat treatment methods on total phenol content, total flavonoid content, total procyanidin content, phenolic compounds content, triterpenic acids content and antioxidant capacities of jujube were analyzed. The results showed that the active compound contents and antioxidant activities of jujube decreased after hot-air drying at 60 ℃, pasteurization at 80 ℃, steaming at 100 ℃ and boiling at 100 ℃. And the active compound contents in baked jujube at 110~140 ℃ showed an upward trend with the increasing of temperature. After baking at 140 ℃, the contents of total phenol, total flavonoid, total procyanidin and total triterpenic acids reached 341.3, 473.8, 659.3 and 560.4 mg UAE/100 g m_d. Baking treatment enhanced the antioxidant activities of jujube. After baking at 130 ℃, the DPPH· scavenging capacity of jujube reached 62.97 mmol TE/100 g m_d, and the ABTS⁺· scavenging capacity reached 47.96 mmol TE/100 g m_d. After baking at 130 and 140 ℃, the contents of active compound in jujube were higher than other groups and the antioxidant activities were stronger than other groups, so baking would be a suitable heat treatment methods for Ziziphus jujuba cv. Huizao processing.