Structure Identification and Antioxidant Activity of Chlorophyll in Yichang Green Meat Kiwifruit

To explore the chlorophyll component and its antioxidant activity in kiwifruit,taking Yichang green meat kiwi fruit pulp as experimental material. Using solvent extraction and column chromatography,6 kinds of high-purity substances including chlorophyll a were obtained through separation and purification. The molecular weights ofM+H⁺ were obtained by mass spectrometry.Combined with nuclear magnetic resonance data,the structure of five kinds of chlorophyll-related substances was speculated,in which C₁ was chlorophyll a. The molecular weight of M+H⁺ of the material A₁ was 927.6967,the molecular formula was C₅₅H₈₄O₇N₄;the molecular weight ofM+H⁺ of the substance B₁ was 588.4304,the molecular formula was C₃₄H₃₃O₅N₄;the molecular weight ofM+H⁺ of the substance D₁ was 601.1116,the molecular formula C₃₅H₃₄O₅N₄,the structure was estimated to be pheophorbide a;the molecular weight ofM+H⁺ of the substance E₁ was 927.6985,the molecular formula was C₅₅H₈₄O₇N₄;the molecular weight ofM+H⁺ of the substance F₁ was 701.5039,and the molecular formula was C₃₇H₃₈O₉N₄.At the same time,the antioxidant activity of the single product was studied by DPPH method and Fe³⁺ reduction method. The results showed that when mass concentration was 0. 12 mg/mL,the clearance rates were 93.14% and 93.39%,respectively,which was slightly lower than the 96.49% clearance rate of V_C. At a mass concentration of 1.0 mg/mL,the absorbance values of the substances E₁ and F₁ were both 1.92,which was second only to 1.95 of V_C. The structure of five chlorophyll-related substances was discovered and presumed,and all of them had certain antioxidant activities,among which E₁ and F₁ were the most active.