| Pummelo (Citrus grandis (L.) Osbeck) belongs to Rutaceae Citrus plants, originating in China and Southeast Asia.It has high nutritional value. Polyphenols are secondary metabolites produced during nonnal plant growth and some stress conditions.They have an important role in plant resistance, pest resistance and so on. Pummelo has delicious flavor and is beneficial for healthy at the same time. Pummelo is rich in polyphenols, such as flavonoids, phenolic acids, etc., which have functions of antioxidant, anti-inflammatory, anti-cancer, prevention of cardiovascular disease, diabetes and other effects. China is one of the main production areas of pummelo and has long cultivation history. There are many distinctive local cultivars. The systematic studies on the detection of active substances and antioxidant capacity of different parts of mature fruit of pummelo local varieties are less. This study took the fruits of ten Chinese local pummelos as an object.The total phenolic contents, total flavonoid contents, flavonoids contents and phenolic acids contents of flavedo, albedo, segment membrane, juice sac and seeds were detected. In addition, the antioxidant capacity of these five parts were evaluated by DPPH, FRAP and ABTS methods, the correlation between the phenolic compositions and the antioxidant capacity of each part were analyzed. The main results were as follows:(1) Comparison of total phenolic contents of different parts:albedo (9.67 mg GAE/g DW)> flavedo (8.24 mg GAE/g DW)> juice sac (7.07 mg GAE/g DW)> segment membrane (6.77 mg GAE/g DW)> seeds (3.72 mg GAE/g DW); Comparison of total flavonoid contents of different parts:seeds (32.4 mg RE/g DW)> flavedo (17.2 mg RE/g DW)> albedo (9.15 mg RE/g DW)> segment membrane (8.39 mg RE/g DW)> juice sac (6.85 mg RE/g DW). The highest total phenolic contents in flavedo, albedo, segment membrane, juice sac and seeds were C. grandis "Hongxinyou", C. grandis "Guanximiyou", C. grandis "Guanximiyou", C. grandis "Zhenlongyou No.3" and C. grandis "Zhenlongyou No.3"; the highest total flavonoid contents in flavedo, albedo, segment membrane, juice sac and seeds were C. grandis "Liangpingyou No.78-8", C. grandis "Guanximiyou", C. grandis "Guanximiyou", C. grandis "Liangpingyou No.78-8" and C. grandis "Yubei shatianyou"(2) Comparison of flavanones contents of different parts:flavedo (178.32μg/g DW)> albedo (165.84μg/g DW)> segment membrane (126.67μg/g DW)> juice sac (42.92μg/g DW)> seeds (2.38μg/g DW). Comparison of flavones contents of different parts:segment membrane (251.39μg/g DW)> albedo (119.79μg/g DW)> juice sac (94.04μg/g DW)> flavedo (77.79μg/g DW)> seeds (0.16μg/g DW). The highest flavanones contents in flavedo, albedo, segment membrane, juice sac and seeds were C. grandis "Yubei shatianyou"’, C. grandis "Dianjiangbaiyou", C. grandis "Kuiyou", C. grandis "Kuiyou" and C. grandis "Dianjiangbaiyou"; the highest flavones contents were C. grandis "Kuiyou’’, C. grandis "Guanximiyou", C. grandis "Wubuyou", C. grandis "Liangpingyou No.78-8", C. grandis "Wubuyou".(3) Comparison of phenolic acids contents of different parts:juice sac (309.87μg/g DW)> flavedo (250.27μg/g DW)> segment membrane (169.11μg/g DW)> albedo (84.13 μg/g DW)> seeds (12.74μg /g DW). The highest phenolic acids contents in flavedo, albedo, segment membrane, juice sac and seeds were C. grandis "Dianjiangbaiyou", C. grandis "Dianjiangbaiyou", C. grandis "Guanximiyou", C. grandis "Wubuyou", C. grandis "Zhenlongyou No.3"(4) Antioxidant capacity was related to detection methods. The DPPH value comparison of different parts:flavedo (152.12μmol TE/g DW)> juice sac (120.52μmol TE/g DW)> segment membrane (70.92μmol TE/g DW)> albedo (67.13μmol TE/g DW)> seeds (42.42 μmol TE/g DW); the FRAP value comparison of different parts:flavedo (140.21μmol TE/g DW)> juice sac (79.39μmol TE/g DW)> segment membrane (62.89μTE/g DW)> albedo (44.92μmol TE/g DW)> seeds (38.55μmol TE/g DW); the ABTS value comparison of different parts:albedo (16.18μmol TE/g DW)> flavedo (11.55μmol TE/g DW)> segment membrane (10.25μmol TE/g DW)> juice sac (8.12μmol TE/g DW)> seeds (3.85 μmol TE/g DW). The highest antioxidant capacity using the antioxidant potency composite index in flavedo, albedo, segment membrane, juice sac and seeds were C. grandis "Yubei shatianyou", C. grandis "Dianjiangbaiyou", C. grandis "Guanximiyou", C. grandis "Liangpingyou No.78-8" and C. grandis "Yubei shatianyou"(5) Correlation analysis between antioxidant capacity and total phenolic contents, total flavonoid contents indicated that the total phenolic contents of flavedo showed significant positive correlation with the DPPH, FRAP, ABTS methods (P< 0.01); the total phenolic contents and the total flavonoid contents of albedo showed significant positive correlation with the DPPH, FRAP, ABTS methods (P<0.05); the total phenolic contents and the total flavonoid contents of segment membrane showed significant positive correlation with the ABTS method (P< 0.01); the total phenolic contents and the total flavonoid contents of juice sac showed significant positive correlation with the DPPH, FRAP, ABTS methods (P< 0.05); the total phenolic contents of seeds with DPPH, FRAP, ABTS, FRAP methods and the total flavonoid contents with FRAP method showed significantly correlated (P< 0.05). |
PDF Full Text Request