Grapefruit of Guipuyou No. 1 planted in Guangxi has high and stable yield, and the flesh is juicy, suitably acidic and sweet. The widely targeted metabolisms of flesh was determined, the differential metabolites were screened and the metabolic pathway was analyzed to understand the difference of flesh composition at different maturity stages. A total of 529 metabolites were detected from grapefruit of Guipuyou No. 1, including 159 flavonoids, 64 Phenolic acids,64 amino acids and derivatives, 53 others (saccharides and alcohols, vitamin, others), 51 lipids, 40 lignans and coumarins,34 nucleotides and derivatives, 29 alkaloids, 28 organic acids, 5 terpenoids and 2 tannins. The differential metabolites at different maturity stages mainly included flavonoids, phenolic acids, amino acids and their derivatives, lipids, lignans and coumarins, and most of them were down-regulated. The down-regulated types of phenolic acids, amino acids and their derivatives, lipids and other types increased, and most of them showed a continuous downward trend with the increase of fruit ripeness. Most of the down-regulated flavonoids showed a sharp decline in the early stage of fruit ripening, and then increased in the late stage of fruit ripening. The types of down-regulated flavonoids first increased and then decreased, with the most in the middle stage of fruit ripening. The relative contents of synephrine, spermidine, betaine, shikimic acid were consistently decreasing. The relative content of limonin increased in the early stage of fruit ripening, and decreased significantly in the middle and late stage of fruit ripening. The most significant enrichment pathway of differential metabolites was flavonoid biosynthesis in the early stage of fruit ripening, but it was phenylpropanoid biosynthesis during the whole ripening process. The fruit of G2 had the best taste, with soluble solids of 12% and solid-acid ratio of 23.24, which was suitable for fresh eating. However, phenolic acids such as caffeic acid and ferulic acid, flavonoids such as isoquercitrin and hyperoside decreased significantly during this period. There were many kinds of metabolites in the pulp of grapefruit of Guipuyou No. 1, which was rich in nutritional and functional components. The best picking time for fresh food is from late October to middle November. Fruits used for health care or medicinal purposes should be picked in advance according to the efficacy requirements. This study would provide a theoretical basis for the study on the nutritional and functional components of grapefruit of Guipuyou No.1, and provide a reference for the best harvest maturity of its different uses.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |