| ’Fangshan’ persimmon (Diospyros kaki Thunb.) is an increasing important fruit in the word due to its superior nutritionand officinal values. The picking time is crucial for the quality of persimmon. The summer strong light of the southern harm normal growth and development of’Fangshan’ persimmon, which leading to its dry leaves, deciduous fruit drop and seriously affecting the quality of the fruit. In September, when the fruit began to mature, the leaves and branches affected the normal growth and fruit quality of persimmon. Therefore, shading in July and August, and reflective film mulching in September and October play an important role in normal development of persimmon, Evaluation of the degree of fruit ripeness and the changes of internal chemical parameters during the development of persimmon can satisfy growers’ selective harvest requirement and bring high economic performance. In addition, growers can decide real-time watering, fertilizing, and other measures, to achieve precise management of persimmon production according to the testing indexes such as fruit maturity and sugar concentration. Recently, the nondestructive techniques have been widely used because of rapid, accurate and non-destructivity. However, at the same time, many instruments used in the nondestructive techniques are costly and difficult to carry to the fruit orchards. Though there are much high nutrients content in fresh persimmon fruit, it tends to soften and easy to lose nutrient at room temperature. To solve the problems above, we have done some researches. The main contents and results can be listed as follows:(1) The study was to evaluate the quality changes and the optimum time for harvesting of persimmon fruit (Diospyros kaki L. cv. Fangshan) under different shading degrees and reflective film mulching. Our results showed that the specific gravity of persimmon fruits with 20% shading and reflective film mulching was higher than other treatments, indicating that 20% shading treatment contributes to the formation of persimmon quality and yield. At the beginning of fruit ripening, total phenolic content significantly increased under the 20% shading and reflective film treatment. In addition, during the fruit riping stages, total phenolic showed positive and significant correlation with DPPH and ABTS+ radical scavenging activity (0.809≤r≤0.849, P<0.01). And the results indicated that total phenolic may contribute more significantly to the total antioxidant capacity than the total flavonoids and ascorbic acid in persimmon fruits.(2) The use of chlorophyll fluorescence measurements and RGB intensity values to noninvasively evaluate changes of the internal nutriments (soluble tannin, ascorbic acid, total phenols, total flavonoid, DPPH and ABTS cation radical scavenging activities and soluble sugar) was investigated during all the development stages (ST) of persimmon fruits under diffetent shading degrees and with or without reflective film treatments in this study. Our resulted showed that chlorophyll fluorescence and RGB intensity have different correlations with the internal nutriments of persimmon fruits in this study. Therefore, it is necessary to select the appropriate method of persimmons’nutriments under different treatments for nondestructive evaluation.(3) The combined use of postharvest treatments,5% CO2 and 1-methylcyclopropene (1-MCP), was evaluated to assess effect of storage temperature (1℃ and 20 ℃) on nutritional quality of ’Fangshan’ persimmon. The 1-MCP and 5% CO2 treatment during cold storage can prolong storage life of ’Fangshan’ persimmon for over 4 months. Ascorbic acid, total phenols and total flavonoid slowly decreased at 1℃ treated with 1-MCP and 5% CO2, and the content of ascorbic acid, total phenols, total flavonoid, DPPH and ABTS+ were higher than the fruits storage at room temperature. Further, sweetness exhibited a slight increment at 1℃ generally, and higher than that of the fruits storage at room temperature. Radical scavenging activity was significantly related to the soluble tannin content of the fruits. Moreover, total phenols, soluble tannin and total flavonoid were significantly positively correlated to DPPH (0.508≤r≤0.624, P<0.01) and ABTS+(0.597≤r≤0.647, P<0.01) radical scavenging ability, respectively. Sucrose was negatively and significantly correlated with fructose and glucose with r of -0.479 (P<0.01),-0.309 (P<0.05), respectively. Glucose was significantly positively correlated with fructose with r of 0.725 (P<0.01).In conclusion, the hading and reflective film mulching can avoid the harm of summer high temperature on the persimmon, and improve fruit quality. Meanwhile, chlorophyll fluorescence and RGB values are effective methods to evaluate the quality changes of persimmon.In addition, using 1-MCP, low temperature and CO2 concentration in persimmon storage can bringing high nutrients content and translating into higher economic performance. |
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