| At middle-subtropical wet hot and less sunshine laurlsilvae-forest region, Jianyang, Sichuan (30.2ç™—,104.6?E), applying 3~4-year old, different Japanese persimmon varieties (a pollination-constant non-astringent cultivar, Diospyros kaki L. cv. Jiro and three pollination-variant astringent cultivars, Diospyros kaki L. cv. Nishimurawase and Tenjingosho et al.) as testing materials, changes in the main quality indexes during fruit growth and maturation of Japanese persimmon, effects of seed number in fruit and treatment with ethylene and bagging on fruit qualities were studied, the result showed:1. During the course of fruit developing and maturating, main quality indexes of Japanese persimmon had changed. The growth curve of Japanese persimmon was double sigmoid pattern, soluble tannin content decreased significantly with the development of fruit, but the mostly time and speed of removal astringency were different for different astringency-type, therein PCNA varieties (eg. Jiro) removed astringency mostly in June, but PVNA varieties (eg. Nishimurawase and Tenjingosho) did from June to time of fruit pre-maturation. Soluble solid content, soluble sugar content, reducing sugar content, reducing sugar content/soluble sugar content and Vitamin C content increased to the highest point and then fell down, but titratable acid content possessed a increasing trend during the course of fruit maturation. The main quality indexes of persimmon, for example fruit weight, firmness, soluble solids content, soluble tannin content, soluble sugar content, titratable acid content, were significantly positively linear correlated with the number of days after blooming. Vc content and CAT activity were different for different de-astringency type persimmon. Planted in middle-subtropic, the early ripping variety 'Nishimurawase' ripped earlier than planted in Japanese or Hangzhou, but the middle-late ripping varieties ripped almost at the same time.2. Under the eco-environment of experimental region, the fruit whose seed42number was 2 could remove astringency completely. The shape of fruit apex embodied its seed number, fruit apex of fruit whose seed number was more than 4 was protruding, that of fruit whose seed number was between 2 and 4 was flat and that of fruit whose seed number was fewer than 2 was concave. Soluble tannin content of fruit was correlated greatly with its seed number, shape of fruit apex and grade of flesh browning, so de-astringency complete or not could be judged from the shape of fruit apex. The more the seed number was, the severer the flesh browning was and the lower soluble tannin content was. Additional, soluble tannin content of fruit was significant correlated with its fruit weight, titratable acid content and CAT activity , but it had no relation with soluble sugar content. Using the 11 measured indexes to express soluble tannin content of fruit, regression equation was that Y (soluble tannin content) =0.771-0.112X4 (grade of flesh browning) -0.0041X10 (Cx activity). If using the grade of flesh browning only to express the astringency condition, regression equation was that Y=0.602-0.148X4.3. Dipping persimmon fruit with ethylene solution, the softening and coloring of fruit was promoted in evidence, firmness decreased rapidly, SSC increased, the solute leakage of fruit pricked up and carotenoid content of pericarp increased. The sweet persimmon are superior to astringent persimmon in the shelf life and the firmness of fruit removed astringency completely. Treated with ethylene, the fruit would not suit for being large distance transported and being stocked; but maturating of persimmon could be advanced, so this is gainful of coming into the market earlier.4. Effects of bagging on the fruit quality of persimmon. Bagging fruit could avail removal astringency in prophase of fruit growth, but influenced fruit flavor. SSC, sugar content, acid content and Vc content of bagged fruit was lower than that of fruit with no bagging, moreover impact of double-la...
|
PDF Full Text Request