• Food Science and Preservation
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• v.6 no.1
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• pp.66-70
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• 1999

The mechanism of natural removal of astringency and seasonal changes of tannin substance in sweet persimmon(Fuyu) and astrigent persimmon(Chungdo Bansi)were investigated. Tannin productivity of astringent persimmon fruit was higher than that of sweet perimmon fruit during growth. In the reactivity of tannin to acetaldehyde, it was observed that tannin from sweet persimmon have a milder chemical properties than that from astrigent persimmon. The threshold value of astringency on sweet persimmon tannin was higher than that of astrigent persimmon tannin. Tannin substances from sweet persimmon distributed mainly in lower molecular weight range at harvest stage, but those from astrigent persimmon distributed mainly in higher molecular weight range. Therefore, the natural removal of astringency was related to difference of tannin productivity, threshold value of astringency, reactivity and qualitative difference of tanni.

• Korean journal of food and cookery science
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• v.30 no.3
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• pp.351-359
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• 2014

The application of persimmon for making new products was investigated by analyzing the degree of astringency removal, softness of fruit, and sensory properties of Daebong persimmons (Diospyros kaki L) treated with three different astringency removal methods of steeping in water, steeping in 1% salt solution, and vacuum packing at $40^{\circ}C$. The weight of persimmon fruit increased with increasing steeping time, but decreased with increasing vacuum packing time. The fruit steeped in $40^{\circ}C$ salt solution (1%, w/w) was not detected with soluble tannin and not developed color with ferric chloride after steeping for 9 h. A total of 12 h of steeping time was required for removing soluble tannin using other methods. The lightness (L) in color and hardness in texture decreased when storage time increased, regardless of astringency removal methods. In overall, the preference was shown with the highest score in persimmon steeped in salt solution for 9 h and 12 h that were vacuum packed at $40^{\circ}C$. In conclusion, the astringency removal condition of Daebong persimmon was good after being steeped on 1% salt solution for 9 h at $40^{\circ}C$.

• Food Science and Preservation
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• v.6 no.4
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• pp.392-397
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• 1999

The quality changes during the removal of astringecy by CO$_2$gas at 2$^{\circ}C$ and 20$^{\circ}C$ of three varieties of persimmons named 'Tonewase', 'Chungdobanshi' and 'Sagokshi' were examined. Astringency index and tannin content showed rapid decrease at 20$^{\circ}C$ and gradual decrease at 2$^{\circ}C$. All was edible 2days from the removal of astringency at 20$^{\circ}C$, while 'Tonewase' and 'Sagokshi' were edible on 6days and 'Chungdobanshi' on 10days after treatment at 2$^{\circ}C$. Soluble solid contents was decreased a little(1∼3%) during the removal of astringency. Hardness was decreased slowly but, kept over 1.0kg/$\phi$5mm till edible period in all varieties at 2$^{\circ}C$ and 20$^{\circ}C$. The hardness of 'Chungdobanshi' was kept well after the removal of astringency at 2$^{\circ}C$. No noticeable color changes in all varieties during treatment. Injury fruits were noticeable in only 'Tonewase' after the removal of astringency treatment at 2$^{\circ}C$.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.105-108
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• 1977

The changes of the contents of acetaldheyde and alcohol in Chungdo Bansi was determined during the removal of astringency by treatment of $CO_2$. On the other hand, the difference of acetaldehyde and alcohol contents were determined to comparedits contents in the part of Chungdo Bansi and Buju, respectively. It showed that the variation of acetaldehyde and alchohol contents was higher 10 times non-astringent persimmon than astringent one, and acetaldehyde and alcohol contents in the core of non-astringent persimmon and sweep one were the higher than the other parts. It was assumed that acetaldehyde and ethanol contents had intimately relation to removal of astringency.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.99-103
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• 1976

The experiment was tested with fruits of eight varieties which were produced in Kyung Pook and Kyung Nam District and was carried out to investigate the changes of sobuble tannin content, hardness and sugar content during the removal of astringency, and, further more, the changes of quality after the removal of astringency. The results were as follows: 1. Soluble tannin content of Sagoksi was most in eight varieties and than was Euisung-Bansi and Chungdo-Bansi in that order. The time required of the removal of astringency tools 2.5 days in Dansungsi, 4.5days in Sagoksi. 2. Hardness was the firmest in Sagoksi and Chungdo-Bansi and it was gradually decreased as the harvest time of fruits was delayed. 3. In content of sugar, Gojongsi was most amount and Sagoksi was least amount in all varieties. Changes of sugar content showed a gradual decrease during the removal of astringency. 4. Quality of fruit after the removal of astringency was of a very superior quality in Chungdo-Bansi, Sagoksi and Euisung-Bansi.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.93-98
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• 1976

The experiment was made to investigate concentrations of $CO_2\;and\;O_2$ in the removal of astringency of persimmon fruits and to study the changes of total, reducing sugar and hardness during the removal of astringency. 1. During the removal of astringency of persimmon fruits, channel of tannin content showed the rapid decrease in high concentration of $CO_2$ and the gradual decrease in low concentration of $CO_2$. 2. Concentration of oxygen did not show effect on the removal of astringency at high concentration of $CO_2$ but at low concentration of $CO_2$ in Chungdo-Bansi. 3. Optimal concentration of the removal of astringency was $60{\sim}70%,\;CO_2$ and $6{\sim}8%\;O_2$ in Chungdo-Bansi and Sagoksi 4. In changes of sugar content total sugar was decreased and reducing sugar was increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.648-652
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• 1998

Astringency in persimmons was removed by immersing in 0.5% acetic acid or various concentrations(0.1%, 0.5%, and 1.0%) of chitosan solutions for 4 days at 18$^{\circ}C$. During 5-days immersion, soluble tannin contents in persimmons decreased more rapidly while pH, 。Brix, and hardness decreased more slowly with increasing chitosan concentration. No noticeable color changes and decay were observed during this period. Sensory analyses 4 days after immersion indicated that persimmons immersed in 1.0% chitosan solution showed the best results for firmness and overall acceptability.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.104-111
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• 1976

The experiment was tested with fruit of 5 astringent cultivars (Chungdo-Bansi, Sagoksi, Euisung-Bolbansi and Gyungsan-bansi) and was carried out to investigate effects of harvest time of fruit and fruit sizes on the removal of astringency and the practical utilization with Chungdo-Bansi was conducted. 1. Soluble tannin content was decreased in all cultivars as fruit was ripening and soluble tannin content at last harvest time was reduced about one half, as contrasted it's content at first harvest time and it showed that the times required of the removal of astringency was gradually shortened. 2. In soluble tannin contents was small fruit size was significantly higher than that of large fruit size. The times for the removal of astringency was required longer small fruit size than large fruit size. 3. In the changes of hardness according to fruit sizes, hardness of large fruit size was decreased rapider than that of small fruit size. This tendency became similar during and after the removal of astringency. 4. According to fruit sizes, sugar content of large fruit size was more amount than that of small fruit size During and after the removal of astringency, reduction of sugar content showed more rapidly large fruit size than small fruit size. 5. Results of the practical utilization in Chungdo-Bansi showed the promising market-ability and persimmons treated by carbon dioxide was increased more income than that treated by $CaC_2$.

• Food Science and Preservation
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• v.4 no.1
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• pp.45-51
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• 1997

In our studies on the role of $\beta$-galactosidase in fruit softening, significant difficulty, was encountered in our attempts to extract RNA from persimmon(Diospyros kaki L. cv. Fuyu) fruit due to astringency and tannin content. Initial, unsuccessful RNA extractions involved methods using guanidinium isothiocyanate/CsCl with and without polyvinylpyrrolidone(PVP), phenol/sodium lauryl sulfate(SDS), guanidinium hydrochloride, as well as polysomal RNA purification method that used 0.2 M Tris-HCI (pH 9.0) containing KCI, Mg-acetate, EDTA, $\beta$-mercaptoethanol, and sucrose. A method was devised which employed treatment of fruit with CO2 gas to diminish astringency prior to RNA extraction, followed by extraction of tissue powders with Proteinase K extraction buffer containing PVP and ascorbate at an alkaline pH. This procedure resulted in the removal of tannins and other polyphenolics and extraction of relatively large amount of high-quality RNA suitable for cDNA library construction and polymerase chain reaction(PCR). Futhermore, the procedure does not use the toxic and corrosive chemical guanidinium isothiocyanate or require ultracentrifugation.

• Food Science and Preservation
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• v.15 no.2
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• pp.225-230
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• 2008

We investigated the effect of modified atmosphere packaging (MAP) on the removal of astringency and overall quality of astringent persimmons (Diospyros kaki T. cv. Miryangbansi). Persimmons were packaged in 0.08, 0.10, or 0.12 mm low-density polyethylene film and then stored at $0^{\circ}C$ for up to 100 days. Concentrations of $O_2$ and $CO_2$ in the packaging maintained lower and higher as the film thickness increased Weight loss was strongly retarded by all three MAP films. Soluble tannin content decreased as the film thickness increased. The astringency of persimmons disappeared after 60-70 days in 0.12 mm film, after 80 days in 0.10 mm film, but did not disappear after 100 days in 0.08 mm film Loss of flesh firmness and decline in external appearance were slower in persimmons in 0.08 and 0.10 mm films than in those in 0.12 mm film. Our results show that 0.10 mm LDPE films can be effective for maintaining the quality and removal of the astringency of astringent persimmons.