73 1. Introduction Persimmons are the edible fruits of deciduous trees in the genus Diospyros, many of which originated in China (Martínez-Calvo et al., 2012), even though some species are native to other parts of the world, including D. lotus, or date plum, which is native to southwest Asia and southeast Europe. The fruit was called “fire of the gods”, or Dios pyros by the ancient Greeks, thus the name of the genus. Persimmons produce popular and nutritious fruits that have become traditional crops in Korea and Japan and are found throughout the world (Veberic et al., 2010; Dem- bitsky et al., 2011; Giordani et al., 2011). They are sweet and are relatively good sources of carotenoids, vitamin C, polyphenols and proanthocyanidins (Gu et al., 2008; Dembitsky et al., 2011; Giordani et al., 2011). Moreover, persimmons have been reported to have health benefits in both traditional and western medicine (Giordani et al., 2011). For example, persimmons of the Triumph variety improved lipid metabolism and atherosclerosis indices in rats that were fed a diet that was high in cholesterol (Go- rinstein et al., 1998; 2011). The most cultivated species is the D. kaki Thunb. (Mar- tínez-Calvo et al., 2012; USDA, 2012), also known as Chinese persimmon, Japanese persimmon, kaki, caqui and Diospyros kaki L. (Martínez-Calvo et al., 2012; USDA, 2012). There is also a species (D. virginiana) that is na- tive to eastern North America (Celik and Ercisli, 2008). Persimmons are climacteric fruits (Veberic et al., 2010). That is, the amount of sugars (particularly sucrose) and total carotenoids increase in the final stages of ripeness and firmness, while soluble tannins and titratable acidity levels decrease, resulting in improved flavor (Candir et al., 2009). In the northern hemisphere, they are harvested be- tween September and December (Dembitsky et al., 2011). On the other hand, the Brazilian caqui cultivar called ‘Giombo’ is very productive and matures late, with fruits being picked from March to the end of May (Martins and Pereira, 1989). This relatively short harvest season, coupled with the lack of information about storage, limits its expansion and causes loss- es in the final processing and marketing of the fruit (Donazzolo and Brackman, 2002). Persimmon cultivars are classified into four groups: pollination-constant astringent, pollination- variant astringent, pollination-constant non-astringent, and pollination-variant non-astringent (Campo-Dall’Orto et al., 1996; Celik and Ercisli, 2008). Persimmons have also been divided into a volatile-independent group (VIG, corresponding to the pollination-constant non-astringent group) and the volatile dependent group (VDG, consisting of the pollination-constant astringent, pollination-variant astringent and pollination variant non-astringent types) (Giordani et al., 2011). Tannins in the VIG type are usually Effect of active modified atmospheres on the quality of non-astringent persimmons (Caqui Giombo) D. kaki Thunb. when stored under refrigerated conditions M.R. De Moraes*, É.R. Daiuto*, R.L. Vietes*, N.C. Cardoso*, R.E. Smith** (1) * Faculty of Agronomic Sciences, UNESP Botucatu, C.P. 237, Botucatu 18610307, SP, Brazil. ** U.S. FDA, 11510 W 80st, Lenexa, KS 66224, USA. Key words: Caqui Giombo, Diospyros kaki L., firmness, persimmon, postharvest. Abstract: The effects of active modified atmospheres were evaluated in ‘Giombo’ persimmons with tannins already re- moved (non-astringent) and stored at 0ºC and 85-90% relative humidity for 35 days. The goal was to maintain quality and delay ripening. The fruits were picked by hand when they were about 50% green, sanitized and subjected to different mixtures of CO2 and O2. Fruits were wrapped in thin film plastic made of nylon + polyethylene and analyzed every seven days for weight loss, respiratory activity, coloration, titratable acidity, soluble solids, ratio, pH, firmness, pectin methyl esterase and polygalacturonase enzyme activities, reducing sugars, ascorbic acid and astringency index. Refrigerated storage and active modified atmospheres were effective in conserving the quality of ‘Giombo’ persimmons. The fruits submitted to the highest CO2 concentrations (7 and 8%) had the lowest weight loss and respiratory intensity with a delay in the climacteric peak. Adv. Hort. Sci., 2013 27(1-2): 73-80 (1) Corresponding author: robert.smith@fda.hhs.gov Received for publication 13 March 2013 Accepted for publication 25 May 2013 74 relatively high in molecular weight and soluble in water. Moreover, their concentrations are maximum at an early stage of development and are <1% of the fresh weight. On the other hand, the VDG types contain tannins that are usually soluble in water, have a lower molecular weight and are not palatable at harvesting time. The seeds of polli- nation-variant non-astringent cultivars can exude ethanol, which makes the water-soluble tannins insoluble (Giordani et al., 2011). All persimmons are edible when soft, but they can be astringent at harvest time (Giordani et al., 2011). Parthenocarpic fruits of pollination-variant non- astringent cultivars, and both seeded and parthenocarpic fruits of astringent cultivars are edible only after removing the astringency artificially or when soft, overripe or dried. This happens when low molecular weight, soluble tannins are made water-insoluble, probably by binding with pec- tins (Giordani et al., 2011). Astringency can be removed by storing persimmons in a modified atmosphere contain- ing elevated amounts of CO 2 or ethanol (Del Bubba et al., 2009; Edagi et al., 2009) and refrigeration can delay the ripening of persimmons picked when only half-ripe (Vie- ites et al., 2012). The heart-shaped ‘Hachiya’ cultivar is the most popu- lar pollination-constant astringent persimmon, while the ‘Fuyu’ is a popular pollination-constant non-astringent cultivar in Japan (Celik and Ercisli, 2008). The Brazilian ‘Giombo’ cultivar is in the variable de- nomination which includes fruits that are yellow and con- tain tannins. Seedless fruits keep their astringency even when ripe, so the tannins must be removed artificially. The biggest inconvenience in accelerating the ripening process to remove tannins is that it diminishes the shelf life (Edagi et al., 2009). According to Antoniolli et al. (2000), this can compromise the firmness of the pulp when stored for a long period. Refrigerated storage is among the practices used to maintain the quality of fruits for a short length of time (Vie- ites et al., 2012); it can prolong the useful storage time, but the majority of workers show that it should not exceed 35 days to remain safe (Ben-Aire and Zutkhi, 1992; Brack- mann and Saquet, 1995; Chitarra and Chitarra, 2005). Other methods have been tested to extend the shelf life of fruits, with modified atmospheres standing out. Also plastic films can increase CO 2 and decrease O 2 however the concentrations of these gases are not controlled and vary with time, temperature, type of plastic and respiratory rate (Sargent et al., 1993). According to Ferri et al. (2004) storing ‘Fuyu’ persimmons at 0oC maintains the firmness of the pulp for 90 days, but when only using refrigerated storage the shelf life is less than 30 days. Another approach is to use a modified active atmo- sphere in which the initial concentration of gases inside the packaging is controlled. ‘Giombo’ persimmons have not yet been tested under these conditions, therefore the objective of this study was to test the effects of a modified active atmosphere on the cold storage of ‘Giombo’ per- simmons that have had the tannins removed, making them non-astringent. 2. Materials and Methods ‘Giombo’ persimmons were from the Sacramento Agropastoril Ltda, Avaré (SP), located at a latitude of 23°05’56”S, longitude 48º55’33”W and altitude of 780 m, with an annual precipitation of 1500-1700 mm yr-1, an- nual temperature between 20 and 24°C and soil classified as purple oxysoil (structured earth, purple, oxidized). The fruits were collected by hand when they were at stage 3 of maturity, medium-ripe, about 50% green. To remove the tannins, fruits were collected in plastic boxes and ex- posed to ethanol fumes at a concentration of 6.6 ml kg-1, in chambers at 25°C for 48 h. Fruits were then submitted to the following gas mixtures: 0.03% CO 2 and 21% O 2 (T1= control; 5% CO 2 and 4% O 2 (T2); 6% CO 2 and 4% O 2 (T3); 7% CO 2 and 4% O 2 (T4) and 8% CO 2 and 4% O 2 (T5). The fruits were wrapped in plastic wrappers made of nylon and polyethylene and stored refrigerated at 0±0.5ºC and 85- 90±5% relative humidity for 35 days, and were analyzed every seven days. For the control group (non-destructive), two whole fruits were analyzed five times and for the de- structive group, two fruits were cut into pieces and then analyzed in triplicate. Loss of mass (%) The weight of fruits was measured with an analytical balance and the results expressed as a percentage. Respiratory activity The liberation of CO 2 was measured following the method of Bleinroth et al. (1976), using a saturated solu- tion of barium hydroxide and 0.1 N potassium hydroxide. The respiratory rate was calculated using the equation: TCO 2 = 2.2 (Vo-V1). 10/P.T. where T CO 2 = respiratory rate (ml of CO 2 . kg-1.h-1); Vo= volume of HCl needed to titrate the potassium hy- droxide solution before and V1, after absorbing CO 2 (ml); P= mass of the fruits; T = time of respiration; 2.2= equivalent weight of CO 2 (44/2), multiplied by the concentration of HCl; 10= adjustment for the total amount of KOH used. Analyses were carried out in triplicate. Titratable acidity Expressed as gram equivalents of malic acid per 100 g of pulp (g of malic acid 100 g-1), obtained by titrating 5 g of homogenized pulp diluted to 100 ml with distilled water with 0.1 N NaOH, using a phenolphthalein indicator, in conformance with Odair et al. (2008). Soluble solids Made using a Palette ATAGO PR-32 refractometer and expressed as (ºBrix), in conformance with Odair et al. (2008). Maturity index (ratio) Determined from the ratio of soluble solids to titratable acidity (2008). 75 pH Measured using a model 300 pH meter in conformance with Odair et al. (2008). Sugars Measured using the methods of Somogy (1945) and Nelson (1944) and a Micronal B 382 spectrophotometer to measure the absorbance at 535 nm. Ascorbic acid Determined by adding 30 ml of 4% oxalic acid to 30 g of pulp and titrating with 0.5% DPI-2,6-diclorophenolin- dophenol with results expressed as ml of ascorbic acid 100 ml-1 of pulp (MAPA, 2011). Astringency index Determined using the method of Gazit and Levy (1963) and modified by Vitti (2009) in which one of the sides of the cut fruit is placed on a piece of filter paper that has been impregnated with a solution of 5% FeCl 3 . Soluble tannins react and turn the paper dark, which is then ana- lyzed visually on a scale of 1 to 5, with 5 being the darkest and most astringent. Coloration Measured in a Konica Minolta (Chroma meter, CR 400/410) colorimeter over the spectral region of 380 to 780 nm. The reflectance reading was obtained with an angle of observation of 2º and illumination C. The color was expressed by a system of rectangular coordinates: L* a* and b* in conformance with the CIE (Comission Internatinale de E’clairage), where L* is the percent lu- minosity (0% = black and 100% = white), a* represents the colors red (+) or green (-) and b* the colors yellow (+) or blue (-). Firmness Measured using a Texture Analyzer (Stevens – LFRA texture analyzer) with a penetration distance of 10 mm and a velocity of 2.0 mm sec-1, and using a TA 9/1000 fixture and a pressure of 15 gram of force per cm2 (gf cm-2). Enzyme activity Activities of polygalacturonase (PG) and pectin methy- lesterase (PME) were determined by the methods of Al- bershein et al. (1967) and Ahmed and Labavitch (1980). The Tukey test at a 5% probability level was used to compare results, as recommended by Gomes (2000) and by linear regression analysis for weight loss. 3. Results and Discussion The respiratory activity of ‘Giombo’ persimmon fruits increased during the storage periods, as shown in Figure 1. Concomitantly, there was a steady weight loss, depend- ing on the treatment (Table 1). The fruits exposed to 7 and 8% CO 2 showed less weight loss than the other treat- ments. In order to have acceptable surface shrinkage for fresh fruits (Finger and Vieira, 2002) the maximum tol- erated weight loss should be between 5 and 10%, thus the weight losses of ‘Giombo’ persimmons found in this study are acceptable. It was also observed that the respiratory rate was less at the highest concentrations of CO 2 (6, 7 and 8%) compared Table 1 - Weight loss (%) of ‘Giombo’ persimmons, with tannins removed and submitted to modified atmospheres and stored at 0°C and 85-90% relative humidity for 35 days Storage days control Treatment 5%CO 2 4%O 2 6%CO 2 4%O 2 7%CO 2 4%O 2 8%CO 2 4%O 2 Averages 7 0.105±0.024 Aa 0.236±0.189 Ca 0.136±0.184 Aa 0.038±0.011 Aa 0.024±0.093 Aa 0.108±0.028 14 0.144±0.09 Aa 0.323±0.127 a 0.216±0.112 Aa 0.098±0.019 Aa 0.093±0.047 Aa 0.175±0.053 21 0.186±0.104 Aa 0.353±0.226 Ca 0.261±0.108 Aa 0.123±0.026 Aa 0.118±0.059 Aa 0.208±0.155 28 0.190±0.023 Ab 0.695±0.068 Ba 0.270±0.120 Ab 0.143±0.046 Ab 0.130±0.068 Ab 0.286±0.141 35 0.268±0.119 Ab 1.041±0.262 Aa 0.355±0.220 Ab 0.221±0,017 Ab 0.222±0.063 Ab 0.421±0.353 Averages 0.149±0.115 0.441±0.281 0.206±0.098 0.104±0.057 0.098±0.015 Small letters compare averages of different treatments on each day. Upper case letters compare averages between different days. Averages followed by at least one letter in common do not differ statistically. Fig. 1 - Respiratory activity (mg CO 2 .Kg -1. h-1) of ‘Giombo’ persim- mons with tannins removed and submitted to modified atmo- spheres and stored at 0ºC, 85-90% relative humidity for 35 days at different concentrations. 76 to fruits exposed to 5% CO 2 and 4% O 2 which reached a peak on the 14th day of storage. The fruits exposed to 6, 7 and 8% CO 2 had maximum respiratory activity after 28 days. The elevated concentrations of CO 2 inhibited the re- spiratory activity of the fruits. The color of the fruits was not statistically different in fruits treated differently, as shown in Tables 2-4. No dark- ening was seen on the surface of the fruits. The values of a* in the apical region of the fruits was less than that of the median or basal regions. Negative a* values were found only on the first day, indicating the presence of a green color and verifying that the fruits did ripen during stor- age. This is in agreement with data reported by Chitarra and Chitarra (2005) who reported that the change in color is associated with ripening, which is a standard attribute for determining fruit quality. The increase in a* and b* color indices each reflected changes from yellowish-green to orangish-red. Brackmann et al. (1997) reported that persimmons stored refrigerated at 5ºC did not show an appreciable change in color since low temperatures inhibit the biosyn- thesis of carotenoids. The differences in color seen in the present study were due to differences at the time of col- lection. Danieli et al. (2002) reported that ‘Fuyu’ persim- mons that were collected when still yellowish-green even- tually changed to red. Still, there were no such changes in the treatments in the current study. This is commercially important since coloration is a primary quality standard. The amounts of soluble solids, titratable acidity and the ratio between the two are reported in Table 5, which shows that there is no significant change, regardless of dose of CO 2 and storage time. Working with the same cultivar, Antoniolli et al. (2000) found that there was little change in the amount of soluble solids, as confirmed also by the current study. Murray and Valentini (1998) reported that limits in the precision of the method and the many factors that affect soluble solids make it difficult at times to establish interactions between the process of maturation and the content of soluble sol- ids. Thus, the amount of soluble solids serves best as a standard of quality rather than an index that measures the effects of storage. The present study also verified that there is a slow in- crease in the titratable acidity of the fruits during storage, with values ranging from 0.07 to 0.10 grams equivalents of malic acid per 100 g of pulp. According to Costa and Balbino (2002), the increase in titratable acidity is due to the formation of galacturonic acid during the process of breaking down cell walls, which occurs during fruit stor- age. The ratios of soluble solids to titratable acidity varied little during storage. The pH of the samples oscillated between 5.49 and 5.87, as shown in Table 6. This is similar to the results reported by Blum et al. (2008) who found no change in pH or acidity in ‘Giombo’ persimmons that were covered with carnuba wax during cold storage. Therefore, the modified atmospheres used in the current study did not affect the pH very much. One of the main concerns about storage is the rapid loss of firmness of the pulp, which makes fruits commercially unacceptable. Thus, the fact that the present study shows only small variations in firmness, as shown in Table 7, is important, and can be explained as a combination of cold storage in a modified atmosphere, each of which decrease metabolism and prolong shelf life. Table 2 - Luminosity (%) of caquis ‘Giombo’ persimmons with tannins removed and submitted to modified atmospheres and stored at 0°C and 85-90% relative humidity for 35 days Days of storage Luminosity Reg. apical Reg. mediana Reg. basal 0 45.3 ab 48.9 ab 46.6 a 7 44.3 b 48.4 b 45.6 ab 14 44.8 b 48.2 b 45.2 ab 21 45.3 ab 48.8 ab 44.7 b 28 46.2 a 49.3 a 45.2 ab 35 45.5 ab 49.3 a 46.0 ab Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% prob- ability. Table 3 - Color a* in ‘Giombo’ persimmons with tannins removed and submitted to modified atmospheres and stored at 0°C and 85- 90% relative humidity for 35 days Storage days Color a* Reg. apical Reg. media Reg. basal 0 -0.1 d 0.5 d 1.4 d 7 2.5 cd 3.0 c 7.5 c 14 2.8 cd 3.1 c 7.3 c 21 6.7 b 9.8 b 11.8 b 28 12.5 a 15.8 ab 15.8 ab 35 15.6 a 18.9 a 18.3 a Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% prob- ability. Table 4 - Color b* in ‘Giombo’ persimmons with tannins removed, sub- mitted to modified atmospheres and stored at 0°C and 85-90% relative humidity for 35 days Storage days Color b* Apical Medium Basal 0 34.5 a 39.0 a 32.9 a 7 31.2 b 37.7 abc 32.1 a 14 32.6 b 36.7 bc 31.9 a 21 29.0 c 35.0 c 26.7 b 28 32.6 b 37.4 bc 28.1 b 35 32.1 b 38.9 abc 32.3 a Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% prob- ability. 77 Table 5 - Amounts of soluble solids (ºBrix), titratable acidity (g malic acid per 100 g of pulp) and ratio in ‘Giombo’ persimmons with tannins re- moved and submitted to modified atmospheres and stored at 0°C and 85-90% relative humidity for 35 days Treatments Soluble Solids (SS) AveragesStorage days 0 7 14 21 28 35 Control 17±0.3 15.7±0.2 16.9±1.8 17.4±1.5 14.4±1.9 17.4±0.5 16.5±1.6 5%CO 2 4%O 2 17±0.3 16.5±0.9 15.8±0.9 16.6±2.0 15.7±1.0 17.0±0.8 16.5±1.1 6%CO 2 4%O 2 17±0.3 16.8±0.2 15.9±0.9 16.4±0.7 15.3±0.5 15.6±0.2 16.2±0.8 7%CO 2 4%O 2 17±0.3 18.1±1.0 16.8±0.7 16.8±0.3 15.2±0.3 17.0±0.8 16.8±1.0 8%CO 2 4%O 2 17±0.3 15.8±0.6 16.9±0.4 16.9±1.6 15.4±1.0 16.1±0.6 16.4±1.0 Average 17A±0.3 16.6A±1.1 16.5A±1.03 16.8A±1.2 15.2B±1.0 16.6A±0.9 Titratable Acidity (TA) Control 0.07±0.01 0.09±0.01 0.07±0.01 0.08±0.05 0.08±0.03 0.08±0.01 0.08±0.02 5%CO 2 4%O 2 0.07±0.01 0.06±0.01 0.08±0.01 0.08±0.05 0.10±0.04 0.09±0.01 0.08±0.03 6%CO 2 4%O 2 0.07±0.01 0.08±0.01 0.07±0.02 0.07±0.05 0.06±0.02 0.09±0.01 0.07±0.02 7%CO 2 4%O 2 0.07±0.01 0.07±0.01 0.06±0.01 0.08±0.03 0.10±0.02 0.14±0.04 0.09±0.03 8%CO 2 4%O 2 0.07±0.01 0.07±0.01 0.06±0.01 0.10±0.04 0.08±0.03 0.09±0.01 0.08±0.02 Average 0.07B±0.01 0.07B±0.01 0.07B±0.01 0.08AB±0.04 0.08AB±0.03 0.10A±0.03 Ratio Testemunha 234±27 183±17 250±34 260±114 195±77 230.5±45 225.3±60 5%CO 2 4%O 2 234±27 267±48 199±10 279±142 183±75 188.2±27 225.0±71 6%CO 2 4%O 2 234±27 221±26 224±32 278±125 265±72 176.4±14 233.2±63 7%CO 2 4%O 2 234±27 283±53 300±63 239±73 155±22 131.8±40 223.9±76 8%CO 2 4%O 2 234±27 222±24 269±7 220±152 215±77 179.6±29 223.2±66 Averages 234AB±23 235AB±48 248.7AB±47.1 255.1A±107.6 202.4AB±68.8 181.3B±42.8 Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% probability. Table 6 - pH of ‘Giombo’ persimmons, with tannins removed and submitted to modified atmospheres and stored at 0°C and 85-90% relative humid- ity for 35 days Treatments Days of storage Averages 0 7 14 21 28 35 Control 5.87±0.28 5.50±0.03 5.52±0.16 5.63±0.13 5.83±0.12 5.91±0.24 5.71a±0.23 5%CO 2 4%O 2 5.87±0.28 5.49±0.16 5.44±0.04 5.49±0.08 5.48±0.11 5.60±0.08 5.56b±0.20 6%CO 2 4%O 2 5.87±0.28 5.50±0.07 5.48±0.08 5.60±0.12 5.52±0.05 5.68±0.14 5.61ab±0.19 7%CO 2 4%O 2 5.87±0.28 5.52±0.11 5.46±0.13 5.44±0.09 5.44±0.02 5.54±0.06 5.55b±0.19 8%CO 2 4%O 2 5.87±0.28 5.48±0.07 5,57±0.02 5.45±0.06 5.54±0.10 5.53±0.06 5.58ab±0.18 Averages 5.87A±0.24 5.50B±0.08 5.49B±0.01 5.52B±0.12 5.56B±0.16 5.65B±0.18 Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% probability. Table 7 - Firmness (gf.cm-2) of ‘Giombo’ persimmons, with tannins removed and submitted to modified atmospheres and stored at 0ºC and 85-90% relative humidity for 35 days Treatment Storage days Averages 0 7 14 21 28 35 Control 671±48 497±26 515±295 568±207 378±204 378±320 501 b±209 5%CO 2 4%O 2 671±48 579±86 651±75 786±43 627±76 732±253 674 ab±123 6%CO 2 4%O 2 671±47 652±49 780±65 766±38 627±89 691±199 698 a±100 7%CO 2 4%O 2 671±47 607±84 634±47 673±169 551±108 647±179 630 ab±1084 8%CO 2 4%O 2 671±47 555±13 661±142 684±170 503±91 694±126 628 ab±1203 Averages 671AB±404 578AB±735 648AB±157 695A±145 537B±141 628AB±232 Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% probability. 78 The activities of the enzymes PME and PG exhibit- ed different tendencies during the 35 days of storage, as shown in Tables 8 and 9. In a previous study, enzyme ac- tivities decreased, remained constant or increased during maturation, depending on the fruit and method of analysis (Lima et al., 2006) For the fruits tested in this study, there was a nearly linear increase in PME activity with storage time. However, there was little difference in the PME ac- tivities of fruits that were exposed to 6, 7 and 8% CO 2 . A reduction in PG activity was also seen. It has been sug- gested that this can be explained by the lack of substrate for the enzyme or the existence of other multi-enzyme complexes (Abeles and Takeda, 1989). Enzymes such as β-galatosidase and other cellular proteins could be acting in the destruction of the cell walls of the fruits, causing the extravasation of cellular fluids. It is also possible that proteases could have catalyzed the hydrolysis of PG. Antunes et al. (Antunes et al., 2006) measured the ac- tivities of PG and PME in blackberries (Rubus spp.) that were stored in different environments for different times. They concluded that the activity of PME increased during storage for all cultivars and storage conditions, while the activity of PG decreased. This was confirmed in the pres- ent study on persimmons. There was a slow decrease in the amount of reducing sugars beginning on the 28th day of storage, as shown in Table 10. The fruits had ascorbic acid levels ranging from 15.6 to 40.4 mg per 100 ml, as shown in Table 11. The amount of ascorbic acid decreased with time. Silva et al., (2011) evaluated the quality of ‘Fuyu’ persimmons and verified that covering them with wax did not affect the levels of ascorbic acid. According to Chitarra and Chitarra (2005) vitamin C tends to decrease during the ripening and stor- Table 8 - Pectin methylesterase (UE.min-1.g-1 of fresh fruit) of ‘Giombo’ persimmons, with tannins removed and submitted to modified atmospheres and stored at 0ºC and 85-90% relative humidity for 35 days Treatment Days of Storage 0 7 14 21 28 35 Control 1343aF±85 3782aC±145 3320cE±140 3490aD±155 10898aA±385 10675aB±375 5%CO 2 4%O 2 1343aF±85 2766bD±130 6081aA±415 2814cC±133 2057dE±125 4830bB±225 6%CO 2 4%O 2 1343aF±85 2446dB±115 2520dA±130 1881eD±114 2074cC±125 1811eE±100 7%CO 2 4%O 2 1343aF±85 2607cA±125 22389eB±128 1913dE±123 2056eC±125 1945dD±105 8%CO 2 4%O 2 1343aF±85 1751eE±102 3879bA±149 3150bB±150 2174bD±130 2189cC±185 Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% probability. Table 9 - Polygalacturonase (min-1g-1 of fresh fruit) of ‘Giombo’ persimmons, with tannins removed and submitted to modified atmospheres and stored at 0ºC and 85-90% relative humidity for 35 days Treatment Storage days 0 7 14 21 28 35 Control 890 aA±143 548±95 aA 591±55 aB 341±55 bC 213±40 aC 206±86 aB 5%CO 2 4%O 2 890 aA±143 453±60 aB 239±37 bC 473±71 bB 243±72 aB 143±84 bC 6%CO 2 4%O 2 890 aA±143 89±4 bC 200±39 bC 648±14 aA 257±88 aA 394±15 aA 7%CO 2 4%O 2 890 aA±143 432±268 aB 257±40 bC 374±30 bB 80±33 dD 175±43 cC 8%CO 2 4%O 2 890 aA±143 333±25 aB 673±24 aA 241±83 cC 166±132 bC 102±47 bC Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% probability. Table 10 - Reducing sugars (%) in ‘Giombo’ persimmons, with tannins removed and submitted to modified atmospheres and stored at 0ºC and 85- 90% relative humidity for 35 days Treatment Storage days Average 0 7 14 21 28 35 Control 13.3±1.8 12.1±2.1 13.9±1.6 13.5±1.1 10.8±0.5 11.1±0.4 12.4±1.7 5%CO 2 4%O 2 13.3±1.8 13.5±1.3 13.7±0.9 13.9±2.0 12.4±0.6 10.9±0.6 13.0±1.5 6%CO 2 4%O 2 13.3±1.8 15.2±1.2 13.8±0.9 12.7±0.5 11.6±0.4 10.0±1.4 12.8±2.0 7%CO 2 4%O 2 13.3±1.8 16.0±1.5 13.6±0.7 13.1±0.8 12.0±0.5 11.1±0.5 13.2±1.8 8%CO 2 4%O 2 13.3±1.8 14.1±0.6 14.1±1.1 13.0±1.6 12.2±0.9 10.6±0.4 12.9±1.6 Average 13.3±1.8 14.2A±1.9 13.8A±0.93 13.2A±1.2 11.8B±0.8 10.7B±0.8 Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% probability. 79 age of many fruits, due to the action of ascorbic acid oxi- dase, other oxidative enzymes and/or peroxidases. The astringency index of ‘Giombo’ persimmons that had their tannins removed and were exposed to modified atmospheres and were stored at 0°C had an index of 1 (no tannins) until the end of storage, which is in agreement with results reported by Núñez-Delicado et al. (2003) who reported that ethanol dissolves the tannins. Refrigerated storage in active modified atmospheres is effective in preserving ‘Giombo’ persimmons. Fruits exposed to 7 or 8% CO 2 gave the best results. This work should not be taken as reflecting FDA policy or regulations. References ABELES F.B., TAKEDA F., 1989 - Increased cellulase activity during blackberry fruit ripening. - HortSci., 24(5): 851. AHMED E.A., LABAVITCH J.M., 1980 - Cell wall metabolism in ripening. I cell wall changes in ripening “Bartlett” pears. - Plant Physiol., 65: 1009-1013. ALBERSHEIM P., NEVINS D.J., ENGLISH P.D., KARR A., 1967 - A method for the analysis of sugars in plant cell wall polysaccharides by gas-liquid chromatography. - Carbohyd. Res.; 5(3): 340-345. ANTONIOLLI L.R., CASTRO P.R.C., KLUGE R.A., SCAR- PARE F.J.A., 2000 - Remoção da adstringência de frutos de caquizeiro ‘Giombo’ sob diferentes períodos de exposição ao vapor de álcool etílico. - Pesq. Agropec. Bras., 35(10): 2083-2091. ANTUNES L.E.C., GONÇALVES E.D., TREVISAN R., 2006 - Alterações da atividade da poligalacturonase e pectiname- tilesterase em amora-preta (Rubus spp.) durante o armaze- namento. - Rev. Bras. Agroci., 12(1): 63-66. BEN-AIRE R., ZUTKHI Y., 1992 - Extending the storage life of ‘Fuyu’ persimmon by modified-atmosphere packaging. - Hort Sci., 27: 811-813. BLEINROTH E.W., ZUCHINI A.G., POMPEO R.M., 1976 - Determinação das características físicas e mecânicas de va- riedade de abacate e sua conservação pelo frio. - Coletânea ITAL, Campinas, 7(1): 29-81. BLUM J., HOFFMANN F.B., AYUB R.A., JUNG D.L., MAL- GARIM M.B., 2008 - Uso de cera na conservação pós-co- lheita do caqui cv. Giombo. - Rev. Bras. Fruticult. Jabotica- bal, SP, 30(3): 830-833. BRACKMANN A., MAZARO S.M., SAQUET A.A., 1997 - Frigoconservação de caquis (Diospyrus kaki, L.) das cul- tivares Fuyu e Rama Forte. - Ciência Rural, Santa Maria, 27(4): 561- 565. BRACKMANN A., SAQUET A.A., 1995 - Efeito da tempera- tura e condições de atmosfera controlada sobre a conserva- ção de caqui (Diospyrus kaki L). - Rev. Ciência Rural, Santa Maria, 25: 375-378. CAMPO-DALL’ORTO F.A., OJIMA M., BARBOSA W., ZULLO M.A.T., 1996 - Novo processo de avaliação da adstringência dos frutos no melhoramento do caquizeiro. - Bragantia Campinas, 55: 237-243. CANDIR E.E., OZDEMIR A.E., KAPLANKIRAN M., TOPLU C., 2009 - Physico-chemical changes during growth of per- simmon fruits in the east Mediterranean region. - Scientia Horticulturae, 121: 42-48. CELIK A., ERCISLI S., 2008 - Persimmon cv. Hachiya (Dio- spyros kaki Thunb.) fruit: some physical, chemical and nu- tritional properties. - Intl. J. Food Sci. Nutr., 59: 599-606. CHITARRA M.I.F., CHITARRA A.B., 2005 - Pós-colheita de frutos e hortaliças: fisiologia e manuseio. - Ed. UFLA, La- vras, Minas Gerais, Brasil, pp. 785. COSTA A.F.S., BALBINO J.M.S., 2002 - Características da fruta para exportação e normas de qualidade, pp. 12- 18. - In: FOLEGATTI M.I.S., and F.C.A.U. MATSUURA (eds.) Mamão: pós–colheita. Papaya: Post-harvest Em- brapa Informação Tecnológica. Brasília, DF, Série Frutas do Brasil, 21. DANIELI R., GIRARDI C.L., PARUSSOLO A., FERRI V., ROMBALDI C., 2002 - Efeito da aplicação de ácido gibe- rélico e cloreto de cálcio no retardamento da colheita e na conservabilidade de caqui. - Fuyu. Rev. Bras. Fruticult. Ja- boticabal, SP, 24(1): 44-48. DEL BUBBA M., GIORDANI E., PIPPUCCI L., CINCINELLI A., CHECCHINI L., GALVAN P., 2009 - Changes in tan- nins, ascorbic acid and sugar content in astringent persim- mons during on-tree growth and ripening and in response to different postharvest treatments. - J. Food Comp. Anal., 22: 668-677. DEMBITSKY V.M. POOV., DEMBITSKYA V.M., POOVARO- DOM S., LEONTOWICZ H., LEONTOWICZ M., VEAR- ASILP SU., TRAKHTENBERG S., GORINSTEIN S., 2011 - The multiple nutrition properties of some exotic fruits: Biological activity and active metabolites. - Food Res. Intl., 44(7): 1671-1701. Table 11 - Ascorbic Acid (mg 100 ml-1) in ‘Giombo’ persimmons, with tannins removed and submitted to modified atmospheres and stored at 0°C and 85-90% relative humidity for 35 days Treatment Storage days Averages 0 7 14 21 28 35 Control 38±11 44±4 33±7 34±15 20±9 18±7 31±13 5%CO 2 4%O 2 38±11 38±2 37±9 37±19 24±11 13±3 31±13 6%CO 2 4%O 2 38±11 36±3 34±7 33±18 21±2 18±2 30±11 7%CO 2 4%O 2 38±11 46±13 30±6 43±22 36±20 13±0 34±16 8%CO 2 4%O 2 38±11 39±2 41±2 19±2 41±11 16±2 32±12 Averages 38AB±9 40A±7 35AB±67 33AB±16 28BC±13 16C±4 Averages followed by the same letter, lower case in columns and capital letters in rows do not differ significantly by the Tukey test at 5% probability. 80 DONAZZOLO J., BRACKMANN A., 2002 - Efeito do CO 2 em atmosfera controlada na qualidade de caqui (Diospyros kaki, L.) Cv. Fuyu. - Rev Bras. Agroci. Pelotas, 8: 241-245. EDAGI F.K., CHIOU D.G., TERRA F.A.T., SESTARI I., KLUGE R.A., 2009 - Remoção da adstringência de caquis ‘Giombo’ com subdosagens de etanol. - Ciênc. Rural, Santa Maria, 39: 2022-2028. FERRI V.C., RINALDI M.M., DANIELLI R., LUCCHETTA L., ROMBALDI C.V., 2004 - Atmosfera modificada na conser- vação de caquis (Diospyrus kaki, L.). cultivar Fuyu. - Rev. Bras. Agroci., 10: 111-115. FINGER F.L., VIEIRA G., 2002 - Controle da perda pós colhei- ta de água em produtos hortícolas. - UFV, Viçosa, pp. 29. GAZIT S., LEVY Y., 1963 - Astringency and its removal in per- simmon. - Israel J. Agr. Res., 13(3): 125-132. GIORDANI E., DOUMETT S., NIN S., DEL BUBBA M., 2011 - Selected primary and secondary metabolites in fresh persimmon (Diospyros kaki Thunb.): A review of analytical methods and current knowledge of fruit composition and health benefits. - Food Res. Intl., 44: 1752-1767. GOMES F.P., 2000 - Curso de estatística experimental. 14. ed. - Fundação de Estudos Agrários Luiz de Queiroz FEALQ, Piracicaba, Brazil. GORINSTEIN S., BARTINIKOWSKA E., KULASEK G., ZEMSER M., TRAKHTENBERG S., 1998 - Dietary per- simmon improves lipid metabolism in rats fed diets contain- ing cholesterol. - J. Nutr., 128: 2023-2027. GORINSTEIN S. LEONTOWICZ H., LEONTOWICZ M., JE- SION I., NAMIESNIK J., DRZEWIECKI J., PARK Y.S., HAM K.S., GIORDANI E., TRAKHTENBERG S., 2011 - Influence of two cultivars of persimmon on atherosclerosis indices in rats fed cholesterol-containing diets: Investigation in vitro and in vivo. - Nutr., 27(7-8): 838-846. GU H.-F., LI C.-M., XU Y.-J., HU W.-F., CHEN M.-H., WAN Q,-H., 2008 - Structural features and antioxidant activity of tannin from persimmon pulp. - Food Res. Intl., 41: 208-217. LIMA M.A.C., ALVES R.E., FILGUEIRAS, H.A.C. 2006 - Mu- danças relacionadas ao amaciamento da graviola durante a maturação pós-colheita. - Pesq. Agropec. Bras., 41(12): 1707-1713. MAPA, 2011 - Modified Tillman’s Method. - Ministério da Agri- cultura, Pecuária e Abastecimento http://www.agricultura. gov.br . MARTíNEZ-CALVO J., NAVAL M., ZURIAGA E., LLáCER G., BADENES M.L., 2012. Genet. Resour. Crop. Evol. Pub- lished on-line. MARTINS F.P., PEREIRA F.M., 1989 - Cultura do caquizeiro. Jaboticabal. - FUNEP, pp. 71. MURRAY R., VALENTINI G., 1998 - Storage and quality of peach fruit harvest at different stages of maturity. - Acta Horticulturae, 465: 455-463. NELSON N.A., 1944 - A photometric adaptation of Somogy method for the determination of Glucose. - J. Biol. Chem., 153: 375-380. NÚÑEZ-DELICADO E., SOJO M.M., GARCíA-CARMONA F., SáNCHEZ-FERRER A., 2003 - Partial Purification of latent persimmon fruit polyphenol oxidase. - J. Agric. Food Chem., 51: 2058-2063. ODAIR Z., NEUS S.P., TIGLEA P., 2008 - Métodos físico-quí- micos para análise de alimentos. Physical-chemical methods for analyzing foods. - Instituto Adolfo Lutz, São Paulo, Brasil. SARGENT S.A., CROCKER T.E., ZOELLNER J.J., 1993 - Storage characteristics of ‘Fuyu’ persimmons. - Proc. Flori- da State Hort. Soc., 106: 131-134. SILVA M.C., ATARASSI M.E., FERREIRA M.D., MOSCA M.A., 2011 - Qualidade pós –colheita de caqui ‘Fuyu’ com utilização de diferentes concentrações de cobertura comestí- vel. Postharvest quality of ‘Fuyu’. - Ciênc, Agrotec. Lavras, 35(1): 144-151. SOMOGY M., 1945 - Determination of blood sugar. - J. Biol. Chem., 160: 69-73. USDA, 2012 - Germplasm Resources Information Network (GRIN). - Website: http://www.ars-grin.gov/cgi-bin/npgs/ html/taxon.pl?14293 VEBERIC R., JURHAR J., MIKULIC-PETKOVSEK M., STAMPAR F., SCHMITZER V., 2010 - Comparative study of primary and secondary metabolites in 11 cultivars of persim- mon fruit (Diospyros kaki L.). - Food Chem., 119: 477-483. VIEITES R.L., PICANÇO N.F.M., DAIUTO É.R., MORAES M.R., 2012 - Optimum temperature and state of maturity for storing persimmons, Diospyros kaki L., caqui ‘Giombo’. - Nat. Prod. J., 2: 180-187. VITTI D.C.C., 2009 - Destanização e armazenamento refriger- ado de caqui «Rama Forte» em função da época de colheita. - PhD, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, Brasil.