PHYSICO-CHEMICAL CHARACTERIZATION OF SUGAR APPLE ( Annona squamosa L . ) FRUITS STORED WITH PVC FILM IN DIFFERENT CONTROLLED TEMPERATURES

Sugar apple (Annona squamosa L.) is tropical climacteric fruit with a very short shelf life, ripening completely in just a few days under favorable conditions. Among the techniques employed to increase the time of cv. Crioula. Fruits were harvested at the stage of physiological ripeness, stored in paperboard boxes (33cm x 27cm x 10cm) covered or not with PVC The experiment was set in a completely randomized design and the treatments evaluated in a factorial scheme 2x4 that lower temperatures did not affect physical-chemical characteristics of the fruits, but increased the time of internal quality of the fruits, but it reduced the amount of total solid soluble of the fruit pulp on the consumption point.

Sugar apple (Annona squamosa L.), native fruit from Central America, has in Brazil one of the main centres for production and consumer market.It is estimated that there are near 6000 hectares cultivated with this species in Brazil, mostly in the Northeast region (Lemos, 2014).Its production is primarily meant for the fresh fruit market of the large Brazilian cities, with considerable distances to be overcome in poorly maintained roads and transport not always adequate (Pinto et al., 2005).This scenario, together with the vulnerable nature of this fruit and the little knowledge of fruit preservation methods by the producers, lead to high post-harvest losses (Durigan, 2013).
The high losses observed in this production chain showed the need to establish procedures to improve fruit harvesting and conservation to minimize losses and maximize fruit shelf-life.Because sugar apple has a climacteric respiration pattern, the fruit has a rapidly maturing and perishing behaviour during the post harvesting period under favorable conditions (Silva et al, 2013).Among the techniques employed to increase shelf-life of fruits and vegetables are the use of controlled packaging (Reis et al, 2014).This work aimed to study the duration of fruit shelf-life using packaging protected Sugar apple cv.Crioula fruits were obtained from a commercial orchard of Paxiuba Farm, in the Palmeira dos Indios, Alagoas,Brazil (9 26 '22.4' 'S,36 41' 2.6 W and 295 m altitude).The fruits were harvested weighing between 250 and 300 grams at the physiological maturity, stage when the green exocarp segments initiate separation (3 to 4 mm) and exhibit a whitish color in the grooves.The harvested fruits were placed in plastic bins in separated layers by a soft sheet of paper to prevent abrasion during transport.
In the laboratory the fruits were selected, paperboard boxes (33cm x 27cm x 10cm) in a single layer.The boxes with fruits were organized according to the following treatments: covered or not covered with in FS-224 SOLAB incubator with temperatures adjusted to 18ºC; 21ºC; 24ºC; and room temperature (average 27 °C ± 2, control treatment).
During the storage period, the fruits were sampled daily to identify the adequate point of consumption, determined physically by the softening of the exocarp (0.30 -0.40 kg on the segment and 0.10 -0.20 kg between segments) measured by digital bench penetrometer (SoilControl,.At this point, the fruits were removed from the boxes to carry out physical and chemical analysis: lateral and transverse diameters; fruit mass, the mass of peel, pulp and seeds; total soluble solids (°Brix); pH; titratable acidity (TTA); external appearance (exocarp) (EA), calculated using a scale of notes at the consumption point varying from 1 to 4, where 1 = > 40% blackish segments, 2 = > 20%<30% blackish segments, 3 = >1%<10% blackish segments, 4 = no blackish segments.The internal appearance (pulp) (IA), was calculated using a scale of notes also varying from 1 to 4, where 1 = brown pulp, 2 = moderately brown pulp, 3 = pale yellow pulp, 4 = white pulp.The experiment was organized on a completely randomized design in a factorial 2 x 4, with four replications and three fruits per plot.Data were subjected to analysis of variance and the means were compared by F test at 5% probability.
The shelf-life of sugar apple fruits varied with the temperature, the fruit ripening process completed and reached the point of consumption with best quality in 3 (Figure 1).Fruit behavior for the evaluated characteristics, shown in Tables 1 and 2. At lower temperatures (24°C and 21°C) the fruit was conserved for a longer period of time (between 7 and 8 days) although the visual quality thereof was preserved only in treatments with PVC packaging.
Figure 1.Shelf-life of Annona squamosa Guimarães et al. (2003) observed that sugar apple nuts kept at 10 ° C with the PVC film had the fruit peel affected, but the internal quality was satisfactory until the 12th day, without changes in the pulp, such as darkening or injury by cold.At the temperature of 18°C the fruits could be stored for up to 13 days without significant loss on its external (note 3.29) or internal (note 3.52) quality in the treatment with PVC film.By contrast, fruits stored in not covered boxes reached the consumption point after 9 days with a reasonable pulp quality (note 3,04) to be consumed, but their external appearance was very poor (note 2,31) to be commercialized (Table 1).difference between treatments of atemoya fruits (Annona cherimola × A. squamosa) conserved individually in observed in all treatments was a natural consequente of the fruits ripenning, however, fruits conserved in PVC (2012) using controled atmosphere and refrigeration to conserve sugar apple fruits observed that the green color of the fruit skin during storage longer than at fruit metabolism and consequently slow down ripenning speed.The PVC barrier formed between the fruits and that is low in O 2 , as a consequence, respiration, ethylene production and clorophil degradation are reduced (Yamashita et al.;2002).Melo et al. (2002) observed that fruits of cherimoya (Annona cherimoya Mill.) could be kept for up to two weeks (15 days) when chilled without PVC showed to be possible to increase more than three fold the shelf-life of sugar apple fruits refrigerated at 18°C, when compared to fruits conserved at room temperature internal quality.
The titratable total acidity (TTA) of the fruits (Table 1), although the fruit maturation process leads to a reduction in the organic acids content of the pulp due to the respiratory process (Chitarra and Chitarra, 2005).Silva et al. (2003), analyzing sugar apple fruits stored at a temperature of 15 °C (wrapped or not in low density polyethylene), observed a decrease in the values of titratable acidity.Nevertheless, Vila et al.
the atmosphere in sugar apples fruits stored at 18 ºC, observed that there was an increase in the titratable acidity values up to the 4th day of storage, but this value decreased after that until the last day of analysis.
Regarding the total soluble solids (TSS), the treatments without PVC packaging provided higher concentration of sugars (28.29 °Brix) than the treatment with PVC (25.05 °Brix).These results show that the fruits by reducing respiration and transpiration and, consequently, delaying ripening and maintaining higher water content in the fruit, thus affecting the concentration of sugars in the pulp (Melo et al., 2002).As fruit ripening progress, total soluble solids increases in the fruit tissues throughout storage as a result of the transformation of the accumulated reserves (usually starch) into sugars and is also corroborated by the loss of water (Silva et al., 2009).
Considering only the studied storage physical and chemical characteristics of sugar apple fruits.However, the analysis of variance showed a and the storage temperatures for certain variables.
The weight of the fruit (exocarp + pulp) decreased its physical barrier effect against dehydration of the barrier to dehydration, preventing fruit from losing mass through the process of transpiration and, at the same time, reducing its respiratory activity.Morais et al. (2010) observed that by modifying the atmosphere with the use of the PVC packaging the integrity of papaya fruits peel was preserved, thus reducing the loss of water and its mass.
the visual characteristics of the fruit, maintaining high notes for exocarp and pulp, which means almost no damage and perfect marketable conditions.The higher sugar content found in fruits without the cover have shown its protection against dehydration and its consequent dilution of sugars present in the pulp (Mizobutsi et al., 2012).The fruits kept in boxes covered with PVC film presented a superior average weight (155.69 g) than treatment without film (133.68 g) evidencing the protection of the film against the dehydration of the fruits exposed in all temperatures studied (Table 2).-----------------g --------------------------mm--------------------------g --------------  matter due to a possible increase of the relative humidity of the air inside the package, saturating the atmosphere around the fruit, which leads to the decrease of the vapor (Silva et al., 2009).Fruits of sugar apple conserved at temperature have their shelf-life extended up to 3 times conserving their marketable appearance and main physic chemical characteristics in the postharvest period.

Table 1
Annona squamosa L. fruits during a storage period of 15 days.

Table 2
Annona squamosa L. during storage period of 15 days.
Means followed by the same letter in columns did not differ by F Test (p=0.