Use of Packaging for 'Hawaii' Papaya Conservation, Sold at CEASA of São Luís, Maranhão, Brazil

Surveys carried out in different microregions of Maranhão highlight papaya as one of the fruits with the postharvest losses estimates. In this context, this study aimed to analyze the efficiency of plastic packaging on postharvest conservation of Hawaii papaya to instruct the Maranhão retail market about viable alternatives to mitigate losses related to this fruit. The papayas were purchased from CEASA of São Luís and sent to the laboratory. Posteriorly, they were randomly separated into 65 groups of 2 units, and then, applying the coverings are made. The experimental design was completely randomized in a split-plot at 4x5 times, with four treatment control [(without packaging), plastic film (FP), hermetic-bag (SH), and perforated-bag (SP)] and five evaluation periods (3, 6, 9, 12, and 15 days of storage); four repetitions and 2-fruits per portion (tray). For the individual biometric characterization, was carried out the measuring of the longitudinal and transverse diameters, fresh mass, pulp yield, seed mass, firmness, and fruit mass loss. Furthermore, for chemical analysis, total soluble solids content, total titratable acidity, and pH were measured. It was found, at the end of the study, that the hermetic-bag is efficient for maintaining the loss of fresh mass, firmness, ripening, total soluble solids content, total titratable acidity, and pH, which are relevant attributes of quality for commercialization of the Hawaii papaya. Therefore, the use of the hermetic-bag is recommended to increase the postharvest shelf life of Hawaii papaya fruit under stored at room conditions and at least for 15 days.


Introduction
Papaya Papaya (Carica papaya L.) belongs to the Caricaceae family and is native to America. It is a climacteric fruit, intensely cultivated and consumed in all tropical and subtropical regions of the world (Costa et al., 2011). Brazil is the world's second-largest papaya producer with a production of 1,517,696 t/year. The largest national producers are the states of Bahia, followed by Espí rito Santo, getting production of 368.8 and 311.1 thousand tons, respectively (Embrapa, 2018). In this context, papaya has been assuming ever greater importance in Brazilian fruit growing, as one of the main fruits destined to the overseas trade (Luz et al., 2015).
Despite the high productivity, papaya postharvest losses are elevated. Globally, it represents about 40 to 50% of fruit production (FAO, 2014). However, in developing countries, about 30 to 40% of production is lost in the postharvest, processing, and distribution stages, representing a waste of resources used in production such as land, water, energy, and inputs (Gustavsson et al., 2011).
In Brazil, fruit and vegetable losses represent a high cost to the retail sector and reach around R$ 600 million per year. Of these, 86% occurs during the exposition of the product for sale; 9% in transportation; and 5% in storage (Melo et al., 2013). According to ABRAS (2015), postharvest losses of products correspond to 8.29% of net income and are the most impactful among all departments.
Several surveys were carried out in different microregions in the state of Maranhã o by Ferreira (2019), Figueirinha (2019) and Silva et al. (2018), among 2017 and 2019, highlight papaya as one of the fruits with the highest estimates of postharvest losses, whose results ranged from 11.64 to 17.90%. Among the causal factors, physiological disorders were the most cited, corroborating with results found by Silva et al. (2018) who showed in their studies the valor of up to 91.24% of total losses. According to Dias et al. (2011) andPimentel et al. (2011), papaya has climacteric respiration, that is, ethylene peak and respiration after harvest. Therefore, the harvest shall be made at the physiological maturation stage before ripening. In this regard, it may be employed some alternatives to increase their shelf time. One method is the use of a modified atmosphere through the packaging of edible coatings.
These might prevent excessive mass loss as well as reduce gas exchange. When these two phenomena are controlled, the senescence of the product can be delayed, increasing its useful life (Damatto Júnior et al., 2010). Besides, it protects against external damage such as adverse temperature and humidity, and mechanical/phytopathological damage resulting from improper handling, transport, and packaging.
Based on the above considerations, this study aimed to analyze the efficiency of plastic packaging on postharvest conservation of Hawaii papaya sold at CEASA (State Supply Center) of Sã o Luí s (MA), to instruct the industry on viable alternatives to mitigate losses related to this fruit.

Material and Methods
The experiment was carried out at the Laboratório de Fitotecnia e Pós-Colheita, Universidade Estadual do Maranhã o (UEMA), in the period from January to February 2019. The papayas were purchased at CEASA of Sã o Luí s (MA) and sent to the laboratory in monobloc boxes. Fruits were selected for size, color, and absence of damage, washed and sanitized with sodium hypochlorite, to 200 ppm for 15 minutes in water at 12 °C.
After drying at room temperature, the separation of fruits was made randomly into 65 groups of 2 units, placed in styrofoam trays, and then, the following treatments were applied: control (without packaging); plastic film (FP), hermetic-bag (SH) and perforated-bag (SP). These were analyzed for 15 days at 3-day intervals.
The experimental design was completely randomized, with the factorial arrangement (4x5) with plots split through time, with four treatments (control, plastic film, hermetic-bag, and perforated-bag), and five evaluation times (3, 6, 9, 12, and 15 days of storage); four repetitions and 2-fruits per plot (tray). The fruits were stored under ambient conditions (T = ± 25 ° C; RH = 48%), to more effectively simulate the environmental conditions occurring in the wholesale/retail markets of Maranhã o.
For individual biometric characterization, were measured the longitudinal and transverse diameters using a digital caliper in millimeters (mm); fruit mass, pulp yield, and seed mass using semi-analytical balance, in grams (g); firmness, using a penetrometer, in Newton (N); and fresh mass loss, using a semi-analytical balance, estimated by the following formula, in percentage (%): The chemical analysis was made from the fruit maceration of each tray and embraced the information about total soluble solids content, total titratable acidity, and pH. The determination of total soluble solids (TSS) had been made by direct reading of the digital refractometer, whose results were expressed in º Brix. The hydrogenic potential (pH) was determined by the potentiometer method in a digital pH device, according to the methodology recommended by the Official Analytical Chemistry Association (AOAC) (1995). Acidity (ATT) (% citric acid) was obtained by titration with a standard solution of 0.1N sodium hydroxide, according to AOAC (1995).
The analysis was carried out by analysis of variance (ANOVA), and when the null hypothesis was rejected, it used the Tukey test to compare the means. The InfoStat® statistical software was used in this study. It is important to point out that fresh mass loss data were analyzed in a completely randomized design, only for the last evaluation day.

Results and Discussion
In Table 1 are reported the mean values for the mass of the fruit during the storage period. There was no interaction between treatments and storage time. Plastic film (FP), hermetic-bag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.
The values ranged from 274.3 to 393.1 g and corroborated with Dantas et al. (2013), who stated that for commercial purposes, Hawaii papaya should weigh around 350 to 600g. Therefore, except for the control (without packaging), it can be inferred poor preservation ISSN 2166-0379 2020 conditions may impair the quality of this fruit for sale.

Journal of Agricultural Studies
The best yields of fresh mass were recorded using a hermetic-bag and perforated-bag, followed by the plastic film (Table 1). Fruits packed with hermetic-bag were presented around 17% more mass than the control (without packaging). According to Santos and Oliveira (2012), this may have occurred because the packaging works as a barrier to water loss in fruit, and thus, increases its shelf life.
As expected from the estimation of the means of fresh mass, the higher losses occurred for the control (without packaging), which was estimated on average twenty-nine times higher than the most effective treatments (hermetic-bag and perforated-bag) ( Table 2). Plastic film (FP), hermetic -ag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.
On the 15th of storage day, it was estimated a loss of fresh mass in the magnitude of up to 25.49% (control), it is twenty times higher than the tolerable limit (5%) recommended by Santos et al. (2008) to commercial conditions. However, for the hermetic-bag, perforated-bag, and plastic film, losses may be considered acceptable on every evaluation day, according to the overall treatment average.
According to Reis (2014), the use of packaging can reduce respiratory activity and increase relative humidity, which delays ripening and water loss through transpiration. Further, Sanches et al. (2017), affirm that the intense process of transpiration causes water deficit in the fruit, which leads to reduced quality and acceptance for commercialization/consumption. Therefore, there may be increased postharvest losses and consequent losses induced by poor storage conditions.
Regarding the cross-sectional diameter, it was observed that there was no interaction between ISSN 2166-0379 2020 coatings and storage time, but there were individual effects of these factors (Table 3). Plastic film (FP), hermetic-bag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.

Journal of Agricultural Studies
The transverse diameter ranged from 70.8 to 82.9 mm and was higher than the results found by Alves et al. (2012), in studies of characterization of Hawaii papaya. The best yields were obtained by adopting a hermetic-bag and perforated-bag, possibly due to the efficiency of these treatments on the maintenance of fresh fruit mass, which presents direct relation to its turgidity.
Mean cross-sectional diameters decreased over storage days, especially in unpacked fruits (control) ( Table 3). Reis (2014) explains that greater exposure of fruits to the environment (without packaging) increases its dehydration rate, causing wilting and changes in its biometric characteristics.
The longitudinal diameter was not affected by the interaction between treatments and storage time. Only time had a significant effect (p <0.05) on this variable, with a 7.77% reduction in fruit cross-sectional diameter, estimated at 15 days of storage, compared to the first evaluation period (Table 4). ISSN 2166-0379 2020  Plastic film (FP), hermetic-bag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.

Journal of Agricultural Studies
The mean ranged from 105.5 mm to 124.8 mm (Table 4). These values were higher than those found by Alves et al. (2012), for Hawaii papaya, whose treatment averages ranged from 101.68 mm to 108.18 mm. It is important to note, despite the interference of treatments on fresh mass, it does not reflect on the longitudinal diameter, as opposed to obtained for the cross-sectional diameter of the fruit.
Concerning physicochemical characteristics, total titratable acidity (ATT) had a significant effect (p <0.05) on the interaction between packaging and storage time (Table 5).  ISSN 2166-0379 2020 Plastic film (FP), hermetic-bag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.

Journal of Agricultural Studies
The use of the hermetic-bag and perforated-bag culminated in a linear decline of ATT with storage time. According to Chitarra and Chitarra (2005), acidity decreases as a result of the respiratory process and, or its conversion to sugars, because volatile and non-volatile organic acids are among the most metabolize cellular constituents in the ripening process.
However, for control and plastic film, there were ATT peaks on the third and fifth days of analysis. According to Fernandes et al. (2010), the papaya ripening process is maintained by the consumption of organic acids, since the fruit has no starch reserves. Valerio et al. (2017) add that acidity peaks may be linked to galacturonic acid synthesis through pectin hydrolysis by pectinamethylesterase. This suggests the use of hermetic-bag and the perforated-bag was effective in the conservation of Hawaii papaya, by reducing water loss and increasing shelf life The ATT results did not differ significantly from each other in all storage periods, which shows lower oscillations of treatments by packaging action (Table 5). Similar results were also obtained by Morais et al. (2010) storing "Tainung 1" papaya at 10 °C and 85% RH for 35 days of storage.
Although it had not shown a significant difference, it was possible to observe that fruits packed with SH and SP maintained a more uniform behavior of ATT contents throughout the storage period, not differing statistically in relation to the time. According to Silva et al. (2009), this behavior is interesting because it delays the biochemical transformations responsible for fruit pH changes; in other words, it slows down the ripening.
On table 6 is shown the values for total soluble solids (SST) contents. There were statistical significance and interaction for both factors evaluated.  ISSN 2166-0379 2020 Plastic film (FP), hermetic-bag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.

Journal of Agricultural Studies
It was possible to observe a progressive increase in the SST content during the storage period. The highest averages were estimated for control at 15 days of storage (13.55 °Brix) and the plastic film at 12 days (10.72 °Brix). It is important to note that, although the values of OSH increased during the storage period, this increase was not significant. According to Bron (2007), papaya accumulates little starch, about 0.5% after anthesis, and it decreases until it stabilizes around 0.1% after 75 days of anthesis. As it has minimum starch quantities to be hydrolyzed in the ripening, there is a little variation in the levels of SST during postharvest.
According to Luz et al. (2015), the soluble solids content is a hard precision characteristic, since there may be wide variation according to the management employed in fruit production. Nevertheless, according to Reis et al. (2015), with rare exceptions, the values obtained in this study are within the recommended standard for papayas from the Solo group (9.58 to 11.80 °Brix). The control treatment papayas during storage 12 and 15 presented higher values than those established by Reis et al. (2015). This high degree may be linked to the early ripening of the fruits analyzed in this treatment.
Fruits packed with hermetic-bag and plastic wrap had lower SST mean than the perforated-bag and control (Table 6). It shows the efficiency of these two packages in retarding organic acid degradation since it is a crucial process in ripening. According to Pimentel et al. (2011), total soluble solids (SST) well represent the fruit ripening and generally, a high SST content indicates a higher degree of fruit maturity. Moreover, for Pego et al. (2015), this parameter is used by many authors as a characteristic that reflects the sensory quality of fruits.
Concerning the maturing of the fruit, it was observed that this variable was significantly affected by storage time (p <0.05) ( Table 7).  ISSN 2166-0379 2020 Plastic film (FP), hermetic-bag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.
The lowest percentages occurred for fruits packed with hermetic-bag. This demonstrates that this package was one of the most effective in delaying the ripening of Hawaii papaya during 15 days of storage (Table 7). These results corroborate Martins (2012) and Barbosa (2012), who described the modified atmosphere as an effective technique to reduce the effects of gas exchange on peel color change and fruit ripening.
In relation to the seed mass, the effect of the interaction between the packages and the storage time was observed (Table 8). Plastic film (FP), hermetic-bag (SH) and perforated-bag (SP); * significant at 5% probability by the F test; CV: coefficient of variation; Uppercase letters do not differ from each other on the same row and lowercase letters in the column.
The increase in storage time culminated in an increase of seed mass. According to Cruz et al. (2016), this may be associated with the fact that seeds continue to develop during fruit ripening until they reach their highest quality. Therefore, these results prove that the fruits were undergoing postharvest metabolization during the study period. And according to the results obtained, the use of Hawaii papaya packaging has delayed seed development, which is possibly associated with the retardation of its maturation.

Conclusion
To sum up, at the end of the study, it was found that the hermetic-bag is efficient for maintaining the fresh mass loss, firmness, maturing, total soluble solids content, total titratable acidity and pH of Hawaii papaya, which are important quality attributes for its marketing.
The use of a hermetic-bag is recommended to increase the postharvest shelf life of Hawaii papaya under environmental storage conditions (T = ± 25 °C; RH = 48%) and for at least 15 days of storage.