The raw fruits contain an alkaloid or proteolytic enzyme âPapainâ, which is a ... 1997). Green fruit, leaves and flowers may also be used as cooked vegetable.
J. Bangladesh Soc. Agric. Sci. Technol., 8 (1&2):105-108, 2011
Shelf life and diseases of papaya as influenced by different postharvest treatments R. R. Roy, M. F. Mondal and M. H. A. Rashid Department of Horticulture, Bangladesh Agricultural University, Mymensingh 2202 Abstract An experiment was carried out at the Laboratories of the Departments of Horticulture, Plant Pathology and Biochemistry, Bangladesh Agricultural University, Mymensingh during the period from February to March 2011 to assess the effects of different postharvest treatments on shelf life, disease incidence and severity in papaya cv. Shahi. The experiment consisted of nine postharvest treatments viz., To= Control (room temperature), T1= Fruits kept in newspaper, T2= Fruits kept at low temperature (13o C), T3= Fruits given hot water treatment (55ºC for 5 minutes), T4= Fruits soaked in neem extract, T5= Fruits soaked in garlic extract, T6= Fruits coated with mustard oil, T7= Fruits covered with straw, T8= Fruits given hot water treatment at 55ºC for 5 minutes then kept in perforated polythene. The single-factor experiment was laid out in a completely randomized design (CRD) with three replications. There was significant variation among the treatments in relation to shelf life, disease incidence and severity of papaya. The shelf life increased due to different postharvest treatments. Disease incidence and severity were higher in control fruits and lower in garlic extract treated fruits. The longest shelf life (16 days) was observed in garlic extract followed by the fruits (15.66 days) stored at 13ºC while the shortest shelf life (9 days) was recorded in untreated fruits preceded by those kept in mustard oil (10.60 days). Key words: Papaya, shelf life, disease, postharvest treatments. Introduction Papaya (Carica papaya L.) belonging to family Caricaceae is an important fruit crop. Carica is the largest of the four genera with 48 species, among which Carica papaya L. is most important and cultivated all over the world. The popularity of papaya fruit has made it ubiquitous in tropical and sub-tropical regions of the world. Papaya is the native of tropical America. It has made its way from kitchen gardens to that of commercial orchards in many tropical and subtropical countries because of its highest production of fruits (75 to 100 tonnes per hectare) and contributed an income next to banana. Papaya is a good source of vitamin A, vitamin C and calcium (Arriola et al., 1980 and Hayes, 1993). The raw fruits contain an alkaloid or proteolytic enzyme “Papain”, which is a commercial product of several tropical American nations and is using in several medicine and food preparations. Economically, Carica papaya is the most important species within the Caricaceae, being cultivated widely for consumption as a fresh fruit and for use in drinks, jams, candies and as dried and crystallized fruit (Villegas, 1997). Green fruit, leaves and flowers may also be used as cooked vegetable. In Bangladesh, papaya occupied 7713 hectares of land with the total production of about 50615 tons with an average yield of 6.6 tons per hectare (BBS, 2009). The per capita availability of fruit is below 40% in Bangladesh (Mondal, 2000). The per capita availability of fruits is further reduced due to a high level of postharvest losses. Its postharvest losses range up to 40-100% (Salunke and Desai, 1984). The perishability of the fruits is attributed due to the adverse physicochemical changes and different microbial attack (Firmin, 1997). In Bangladesh, a considerably amount of papaya is being spoiled due to prevailing high temperature and humidity. Its edible quality and marketability deteriorates rapidly, once it is fully ripe. Papaya fruits are susceptible to many fungal diseases causing enormous loss to quality of the fruits. Reduction of postharvest losses by prolongation of shelf life of fruits can improve the situation. Therefore, the present study was undertaken to study the effects of different postharvest treatments on shelf life and diseases of papaya. Materials and Methods The experiment was carried out at the laboratories of the Departments of Horticulture, Plant Pathology and Biochemistry, Bangladesh Agricultural University, Mymensingh during the period from February to March, 2011. The papaya variety Shahi was selected as experimental materials. The papayas used in the experiment were collected from farmer‟s field from Madhupur at Tangail district. Commercially mature hard fruits of papaya were harvested on 5 February, 2011. Maturity of papaya was identified by external features i.e. when the latex of the fruits became watery and the color of the fruit was pale green that indicated maturity of papaya. In 1992, BARI develop an improved variety of papaya from the line p-011 was recommended for commercial cultivation in Bangladesh by the name of Shahi. The experiment consisted of different postharvest treatments viz., To= Control (room temperature), T1= Fruits kept in newspaper, T2= Fruits kept in low
Shelf life and diseases of papaya
temperature (13o C), T3= Fruits given hot water treatment at 55ºC for 5 minutes, T 4= Fruits soaked in neem extract, T5= Fruits soaked in garlic extract, T6= Fruits coated with mustard oil, T7= Fruits covered with straw, T8= Fruits given hot water treatment at 55ºC for 5 minutes then kept in perforated polythene. The one-factor experiment was laid out in a completely randomized design (CRD) with three replications. The postharvest treated fruits were assigned randomly under each replication. The collected data from the experiment were statistically analyzed using ANOVA method. The significance of difference between pair of means was tested by the least significant difference (LSD) test at 5 and 1% levels of probability (Gomez and Gomez, 1984). Th e per cent fruit area di seased wa s m ea sur ed based on eye estimation. The fruits were critically examined every day for the appearance of rot. The incidence of fruit rot was recorded every 2nd day. The first count was made at the 6th day of storage. The fruit rot of papaya was identified by the visual comparison. Results and discussion Shelf life The postharvest treatments had significant influence on extending shelf life of papaya during storage. The longest shelf life (16 days) was recorded in fruits treated with garlic extract followed by (15.66 days) of the fruits kept at low temperature (13ºC), while the shortest shelf life (9.00 days) was recorded in untreated fruits preceded by those kept in mustard oil (10.60 days), straw (11.40 days), news paper (11.66 days), neem extract (11.86 days), hot water +polythene (12.93 days) and hot water (13.80 days), respectively (Fig. 1). Geetha et al. (2010) concluded that the shelf life papaya fruits increased under vacuum packing with room and refrigeration temperatures for one and four weeks, respectively. Souza et al. (2005) studied the low temperature effect (3, 6, 9ºC) on shelf life in papaya and reported that shelf life increased 10 days over control under low temperature Osuna-Garcia et al. (2005) observed the effects of 1-methylcyclopropene (1-MCP; 1,100 and 200 ml/litre) on the shelf life and quality of papaya cv. Maradol, stored for 4 days at room temperature, 4 days under refrigerated conditions and 6 more days at room temperature. Alongside this, the effects of 200 ml 1- MCP/ litre on the shelf life and quality of papaya compared to a control were determined. Under room and refrigerated conditions, 1-MCP increased the shelf and quality life of papaya by inhibiting weight losses, delaying the development of external and internal color and evolution of soluble solids. The treatment also reduced the incidence of diseases and maintained fruit firmness for a longer time. Mondal et al. (2010) reported that the fruits harvested at brownish green stage and treated at 55ºC water for 10 minutes when kept in non-perforated plastic bag containing 5 g KMnO4 was the best treatment for extending shelf life of papaya. 18 16 14
12 10 8 6 4 2 0 T0
Fig. 1. Effect of different postharvest treatments on shelf life of papaya. The vertical bar represents LSD at 5% level of probability. [T 0= Control (room temperature), T1= Fruits kept in newspaper, T2= Fruits kept in low temperature (13o C), T3= Fruits given hot water treatment at 55ºC for 5 minutes, T4= Fruits soaked in neem extract, T5= Fruits soaked in garlic extract, T6= Fruits coated with mustard oil, T7= Fruits covered with straw, T8= Fruits given hot water treatment at 55ºC for 5 minutes then kept in perforated polythene].
Roy et al.
Disease incidence The postharvest treatments exhibited significant effect on the percent disease incidence during storage of papaya. At 6 DAS, the highest disease incidence was identified in control fruits (26.66%) followed by the fruits wrapped with paper bag while the lowest (0.0%) in garlic extract, low temperature and hot water, respectively. The maximum disease incidence (60.00%) was recorded at the 8th day of storage that increased from 86.66 to 100% at 12th day of storage while the minimum infection (13.33%) was observed in garlic extract at 8th day of storage that increased from 40.00 to 60.00%, respectively, at 12th day of storage (Table 1). Dantas et al. (2003) reported that fungal diseases constitute one of the main causes of loss during commercialization of tropical fruits. Papaya fruits were analyzed in relation to disease incidence and frequency of the pathogenic species for 6 months in Pernambuco, Brazil. A great diversity of diseases occurred in papaya fruits where incidences ranged from 39.71 to 80.07%, with the higher level for stem end rot. The pathogens that presented higher frequencies were Colletotrichum gloeosporioides (Glomerella cingulata) (44. 95%) in papaya. Echerenwa and Umechuruba (2004) carried out an experiment on postharvest fungal diseases of papaya (Carica papaya L.) fruits and the following fungi were isolated from the tissues of diseased fruits: Fusariurn solani, Phoma caricae papayae, Aspergillus flavus, Aspergillus niger, Botrrydiplodia theobrimae, Cladosporium herbarurn, Colletotrichum dematiurn, Fusarium moniliforme (Gibberella moniliformis,), Phornopsis caricae-papavae, Penicilliurn sp., and Rhizopus stlionifer and F. solani caused the greatest rot on the fruits. Raheja and Thakore (2002) reported that extracts from medicinal plants like Allium sativum (cloves), Azadirachta indica (leaves), Mentha arvensis (leaves) and Psoralea corylifolia (seeds) were found most effective to check the mycelial growth of C. gloeosporioides followed by Curcuma longa (Rhizomes), Coriander sativum (leaves) and Lantana camara (leaves and flowers). Singh et al. (1999) conducted an experiment to study the use of crude plant extracts as an alternative to commercial fungicides in the control of Capsicum anthracnose. The efficiency of neem (Azadirachta indica), garlic (Allium sativum) and Tagak-tagak (Rhinocanthus nasuta) at 5000 ppm on Capsicum annuum was comparable with the fungicide Carbendazim (Bavistin) at 100 ppm. Garlic extracts performed well under room humidity, while tagak-tagak extracts showed good control of chilli anthracnose under high moisture conditions. Neem extracts minimized the ripe chilli rot. Disease severity The postharvest treatments used in the experiment had significant effects on disease severity of papaya. The highest disease severity was investigated in control fruits and no disease severity was observed in hot water treated fruits and the fruits kept in low temperature (13ºC) and garlic extract at the 6 th day of storage. At 8 th , 10th and 12th day of storage the maximum (23.33, 38.66, 60.66%) disease severity was noted in control and the minimum (0.26, 1.73, 4.33%) was observed in garlic extract (Table 1). Muniz et al. (2003) conducted an experiment to identify the fungal diseases on eight different fruit cultivars during storage. The Table 1. Effect of different postharvest treatments on percent disease incidence and severity of papaya Treatments Disease incidence (%) at DAS Disease severity (%) at DAS 6 8 10 12 6 8 10 12 T0 26.66 60.00 86.66 100.00 8.00 23.33 38.66 60.66 T1 13.33 40.00 60.00 93.33 0.66 3.33 19.33 36.66 T2 0.00 20.00 40.00 60.00 0.00 0.40 1.73 6.00 T3 0.00 20.00 46.66 73.33 0.00 1.00 11.66 19.46 T4 13.33 40.00 60.00 93.33 0.66 4.66 20.00 36.66 T5 0.00 13.33 40.00 60.00 0.00 0.26 1.73 4.33 T6 13.33 33.33 80.00 100.00 2.66 10.66 27.00 47.33 T7 13.33 53.33 80.00 100.00 1.00 10.00 29.33 44.33 T8 6.66 46.66 66.66 86.66 1.66 3.46 23.00 29.66 LSD(0.05) 8.710 29.41 32.66 30.23 0.664 2.711 22.76 35.01 LSD(0.01) 11.930 40.29 44.75 41.42 0.910 3.715 31.91 47.97 Level of ** * * * ** ** * * significance (* = Significant at 5% level of probability, ** = Significant at 1% level of probability, T 0= Control, T1= Newspaper, T2= Low temperature (130C), T3= Hot water treatment at 55º for 5 minutes, T4= Neem extract, T5= Garlic extract, T6= Mustard oil, T7= Straw, T8= Hot water +Perforated polythene)
Shelf life and diseases of papaya
fungi were isolated on PDA medium and their pathogencity was tested by wound inoculation on several healthy fruits. Among the identified fungi, Colletotrichum gloeosporioides (Glimerella cingulata) was the most frequently isolated which was the causal agent of anthracnose of papaya and Acrernonium sp, F. anthophilurn and F. equiseti were the causal agents of diseases associated with postharvest decay on tropical fruits. Hassan et al. (2003) carried out an experiment and stated that disease severity in banana fruit was significantly reduced by hot water treatment (50±ºC for 5 min). At the 25h day of storage, the highest disease severity (61.8%) occurred in the untreated fruits at room temperature, whereas the fruits treated with fungicide and hot water showed remarkably small areas of the fruit covered by disease (