Effect of Waxing and Gum Arabic Coating on Quality andshelf-life of Mango Fruits

International Journal of Agricultural and Environmental Sciences 2018; 3(5): 71-77 http://www.openscienceonline.com/journal/ijaes Effect of Waxing and Gum Arabic Coating on Quality andshelf-life of Mango Fruits Mohamed Magzoub Elzubeir 1, *, Abu-bakrAli Abu-Goukh 2, Osman Adam Osman 1, Ahmed Ismail Ahmed Saf 3 1 Faculty of Natural Resources and Environmental Studies, University of Kordofan, Elobeid, Sudan 2 Faculty of Agriculture, University of Khartoum, Shambat, Sudan 3 Institute of Gum Arabic Research and Desertification Studies, University of Kordofan, Elobied, Sudan Email address * Corresponding author To cite this article Mohamed Magzoub Elzubeir, Abu-bakr Ali Abu-Goukh, Osman Adam Osman, Ahmed Ismail Ahmed Saf. Effect of Waxing and Gum Arabic Coating on Quality and Shelf-Life of Mango Fruits. International Journal of Agricultural and Environmental Sciences. Vol. 3, No. 5, 2018, pp. 71-77. Received: May 8, 2018; Accepted: July 3, 2018; Published: September 21, 2018 Abstract The aim of the experiment was to evaluate the effect of waxing and gum Arabic coating, in aqueous solutions, on the quality and shelf-life of 'Kitchner' and 'Abu-Samaka' mango fruits in 'Abu-Gebeha' Area. Coating of fruits with gum Arabic in aqueous solution significantly delayed the onset on the climacteric peak of respiration and fruit ripening, reduced weight loss, fruit softening, peel color development, TSS accumulation and titertable acidity changes, retained ascorbic acid, maintained quality and extended shelf-life of mango fruits. Waxing in addition to the gum Arabic coating was more effective than gum coating alone in all parameters studied. Gum Arabic coating at 5% and 10%, without waxing reduced weight loss by 3.6% and 7.7% and peel color development by 3.8% and 9.6% in 'Kitchner' and 'Abu-Samaka', respectively, compared with the control. Gum Arabic coating at 5% and 10%, with waxing reduced weight loss by 13.5% and 19.6% and peel color development by 10.5% and 21.0% in 'Kitchner' and 'Abu-Samaka', respectively, compared with the control. Keywords 'Kitchner' and 'Abu-Samaka' Mango Fruit, Wax, Gum Arabic, Quality and Shelf-life 1. Introduction The mango fruit (Mangiferaindica L.) is the most popular fruit in many countries among millions of people in the world. It is considered as one of the best fruits in the world market, due to its excellent flavor, attractive fragrance, beautiful color, delicious taste and health giving properties [23]. In Sudan, mango is an important and popular fruit crop. Its annual production is about 651 thousand tons, representing 60% of total Sudan exports of horticultural crops [8]. Abu-Gebeha area in Southern Kordofan is considered as one of the most important area in Sudan for producing mango, guava and citruses, under rain-fed conditions. Although more than 100 thousand tons of good quality mango fruits are produced, only about 15% of the produce is marketed due to poor harvesting techniques, unsatisfactory handling practices and unadequate transportation and storage facilities [21]. These post-harvest handling practices need a lot of improvement for the development of a sound mango industry in the area. Waxing retards the rate of moisture loss, maintains turgidity and plumpness, and covers injuries on the surface of the commodity [25]. It significantly alters permeability of the skin to gases, the commodity, through respiration, is used to reduce oxygen and increase carbon dioxide and a modified atmospheric condition may be generated [12]. Coating of fruits with gum Arabic has been found to delay fruit ripening, maintain post-harvest quality and enhance their shelf-life in tomato [7] and banana [13]. This study was carried out to evaluate the effect of waxing and gum Arabic coating in aqueous solutions on quality and

International Journal of Agricultural and Environmental Sciences 2018; 3(5): 71-77 72 shelf-life of 'Kitchner' and 'Abu-Samaka' mango fruits. 2. Materials and Methods 2.1. Experimental Material Two of the most important mango cultivars grown in Sudan: an early 'Kitchner' and late maturing 'Abu-Samaka' were selected for this study. Mature-green fruits were harvested from an orchard at Abu-Gebeha area in South-East Kordofan (11 27 N, 31 14 E), theypicked by a hook attached to a long bamboo pole equipped with a long cloth bag held open by a ring. About 900 fruits of each cultivar were selected for uniformity size, color and freedom from blemishes, then washed with tap water to remove latex and dust, and then washed by distilled water, treated with 200 ppm sodium hypochlorite (Clorox, 5%) as disinfectant and air dried. 2.2. Fruit Treatment The fruits were distributed among the six treatments in a completely randomized design with four replicates. The treatments were: (1) control, (2) wax, (3) 5% gum Arabic, (4) 10% gum Arabic, (5) 5% gum Arabic with wax, and (6) 10% gum Arabic with wax. The fruits treated with aqueous solutions of 5% or 10% gum Arabic by dipping them of each designated concentration for three minutes and then air dried. Food-grade wax (Flucka AG, CH-9470 Buchs) was applied in a thin layer by brushing over the surface of the fruits. In the composite treatment, wax was applied after gum Arabic treatment. The fruits were then packed in carton boxes and stored at 18 ± 1 C and 85-90% relative humidity. 2.3. Parameters studied Respiration rate (RR), peel color (PC), weight loss (WL) percentage were determined daily during the storage period on 12 fruits from each replication. The total absorption method was used [18] and RR was expressed in mg CO 2 per kg-hr. The color score used was: mature green (=0), trace yellow on skin (=1), 20% yellow (=2), 40% yellow (=3), 60% yellow (=4), 80% yellow (=5), and 100% yellow (=6). WL percentage is calculated according to the formula: W 1 = [(W o - W t ) / W o ] x100%; where W1 is the percentage WL, W o is the initial weight of fruits at harvest and W t is the weight of fruits at the designated time. Flesh firmness (FF), total soluble solids (TSS), titratable acidity (TA) and ascorbic acid (AA) were determined in three fruits picked randomly from each replicate, other than those used for previousparameters in 2- day intervals and later every day during the storage period. (FF) was measured by Magness and Taylor firmness tester (D. Ballauf Meg. Co.), equipped with an 8 mmdiameter plunger tip. Two reading were taken from opposite sides of each fruit after the peel was removed, and expressed in kilogram per square centimeter. TSS was measured directly from the fruit juice extracted by pressing the fruit pulp in a garlic press, using a Kruss hand refractometer (model HRN-32). Two readings were taken from opposite sides of each fruit and the mean values were calculated and corrected according to the refractometer chart. Thirty grams of fruit pulp were homogenized in 100 ml of distilled water (oxalic acid for AA) for one minute in a Sanyo Solid State blender (model SM 228P) and centrifuged at 10 000 rpm for 10 minutes usingagallenkamp portable centrifuge (CF-400). The volume of supernatant, which constituted the pulp extract, was determined (was topped to 250 ml oxalic acid for AA). (TA) was measured according to the method described by [20] and expressed as percent citric acid. (AA) was determined by using the 2,6-dichloro-phenolindophenol titration method of [22] and expressed in mg per 100g fresh weight. 2.4. Statistical Analysis Analysis of variance (ANOVA) followed by Fisher ' s protected LSD test with a significance level of P 0.05 were performed on the data [10]. 3. Results and Discussions Waxing and gum Arabic coating significantly delayed fruit ripening and senescence, retarded moisture loss, maintained quality and extended shelf-life of the two mango cultivars studied. These effects of waxing and gum Arabic coating on ripening, quality and shelf-life were reflected in changes in respiration, weight loss, peel color development, flesh firmness, total soluble solids (TSS) and ascorbic acid content. 3.1. Effect on Respiration Rate (RR) The respiration curves of the two mango cultivars exhibited a typical climacteric pattern. Similar pattern of respiration were observed during ripening of several mango cultivars [2]. The untreated fruits had reached the climacteric peak after 8 days in 'Kitchner' and 10 days in 'Abu-Samaka' cultivar. The GA coating at 5% and 10% aqueous solutions delayed the onset of the climacteric peak by one and two days, respectively, compared with the untreated fruits. This is in line with the findings of [13]. The wax treatment delayed the onset of the climacteric peak by two days in the two cultivars. Waxing in addition to the GA coating further delayed the onset of the climacteric peak by two more days in both cultivars, compared to GA treatment. This is in agreement with previous reports in mango [16] and oranges [14]. Waxing has been reported to influence respiration rate by decreasing oxygen and increasing carbon dioxide content in the internal atmosphere of the fruits [11].

73 Mohamed Magzoub Elzubeir et al.: Effect of Waxing and Gum Arabic Coating on Quality and Shelf-Life of Mango Fruits Figure 1. Changes in respiration rate of 'Kitchner' (a) and 'Abu-Samaka' (b) mango fruits treated with gum Arabic aqueous solutions at zero (o), 5% ( ) or 10% ( ) without waxing ( )ــــــ or with waxing (----) during storage at 18 ± 1 C and 85% 90% relative humidity. 3.2. Effect on Weight Loss (WL) WL progressively increased with storage. Significantly lower percentages of WL were observed in the fruits coated with GA in aqueous solution, with or without waxing, compared with the control (Figure 2 (a) and (b)). WL was reduced by an average of 3.6% 1nd 7.7% in the fruits coated with GA in aqueous solution at 5% and 10%, respectively, compared with the control. [13] found that WL was 24% lower in banana fruits treated with 10% GA plus 1.0% Chitosan composite coating than control fruits. Similarly, 10% GA in aqueous solutions significantly reduced weight loss during storage of tomato fruits at 20 C and 20-90% relative humidity [7]. Waxing in addition to GA coating at 5% and 10%, decreased WL in both mango cultivars by an average of 13.5% and 19.6%, respectively, compared with control fruits. Waxing decreases water loss from the fruits in mango [16], guavas [17], tomato [6], oranges [14], grapefruit [3] and lime [1]. Wills et al. (1998) reported that the rate of water loss can be reduced by 30% to 50% in waxed fruits, under commercial conditions particularly if the stem scar and other injuries are coated with wax. Figure 2. Changes in weight loss of 'Kitchner' (a) and 'Abu-Samaka' (b) mango fruits treated with gum Arabic aqueous solutions at zero (o), 5% ( ) or 10% ( ) without waxing ( )ــــــ or with waxing (----) during storage at 18 ± 1 C and 85% 90% relative humidity. 3.3. Effect of Peel Color (PC) PC score continuously increased during storage of the two mango cultivars. At the end of the storage period the untreated fruits reached the full yellow stage (color score 6) after 10 days in 'Kitchner' and 13 days in 'Abu-Samaka' mango cultivars (Figure 3 (a) and (b)). When the untreated fruits reached the full yellow stage, PC development was reduced in both mango cultivars by an average of 3.8% and 9.6% in fruits coated with 5% and 10% GA aqueous solutions, respectively. This is in agreement with previous reports that color development was delayed in tomatoes [7] and banana [13] coated with gum Arabic aqueous solutions. The wax treatment delayed PC development in both cultivars

International Journal of Agricultural and Environmental Sciences 2018; 3(5): 71-77 74 by two days, compared to unwaxed control fruits. Waxing with the GA coating at 5% and 10% aqueous solutions, delayed PC development by three and five days, respectively, compared with the control fruits. Color score was reduced in both cultivars by an average of 10.5%, 21.0% and 32.5% in fruits treated with 0, 5 and 10% aqueous solutions of GA respectively, compared with the control. The delay in color development in the waxed fruits was due to reduce oxygen and increase carbon dioxide content in the internal atmosphere of the fruit [12]. Waxing delays PC development in mango [16], guava [17] tomato [6], orange [14], grapefruit [3], and lime [1]. Figure 3. Changes in peel color of 'Kitchner' (a) and 'Abu-Samaka' (b) mango fruits treated with gum Arabic aqueous solutions at zero (o), 5% ( ) or 10% ( ) without waxing ( ( or with waxing (----) during storage at 18 ± 1 C and 85% 90% relative humidity. 3.4. Effect on Fruit Flesh Firmness (FF) FF decreased steadily during storage of both mango fruit cultivars (Figure 4 (a) and (b)). The untreated fruits reached the final soft stage (0.17 Kg/cm 2 shear resistance) in 12 and 16 days in 'Kitchner' and 'Abu-Samaka' cultivars, respectively. GA and wax treatments delayed the decrease in FF during storage of both cultivars. The treated fruit with GA and/or wax were more firm than the control at any time during the storage period, but the difference diminished at the end of the storage period. This is in line with previous reports that FF was higher in tomato and banana treated with GA aqueous solution than the control [7, 13]. Similarly, waxing was reported to delay fruit softening in mango [16] orange [14], grapefruit [3], and lime [1]. Figure 4. Changes in fruit flesh firmness of 'Kitchner' (a) and 'Abu-Samaka' (b) mango fruits treated with gum Arabic aqueous solutions at zero (o), 5% ( ) or 10% ( ) without waxing ) ) or with waxing (----) during storage at 18 ± 1 C and 85% 90% relative humidity. 3.5. Effect on Total Soluble Solids (TTS) During storage period, the TSS progressively increased in both mango cultivars. The maximum TSS value reached by the untreated fruits was 20.3% in 'Kitchner' after 11 days and 17.8% in 'Abu-Samaka' after 13 days (Figure 5 (a) and (b)). These

75 Mohamed Magzoub Elzubeir et al.: Effect of Waxing and Gum Arabic Coating on Quality and Shelf-Life of Mango Fruits maximum values were reached after one and two days later in fruits coated with 5% and 10% GA without waxing and after three and five days with waxing in both cultivars, respectively, compared to control. This agrees with the reports that fruits coating with 10% GA delayed TSS changes during storage of tomato [7] and banana fruits [13]. Waxing of fruits delays changes in TSS during storage in mango [16], guava [17], tomato [6], orange [14], grapefruit [8] and lime [1]. Figure 5. Changes in total soluble solids of 'Kitchner' (a) and 'Abu-Samaka' (b), mango fruits treated with gum Arabic aqueous solutions at zero (o), 5% ( ) or 10% ( ) without waxing ) ) or with waxing (----) during storage at 18 ± 1 C and 85% 90% relative humidity. 3.6. Effect on Titratable Acidity (TA) TA progressively decreased during storage period of both mango cultivars. It decreased from 2.65% to 0.19% in 12 days in 'Kitchner' (Figure 6(a)) and from 3.1% to 0.2% in 14 days in 'Abu-Samaka' (Figure 6(b)). This in line with earlier reports [15, 24]. These minimum values were reached after one and two days later in fruits treated with GA at 5% and 10% without waxing and after three and five days later with waxing in both cultivars, respectively, compared with the control. Similar results were reported in tomatoes [7] and bananas [13] coated with GA aqueous solutions. Waxing was repeatedly demonstrated to decrease TA during storage of mango [19], orange [14], tomato [6], grapefruit [3], lime [1] and papaya [4]. Figure 6. Changes in titratable acidity of 'Kitchner' (a) and 'Abu-Samaka' (b), mango fruits treated with gum Arabic aqueous solutions at zero (o), 5% ( ) or 10% ( ) without waxing ) ) or with waxing (----) during storage at 18 ± 1 C and 85% 90% relative humidity. 3.7. Effect of Ascorbic Acid Content (AA) AA showed continuous decline during storage of both mango cultivars in all treatments. It significantly decreased from 40.1 to 15.0 mg/100g fresh weight at the ripe stage after 12 days in 'Kitchner' (Figure 7(a)) and from 32.8 to 15.0 mg/100g fresh weight at the ripe stage after 14 days in 'Abu- Samaka' (Figure 7(b)). This agrees with previous reports that AA declined rapidly during storage in mango [2, 16], guava [9], orange and pineapple [5] and lime [1]. The amount of ascorbic acid retained at the final ripe stage after 12 and 14 days in 'Kitchner' and 'Abu-Samaka was 37.4% and 45.7% of the initial amount in the two cultivars, respectively. At that time, AA retained was on average 5.5% and 12.5% more in the fruits coated with GA at 5% and 10% aqueous solutions without waxing, and 22.1% and 33.4% more in the fruits

International Journal of Agricultural and Environmental Sciences 2018; 3(5): 71-77 76 coated with GA with waxing, respectively, compared with the control. [7] reported that fruit coating with 10% GA significantly delayed changes in AA in tomatoes. Waxing reduced water loss during storage of both mango cultivars and consequently reduced AA losses in the waxed fruits. Waxing was reported to retain AA in mango [16], tomato [6], grapefruit [3] and lime [1]. Figure 7. Changes in ascorbic acid of 'Kitchner' (a) and 'Abu-Samaka' (b) mango fruits treated with gum Arabic aqueous solutions at zero (o), 5% ( ) or 10% ( ) without waxing ( ( or with waxing (----) during storage at 18 ± 1 C and 85% 90% relative humidity. 4. Conclusion Waxing and gum Arabic coating significantly delayed fruit ripening and senescence, retarded moisture loss, maintained quality and extended shelf-life of the two mango cultivars studied. These effects of waxing and gum Arabic coating on ripening, quality and shelf-life were reflected in changes in respiration, weight loss, peel color development, flesh firmness, total soluble solids (TSS) and ascorbic acid content. References [1] Abdallah, E. H. and Abu-Goukh, A. A. (2010). Effect of gibberellic acid and waxing on quality and storability of lime fruits. University of KhartoumJournal of Agricultural Sciences, 18 (3): 349-362. [2] Abu-Goukh, A. A. and Abu-Sarra, A. E. (1993). Compositional changes during mango fruit ripening. University of Khartoum Journal of Agricultural Sciences 1 (1): 32-51. [3] Abu-Goukh, A. A. and Elshiekh, F. A. (2008). Effect of waxing and fungicide treatment on quality and storability of grapefruits. Gezira Journal of Agricultural Science, 6 (1): 31-42. [4] Abu-Goukh, A. A. and Shattir, A. E. (2012). Effect of maleic hydrazide and waxing on quality and shelf-life of papaya fruits. University of Khartoum. Journal of Agricultural Sciences, 20 (1): 62-76. [5] Adisa, V. A. (1986). The influence of molds and some storage factors on the ascorbic acid content of orange and pineapple fruits. Journal of Food Chemistry 22: 139-146. [6] Ahmed, I. H. and Abu-Goukh, A. A. (2003). Effect of maleic hydrazide and waxing on ripening and quality of tomato fruit. Gezira Journal of Agricultural Science, 1 (2): 59-72. [7] Ali, A; Magbool, M; Ramachandran, S. and Anderson, P. G. (2010). Gum Arabic as a novel edible coating for enhancing shelf-life and improving postharvest quality of tomato (Solanumlycopersicum L.) fruit. Postharvest Biology and Technology, 58 (1): 42-47. [8] AOAD. (2009). Arab Agricultural Statistics Yearbook, Vol, 29. Arab Organization for Agricultural Development. (AOAD). Dec, 2008. Khartoum, Sudan. [9] Bashir, H. A. and Abu-Goukh, A. A. (2003). Compositional changes during guava fruit ripening. Journal of Food Chemstry, 80 (4): 557-563. [10] Gomez, K. W. and Gomez, A. A. (1984). Statistical Procedures for Agric-ultural Research. 2 nd edition. John Willey and Sons Inc., New York. U.S.A. pp 75-165. [11] Irving, L. E. and Warren, A. L. (1960). Effect of temperature, washing and waxing on the internal atmosphere of orange fruit. Journal of American Society for Horticultural Science 76: 220-228. [12] Kader, A. A. (2002). Post-harvest Technology of Horticultural Crops. 3 rd Edition. Publication 3311, Cooperative Extension, Division of Agric-ulture and Natural Resources, University of California. Oakland, California, U.S.A. 535pp. [13] Magbool, M.; Ali, A.; Anderson, P. G.; Zahid, N. and Siddiquei, Y. (2011). Effect of a novel edible composite coating based on gum Arabic and chitosan on biochemical and physiological responses of banana fruits during cold storage. Journal of Agricultural and Food Chemistry, 59 (10): 5474-5482. [14] Martinez, J. M.; Cuquerella, J.; Rio, M. D.; Mateos, M. and Ded, R. M. (1991). Coating treatment in postharvest behavior of oranges. Paperpresen-ted at a conference of technical innovations in freezing and refrig-eration of fruits and vegetables. Davis, California, U.S.A. July 1989. 79-83pp.

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