J. Agric. Sci. Mansoura Univ., 33 (3): 2075 - 1089, 2008 HOT AIR AND SALICYLIC ACID POSTHARVEST TREATMENTS ALTERNATIVE TO FUNGICIDE IN NAVEL ORANGES DURING SHELF LIFE El-Abbasy, U. K.*and H. M El-Zahaby** * Hot. Dept., Fac. Agric., Tanta Univ. ** Agric. Bot. Dept. Fac. Agric., Tanta Univ. ABSTRACT Navel oranges were treated either with hot air at 45 oC for 30 min or dipped in salicylic acid solutions at 1000 and 2000 ppm concentrations for 15 min, whereas controlled fruits treated with 1400 ppm thiabendazol + 375 ppm imazalil fungicides. Fruits were held at 15 ± 2 oC and 80-85 % RH for 4 weeks; simulating shelf life period to examine the potential use of hot air as an environmentally benign and or salicylic acid as a natural and safe phenolic compound for maintaining oranges quality characteristics of fruits during their shelf life period. Salicylic acid at 2000 ppm showed the highest marketable fruit percentage and lowest decayed percentage, after 4 weeks of shelf life period, without significant difference comparing with fungicide treatment. Marketable fruit percentage was decreased, however decayed fruits were increased by advancing shelf life period and heat treatment applied. Soluble solid content: acid ratio was significantly increased by 32.71 and 31.25 % after 4 weeks compared with 2 weeks shelf life period, but it was significantly decreased by 20.64 and 14.76 % as affected by heat treatment. Salicylic acid at 2000 ppm significantly decreased soluble solid content: acid ratio as a result of maintaining titratable acidity values. Electrolytic leakage percentage of fruit's peel was significantly decreased as affected by prolonging shelf life period and heat treatment. Salicylic acid (1000 & 2000 ppm) did not reduce either spore germination or mycelial radial growth of Penicilium Digitatum Sacc in vitro compared with postharvest fungicides (thiabendazole and imazalil) treatment. However, salicylic acid had almost the same protective action against postharvest decay of Navel oranges caused by Penicilium digitatum. Keywords: Navel oranges, postharvest treatment, salicylic acid, heat treatment, fruit quality, shelf life. INTRODUCTION Citrus industry considers to be pronounced, marked and technological competition among the leading export countries. It's obvious that fruit quality which includes nutritional content, flavor and appearance are being important for consumers. In addition, consumer demand is mainly focused on producing fruits free from both visible defects and chemicals residues that may be unhealthy. Up till now such chemicals have been widely employed in postharvest handling and cold storage of citrus fruits. Postharvest rot is the major factor limiting the extension of storage life of many freshly harvested fruit including Navel oranges, and there are very few registered, postharvest fungicides for control of decay-causing organisms. Fresh citrus fruit are susceptible to decay caused by fungi during the interval between harvest and the consumption. Green mold of citrus fruit, caused by Penicillium digitatum (Pres.: Fr.) Sacc., is the main wound pathogens of citrus fruit, causing the El-Abbasy, U. K.and El-Zahaby, H. M. most common and devastating postharvest diseases (Plaza et al., 2004). Control of green mold traditionally has relied on sanitation, avoidance of fruit wounding, and use of preharvest and postharvest fungicides. Penicillium digitatum, however, frequently develops resistance to the commonly applied fungicides such as, benomyl, thiabendazole (TBZ) and imazalil (Eckert et al., 1994 and Wild, 1994). Some isolates of P. digitatum are resistant to both thiabendazole and imazalil (Bus, 1994; Bus et al., 1991 and Holmes and Eckert, 1995). Additional control methods are subsequently needed for use in combination with, or without fungicides. Although the use of synthetic fungicides is a most effective decay control treatment, there is a dire need to find another effective and safe nonfungicide means to control postharvest pathogens; because of the toxicity of the synthetic fungicide residues to the human health (Conway et al., 2005 and Droby, 2006). Postharvest heat treatments have attracted research interest as a promising alternative method to replace or to reduce the use of toxic chemical during storage (Lurie, 1998 and Fallik, 2004). The beneficial effect of heat treatments on storability of different fruits is well documented. The exposure to temperatures higher than 35 oC has caused ripening inhibition in different fruits (Paull, 1990 and Lurie, 1998). Heat treatment of orange fruits at 44 or 46 oC appear to be an important commercial application and alternative to toxic chemical fumigants and approved disinfestations treatment as cold quarantine (Mario et al., 2004). The effect of heat treatment on fungal decay may be due to a combination of direct inactivation of the pathogen and to the induction of some kind of natural resistance in the fruit (Fallik et al., 1995). Salicylic acid, a natural and safe phenolic compound, exhibits a high potential in controlling postharvest losses (Mesbah et al., 2007). Salicylic acid (SA), a simple ubiquitous plant phenolic, has been reported to regulate a number of processes in plants including reduced fruit ethylene production, fungal decay and retained overall quality (Zhang et al., 2003 and Mesbah et al., 2007). In addition, as a hormone-like substance, salicylic acid has provide to be a major component in signal transduction pathways and plays an important role in the regulation of plant growth and development, including transpiration, stomatal closure (Ananieva et al., 2004). It is believed that systemic acquired resistance is dependent on SAmediated signaling and is associated with the production of proteins (Linda, 2001). In the field of disease control, SA has received particular attention because its accumulation is essential for expression of multiple modes of plant disease resistance. Exogenous application of SA at non-toxic concentrations to susceptible could enhance resistance to pathogens (Murphy et al., 2000 and Galis et al., 2004). The objectives of our studies aimed to evaluate the efficacy of hot air exposure, as an environmentally benign method, and salicylic acid, as antioxidant treatments in comparison with other chemical treatments currently used in citrus packinghouse to maintain higher marketable fruits and to determine the impacts of these treatments on Navel orange fruits quality during their shelf life (15 oC & 80-85 % RH) as stimulating marketing period. 2076 J. Agric. Sci. Mansoura Univ., 33 (3), March, 2008 MATERIALS AND METHODS This work was carried out during two successive seasons (2005 & 2006). In March of both season, Navel orange fruits were obtained from the packinghouse line after washing and treating with 0.5 % sodium orthophenylphenol and finally air dried. The fruits were divided into two main groups. The first group was put in an air oven, set at 45 oC for 30 min, and then the fruits get out and held on the ambient temperature (15 ± 2 o C & 8085 % RH). The second group was held on the ambient temperature without heat treatment. All of the fruits in both main groups were divided into three subgroups. One third of the three subgroups were dipped in 1400 ppm thiabendazol (TBZ) + 375 ppm imazalil (IMZ), as a control treatment for packinghouse, the second third subgroup was dipped in 1000 ppm salicylic acid (dissolved in 0.5 % ethyl alcohol) and the last third subgroup was dipped in 2000 ppm salicylic acid for 15 min for each. Every treatment was represented by three replicates with eight orange fruits for each. After treatments, the fruits were held at ambient temperature (15 ± 2 o C & 80-85 % RH), simulated retail shelf life condition, for 4 weeks period. Half of the treated fruits were taken out after 2 weeks and the second half were taken out after 4 weeks, to evaluate the fruit quality parameters. Marketable fruits were recorded and expressed as percentage of sound fruits, without any defect, related to the initial fresh weight before the treatment. Four fruits for every treatment in each replication were juiced to determine: soluble solid content (SSC), using hand refractometer (ATAGON-1-E), titratable acidity (TA) as citric acid percentage by titrating against 0.1 N NaOH. SSC: acid ratio was calculated. Ascorbic acid was determined by using titermetric method and 2, 6 diclorophenolindophenol dye. The rate of electrolyte leakage of peel tissue excised from two fruits per replication for each treatment was determined (Schirra and D'hallewin, 1997) and then expressed as a percentage. An informal panel of untrained assessors evaluated the fruit segments samples. The evaluation based on degree of acceptability of fruit freshness and taste of the fruit segments by using a scale ranging as follow: freshness (5, excellent; 4, fresh; 3, acceptable; 2, welt; 1, severe welt). Taste evaluation was scored on a 10- point scale (0 very bad; 5, acceptable for commercial purpose; and 9, excellent). Pathogen, salicylic acid and fungicides: A Penicilium digitatum isolate used in these tests was isolated from naturally infected citrus fruits. The culture was initiated by using cultures of a single spore. The pathogen was maintained in potato dextrose agar (PDA) slants in test tubes stored at 4°C. The pathogenicity and virulence were tested on citrus fruits. Salicylic acid (El Gomhoria Company) and commercially citrus postharvest fungicides; thiabendazol )45% w/v) and imazalil (70% w/v) were used. Spore suspension preparation of P. digitatum: Prior to each, P. digitatum was recovered from PDA slants in storage and grown in 9-cm plates with PDA at 25°C for 7 to 10 days. Spores were 2077 El-Abbasy, U. K.and El-Zahaby, H. M. harvested from a PDA plate by adding about 8 ml of sterile water with 0.05% Triton X-100 and rubbing the fungal colony with a sterile glass rod. The spore suspension was filtered through two layers of sterile cheesecloth to remove the mycelia and medium particles, and diluted with sterile water to an absorbance of 0.1 at 420 nm using a spectrophotometer. This density of the spore suspension was equivalent to a concentration of approximately 10 6 spores per ml (Smilanick et al., 1999). The spore concentration was confirmed using a hemacytometer to determine actual spore counts of the suspension. Natural injury and infection: Navel orange fruits which naturally infected by P. digitatum, whereas injuries resulted from harvest and subsequent postharvest handling procedures, were used in this study. In vitro antimicrobial activity assays: a) Germinability of spores To determine the effect of SA or commercial control (1400 ppmTBZ + 375 ppm IMZ) treatments on spores germinability of P. digitatum, 1 ml from fresh spore suspension containing 1 X 106 spores / ml was added to 9 ml of distilled water alone (absolute control) or solutions from each of SA (1000 or 2000 ppm) or fungicide control (1400 ppm TBZ + 375 ppm IMZ) and incubated at 25 °C for 10 h. The proportion of germinated spores was determined by examination of 100 spores by light microscope at 100 X magnification. Each treatment was carried out as three replicates sample. b) Effect on fungal radial growth: To determine the effect of SA or TBZ + IMZ of the radial growth of P. digitatum, trials were performed using PDA medium amended with a SA or fungicide. A 10 µl drop of fresh spore suspension, containing 106 spores per ml was placed on the center of plates of potato dextrose agar (PDA) amended with SA or TBZ + IMZ at the same concentrations mentioned previously, and on unamended PDA (absolute control). In each case, grade material was dissolved and added to autoclaved, cooled, PDA. The test was performed three times; each trial included 3 plates of each treatment. Plates were incubated at 25 ºC and colony diameter was recorded 5 d after transferring spore suspensions to the plates. The experimental design was randomized complete block design with factorial arrangement of treatments (Byrkit, 1987). A group of three replicates of 8 fruits per treatment was used. Data in percentage was transformed to the arcsine of the square root. The data was analyzed by "ANOVA" and the significance among treatment means values were determined by Duncan's multiple range test (DMRT) at probability level 0.05. RESULTS AND DISCUSSION Marketable fruits (MF), as shown in Table 1& Fig. 1a, were slightly decreased by progressing shelf life period and heat treatment application as a result of accelerate the fruit weight loss, mainly due to the elevated transpiration rate at the higher temperature and longer shelf life period. 2078 J. Agric. Sci. Mansoura Univ., 33 (3), March, 2008 Increases in decayed fruit percentage (Table, 1 & Fig. 1b) were detected as a result of hot air treatment. These results are contrary to the findings of Mario et al., (2004) on "Blood oranges"; and Seok et al., (2007) on "Satsuma" mandarin and this might be due to use of either hot water, as a source of heat treatment instead of hot air, or shorter exposure time. After 2 weeks shelf life period, control treatment with fungicide showed the highest marketable fruit percentage (MF) (93.00 & 90.18 %) and the lowest decayed fruit percentage (DF) (3.41 & 2.89 %) in the two seasons, respectively. However, after 4 weeks, Salicylic acid treatment at 2000 ppm showed the highest MF (87.45 & 86.36 %) and the lowest DF (3.21 & 3.88 %) without significant difference compared to fungicide treatment in the two seasons, respectively. The inhibitory effects of fruit postharvest treatment with SA on fungal decay confirm the previous reports about its antifungal effects (Cai and Zheng, 1999; Amborabe et al., 2002 and Lu and Chen, 2005). SA increases activation of peroxidase. Peroxidases represent a component of an early response system may formed in plant to face pathogen attack, which are usually associated with plant defense mechanisms such as lignification and suberization of cell wall forming mechanical barrier substances which limit extent of pathogen spread and generation of hydrogen peroxides or other free radicals which exhibit antimicrobial effects (Tuzun, 2001 and Passardi et al., 2004). It could be observed in Table, 1 that with prolonging shelf life period a significant decrease in electrolytic leakage by 21.30 and 20.66 % after 4 weeks comparing with 2 weeks was observed in the two seasons, respectively. Heat treatment also appears to decrease electrolytic leakage by 4.07 and 4.14 % comparing with non heated-fruit in the two seasons, respectively. These results might due to the integrity of fruit membrane components (plasmalemma and / or tonoplast) which responded by heat treatment (Ariel et al., 2006). The present data revealed that there was no significant difference between salicylic acid and fungicide treatments. Natural injury and infection: Effect of SA and postharvest fungicides on natural injury and fungal infections (decayed fruits) is indicated in Table (1). Toxicity to spores In Vitro and Effect on fungal radial growth: Data in Table, 2 shows that SA treatment, at both concentrations, had slight effect on reducing spore germination and linear growth; however fungicides treatment was highly effective in inhibiting of spores germination and linear growth of P. digitatum on potato dextrose agar. Salicylic acid (1000 & 2000 ppm) was not able to reduce either spore germination or mycelial radial growth of P. digitatum in vitro compared with postharvest fungicides (thiabendazole and imazalil) treatment. 2079 El-Abbasy, U. K.and El-Zahaby, H. M. T1 2080 J. Agric. Sci. Mansoura Univ., 33 (3), March, 2008 f 2081 El-Abbasy, U. K.and El-Zahaby, H. M. Table, 2: Effect of salicylic acid (SA) and thiabendazole (TBZ) + imazalil (IMZ) on the germinability of spores, linear growth (cm) and reduction of colony diameter of Penicillium digitatum Treatment Control (1400 ppmTBZ+ 375 ppm IMZ) Germination Of P. digitatum L.G. (cm) conidia (%) 13 c 0.60 c R. (%) 93.33 a Salicylic acid (1000 ppm) 85 b 7.12 b 20.88 b Salicylic acid (2000 ppm) 78 b 6.85 b 23.89 b unamended PDA (absolute control) 100 a 9.00 a 0.00 c L.G. = fungal linear growth (cm), R. = % reduction of colony diameter. Means followed by the same letter are not significantly different at the level of 5 % according to DMRT. Each value is the mean of three replicates. However, SA had almost the similar protective action against postharvest decay of Navel oranges caused by P. digitatum. This conclusion suggests that, application of SA induced some defense mechanism within the fruit or a pathogenicity strategy of the fungus, during infection of Navel oranges by P. digitatum. These results are consistent with those obtained by Ballester et al., (2006) which indicated that some antioxidant enzymes may play a role in the defense response of citrus fruit against P. digitatum invasion and especially in the resistance of flavedo tissue to infection of this fungus. Ascorbic acid content (Table, 3) was increased with advancing shelf life period and applying hot air treatments. However, salicylic acid treatment did not significantly reduce ascorbic acid content compared to fungicide treatment. Fruit freshness (Table, 3) was decreased as the shelf life period prolonged and fruits applied with heat treatment, especially in the second season, which may be attribute to fruit transpiration (Seok et al., 2007). However, salicylic acid at 2000 ppm treatment maintained the fruit freshness comparing with fungicide treatment. Fruit segments taste, as shown in Table 3, was decreased by 8.67 and 17.60 % as affected by heat treatment comparing with non heated-fruit; however it showed in significant difference after 4 weeks compared to 2 weeks shelf life period in both seasons, respectively. The heat-treated fruit showed lower taste score. These results supported previous findings of Schirra et al., (2002) on "Tarocco" oranges and Mario et al., (2004) on "Blood" oranges. It could be also observed that salicylic acid treatment decreased fruit taste especially in the second season. The lower taste score might due to other components as ethanol accumulated in fruit, which contribute negatively on organoleptic characteristics (Moshonas and Shaw, 1997). 2082 J. Agric. Sci. Mansoura Univ., 33 (3), March, 2008 Soluble solid content (SSC) did not show significant difference as affected by heat and SA treatments; however it showed different trends in two studied seasons as affected by shelf life period. Titratable acidity (TA) was significantly decreased by 25.68 and 27.63 % after 4 weeks compared with 2 weeks of shelf life period, while it was increased by 32.14 and 27.58 % as affected by hot air treatment compared with non heated-fruit in the two seasons, respectively (Table, 4 & Fig. 1 c). Heat treatment disrupts ripening and inhibits ethylene formation. Although this inhibition of ethylene synthesis is usually reversible, the recovery requires protein synthesis (Paull, 1990). The obtained data showed that salicylic acid treatment maintained titratable acidity content at higher levels; however control (fungicide) treatment significantly decreased titratable acidity content. SSC: acid ratio (Table, 4 & Fig. 1d) was significantly increased by 32.71 and 31.25 % after 4 weeks compared with 2 weeks shelf life period, however it was significantly decreased by 20.64 and 14.76 % with hot air treatment compared with non heated-fruit in two seasons, respectively. The present data revealed that SSC: acid ratio might be depend on TA (r = - 0.919 P = 0.000) more than SSC (r = 0.340 P=0.000). Salicylic acid treatment at 2000 ppm decreased SSC: acid ratio by 22.44 and 16.8 0 % comparing with fungicide treated-fruit, in the two seasons, respectively. These results might be due to that SA decrease ethylene production leading to noticeable decrease in metabolic activity almost including respiration. Decrease in fruit metabolic activities eventually delays fruit senescence process (Wills et al., 1998; Wolucks et al., 2005 and Mesbah et al., 2007). In conclusion, in the present work the treatment of 2000 ppm salicylic acid postharvest application have the apparent effect than fungicide on maintenance of marketable fruits and decrease decayed fruit percentages, and may be applied as alternative to thiabendazol and imazalil fungicides treatment to maintain Navel oranges for more than two weeks in shelf life. However, treatment by hot air at 45 oC for 30 min increased fruit weight loss, decayed fruit, decreased marketable fruit, lowered fruit freshness, fruit segment taste scores, and increased titratable acidity, and could not recommended to Navel oranges. 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Journal of Experimental Botany, 56:2527-2538‬‬ ‫‪Zhang, Y.; K. Chen; S. Zhang and I. Ferguson (2003). The role of salicylic‬‬ ‫‪acid in postharvest ripening of kiwifruit. Posth. Biol. Technol. 28:67-74.‬‬ ‫معامالت مابعد الحصاد بالهواء الساخن وحامض السلسيليك كبديل للمبيدات الفطري ة‬ ‫للبرتقال بسرة اثناء حياة الرف‬ ‫أسامة كمال العباسي* و حسان محمد الذهبي**‬ ‫* قسم البساتين و **قسم النبات الزراعي ‪ -‬كلية الزراعة‪ -‬جامعة طنطا‬ ‫اجريتتهذهتتلدذاسةراالتتمذستتن ذتتالتتتي ذت ت سيي ذ ‪2005‬ذ&ذ‪)2006‬ذحيت ذعتتلتتهذ تت رذتر لت ذتالتتر ذ‬ ‫تتاالطذاسهتاءذاسال س ذ ‪45‬ذةرجمذتئتيتمذستتة ذ‪30‬ذةقيلتمذ)ذتذ ذوتذعتتلتهذاس تت رذتت سنلعذفت ذحت تاذاسال التيليكذ‬ ‫‪1000‬ذ&ذ‪2000‬ذج ت ءذف ت ذاستليتتت )ذستتتة ذ‪15‬ذةقيلتتمذف ت ذحتتي ذ تتتهذت تلتتمذ ت ت رذاسكن تترت ذتتاالتتطمذاستتيتتةذ‬ ‫اسفطريذ ي تنةا ت ذ ذ‪1400‬ذح ءذف ذاستليتت ذ ذ‪375‬ذجت ءذفت ذاستليتت ذييت اسيت )ذ ت ذ ت ذت تعذاس تت رذعلت ذ‬ ‫ةرجمذحرار ذاسغرفتمذ ‪15‬ذةرجتمذتئتيتمذذ&ذ‪80‬ذ–ذ‪85‬ذ‪%‬ذرطتتتمذنالتتيم)ذستتة ذوالتتتعي ذتلستكذرس تت رذتتة ذ‬ ‫يتك نيمذاال سةا ذاسهتاءذاسال س ذت ذوتذح تاذاساللاليليكذتلستكذسلحفت عذعلت ذتتف هذاسجتتة ذس ت راستر لت ذتالتر ذ‬ ‫و نت ءذحيت ذاستترد ذتقتتةذوعهتترهذاسةراالتتمذو ذاست تلتتمذتحت تاذاساللالتتيليكذت ركيت ذ‪2000‬ذجت ءذفت ذاستليتتت ذقتتةذ‬ ‫اعطتتهذوعل ت ذنالتتتمذتئتيتتمذسل ت ت رذاسل تلتتمذسل التتتي ذتوق ت ذنالتتتمذت ت ذاس ت ت رذاس سفتتمذتلستتكذتتتةت ذاس ت ندذت نتتتيذ‬ ‫ت ستل رنمذتت تلمذاستتيةاهذاسفطريمذتلسكذعنةذ‪4‬ذوال تيعذت ذحي ذاسرد ذهلاذتقةذينسفعتهذاسنالتتمذاستئتيتمذسل تت رذ‬ ‫اسل تلمذسل التي ذتينتت ذير ف تهذنالتيمذاس تت رذاس سفتمذتلستكذت يت ة ذطتت ذف تر ذحيت ذاستردذتكتلسكذت الت سةا ذت تلتمذ‬ ‫اسهتتتاءذاسال ت س ذتقتتةذا ةاةهذنالتتتمذاستتتتاةذاستتتلتمذاسلائتتتمذاسكليتتمذ ذاسحتت تتمذ ي ت ة ذت نتيتتمذينالتتتمذ‪32.71‬ذ&ذ‬ ‫‪%31.20‬ذف ذتتالت ذاسةراالمذعل ذاس تتاس ذي تةذ‪4‬ذوالت تيعذتل رن ت ذت التتتعي ذتت ذحيت ذاستردذتينتت ذانسلتتهذ‬ ‫نالتمذاستتاةذاستلتمذ ذاسحتت مذانسف ذت نتي ذتنالتتمذ‪20.64‬ذ&ذ‪14.76‬ذ‪%‬ذن يجتمذاست تلتمذتت سهتاءذاسالت س ذ‬ ‫ق ت ذتتالتتت ذاسةراالتتم‪,‬ذهتتلاذتقتتةذوةهذاست تلتتمذت ت ذذ‪2000‬ذج ت ءذف ت ذاستليتتت ذح ت تاذاللالتتيليكذاس ت ذارنسف ت اذ‬ ‫است نتيذس لكذاسنالتمذاي ذ ذكت ذستحعذونسف ذت نتي ذف ذاس تتي ذاسكهرتت ئ ذسلرتر ذ تت رذتر لت ذتالتر ذتلستكذ‬ ‫ن يجمذس ي ة ذطت ذف ر ذحي ذاسردذتكلسكذاست تلمذت سهتاءذاسال س ذ‬ ‫اعهتتترهذاسن تتت ئلذا ذاست تلتتتمذتحتتتتاذاساللالتتتيليكذتكتتت ذتتتت ذاس ركيتتت ي ذ ‪1000‬ذ&ذ‪2000‬ذجتتت ءذفتتت ذ‬ ‫است ت يت )ذك ت ذلاهذ تتن يرذتتتنسفاذجتتةاذعل ت ذك ت ذت ت ذ تتتيطذانت ت هذاسجتترا ي ذاسكتنيةيتتمذتكتتلاذعل ت ذ تتتيطذاسنتتتتذ‬ ‫اسلطتتتريذسفطتتترذتنالتتتليت ذةيجي تتت ذاسن تيتتتمذفتتت ذاطتتتت تذت تتتريذتلستتتكذتل رن تتت ذت س تتتن يرذاست تتتتطذسلتتيتتتةاهذاسفطريتتتمذ‬ ‫استال سةتم ذتعل ذاسج نبذاآلسرذفت ذحت تاذاساللالتيليكذكت ذست ذنفتثذاس تن يرذ لريتت ذتل رن ت ذت ستتيتةاهذاسفطريتمذ‬ ‫استال سةتمذف ذحفعذ ت رذاستر ل ذتالر ذ ةذاس ف ذت ةذاسحت ةذتاست التبذت ذاست الليت ذةيجي ذ‬ ‫‪2088‬‬ J. Agric. Sci. Mansoura Univ., 33 (3): 2075 - 1089, 2008 Table, 1: Effect of hot air, salicylic acid treatments and shelf life period on marketable, decayed fruits percentages and fruit peel electrolytic leakage of Navel oranges e period(P) Marketable fruits (%) Decayed fruits (%) Season 2005 Two Four weeks weeks Season 2006 Two Four weeks weeks Season 2005 Two Four weeks weeks ntrol @ 00 ppm 0 ppm 93.00 a 87.46 b 84.58 c 90.82 a 82.94b 86.23b 90.18 a 89.95 a 87.92 a (H) Non heated treatment 84.26 b 3.41 b 5.61 a 2.89 a 88.81 a 3. 46 b 4.21 ab 3.17 a 88.07 a 7.27 a 3.46 b 5.20 a nt mean 88.60AB 87.98B 89.37A 87.11B Electrolytic leakage (%) Season 2005 Two Four weeks weeks Season 2006 Two Four weeks weeks 5.90 a 3.43 ab 2.86 b 64.77 a 68.50 a 67.61 a 45.99 a 53.12 a 50.43 a 65.95 a 72.31 a 72.49 a 50.11 a 47.13 a 52.73 a 3.69 A 3.97 A 66.97 A 49.85C 70.29A 58.30B (H) Hot air treatment at 45 C/ 30 min 84.03 a 5.28 a 5.81 a 4.40 b 85.88 a 6.60 a 7.21 a 7.55 a 86.36 a 7.58 a 3.21 a 5.55 ab 6.67 a 3.69 b 3.88 b 58.70 a 59.24 a 62.92 a 55.68 a 53.06 a 46.57 a 57.93 a 54.13 a 62.78 a 53.87 a 51.59 a 50.48 a 4.66 A 60.29 B 51.78 49.99C 51.98C 4.40 63.66 50.81 64.26 4.60 B 4.38 B Season 2006 Two Four weeks weeks o 0 ppm 0 ppm 92.72 a 85.54 c 88.25 b 86.52 a 86.55 a 87.45 a 88.17 a 85.15 a 85.69 a tment mean 89.20A 86.84C 86.37C eriod mean 88.59 87.98 87.87 P ** NS ** ** * * NS ** NS ** * NS @ 85.44C 6.45 A 86.27 5.62 NS ** * ** * NS 5.28 B 5.76 A 4.92 4.71 NS * NS ** NS NS Fungicides (1400 ppm thiabendazol + 375 ppm imazalil), ● salicylic acid. In the same cell, means followed by the same letter are not significantly different at the level of 5% according to DMRT. ** NS NS NS * NS 50.99 ** * NS NS ** NS El-Abbasy, U. K.and El-Zahaby, H. M. Table, 3: Effect of hot air, salicylic acid treatments and shelf life period on ascorbic acid content and sensory evaluation of Navel oranges Shelf life period(P) Season 2005 Two Four weeks weeks Season 2006 Two Four weeks weeks 44.85 a 41.2 1a 45.24 a 44.38 a 43.89 a 40.66 a 44.57 a 44.66a 43.13 a (H) Non heated treatment 41.34 a 3.25 a 3.08 a 3.67 a 42.37 a 3.58 a 3.00 a 3.25 b 43.32 a 2.75 b 3.00 a 3.17 b Air treatment mean 43.77A 42.98A 44.12BC 42.34C Control SA 1000 ppm SA 2000 ppm 47.73 a 47.54 a 47.34 a 43.89 b 51.58 a 51.11 a 50.60a 46.20 a 45.43 a Hot air treatment mean 47.54 A 48.89 A 47.41AB Treatments (S) Control @ ● SA 1000 ppm SA 2000 ppm Season 2005 Two Four weeks weeks Fruit segments taste (0-9) z Season 2005 Two Four weeks weeks Season 2006 Two Fou weeks week 4.00 a 3.08 b 3.33 b 6.17 a 6.17 a 4.75 a 5.67 a 4.83 b 3.42 c 5.83 a 6.00 a 6.17 a 5.33 3.42 4.42 3.36 A 3.47 A 5.69 A 4.64 B 6.00 A 4.19 (H) Hot air treatment at 45 oC/ 30 min 49.59a 3.17 a 2.75 b 3.92 a 55.10 a 2.92 a 2.83 b 3.33 b 49.59a 3.11 a 3.33 a 3.33 b 2.58 b 2.42 b 3.08 a 5.00 a 4.83 a 4.50 a 3.08 b 3.92 a 4.25 a 5.33 a 4.67 a 4.83 a 4.42 4.83 4.33 2.69 B 4.78 B 3.75 C 4.94 B 4.53B 3.08 5.24 4.19 5.47 3.19 A 51.43 A 3.02 A 3.03 A Shelf life period mean 45.65 45.94 45.78 48.61 3.11 P NS NS H ** * SxH NS NS Sx P NS NS HxP NS * SxHxP NS NS @ Fungicides (1400 ppm thiabendazol + 375 ppm imazalil), ● salicylic acid; Y fruit freshness (5, excellent; 4, fresh; 3, acceptable; 2, welt; 1, severe welt). z Taste evaluation was scored on a 10- point scale (0 very bad; 5, acceptable for commercial; purpose; and 9, excellent). In the same cell, means followed by the same letter are not significantly different at the level of 5% according to DMRT. Season 2006 Two Four weeks weeks 2.97 A 3.53 A 3.00 3.44 ** ** ** ** NS NS NS NS * * ** ** ** * ** NS * ** Table, 4: Effect of hot air, salicylic acid treatments and shelf life period on some quality indices of Navel oranges fe period(P) ontrol @ 1000 ppm 00 ppm Fruit freshness (1-5) y Ascorbic acid (mg/100ml juice) SSC (%) Titratable acidity (%) Season 2005 Two Four weeks weeks Season 2006 Two Four weeks weeks 13.87 a 14.00 a 13.40 a 14.53 a 14.13 a 14.00 a 15.10 a 14.40 a 14.80 a Season 2005 Two Four weeks weeks Season 2006 Two Four weeks weeks (H) Non heated treatment 14.00 a 0.58 b 0.48 b 0.65 a 14.93 a 0.61 a 0.53 ab 0.66 a 14.73 a 0.63 a 0.58 a 0.58 a 1914 SSC/acid ratio 0.57 a 0.53 a 0.52 a Season 2005 Two Four weeks weeks Season 2006 Two Four weeks weeks 26.42 a 23.01b 21.45b 22.25 a 21.59 a 24.09 a 31.41 a 27.00b 25.41b 24.53b 27.89 a 28.21 a 4.46 ** ** NS NS ** ** J. Agric. Sci. Mansoura Univ., 33 (3), March, 2008 tment mean 13.76 B 14.77A 14.22 B ol 00 ppm 00 ppm 14.33 a 13.80 a 13.67 a 14.40 a 14.27 a 14.10 a 14.53 a 15.47 a 14.60 a tment mean 13.93 B 14.26AB 14.86A eriod mean 13.84 14.51 14.54 P * NS NS NS * NS 14.59AB 0.63 B 0.54 C 23.63 B 27.94 A 22.65 B 26.88 A (H) Hot air treatment at 45 oC/ 30 min 14.61 a 0.66 b 0.55 b 0.65 b 14.29 a 1.03 a 0.55 b 1.04 a 13.73 a 1.05 a 0.63 a 1.05 a 0.62 a 0.55 a 0.54 a 21.97a 13.34b 13.03b 26.23 a 25.83 a 22.35b 22.35 a 14.89b 13.88b 24.26 a 26.03 a 25.35 a 0.57 C 16.12 C 24.80 A 17.04 C 25.21 A 26.37 19.84 26.04 14.21 B 0.59 B 0.90 A 0.53 B 0.58 B 0.91 A 14.40 0.75 0.55 0.77 0.56 19.87 NS ** ** NS ** ** NS ** ** NS ** ** * ** ** NS ** ** @ Fungicides (1400 ppm thiabendazol + 375 ppm imazalil), ● salicylic acid. In the same cell, means followed by the same letter are not significantly different at the level of 5% according to DMRT. 1915 ** ** ** ** * NS ** ** NS NS * NS El-Abbasy, U. K.and El-Zahaby, H. M. 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 1916