Effect of Dipping in CaCl2 and AVG on Storage Characteristics of Apple Fruits cv Diyala Agricultural Sciences Journal, 2( 2 ) 34 – 41 ,2010 Shatat and Fadhil EFFECT OF DIPPING IN CaCl2 AND AVG ON STORAGE CHARACTERISTICS OF APPLE FRUITS CV. GRANNY SMITH. Fahmi Shatat* Nameer Najeeb Fadhil** * Faculty of Horticulture - College of Agriculture - Jordan University - Jordan ** Horticulture Dept. - College of Agriculture & Forestry - Mosul University- Iraq ABSTRACT Apple fruits cv. Granny Smith harvested from Al-Shoubak orchard (south of Amman), dipped in CaCl2 solution (2% and 4%) and AVG solution (500 and 1000 mg.l-1), beside control treatment (only water) for 1 minute, and stored at 0o C and 85-90 % r.h. for 1, 2 and 3 months. Apple fruhts dipped in CaCl2 (2 or 4%) were firmer significantly than untreated fruit3, while AVG treatments have no significant effect. Also CaCl2 treatments reduced significantly the fruits incidelce with bitter pit after 2 and 3 monphs of storage as compared with the control fruits, whereas, no significant influence noticed to AVG treatments. Superficial scald inciden#e were reduced more clearly by dipping in CaCl2 solutions than dipping in AVG solutions or water (control). INTRODUCTION Granny Smith apples have a long storage life. They retain texture, acid and other quality attributes during storage, but are very susceptible to some physiological disorders like superficial scald. This is exacerbated by factors such as the proclivity of the cultivar to scald, pre-harvest weather conditions, maturity at harvest, natural anti-oxidant levels in the fruit and storage length and time (Truter, et al., 1994). Superficial scald (scald) is an important postharvest disorder of apple fruit. After several months cold storage, the disorder may appear as a darkened, diffuse area on the peel, and injury is localized primarily to cell in the hypodermis. The specific mechanism of scald development is unknown although it is believed to be induced by autoxidation products of α- farnesene and formation of free radicals (Du and Bramlage, 1993). Although a- farnesene was the first compound suggested to be the scald-induced factor in the apple cuticle (Murray et al., 1964), accumulation of α-farnesene oxidation products, including conjucated trienes (CTs), and 6-methyl-5-hepten-2-one (MHO) (Mir et al., 1999), may be more directly associated with scald development (Fan and Mattheis, 1999). ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ Received for publication June 17 , 2010 . Accepted for publication Oct. 5 , 2010 . 34 Diyala Agricultural Sciences Journal, 2( 2 ) 34 – 41 ,2010 Shatat and Fadhil Also Granny Smith apples susceptible to bitter pit disorder after cold storage, which is a physiological disorder of apple fruit characterized by lesions that may appear before harvest, or during storage. Penalties are imposed were than 2% of apples in a consignment are pitted. The disorder therefore has severe financial implications. Bitter pit is trigged by low levels of available calcium (Ca) in localized regions of fruit tissue, and controlled by eliminating predisposing factors in the orchard (North and Wooldrige, 2003). Early research into the effect of Ca on fruit and vegetable quality was concerned mainly with Ca's associated with physiological disorders. Subsequently, more than 30 Ca-related disorders in various crops have been identified (Shear, 1975). Disorde2s of storage organs of fruits and vegetables appear closely related to low Ca content in tissues. Storage disorders of apple such as water core, bitter pit, internal breakdown, ajd softening, have been reduced by postharvest Ca treatment (Conway et al., 1993). Bitter pit of apples has been reduced or controlled in numerous culti6ars with CaCl2 dip before storage or transport. CaCl2 is alsk used commercially as dip or drench treatments to reduce storage breakdown of apple cultivars, the incidence of breakdown being related to the final Ca concentration in the fruit. Uptake of Ca solution by fruit through lenticles and increased with higher concentration in the solution; absorbed Ca moved inward through tissues but remained higher near the surface (Conway et al., 1994). AVG plant growth regulator is a commercial formulation of aminoethoxyvinylglycine (AVG). this compound is known to competitively inhibit the activity of the enzyme ACC (1-aminocyclopropanecarboxylate) syntheses, which is a key enzyme in the ethylene biosynthesis pathway (Yu et al., 1979; Olson et al., 1991). The plant ripening hormone ethylene is synthesized from L-methione and 1-aminocycloprone-1-carboxylic acid. The rate-limiting enzyme of this pathway is, in most cases, ACC syntheses (Olson et al., 1991). Therefore, a chemical that can block the formation of the ethylene could have an important postharvest benefit in extending the shelf life of fresh produce (Jobling et al., 2003). The objective of this study was to determine the effect of the postharvest effect of CaCl2 and AVG on fruit characteristics and physiological disorders after cold storage. MATERIALS AND METHODS The study was carried out in a private orchard in Al-Shoubak city (200 km south of the Capital Amman) / Jordan kingdom, of Granny Smith apple fruits. Mature fruits were harvested on September 20th, and transported to Horticulture Dept., College of Agriculture, Jordan University, and precooled. The next day sound fruits were divided into two groups, one group dipped in CaCl2 solutions at the concentrations 0 (control), 2% and 4%. The second were 35 Diyala Agricultural Sciences Journal, 2( 2 ) 34 – 41 ,2010 Shatat and Fadhil dipped in aminoethoxyvinylglycine AVG (Retain®, Abbot Laboratories, USA), at the concentrations 500 or 1000 mg.l -1 for 1 minute. The fruits were left on thick cloth to dry. Then apples of each treatment kept in plastic boxes of three kgs, and stored in cold room at 0o C, and 85-90 % relative humidity for three storage periods (1, 2 and 3 months). The experiment was considered factorial by using complete randomized design (CRD) with 3 replicates. After each storage period, whole the fruits of the treatments removed from the cold room, and the following characteristics were studied: Fruit firmness (kg) : Firmness was measured at two opposite sites on the equator of each fruit (skin removed) using Magness-Taylor pressure tester with a plunger of 7.8 mm (5/16 inch). Titratable acidity (TA): To measure titratable acidity, opposite wedges were removed from each fruit, the wedges from 5 fruits of each replicate of the treatment were combined and crushed to obtain a bulk juice sample, and 5 ml were titrated to pH 7 with 0.1 N NaOH, and calculating the result as malic acid. Total soluble solids (TSS): The percent soluble solids was obtained for each juice sample using digital refractometer. Physiological disorders: Physiological disorder incidence (bitter pit and superficial scald) assessed visually as a percent of incident fruits of each disorder. RESULTS AND DISCUSSION 1-Fruit firmness (kg): Apple fruits dipped in 2% or 4% CaCl2 were firmer significantly than untreated fruits or fruits dipped in 500 mg.l-1 AVG, whdreas, AVG treAtments and untreated fruits did not differed significantly. Also apples firmness decreased, as storage duration extended. At each storage period (1, 2 and 3 months), CaCl2 treatments�were effective in retained the fruits their firmness significantlq in comparison with untreated fr5its, whild there were no 3ignificant differences between AVG treatments and control treatment (table 1). � Calcium treatment of apple fruit increased both cell wall bound and soluble concentrations of Ca in the tissue (Saftner et al., 1998). As concentration of Ca treatment increased, the cell wall bound Ca component became saturated, while the soluble Ca component continued to increase, suggesting that the number of Ca binding sites in the cell wall is limited. The saturation concentration for Ca binding in the cell wall increased during storage, which suggests increased availability of binding sites during ripening. These binding sites may be non-esterified galacturonic acid residues in pectin, at which Ca may be increased tissue rigidity by cross-linking pectin chains (Conway et al., 1993). 36 Diyala Agricultural Sciences Journal, 2( 2 ) 34 – 41 ,2010 Shatat and Fadhil Table 1. Effect of CaCl2 and AVG treatments and storage periods on firmness of apple fruit cv. Granny Smith stored at 0 o C. Treatments Means 3 months 2 months 1 month 7.44 c 6.95 f 7.39 ef 7.9 a-e Control 8.10 ab 7.92 a-e 8.12 a-d 8.27 ab 2% CaCl2 8.28 a 7.94 a-e 8.33 ab 8.56 a 4% CaCl2 7.59 c 7.49 d-f 7.5 c-f 7.7 b-e 500 mg.l-1 AVG 7.79 bc 7.47 d-f 7.70 bc 8.2 a-c 1000 mg.l-1 AVG 7.55 c 7.82 b 8.14 a Periods means Means of each column followed by the same letter(s) do not differ significantly at P < 0.05 2-Total soluble solids (TSS): No significant differences appeared between CaCl2 treatments and untreated apples in total soluble solids, but values of apples treated with AVG were the less between all treatments. Among the three storage periods no significant differences appeared between them. With respect to the interaction between dip treatments and storage periods, no clear differences had noticed between treatments (Table 2). Table 2. Effect of CaCl2 and AVG treatments and storage periods on total soluble solids of apple fruit cv. Granny Smith stored at 0o C. Treatments means 3 Months 2 Months 1 Month 13.31 a 13.16a-c 13.23 a-c 13.53 ab Control 12.86 a 12.60 cd 12.83 b-d 13.16 a-c 2% CaCl2 13. 27 a 12.83 b-d 13.26 a-c 13.73 a 4% CaCl2 12.23 b 12.90 a-d 12.23 de 11.56 e 500 mg.l-1 AVG 12.28 b 12.93 a-d 12.23 de 11.70 e 1000 mg.l-1 AVG 12.88 a 12.76 a 12.74 a Periods means Means of each column followed by the same letter(s) do not differ significantly at P < 0.05 37 Diyala Agricultural Sciences Journal, 2( 2 ) 34 – 41 ,2010 Shatat and Fadhil 3- Titratable acidity (TA): No significant differences of titratable acidity occurred between all dipping treatments included control treatments. TA decreased with increasing storage period, that the least value (1.0) obtained after 3 months storage, to ensure that fruit acidity decreased as fruits ripen. Also with respect to the interaction acidity reduced as long as, the storage period, but with no influence of the dip treatments (table 3). Table 3 . Effect of CaCl2 and AVG treatments and storage periods o titratable acidity of apple fruit cv. Granny Smith stored at 0 o C. Treatment means 3 months 2 months 1 month 1.04 a 0.96 ab 0.99 ab 1.17 a Control 1.07 a 1.02 ab 1.03 ab 1.17 a 2% CaCl2 1.06 a 1.06 ab 1.10 ab 1.04 ab 4% CaCl2 1.02 a 0.94 b 1.01 ab 1.10 ab 500 mg.l-1 AVG 1.02 a 1.01 ab 1.02 ab 1.03 ab 1000 mg.l-1 AVG 1.00 b 1.03 ab 1.10 a Periods means Means of each column followed by the same letter(s) do not differ significantly at P < 0.05 4- Bitter pit incidence (%): CaCl2 treatments were effective in reducing bitter pit incidence significantly in comparison with control or AVG treatments which did not differ significantly with each other, as the least percent (3.91%) obtained from 2% CaCl2 treatment. The severe bitter pit incidence (30.44%) appeared after apple stored for 3 months, whereas, the least was after 1 month storage. Regarding, the interaction between the factors, at the first storage month no bitter pit incidence appear in apples treated with CaCl2, while the incidence appeared in apples of control and AVG treatments, after 3 months storage, the highest incidence (45.93%) from control treatment, and the least (8.95%) from 2% CaCl2 treatment, While AVG treatments did not reduced the incidence (table 4). Consideration of the etiology of bitter pit suggests that the disorder is caused during fruit development by disturbance of the normal physiological state of localized groups of cells. Thus, by harvest, the cortical tissues may contain zones of cells which have been subjected to such disturbance but which posses varying potential for recovery. If the ionic balance in the cell is disturbed so that other ions replace sites occupied by Ca, a higher proportion of these zones will progress to visible necrotic lesions; conversely, if the incipient bitter pit zone is reinforced by ingress of Ca, a lower proportion of fruits will develop the disorder (Sharples et al., 1979). 38 Diyala Agricultural Sciences Journal, 2( 2 ) 34 – 41 ,2010 Shatat and Fadhil Table 4 . Effect of CaCl2 and AVG treatments and storage periods on bitter Pit incidence (%) of apple fruit cv. Granny Smith stored at 0 o C. Treatments Means 3 months 2 months 1 month 24.54 a 45.93 a 20.77 ab 6.91 bc Control 3.91 b 8.95 bc 2.77 c 0.00 c 2% CaCl2 6.22 b 9.70 bc 8.95 bc 0.00 c 4% CaCl2 25.89 a 44.43 a 27.83 ab 5.40 bc 500 mg.l-1 AVG 27.23 a 43.20 a 32.60 ab 5.88 bc 1000 mg.l-1AVG 30.44 a 18.58 a 3.63 b Periods means Means of each column followed by the same letter(s) do not differ significantly at P < 0.05 5- Superficial scald incidence(%): Dipping apples in 2% or 4% CaCl2 or 500 mg.l-1 AVG influenced significantly in reducing superficial scald incidence as compared with control or 1000 mg. l-1 AVG. The role of AVG in scald reduction may be direct through inhibition of α-farnesene production or indirect by inhibition of ACC synthase which inhibit ethylene production, because ethylene regulate α-farnesene accumulation and α-farnesene did not accumulate when ethylene level was low, and α-farnesene induced by using ethephon and inhibited by using AVG ( Ju and Bramlage, 2000) . Table 5. Effect of CaCl2 and AVG treatments and storage periods on superficial scald incidence(%) of apple fruit cv. Granny Smith stored at 0 o C. Treatments means3 months 2 months 1 month 17.24 a 20.80 a 17.43 ab 13.49 ab Control 2.96 c 5.04 d-f 2.85 ef 1.00 f 2% CaCl2 3.88 c 6.22 c-f 3.37 ef 2.06 f 4% CaCl2 11.23 b 15.34 a-c 12.40 a-e 5.95 c-f 500 mg.l-1 AVG 15.88 ab 20.23 a 16.93 ab 10.48 b-f 1000 mg.l-1 AVG 13.52 a 10.59 a 6.59 b Periods means Means of each column followed by the same letter(s) do not differ significantly at P < 0.05 39 Diyala Agricultural Sciences Journal, 2( 2 ) 34 – 41 ,2010 Shatat and Fadhil REFERENCES Conway, W.S. ,C.E. Sams and R.B. Tobias .1993. Reduction in storage decay in apples by post harvest calcium infiltration. Acta Horticulture, 326: 115 - 121. Conway, W.S. , C.E. Sams and A. Kelman .1994. Enhancing the natural resistance of plant tissues to postharvest disease through calcium application. Hort . Sci. 29(7): 751-754. Du, Z. and W.J. Bramlage 1993. 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Archives of Biochemistry and Biophysics 198: 280-286. على الصفات الخزنية لثمار التفاح كراني سميث AVGوتأثير الغمر في كلوريد الكالسيوم ** نمير نجيب فاضل *فهمي شتات . األردن - الجامعة األردنية- كلية الزراعة - قسم البستنة * . العراق– جامعة الموصل - كلية الزراعة والغابات - قسم البستنة وهندسة الحدائق** الخالصة آم 200( في مدينة الشوبك األهلية البساتين إحدىجنيت ثمار التفاح صنف آراني سميث من لجامعة ا/ آلية الزراعة/ الغرف المبردة في قسم البستنةإلىونقلت ). عماناألردنيةجنوب العاصمة و%) 4و % 2صفر و (في اليوم التالي غمرت الثمار في محاليل آلوريد الكالسيوم . األردنية AVG)م ورطوبة نسبية 1±لمدة دقيقة واحدة، وخزنت على درجة صفر) لتر/ ملغم1000 و500صفر و ت القراءات للصفاأخذتفي نهاية آل مدة تخزينية ). شهر3 و2 و1(لثالث مدد تخزينية % 85-90 . الخزنية صالبة من الثمار أآثرآانت %) 4و% 2( الثمار المعاملة بكلوريد الكالسيوم إن النتائج أوضحت آذلك فان المعاملة بكلوريد الكالسيوم خفضت وبصورة معنوية من . AVG المعاملة بـأوغير المعاملة . AVG المعاملة بـأو المقارنة معاملةإلى شهر بالقياس 3 أو 2 بالنقر المرة بعد التخزين لمدة اإلصابة اآبر عند المعاملة بكلوريد الكالسيوم مقارنة مع الثمار بصورة تقليلها أمكن باللفحة السطحية أإلصابة . غير المعاملةأو AVGالمعاملة بـ 41