Impaginato 31 1. Introduction Apple (Malus domestica Borkh) is one of the most important horticultural crops considered as the third major fruit in the world (Garming, 2014). The main proportion (½ million tons) of apple production in Iran is used for fresh consumption (Iranian Ministry of Agriculture, 2016), while some problems such as tissue softening during storage, tissue browning due to physical damages at post-harvest handling, high water loss and some physiological disorders such as bitter pit, water core, scald and internal browning are the most dominant post-harvest restriction factors ( E s n a - A s h a r i a n d Z o k a e e K h o s r o s h a h i , 2 0 1 1 ) . Generally, quality apple must be mature, firm, crispy and juicy with a good flavor composition and free from mechanical damage, physiological disorders, and pathological diseases (Baldwin, 2002). However, reducing consumer acceptance or nutritional value usually happens in the period after harvesting. Apples contain several health-promoting compounds functioning as antioxidants, or modulators of enzyme activity. Peel of red apples contains higher antioxi- dant than their flesh. Meanwhile, Drougoudi et al. (2008) discovered a positive correlation between phenolic content and antioxidant capacity in both flesh and peel of apple. Color is also another impor- tant factor regarding fruit evaluation. There is a close correlation between color and overall quality of fruits (Ritenour and Khemira, 2007). Salicylic acid (SA) is a natural compound that func- tions as plant growth regulator. SA carries a high potential of controlling post-harvest losses of horti- cultural crops. It has been discovered that the SA is associated with a delay in fruit ripening, (Srivastava and Dwivedi, 2000; Zhang et al., 2003; Mo et al., 2008), induction of disease resistance (Shafiee et al., 2010), increasing antioxidant and phenolic com- pounds (Peng and Jiang, 2006; Geransayeh et al., 2 0 1 5 ) , m a i n t e n a n c e o f p o s t - h a r v e s t q u a l i t y (Srivastava and Dwivedi, 2000; Zhang et al., 2003; Wang et al., 2006; Mo et al., 2008; Harindra et al., Adv. Hort. Sci., 2017 31(1): 31-38 DOI: 10.13128/ahs-20723 Effect of pre- and post-harvest salicylic acid treatments on quality and antioxidant properties of ‘Red Delicious’ apples during cold storage M. Hadian-Deljou, M. Esna-Ashari*, H. Sarikhani Department of Horticultural Sciences, Bu-Ali Sina University, Hamedan, Iran. Key words: anthocyanin, firmness, phenolic compound, soluble solid content, weight loss. Abstract: Salicylic acid is a natural phenolic compound known as a plant hormone having positive effect on storage life and quality of fruits. This study aimed to investigate the effects of pre- and post-harvest application of salicylic acid on antioxidant properties and quality of ‘Red Delicious’ apples during 193 days cold (0±0.5°C) storage. Both pre- and post- harvest salicylic acid treatments did not affect soluble solid content, titratable acidity and fruit firmness, with the excep- tion of 1 mM at pre-harvest application for titratable acidity. Fruit juice pH was reduced in all fruits at the end of storage, while it was not quite uniform during storage. Although there was no significant difference between the concentrations of salicylic acid in terms of fruit weight loss, but the highest amount of weight loss was observed in post-harvest treat- ments. Salicylic acid application increased total phenolics and antioxidant activity at the earlier stages of storage show- ing the highest capacity with 2 mM followed by 1 and 4 mM salicylic acid concentrations, while 1 mM concentration belonged to the highest antioxidant capacity at the end of storage. Anthocyanin content showed a gradual increase dur- ing storage until day 60, then decreased right afterwards. The highest amounts of anthocyanin were obtained from the concentrations of 1 and 2 mM salicylic acid in pre-harvest treatments, while 4 mM treatment was not encouraging. Overall, salicylic acid treatments could increase apple storage life and quality for a short period of time only. (*) Corresponding author: m.esnaashari@basu.ac.ir Received for publication 6 December 2016 Accepted for publication 7 February 2017 Copyright: © 2017 Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Adv. Hort. Sci., 2017 31(1): 31-38 32 2015) and increasing storage life of horticultural crops. Hence, SA is suggested to be utilized in post- harvest handling of fruits and vegetables (Peng and Jiang, 2006) which necessitates further investigation into know-how of its application. Wen et al. (2008) found that treatment of grape berries with SA could induce an increase in phenylpropanoid and pheny- lalanine ammonia-lyase (PAL). Qin et al. (2003) reported a significant increase in polyphenoloxidase, PAL and β-1, 3-glucanase activity in cherries fruit through SA treatment. Exogenous application of SA on tomato green mature fruits has shown a delay in b i o s y n t h e s i s o f s o m e b i o c h e m i c a l s i n c l u d i n g carotenoids, lycopene, ascorbic acid, total phenolics, free amino acids and γ-amino butyric acid that led to increase in the keeping quality of fruits (Kant et al., 2016). Pre-treatment of SA combined with lower storage temperature could provide a useful means of maintaining beneficial antioxidant activity during s t o r a g e o f n a v e l o r a n g e ( H u a n g e t a l . , 2 0 0 8 ) . Exogenous application of SA enabled grape leaves to maintain relatively higher activities of antioxidant enzymes under normal temperature, heat, or cold stress. The effect of SA on alleviating chilling injury of peaches during cold storage may be attributed to its ability to induce antioxidant systems (Wang et al., 2006). The aim of this study was to maintain apple quality through the application of SA controlling physiological damages as well as investigating con- tent of phenolic compounds, anthocyanin and antiox- idant activity of fruits during cold storage. 2. Materials and Methods Plant materials and salicylic acid treatments Apples (Malus domestica Borkh cv. Red Delicious) w e r e p r o v i d e d f r o m a 2 0 y e a r s o l d o r c h a r d i n Horticultural Research Center, Bu-Ali Sina University, Hamedan, Iran. This study was conducted as a factor- ial experiment based on a complete randomized block design with three replications. First stage of experiment launched on September when apples’ green skin had just started to turn reddish. Four con- centrations of SA including 0 (control), 1, 2 and 4 mM were sprayed on previously-selected trees, branches and fruits. SA concentrations were made by dissolv- ing powdered SA (Merck, Germany) in hot water. In the second stage of experiment, non-treated fruits were first harvested according to the maturity index (starch test) using Cornell Starch-Iodine Chart in late September. Starch test is a standard method of determining apple maturity to estimate optimum harvest dates well before picking fruit (Blanpide and Silsby, 1992). The harvested fruits then dipped in the same concentrations of SA solution for approximate- ly three minutes at room temperature (25±1ºC). Previously-treated apples were also harvested at this time. In this experiment, 15 apple fruit were used in each replicate for a totally of 45 fruit for each treat- ment. Two apples per each replicate were used for the measurments of all parameters (except for the weight loss) at any time of determination (totally 6 times). Three remaining apples from each replicate were kept to weigh at any time of determination for the evaluation of weight loss. For the packaging of the samples, each group of five apples was packed in a cubic plastic container with two small pores (2.5 mm in diameter) in each side, and stored at 0±0.5°C with 90% relative humidity and kept up to 193 days. Measurements of all parameters started at the beginning of the storage and then continued until the day of 90 with 30 days intervals. Two other mea- surements were taken 157 and 193 days of storage. Soluble solid content, titratable acidity and juice pH Apple juice was first prepared using a domestic electric apple juice maker available in the local shops. Soluble solid content (SSC) was determined by mea- suring refractive index of the juice with a handhold refractometer (N1, Atago Co., Tokyo, Japan) at room t e m p e r a t u r e ( 2 5 ± 1 ° C ) a n d t h e r e s u l t s w e r e expressed as °Brix. Titratable acidity (TA) was mea- sured by titration with a calibrated titrator using a solution of the juice and water (2/10 ratio) with 0.1 N NaOH to pH 8.2±0.1 and converted to malic acid per- centage. Fruit juice pH was determined using an Aqualitic digital pH meter (model AL10 pH) with a gel elec- trode. Fruit firmness and weight loss Firmness values of each individual apple were measured at three points of their equatorial region after which the peel was removed by using a manual p e n e t r o m e t e r ( F D K ; W a g n e r I n s t r u m e n t s , Greenwich, CT, USA) with a 2 mm diameter flat probe (Zhang et al., 2009). Total phenolic content Total phenolic content (TPC) of treated fruits were determined through a slightly modified version of Folin-Ciocalteu’s method as suggested by Slinkard and Singleton (1977). Chlorogenic acid was used as standard phenolic compound. Extraction was per- formed by homogenizing 0.5 g flesh tissue powder in 3 ml of 85% MeOH and the extract was filtered with Hadian-Deljou et al. - Effect of salicylic acid on quality and antioxidant properties of ‘Red delicious’ during cold storage 33 No.1 Whatman filter paper. Sample extract (300 µl) was mixed with 1500 µl of Folin-Ciocalteu’s reagent. After 5 min, 1200 µL of sodium carbonate solution (7.0%, w/v) was added, and the mixture vortexed and allowed to stand at room temperature (25±1°C) in the dark for 90 min. The absorbance was read at 765 nm in a UV/vis spectrophotometer (Carry 100, Varian Analytical Instruments, Walnut Creek, CA, USA), and the total phenolic concentration was calcu- lated from a calibration curve, using chlorogenic acid as the standard. Results were expressed as mg L-1 chlorogenic acid equivalents. Total anthocyanin content For the assessment of anthocyanin contents of the apples, only their peels were used through apply- ing a pH differential protocol (Giusti and Wrolstad, 2003). The absorbance was measured at 510 and 700 nm with a UV/vis spectrophotometer (Carry 100, Varian Analytical Instruments, Walnut Creek, CA, USA). Anthocyanin content was then calculated using the following equation and expressed as mg cyanidin 3-galactoside equivalent per gram of fresh weight. mg Cya-3-gal /g FW = [(A 510 - A 700 ) pH1 - (A 510- A 700 ) pH4.5 ]×MW×F×1000/ε×d where: A= absorbance, MW= molecular weight of cyanidin 3-galactoside = 445.2 [g/mol], F= dilution factor = 10, d= cell pathlengths [cm], ε= molar absorbance of cyanidin 3-galactoside = 34300 [L/ mol×cm] and 1000= Factor for mg. Total antioxidant activity Antioxidant activity was estimated using the sta- ble 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical (Arnous et al., 2001) with slight modifications. The absorbance was read at t = 0 and t = 30 min with a spectrophotometer (Carry 100, Varian Analytical Instruments, Walnut Creek, CA, USA). For all the above assessments (except the antho- cyanin measurement), the apple flesh was used. Statistical analysis Statistical analysis (analysis of variance) of the data was performed with SAS software (version 9.1, 2002-2003, SAS Institute Inc., Cary, NC, USA). Means were compared with Duncan’s Multiple Range Test. Differences at p=0.05 were considered as significant. 3. Results and Discussion Soluble solids content, titratable acidity and juice pH Soluble solids content increased gradually during storage with no significant differences between the treatments (Fig. 1). With pre-harvest application of 1 mM SA, TA slightly increased until the 60th day of storage, when reached its maximum value being sig- nificant with the other treatments, but decreased gradually afterwards (Fig. 2). Fruit juice pH was reduced in all fruits at the end of storage, while it was not quite uniform during storage (Table 1). SSC may increase during fruit ripening due to the action of sucrose-phosphate synthase, a key enzyme in sucrose biosynthesis. This enzyme is activated by eth- ylene and the ripening process itself during storage. Because organic acids are substrates of respiration, their levels decrease during ripening. Utilization of these compounds over post-harvest period is the main reason of increasing sweetness in originally Fig. 1 - Effect of pre- and post-harvest salicylic acid treatments on SSC of ‘Red Delicious’ apples stored at 0±0.5°C for 193 days. Comparison of the means was conducted through the Duncans’ Multiple Range Test (P<0.05). Pr= pre-harvest; Po= post-harvest; T0 to T3= control, 1, 2 and 4 mM SA treatment respectively. Fig. 2 - Effect of pre- and post-harvest salicylic acid treatments on TA of ‘Red Delicious’ apples stored at 0±0.5°C for 193 days. Comparison of the means was conducted through the Duncans’ Multiple Range Test (P<0.05). Pr= pre-harvest; Po= post-harvest; T0 to T3= control, 1, 2 and 4 mM SA treatment respectively. Adv. Hort. Sci., 2017 31(1): 31-38 34 high-sugar, high-acid apples or insipidity and bland- ness of fruit when sugar and acid concentrations are initially low (Jackson, 2003). Similar to our founding have been reported by Sayyari et al. (2011) in which SSC increased during storage in both control and treated fruits. As previously reported, in climacteric fruits such as apples, starch turns into sucrose during p o st-h arvest sto rage. Mo et al . ( 2008) stu d i es showed SSC in treated fruits to be lower than the control, suggesting that SA slowed starch degrada- t i o n . T h i s c o u l d b e a p o s s i b l e r e a s o n w h y S S C increased in this study. However, dehydration of fruits during storage could be mentioned as another reason. Organic acids are consumed in the process of respiration during post-harvest storage. It could be concluded that, the apples’ respiration rate in this study was possibly higher at the first two months of storage, and for this reason, the TA values were increased over this period, then lowered afterwards. Srivastava and Dwivedi (2000) stated that SA treat- ment has made TA fixed in banana. Similar results have been reported while investigating chestnut by Peng and Jiang (2006). As the contents of organic acids in fruit are mainly dependent to the activities of their synthetic and hydrolytic enzymes, SA treatment was probably regulated the activities of related enzymes (Ding et al., 2007). Effects of salicylic acid on fruit softening Fruits showed signs of softening during storage (Fig. 3). Firmness of apples was initially decreased in b o t h c o n t r o l a n d S A - t r e a t e d f r u i t s , a n d t h e n appeared rapidly. Similar results was found by Ding et al. (2007) and Sayyari et al. (2011) who reported that fruit firmness decreased during storage. A close relationship between the change at endogenous SA level and the rate of fruit ripening and softening in ki wi f ru i t was o b served b y Z h an g et al . ( 2003) . Softening could be the result of turgor loss, starch degradation, and most importantly cell wall degrada- tion associated with weakening intercellular cohesive forces (Jackson, 2003). SA decreases production of ethylene and inhibits activation of cell wall and mem- brane degrading enzymes such as polygalacturonase, lipoxygenase, cellulose and pectinemethylesterase resulting in the reduction of softening (Srivastava and Dwivedi, 2000; Zhang et al., 2003). Adding SA to the nutrient solution could induce firmness and delay the softening process in strawberry and apple fruits (Shafiee et al., 2010; Kazemi et al., 2011). Effects of SA on weight loss SA-treated fruits demonstrated controlled weight loss during initial stages of post-harvest. The lowest amount of weight loss was observed in 2 mM con- centration of SA- pre-harvest-treated fruits. Higher concentrations of SA could induce fruit weight loss, but did not control it (Fig. 4). It was observed that the apples kept their quality until the 157 days of stor- age, so that they were still suitable to be transferred to the market, but they gradually started to show vis- ible defects on the peel losing their quality after- wards. Therefore, we recommend our method to be suitable for the storage of Red Delicious apples for the period of five months. Weight loss is caused by both dehydration and consumption of soluble solids during respiration. SA Table 1 - Effect of pre- and post-harvest salicylic acid treat- ments on pH of ‘Red Delicious’ apples stored at 0±0.5°C for 193 days The same letters in any column show no significant difference between the data. Comparison of the means was conducted through the Duncans’ Multiple Range Test (P<0.05). Pr= pre-harvest; Po= post-harvest; T0 to T3= control, 1, 2 and 4 mM SA treatment respectively. Treatment Days of storage 0 30 60 90 157 193 Pr 4.55 a 4.34 b 4.36 a 4.39 a 4.28 a 4.18 a Po 4.56 a 4.54 a 4.34 a 4.43 a 4.31 a 4.10 b T0 4.52 a 4.39 c 4.35 a 4.41 a 4.27 a 4.13 a T1 4.54 a 4.42 bc 4.35 a 4.42 a 4.31 a 4.14 a T2 4.58 a 4.49 a 4.33 a 4.39 a 4.28 a 4.13 a T3 4.55 a 4.46 ab 4.37 a 4.42 a 4.33 a 4.15 a PrT 0 4.53 a 4.30 d 4.34 a 4.36 a 4.26 a 4.15 abc PrT 1 4.57 a 4.34 cd 4.36 a 4.41 a 4.30 a 4.25 a PrT 2 4.52 a 4.36 cd 4.34 a 4.38 a 4.26 a 4.19 ab PrT 3 4.59 a 4.37 c 4.40 a 4.40 a 4.32 a 4.15 abc PoT 0 4.40 a 4.49 b 4.36 a 4.46 a 4.28 a 4.12 bc PoT 1 4.53 a 4.50 b 4.34 a 4.43 a 4.32 a 4.03 c PoT 2 4.46 a 4.62 a 4.32 a 4.40 a 4.31 a 4.08 bc PoT 3 4.51 a 4.55 b 4.34 a 4.43 a 4.34 a 4.16 ab Fig. 3 - Effect of pre- and post-harvest salicylic acid treatments on firmness of ‘Red Delicious’ apples stored at 0±0.5°C for 193 days. Comparison of the means was conducted through the Duncans’ Multiple Range Test (P<0.05). Pr= pre-harvest; Po= post-harvest; T0 to T3= control, 1, 2 and 4 mM SA treatment respectively. Hadian-Deljou et al. - Effect of salicylic acid on quality and antioxidant properties of ‘Red delicious’ during cold storage 35 could decrease water loss and respiration rate through controlling degradation of cell wall and reducing ethylene biosynthesis (Srivastava and D w i v e d i , 2 0 0 0 ) , r e s p e c t i v e l y . J o n a g o l d a p p l e s immersed in SA have shown a significant decrease in weight loss during cold storage (Kazemi et al., 2011). In pear fruits, ratio of weight loss has been decreased at 0.5 mM SA after 48 h of treatment (Imran et al., 2007). Strawberries dipped in SA solution demon- strated less weight loss as well (Shafiee et al., 2010). It seems that high concentrations of SA could induce aggregation of intoxicated materials such as certain polyphenols in later stages of storage, which is prob- ably why plant tissues degrade followed by increas- ing weight loss. Further investigations are needed to clarify this. Effects of salicylic acid on accumulation of phenolic compounds Application of SA partially induced accumulation of phenolic compounds and these effects were signif- icant only from the 60th day until the end of storage (Fig. 5). Since then, SA-treated fruits contained higher quantities of phenols than the control. These results are in agreement with the findings of Harindra et al. (2015) in grapes and Geransayeh et al. (2015) in strawberries. In contrast with the results of this work, Kant et al. (2016) reported a delay in the biosynthesis of total phenolics in tomato green mature fruits dipped in SA solution resulting in an increase in fruit quality that is possibly related to the different physi- ological status of tomato green mature fruits during storage. Apples contain many bioactive compounds including phenols. SA may act as modulator of phenylpropanoid metabolism leading probably to the accumulation of phenolics correlated with the induc- tion of enzymes which are involved in general phenylpropanoid metabolism, e.g. PAL (Godoy- Hernandez and Loyola-Vargas, 1997). It has shown that PAL activity could be induced by SA elicitation in citrus (Lafuente et al., 2001) and grapes (Chen et al., 2006), which would result in the accumulation of plant secondary metabolites. Effects of salicylic acid on anthocyanin content A n t h o c y a n i n c o n t e n t o f a p p l e s r e v e a l e d a n increasing trend until the 60th day of storage while decreased right afterwards (Table 2). Initially, effects Fig. 4 - Effect of pre- and post-harvest salicylic acid treatments on weight loss of ‘Red Delicious’ apples stored at 0±0.5°C for 193 days. Comparison of the means was conducted through the Duncans’ Multiple Range Test (P<0.05). Pr= pre-harvest; Po= post-harvest; T0 to T3= control, 1, 2 and 4 mM SA treatment respectively. Fig. 5 - Effect of pre- and post-harvest salicylic acid treatments on TPC of ‘Red Delicious’ apples stored at 0±0.5°C for 193 days. Comparison of the means was conducted through the Duncans’ Multiple Range Test (P<0.05). Pr= pre-harvest; Po= post-harvest; T0 to T3= control, 1, 2 and 4 mM SA treatment respectively. Table 2 - Effect of pre- and post-harvest salicylic acid treat- ments on anthocyanin content (mg/g FW) of ‘Red Delicious’ apples stored at 0±0.5°C for 193 days The same letters in any column show no significant difference between the data. Comparison of the means was conducted through the Duncans’ Multiple Range Test (P<0.05). Pr= pre-harvest; Po= post-harvest; T0 to T3= control, 1, 2 and 4 mM SA treatment respectively. Treatment Days of storage 0 30 60 90 157 193 Pr 5.57 a 7.39 a 12.41 a 9.15 a 4.91 a 2.54 a Po 3.74 a 5.53 b 10.92 a 9.10 a 5.13 a 2.22 a T0 5.75 a 6.32 ab 12.08 a 7.84 b 4.59 a 2.83 a T 1 7.37 a 8.29 a 13.08 a 11.62 a 5.07 a 1.54 a T 2 4.33 a 6.46 ab 11.63 a 10.02 ab 5.44 a 2.22 a T 3 3.29 a 4.68 b 10.06 a 7.29 b 4.85 a 2.91 a PrT 0 5.26 a 5.66 bc 12.50 a 7.65 b 4.04 a 2.88 ab PrT 1 5.68 a 8.54 ab 15.39 a 12.98 a 5.24 a 1.35 b PrT 2 7.56 a 10.13 a 12.02 a 9.43 ab 5.94 a 2.47 ab PrT 3 4.46 a 5.38 bc 9.69 a 6.46 b 3.93 a 3.64 a PoT 0 5.17 a 7.14 abc 11.53 a 8.00 b 5.14 a 2.79 ab PoT 1 5.67 a 7.98 ab 10.78 a 10.27 ab 4.96 a 1.70 ab PoT 2 2.75 a 3.52 c 11.23 a 10.74 ab 5.02 a 2.03 ab PoT 3 2.10 a 3.97 c 10.43 a 7.96 b 5.54 a 2.36 ab Adv. Hort. Sci., 2017 31(1): 31-38 36 of SA on anthocyanin content were significant. The highest contents of anthocyanin were obtained in the concentrations of 1 and 2 mM at pre-harvest treat- ments with no significant differences between one and with 1mM of post-harvest treatment. Similar result has been reported by Jamali et al. (2013) who sprayed strawberry plants by SA together with nickel sulfate and found higher amounts of anthocyanin in strawberry fruits. Anthocyanins degrade by polyphe- nol oxidase during post-harvest, and this might be the main reason behind the reduction of anthocyanin compounds. The role of SA on anthocyanin produc- tion is unknown, one may hypothesize that SA could activate the key enzyme (Chalcone synthase) in the a n t h o c y a n i n b i o s y n t h e t i c p a t h w a y ( G o d o y - Hernandez and Loyola-Vargas, 1997). Obinata et al. (2003) reported that SA could markedly increase the production of procyanidin in grape. Total antho- cyanin has also been increased with storage period in both control and treated pomegranates (Sayyari et al., 2011). Our results agree with findings of Obinata et al. (2003) and Sayyari et al. (2011). Effects of salicylic acid on antioxidant activity Antioxidant activity increased in all treatments during storage (Table 3). Antioxidant activity was increased in SA-treated fruits, but this process was not uniform, i.e. changes antioxidant activity was not f o l l o w e d f r o m f i x e d p a t t e r n d u r i n g s t o r a g e . Antioxidative potential of apple, however, is known to depend on the concentration and composition of phenolics. Numerous researchers have indicated that SA and its functional analogs have inhibitory effects on CAT and POD activities or serve as substrates for POD. Knorzer et al. (1999) reported, when applied exogenously at suitable concentrations, SA was found to enhance the efficiency of antioxidant sys- tem in plants. Imran et al. (2007) and Sayyari et al. (2011) found that SA have the capacity of increasing antioxidant, the result that confirms the present study. Kazemi et al. (2011) also observed the higher ascorbic acid (vitamin C) content as well as peroxi- dase and superoxide dismutase activities in apples treated with SA exogenously. SA is possibly effective through the activation of responsible genes for pro- ducing antioxidant compounds (Wang et al., 2006) and increasing activity of the antioxidant enzymes such as superoxide dismutase, peroxidase, catalase and ascorbate peroxidase (Mo et al., 2008). 4. Conclusions This study showed the effectiveness of pre- and post-harvest treatment of SA on the quality of ‘Red Delicious’ apples. Application of SA affected on juice pH and anthocyanin content until the middle of stor- age, maintaining phenolic compounds and increasing a n t i o x i d a n t a c t i v i t y . N o s i g n i f i c a n t d i f f e r e n c e between SA treatments was seen in terms of SSC, TA and fruit firmness. The lowest weight loss was o b s e r v e d o n p r e - h a r v e s t - S A t r e a t m e n t w h e n sprayed, and the highest concentration of phenolic compounds was observed in post-harvest treatment w h e n d i p p e d . A n t h o c y a n i n c o n t e n t w a s a l s o increased during storage up to 60 days, but by the day 90, it was gradually decreased until the end of storage when reached to the lower level. As a conclu- sion, treatment of ‘Red Delicious’ apples with SA could properly maintain the quality of fruits and increase their post-harvest life and antioxidant capacity for at least 2 months. References ARNOUS A., MAKRIS D.P., KEFALAS P., 2001 - Effect of prin- cipal polyphenolic components in relation to antioxi- dant characteristics of aged red wines. - J. Agric. Food Chem., 49: 5736-5742. 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Treatment Days of storage 0 30 60 90 157 193 Pr 60.20 a 74.34 a 62.00 b 73.67 b 78.67 a 82.18 a Po 47.40 a 67.35 b 84.25 a 81.53 a 76.79 a 82.49 a T 0 59.29 a 62.43 c 55.62 b 68.22 b 72.50 c 78.76 b T 1 50.14 a 69.88 b 79.16 a 78.26 a 83.93 a 83.67 ab T 2 61.03 a 81.16 a 81.52 a 81.93 a 79.84 ab 80.36 b T 3 58.24 a 70.27 b 79.68 a 81.42 a 74.55 bc 86.33 a PrT 0 58.46 a 70.85 cd 50.37 d 70.33 cd 82.55 a 63.54 c PrT 1 61.94 a 68.59 d 68.09 b 73.09 bcd 84.57 a 77.94 b PrT 2 56.35 a 78.56 b 60.33 c 75.35 bcd 81.73 a 87.23 a PrT 3 60.13 a 77.82 bc 66.23 b 76.76 abcd 61.65 b 91.00 a PoT 0 49.36 a 54.01 e 59.82 c 64.71 d 60.44 b 90.17 a PoT 1 52.22 a 71.48 bcd 92.99 a 82.39 abc 83.29 a 87.49 a PoT 2 63.47 a 86.35 a 92.12 a 88.52 a 78.25 a 71.20 bc PoT 3 45.92 a 63.99 d 90.90 a 85.15 ab 84.87 a 78.54 b Hadian-Deljou et al. - Effect of salicylic acid on quality and antioxidant properties of ‘Red delicious’ during cold storage 37 Raton, FL, USA, pp. 320. 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