Postharvest physiology
Masumeh Kiaeshkevarian; Tahereh Raiesi; Bijan Moradi; Javad Fattahi Moghadam; Maziyar Faghih Nasiri
Abstract
Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment ...
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Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment can improve the quality and storability of the product. Kiwifruit is one of the most important agricultural products in north of Iran, which plays an effective role in trade and employment of the people. Fertilization is one of the main factors affecting the yield and quality of kiwifruit. Growers use organic manures and chemical fertilizers in their orchard to achieve higher yields. It is necessary to study the effect of various organic manures available in the region on the nutrition of kiwifruit vines due to increase chemical fertilizer prices and the formation of the market for organic fruits. Therefore, the aim of this study was to compare the effect of using five types of organic manures and chemical fertilizer on the quality of Hayward kiwi fruit during cold storage.
Materials and Methods
This research was conducted as randomized complete block design consisting six treatments (including complete chemical fertilizer, sheep manure, cow manure, chicken manure, vermicompost and azolla) on Hayward kiwifruit vines in orchard and factorial experiment with three replicates in cold storage during four years. The fruits were harvested at TSS: 6.5 (approximately mid-November) and then stored at 0.5 ° C and 90% RH for three months. Sampling was performed every month and physicochemical characteristics, including flesh color parameters (L*, C*, h◦), total soluble solids, titratable acidity, firmness and weight loss of fruit were measured. Sensory evaluation of fruits was also performed at the end of three months cold storage. Analysis of variance of the data was done using SAS 9.1 software. The significance of differences between the mean of treatments was determined by using Duncan’s test.
Results and Discussion
The results showed the interaction between year, type of nutrition and cold storage period affected color indices, lightness and chroma. Lightness and chroma value didn’t show significant differences between organic and chemical fertilizer treatments. In addition, their value decreased during cold storage period, significantly. The chroma value indicates the degree of saturation of the green color and is associated with fruit firmness. The hue value was also influenced by the interaction between year and cold storage period and the simple effect of the nutrition type. The highest hue value was observed in chicken manure (108.63) and the lowest in vermicompost (107.66). The hue value decreased significantly after 90 days cold storage. According to the results, a decrease in fruit firmness, TA and an increase in TSS and TSS/TA were observed during cold storage irrespective of treatments. After 90 days, total soluble solids content was higher when organic fertilizers were applied. During the storage of kiwifruit, total soluble solids content increased, significantly. The titratable acidity value in organic fertilizer treatments was higher than chemical fertilizer after 90 days cold storage, significantly. Moreover, titratable acidity value decreased at the end of the cold storage period, significantly. The highest flesh fruit firmness was obtained in cow manure (8.74 kg/cm2) in forth year and chemical fertilizer treatment had the lowest flesh firmness (3.2 kg/cm2) in third year. Fruit lost firmness gradually during the cold storage period. However, no significant difference was found in maturity index (TSS/TA) between treatments. The TSS:TA ratio is highly increased after 90 days. Based on the results of the last two years, azolla, cow and chicken manures showed less weight loss percentage than chemical fertilizer treatment. Moreover, weight loss increased significantly during cold storage period in all treatments and years. Also the results of sensory analysis showed that fruits treated with vermicompost had a higher overall acceptance than other treatments.
Conclusion
Generally, organic nutrition plays an important role in increasing the nutritional value and shelf life of kiwifruit cv.Hayward. Organically produced fruits had higher firmness than conventionally grown fruits during storage. Application of cow manure and vermicompost showed favorable effects on important properties of kiwi fruit such as firmness, weight loss, TSS, TA and sensory quality. Therefore, organic fruits will have better quality in the cold storage. As a result, it seems that by reducing the use of chemical fertilizers in the current orchards, kiwi production will be close to the standards defined for organic fruit.
Pomology
Javad Fattahi Moghadam; Seyyedeh Elham Seyedghasemi; Tahereh Raiesi
Abstract
Introduction: The foreign and domestic markets are demanding for high quality citrus varieties. The physical and chemical properties of the newly released cultivars are also important for fresh market or processing. The fruit quality is a complex combination of size, firmness, taste, texture, pleasant ...
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Introduction: The foreign and domestic markets are demanding for high quality citrus varieties. The physical and chemical properties of the newly released cultivars are also important for fresh market or processing. The fruit quality is a complex combination of size, firmness, taste, texture, pleasant aromas caused by a chemical compounds (soluble solid content, sugars, organic acids, aromas) and bioactive properties. Therefore, it is important to consider these indices for the introduction of a new cultivar. In this regard, the Citrus and Subtropical fruits Research Center has focused on improving its appearance, internal and organoleptic quality in releasing the new Jahangir cultivar compared to the Clementine as control.Materials and Methods: In this study, Jahangir fruits a hybrid between Clementine mandarin (female parent) and Salustiana orange (male parent) (Citrus clementina Hort. Ex Tanaka × C. sinensis (L.) Osbeck cv. Salustiana) was used for comparison with Clementine (Citrus clementina Hort. Ex) Tanaka) as control during the last two years lead to the cultivar introduction. Fruits were randomly selected from different locatiosn on the tree (15 fruits from three trees) and evaluated at harvesting time (zero storage point). Then 30 fruits per box selected and placed in cold storage (5 °C, 85% RH). Different physico-biochemical and sensory characteristics of fruits were evaluated at 0, 20 and 40 days intervals during storage. Characteristics evaluation were including fruit lenght, width, thickness, arithmetic, geometric, equivalent and harmonic means, fruit aspect ratio, sphericity, surface area, true volume, apparent volume, volume error, density, peel and pulp firmness, peel thickness, weight, juice percentage, seed number, peel color indices (L*, a*, b*, hue angle, chroma and CCI), total soluble solid (TSS), titratable acidity (TA), technological index (TI), pH, electrical conductivity (EC), total phenol, ascorbic acid and antioxidant capacity during experiment.Results and Discussion: Results showed that fruit size (length and two diameters), weight, means of arithmetic, geometric, equivalent and harmonic diameters, surface area and true volume of Jahangir mandarin were significantly higher than Clementine. The different mean diameters of each cultivar was the same as that equivalent diameter that is the most real mean fruit diameter. The higher spherical coefficient (>1) also indicated that Jahangir fruit was longer than the control. Additionally, aspect ratio of Jahangir was also higher than Clementine, which means that Jahangir fruit was a few flat than control. Jahangir had higher levels of L*, b*, C and hue than the control of clementine. In contrast, Jahangir's a* and CCI indices were lower than those of clementine. Therefore, except for L* which is slightly lower than citrus standard (65-70), other indices in both cultivars were conformity within the citrus standard range. Seeds of Jahangir were more than control but both were in the mid seed group (9-15 seeds) of citrus. Jahangir peel was also less easily peeled than control. The weight loss of Jahangir fruit was significantly (almost half) lower than that of clementine at each sampling but increased during storage. It seems Jahangir has a peel with higher density and adhesion than to clementine, which partly prevents the fruit from dehydration. The amount of TSS of fruit juice was higher than that of clementine at harvest and storage but increased in both cultivars during storage. In addition, TA (0.34%) was lower in Jahangir fruit than Clementine (0.45%). Therefore, the ratio of TSS to TA was much higher in Jahangir mandarin (44.25) than clementine (26.16). Juice percentage of Jahangir fruit (44.87%) was significantly higher than Clementine (40.12%). The high percentage of Jahangir fruit juice is a positive trait for this cultivar. Technology index changed depending on cultivar and also during storage. This index was higher in Jahangir fruit than in Clementine with 6.45 and 4.67, respectively. The antioxidant capacity only affected significantly by storage time which showed a decreasing trend during storage. Ascorbic acid content was only affected by cultivar and was higher in control than Jahangir. Lower levels of ascorbic acid in the Jahangir may be due to increased respiration that results in the elimination of ascorbic acid. The phenolic content of Jahangir fruit was higher (0.43 mg/g) than clementine (0.4 mg/g). PCA analysis showed that most of the Jahangir samples placed in the left part of the PCA graph which were dominated by the traits such as taste, sweetness, good peel and pulp appearance and overall acceptance and were more accepted by the sensory evaluators.Conclusion: In this study, different qualitative characteristics of Jahangir fruit compared to Clementine which are important for the producers. Accordingly, the Jahangir fruit was larger in size but slightly flatter than the Clementine fruit. Jahangir fruit peel color indices were within the standard range of citrus fruits. Jahangir fruit is favored among commercial available mandarins due to ease of peeling, high juice percentage, technology index, vitamin C, phenol and antioxidant capacity. It also had better storability than Clementine because of less water loss and decline of organoleptic properties.
Javad Fattahi Moghadam; Seyyedeh Elham Seyedghasemi; Kazem Najafi
Abstract
Introduction: According to a breeding program that was carried out in Citrus and Subtropical Fruits Research Center, Noushin (C. reticulata cv Clementine × C. sinensis cv. Salustiana) and Shahin (C. reticulata cv Clementine × C. sinensis cv. Hamlin) mandarins were released by using crossing method ...
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Introduction: According to a breeding program that was carried out in Citrus and Subtropical Fruits Research Center, Noushin (C. reticulata cv Clementine × C. sinensis cv. Salustiana) and Shahin (C. reticulata cv Clementine × C. sinensis cv. Hamlin) mandarins were released by using crossing method in 20-year program. In general, mandarins do not have the ability of being kept in common or cold storage for long time compared to oranges. The main problem is the change of fruit taste during storage, therefore, it is an attracted subject for researchers. Furthermore, storage temperature plays an important role in the quality of the taste of mandarins. The new released mandarins, which hve not been yet studied completely for their storability, need to be evaluated. Therefore, the aim of this study was to investigate fruit physico-chemical and sensory characteristics of Noushin and Shahin varieties in common and cold storages for two years.
Materials and Methods: In this study, fruits of Noshin and Shahin mandarins were harvested at seasonal harvesting time and then placed in could storage (5 oC and 85% RH) and common storage (7-10 oC and 60-70 %RH) based on completely randomized design with three replications for 60 days every year. Fruits on days 0 (at harvesting time), 20, 40 and 60 of storage were sampled. Various physico-chemical and sensory characteristics were evaluated including iuice percentage, weight loss, peel color indices (L*, a*, b*, hue angle, chroma and CCI), total soluble solid (TSS), titratable acidity (TA), technological index (TI), skin disorder index (SDI), pH, electrical conductivity (EC), total phenolic, ascorbic acid, antioxidant capacity and sensory parameters during experiment. Statistical analysis of the data was performed using statistical software MSTAT-C. Analysis of variance combined in a randomized complete design (two years) with three replications for each variety.
Results and Discussion: The results showed that the amount of fruit weight loss and juice percentage did not show significant changes during storage. The ranges of weight loss in Noushin and Shahin varieties were 7-8% and 3.45-5.1%, respectively. Generally, peeling in Shahin was harder than Noushin but it gradually decreased until the end of storage. With the exception of citrus color index (CCI) in Noushin that was high at the beginning of storage, other color indices had no significant differences according to the type of variety and storage. Totally, TSS: TA ratio increased during storage depending on the type of storage, so that the ratio was higher (Noushin with 39.64 and Shahin with 13.34) in common storage than cold storage (Noushin with 31.04 and Shahin with 13.62) at the end of storage. Amount of electrical conductivity (EC) and technological index (TI) increased significantly in both varieties and storages. Shahin variety with 3.74 and 26.19% was so sensitive to rind disorder index and rind disorder percentage, respectively. Phenolic compounds in both varieties declined during both cold and common storages. The amount of reduction depends on the type of mandarin, with Shahin showing higher decline than Noushin variety. Besides, the content of ascorbic acid and antioxidant capacity in both peel and pulp showed a decreasing pattern with the passing of harvesting time during storage. According to sensory analysis, Noushin fruit can be stored in common storage for 20 days and in cold storage for 40 days. Moreover, results revealed that Shahin fruits did not have storability more than 40 days in common and cold storages.
Conclusion: Generally, Noushin variety was sensitive to low moisture of the storage and fruits lost extra moisture during storage. Since Noshin was an early ripening variety, TSS: TA ratio increased rapidly at the end of storage. Although Noushin had the lowest ascorbic acid content but its fruit antioxidant capacity was higher than shahin at the end of storage. On contrast, Shahin was a mid-ripening variety with higher ascorbic acid content. On the other hand, shahin peel was so sensitive to skin disorder index (SDI), therefor it should not be maintained in low moisture and temperature storage. Based on sensory analysis and physicochemical measurements, Noushin can be stored for 20 days and shahin for 40 days in common and cold storage. Finally, we found that Noushin and Shahin cannot be maintained in storage longer than other mandarins.
Ebrahim Abedi Gheshlaghi; Vali Rabiei; Malek Ghasemi; Javad Fattahi Moghadam; Farhang Razavi
Abstract
Introduction: It is important to understand the structural events associated with flower morphogenesis in horticultural plants, because it has many aspects of practical horticultural significance. Information about different stages of flower initiation and development is important for better management ...
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Introduction: It is important to understand the structural events associated with flower morphogenesis in horticultural plants, because it has many aspects of practical horticultural significance. Information about different stages of flower initiation and development is important for better management of the vineyardsand fruit set. Knowledge of floral ontogeny in kiwifruit is also important for the establishment of breeding programs and for the understanding of the evolutionary processes involved in the development of the floral organs. The main objective of this study was documentation of the differentiation stages of flower buds for better understanding of morphological and external changes in (Actinidiadeliciosa[A. Chev.] C.F. Liang &A.R. Ferguson var.deliciosa) cvs.Hayward (female) and Tomuri (male).
Materials and Methods: The experiment was carried out over two years in a mature 'Hayward' and ‘Tomuri’ kiwifruit vineyard at the Citrus and Subtropical Research Center of Iran (Ramsar city). Pistillate and staminate flowers development was followed from the stage of undifferentiated primordia, present in the axils of leaf primordia in dormant buds since mid-March to early June 2015 and 2016. Equally buds in diameter and size from sixth to twentieth buds on one-year old cane of Hayward and Tomuri selected at 5 to 7 days intervals. They were sampled and fixed in a solution of formalin, ethanol 70%, glacial acetic acid (2:5:1 FAA) then stored in refrigerator. Fifteen buds of each sample dissected under a Nikon SMZ645 stereo zoom microscope. The very dense pubescence within the buds was removed manually without damaging the axillary flower primordia. The remaining pubescence was removed using dissecting needles. Various stages of flower differentiation were explained with principal growth stage 5 of BBCH scale.
Results and Discussion: The first signs of the flower on Tomuri were observed 2 days before bud swelling stage (01), on the March 12th, about one month before bud break in 2015. While in the Hayward variety the first signs of the flower primordia were observed on the March 21th of 2015 (9 days later). At the beginning of bud swelling (01), flower primordia begin to differentiation and at advanced bud swelling stage (03), bracts and sepals initiated. As development proceeded, different parts of flowers initiated acropetally. Lateral flowers were formed in the bud break (07), before initiation of petals. In advanced budburst stage (09) stamen primordia appear almost immediately after petal initiation, as two whorls in 'Hayward' and as three whorls in the Tomuri cultivar. Stigma initiated in the open cluster stage (10) in Hayward cultivar about 24-25 days after bud swell stage. The process of differentiation of buds and reproductive organs in the second year was the same as the first year with the exception that differentiation began earlier than that in the first year. Climatic conditions were affected flower development and in the second year primordia differentiation began earlier two days in Tomuri and six days in Hayward than those in the first year. The advanced budburst stage (09) in Tomuri 9 days and in the Hayward 10 days was occurred earlier than that in the first year. Unlike other tree fruits, flower induction in the kiwifruit occurred about 6 months before flower initiation. Flower primordia differentiation initiated shortly before bud break stage and approximately two months before full bloom. Flower initiation and differentiation time may be partly estimated with external changes of buds development. According to cultivar, chilling and heat requirements and climatic conditions during the research, flower initiation and differentiation period have fluctuation. A reason for the difference between the development stages and different varieties can be caused by the chilling and heat requirements. The more heat requirement, the longer reproductive meristem differentiation period.
Conclusion: An understanding of the flower initiation and development is very important for the research and management of fruit trees. A knowing of flower initiation and differentiation can be developed corrective vineyard management and practices in crisis period and prepared breeding programs. Tomuri initiated and developed their floral organs earlier than those in Hayward. Different external changes in the bud may be partly used to estimate of flower development status. The results showed that flower initiation and differentiation in buds coincided with the beginning of development and elongation of bud in the early of spring.
Nastaran Hemmati; Azim Ghasemnezhad; Javad Fattahi Moghadam; Pooneh Ebrahimi
Abstract
Introduction: all fruits that called citrus are from rutaceae family and aurantioideae subfamily. This subfamily have more than 33 different genus that only three of its genus (citrus, poncirus and fortunella) have economic aspects and in citrus producing country are important. It's reported that orange ...
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Introduction: all fruits that called citrus are from rutaceae family and aurantioideae subfamily. This subfamily have more than 33 different genus that only three of its genus (citrus, poncirus and fortunella) have economic aspects and in citrus producing country are important. It's reported that orange skin has a phenolic compounds which play a role in natural defense mechanism. Also various compounds of phenolic and antioxidant have a major role in fruit tolerance to stressful condition suh as cold and drought. Metabolites found in citrus fruits have antioxidant properties and it's very useful in pharmaceutical, food and cosmetics industries. Oranges, like other citrus fruits, are an excellent source of vitamin C; Vitamin C is a powerful natural antioxidant. Consumption of foods rich in vitamin C helps the body develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals from the blood. Various factors such as rootstock type can effect on quality and quantity of citrus fruits. Also, the usage of rootstock causes the change in plant characteristics such as flowering time, ripening time, fruit quality and antioxidant characters of the fruits. Other factors except the rootstock such as scion, geographical and climate factors are effective on producing secondary metabolites. Also active substances or secondary metabolites are producing by the conduction of genetic processes, but their production are being effected by other factors obviously. The aim of this study is to investigating the biochemical changes grafted tree fruit that affected by rootstock with study the correlation between grafted tree and rootstock changes.
Materials and Methods: This study was done to compare the amount of total phenol, total flavonoids and antioxidant features of fruit flesh and skin with investigating the effect of cultivar and rootstock on these parameters based on completely randomized factorial design with three replications. For this purpose total phenol, total flavonoid and antioxidant activity in two citrus cultivar (morro and mars) that grafted on four rootstock (yuzu, citrumelo, sour orange and shel mahalleh) with seedling rootstocks fruit were studied in fruit skin and flesh. Fruits were harvested in the middle of December according to their total soluble solid materials (TSS) which was 10 and then transferred to the researching laboratory in Gorgan Agricultural Science and Natural Resources University. Antioxidant properties using DPPH method in 517 nm wavelength, total amount of phenol using folin siocalteu method in 765 nm wavelength and the total amount of flavonoid were done using the aluminum chloride method in 415 nm wavelength and they were measured using spectrophotometer.
Results and Discussion: the result showed that the two factors consisting rootstock and scion have significant effect on the amount of total phenol, total flavonoid and antioxidant properties of extracts of citrus skin and flesh. The greatest amount of phenolic compounds was produced in the skin of morro cultivar that grafted on shel mahalleh rootstock and the lowest amount was observed in the flesh of yuzu seedling rootstock. Total flavonoid was affected by fruit tissue, cultivar and rootstock. The maximum amount of that was seen in the skin of morro and mars cultivar that was grafted on yuzu rootstock and the minimum amount was recorded in the flesh of morro cultivar that grafted on sour orange rootstock. Also the highest antioxidant activity was produced in skin of citrumelo seedling rootstock and the lowest amount was seen in flesh of yuzu seedling rootstock. The investigation on citrus rootstock showed that, antioxidant activity, total phenol and total flavonoid had significant effect in different rootstock and cultivar fruit. These compounds were affected by climatic condition. Because the light is effective in biosynthesis of phenolic compounds, in fact, these substances have a protective role against the light, especially short wavelengths. Therefore their more accumulation is in skin. The results of this experiment and also the results of the other researcher show that the rootstock effect is related to the quality of grafted species with the species, rootstock type and their interaction.
Conclusion: Based on these experiments, there was significant difference between antioxidant compounds of grafted tree fruit with rootstock fruit but there wasn’t a clear relationship between them. It seems this difference was due to combination and physiological characteristic of each fruit. It seems that the accumulation of chemicals in citrus fruit superior than every factors depends on genetic characteristics and inherent abilities. So that some factors specially rootstock has an important and determinant role in accumulation of these substances.
Sonia Jamali; Vali Rabiei; Javad Fattahi Moghadam
Abstract
The effects of coatingtreatments (waxand plasticbags) combined with methylsalicylate on the fruit quality and chilling injury of Moro blood orange were studied during storage. Treated fruits were kept in storage for 80 days at 5 oC and 90-95% relative humidity. Some characteristics such as pulp and skin ...
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The effects of coatingtreatments (waxand plasticbags) combined with methylsalicylate on the fruit quality and chilling injury of Moro blood orange were studied during storage. Treated fruits were kept in storage for 80 days at 5 oC and 90-95% relative humidity. Some characteristics such as pulp and skin total phenolics, antioxidant capacity, total anthocyanin, lipid peroxidation, and the chilling injure index were assessed at 0, 20, 40, 60, 80 days after storage. Total phenolics in the skin and pulp were reduced during storage. Peel Total phenol of wax coating treatment with methyl salicylate (0.26 mg) had the lowest reduction after 80 days storage. Pulp total phenolic of fruits in pair plastic bag fruits (0.25 mg) had minimal changes during storage. Coating combined with methyl salicylate to retain moisture and delay the aging process reduced chilling injury. Generally, the amount of pulp total anthocyanins and antioxidant capacity increased during storage. The antioxidant capacity of the wax coating fruits, pair plastic bag fruits and pair plastic bag fruits combined with methyl salicylate was 42.98, 37.46 and 37.42, respectively. Wax combined with methyl salicylate (0.18 mM) and pair plastic bag fruits (0.17 mM) has the lowest lipid peroxidation during storage. Individual plastic bag with methyl salicylate (44.54%) had the least amount and methyl salicylate (77.41%) had most ion leakage. The best treatments were individual fruit packing combined with methyl salicylate and wax coating combined with methyl salicylate that reduced the incidence of fruit chilling injury to one percent. Ion leakage, lipid peroxidation and chilling injury increased during cold storage. Treated fruit with wax combined with methyl salicylate and individually and pair packed fruit combined with methyl salicylate had the best visual fruit quality. Combined treatments had more effects than individual treatments alone.
Javad Fattahi Moghadam; Mohammad Fazel Halajisani
Abstract
The harvest date more influenced on postharvest quality during storage. In present study, fruits were harvested at four date base on total soluble solids content (5.5, 6.5, 7.5, and 8.5%) and then stored at 0.5 ºC and 80-90% RH, for 18 weeks. The samples were taken in 6th, 12th and 18th interval weeks ...
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The harvest date more influenced on postharvest quality during storage. In present study, fruits were harvested at four date base on total soluble solids content (5.5, 6.5, 7.5, and 8.5%) and then stored at 0.5 ºC and 80-90% RH, for 18 weeks. The samples were taken in 6th, 12th and 18th interval weeks and evaluated some parameters including weightless, losses, firmness, TSS, TA, TSS/TA, ascorbic acid, pH, EC, Skin and pulp lightness and sensory analysis. Results showed that different harvesting time had not significant effect on wieghtloss and pH parameters during storage. Also, we observed that fruits which were harvested at brix of 5.5 had high firmness specialy during primery 6 weeks storage. The skin of fruits picked with 5.5 and 6.5 % brix was a little darker than other treatments. EC showed reverse relationship with storage period during storage. With TSS increasing, TA level decreased during storage. Although, ascorbic acid content was higher during 6 weeks of storage but it was lower in fruits which picked with 5.5 % brix than other times of harvest. Finally sensory analysis revealed that fruits which harvested at least 6.5 oBrix content, would have excellent quality after storage and handling.
Javad Fattahi Moghadam; Yousef Hamidoghli; Reza Fotouhi; Mahmood Ghasemnejad; Davoud Bakhshi
Abstract
Abstract
In this study, the physicochemical quality and antioxidant activities of fruits peel from 6 citrus varieties which commonly consumed in the North of Iran were determined. Some parameters were measurement such fruit size, peel thickness, residue percentage, peel color indices, total phenolics, ...
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Abstract
In this study, the physicochemical quality and antioxidant activities of fruits peel from 6 citrus varieties which commonly consumed in the North of Iran were determined. Some parameters were measurement such fruit size, peel thickness, residue percentage, peel color indices, total phenolics, total flavonoid, total anthocyanins, total carotenoids, total chlorophyll, ascorbic acid content and antioxidant capacity by DPPH● assay and ABTS +● scavenging activity. Results showed that there were a positive relationship between fruit size, peel thickness and residue percentage. Thamson variety was largest among all varieties. Generally, all varieties had standard peel color at harvesting time. The total content of phenolic was superior in peel of ‘Siavaraz’ (0.49 mg/ml) and ‘Page’ (0.43 mg/g) varieties. The peel of ‘Moro’ with 7.68 mg/g and 13.29 mg/l had highest total flavonoid and anthocyanin respectively. The highest of total carotenoid and chlorophyll accumulation with 0.84 and 3.5 mg/ml were observed in ‘Tarocco’. Perfectly, peel carotenoid concentration ranged from 0.12 to 0.84 and also from 0.87 to 3.5 mg/g to total chlorophyll. The quantity of ascorbic acid content ranged from 18.17 (Siavaraz) to 23.56 mg/100g FW (Thamson). Also, results showed ‘Sanguinello’ peel had the lowest IC50 values (0.2 mg) of DPPH radical scavenging activities. Base of AE results, significant differences only observed between ‘Sanguinello’ and other varieties. According to the ABTS assay, the antioxidant activity was at least 68.58% in ‘page’ variety. Finally, this peel of citrus varieties possessed relatively high antioxidant activity and might be rich sources of natural antioxidants.
Keywords: Citrus, Peel, Color, Antioxidant activity, Carotenoid, Flavonoid, Ascorbic acid
